JP4443497B2 - Multi-degree-of-freedom robot positioning error correction apparatus and positioning error correction method - Google Patents

Description

The present invention relates from the supporting mechanism having a plurality of degrees of freedom in multiple degrees of freedom positioning error correction device and the positioning error correction how support mechanism tip of a robot constructed.

  In general, in a multi-degree-of-freedom robot composed of a support mechanism having a plurality of degrees of freedom, for example, a multi-joint robot configured by movably connecting a plurality of arms to each other, it is necessary to manufacture each component constituting the multi-joint robot. There is a positioning error between the arm tip position instructed or recognized by the control device of the articulated robot and the actual arm tip position due to variations in assembly and assembly errors of each component. For this reason, the repeat position accuracy (or position repeat accuracy) in the articulated robot is improved by adding a correction corresponding to the positioning error to the arm tip position indicated or recognized by the controller of the articulated robot. This repeat position accuracy (or position repeat accuracy) is one of the indices used to evaluate the performance of articulated robots, and represents the repeatability of the positioning accuracy by repeatedly positioning the position of the arm tip at a specific position. is there.

As an articulated robot provided with a positioning error correction device that calculates the positioning error in an articulated robot and corrects the positioning error, for example, there is an articulated robot disclosed in Patent Document 1 below. In this articulated robot, the position of the arm tip detected by the calibration jig is determined by using a calibration jig for positioning error correction called a calibration device that detects the actual position of the arm tip of the articulated robot. The difference from the position of the arm tip specified by the control device of the articulated robot is calculated as a positioning error. Specifically, one end of a calibration jig having a movable part having three degrees of freedom orthogonal to each other and a detection part for detecting the displacement state of the movable part for each degree of freedom is connected to the arm of the articulated robot. While being connected to the tip, the other end of the calibration jig is fixed at an arbitrary location around the articulated robot. In this case, the calibration jig is fixed in a state in which the direction of each coordinate axis of the coordinate system possessed by the calibration jig coincides with the direction of each coordinate axis of the coordinate system possessed by the articulated robot. Then, the arm tip position of the articulated robot is calculated from the displacement states of the three axes detected by the calibration jig, and the difference between the calculated arm tip position and the arm tip position specified by the controller of the articulated robot is calculated. Is calculated as a positioning error, and the arm tip position designated by the control device is corrected.
International Publication No. 98/32571 Pamphlet

  However, the above-described calibration jig for correcting the positioning error is complicated and extremely high precision and is very expensive for accurately detecting the displacement of the arm tip position in the articulated robot. For this reason, there exists a problem that the cost for correct | amending the positioning error in an articulated robot becomes high. Further, the work of arranging the coordinate axes in the coordinate system of the calibration jig so as to coincide with the directions of the coordinate axes in the coordinate system of the articulated robot is a troublesome work that takes time and has a problem that work efficiency is poor. .

  The present invention has been made to cope with the above-described problem, and an object of the present invention is to detect the positioning error with high work efficiency while maintaining good accuracy of positioning error correction in a multi-degree-of-freedom robot such as an articulated robot. A positioning error correction apparatus and a positioning error correction method capable of performing a positioning error correction, and a positioning error correction calibration jig for a multi-degree-of-freedom robot configured to be used in the positioning error correction apparatus and the positioning error correction method are provided. It is in.

In order to achieve the above object, a feature of the present invention is that a support mechanism (20) having a plurality of degrees of freedom and capable of attaching a three-dimensional shape measuring device (30) for measuring a three-dimensional surface shape of an object to the tip is provided. In the positioning error correction apparatus that corrects the positioning error of the tip in the multi-degree-of-freedom robot, a plurality of calibration objects (53 that can be distinguished from each other and that can define at least one straight line for each dimension in three dimensions , together with the previously prepared calibration jig (50) with a 51 '), a straight line defining parameters for defining the straight line for each dimension in each of the calibration object _{(C m, V mA, V} mB, V _mC), identification parameter for identifying the respective calibration objects _{(R m, L m, θ} mAB, θ mBC, θ mCA, L mAB, L mBC, L mCA) Together and stored in advance in storage means coordinate values representing the position of each fixed point (T _m) that is identified by the preliminary each calibration object, predetermined origin coordinates of the three-dimensional coordinate system related to the three-dimensional shape measuring apparatus An origin position relation parameter indicating the amount of movement from the position to the predetermined position of the tip of the multi-degree-of-freedom robot, which is the origin coordinate position of the three-dimensional coordinate system related to the multi-degree-of-freedom robot, is stored in the storage means in advance. The three-dimensional shape measuring apparatus is attached to the tip of the support mechanism, and the three-dimensional shape measuring apparatus is configured to measure one of the plurality of calibration objects as a reference calibration object. First image data acquisition means (S402, S404) for acquiring three-dimensional image data relating to the measured reference calibration object expressed in a three-dimensional coordinate system relating to the shape measuring device; For defining at least one straight line for each dimension using the identification parameter stored in the storage unit and related to the reference calibration object based on the acquired 3D image data related to the reference calibration object First parameter calculation means (S406, S408, S412) for calculating a reference calibration object straight line definition parameter and a coordinate value of a fixed point specified by the reference calibration object, and the calculated reference calibration object straight line definition The coordinates of the three-dimensional coordinate system related to the three-dimensional shape measuring apparatus using the parameters, the straight line definition parameters related to the reference calibration object stored in the storage means, and the origin position relation parameters stored in the storage means The value corresponds to each dimension defined by the calculated reference calibration object straight line definition parameter. The direction of the three straight lines is matched with the direction of the three straight lines corresponding to the dimensions defined by the straight line definition parameters stored in the storage means and related to the reference calibration object, and the multi-degree-of-freedom robot First coordinate conversion function for calculating a reference calibration object coordinate conversion function (Gd _CM ) for coordinate conversion to a coordinate value of a conversion coordinate system (CM coordinate system) with the origin coordinate of the three-dimensional coordinate system as the origin coordinate Using the calculation means (S410) and the calculated reference calibration object coordinate conversion function, the coordinate value of the fixed point specified by the calculated reference calibration object is converted into the coordinate value of the conversion coordinate system and used as a reference. A first coordinate conversion means (S412) that takes the coordinate value of a fixed point, and one calibration object other than the reference calibration object designated from the plurality of calibration objects, The position of each fixed point of the reference calibration object and the measurement target calibration object stored in the storage means so that the three-dimensional shape measuring apparatus measures the measurement target calibration object. The moving position of the three-dimensional shape measuring apparatus is calculated using the coordinate value representing the position, and the three-dimensional shape measuring apparatus is moved to the calculated moving position, and the direction of the three-dimensional shape measuring apparatus is designated. A moving means (S414 to S422, in particular S420, S422) for setting the orientation, and the moved three-dimensional shape measuring apparatus to measure the object to be measured, and a three-dimensional coordinate system related to the three-dimensional shape measuring apparatus. The second image data acquisition means (S424) for acquiring the three-dimensional image data relating to the object to be measured to be measured, which is shown, and the acquired object to be measured for calibration A measurement object calibration object for defining at least one straight line for each dimension based on three-dimensional image data and using an identification parameter stored in the storage means and related to the measurement object calibration object Second parameter calculation means (S426, S428, S432) for calculating a straight line definition parameter and a coordinate value of a fixed point specified by the measurement target calibration object, and the calculated measurement target calibration object straight line definition The three-dimensional coordinate value related to the three-dimensional shape measuring apparatus using the parameter, the straight line definition parameter related to the calibration object to be measured and stored in the storage means, and the origin position relation parameter stored in the storage means Corresponding to each dimension defined by the calculated calibration object straight line definition parameter The direction of the three straight lines is matched with the direction of the three straight lines corresponding to the dimensions defined by the straight line definition parameters stored in the storage means and related to the calibration object to be measured, and the multi-degree-of-freedom robot Second coordinate conversion function for calculating the object coordinate conversion function Gs _CM for calibration of the measurement target for converting the coordinate value of the three-dimensional coordinate system to the coordinate value of the conversion coordinate system with the origin coordinate (CM coordinate system) as the origin coordinate Using the calculating means (S430) and the calculated object coordinate conversion function for measurement object to be measured, the coordinate value of the fixed point specified by the calculated object to be measured object to be measured is converted into the converted coordinate system. a second coordinate transformation means for coordinate values of the measurement target fixed point (S432), the coordinate transformed with each coordinate value of the reference fixed point that the coordinate transformation between coordinate values of the measurement target fixed point And using a positioning coordinate error calculating means for calculation by the positioning coordinate error (S434), the a computation object to be measured for calibration object coordinate transformation function and said calculated reference calibration object coordinate conversion function, the first Direction of the three-dimensional shape measuring apparatus when the three-dimensional image data of the calibration object to be measured is acquired by the two image data acquiring means, and the direction of the three-dimensional shape measuring apparatus designated by the moving means the deviation between the rotational deviation calculating means for calculation by the rotational deviation and (S436), based on the rotational deviation of said calculated the positioning error and the calculation to correct the positioning error of the tip correction means (S604) It is in having prepared. In this case, the identification parameter may be the reflectance, shape, size of the surface of the calibration object or the arrangement state between the calibration objects.

In this case, each of the plurality of calibration objects in the calibration jig constitutes one calibration object by at least three or more objects, and the first parameter calculation means constitutes the reference calibration object. At least three or more in total to calculate the coordinates of a fixed point specified by the object, the second parameter calculating means, fixed point identified by the at least three or more objects constituting the object for the object to be measured calibration the coordinate values may be configured to calculate. In this case, each straight line definition parameter stored in the storage means is a specific point specified by each object for each of the at least three or more objects, and the first parameter calculation means includes : A coordinate value of a specific point specified by each object is calculated for each of the at least three objects, and the center position of the specific point corresponding to each of the calculated objects is calculated as the reference calibration object. total was calculated as a fixed point specified by the second parameter calculation means, said at least three or more to calculate the coordinate value of the specific points respectively specified by the respective object for each object, the calculated the was the central position of the specific point corresponding to each object, the better to be calculated as a fixed point identified by the object to be measured for calibration object. In this case, at least three or more each object is a sphere, the specific point that is identified each of the at least three for each object by the respective object, the Ru sphere center der each sphere Good.

Alternatively, each of the plurality of calibration objects is formed of a polyhedron and at least three of the surfaces constituting the polyhedron can be simultaneously measured by the three-dimensional shape measuring apparatus. Each straight line definition parameter provided in the calibration jig and stored in the storage means is a normal vector for each of the at least three surfaces, and the first parameter calculation means includes the at least three or more parameters. the coordinate values of the vertex formed by the surface of, in total and calculated as a fixed point specified by the reference calibration object, the second parameter calculating means, the coordinates of the vertex formed by the at least three or more surfaces The value may be calculated as a fixed point specified by the object to be measured .

According to the feature of the present invention configured as described above, in a calibration jig including a plurality of calibration objects, one calibration object is used as a reference calibration object, and the other calibration objects are used as calibration objects to be measured. A three-dimensional shape measurement device is used to measure a three-dimensional shape. In this case, by the moving means, the three-dimensional shape measuring apparatus is moved in accordance with the positional relationship stored in advance have that school Tadashiyo object in the storage means with respect to the reference calibration object, the object for calibration measurement object Positioned. Therefore, if there is no positioning error in the three-dimensional shape measuring apparatus, there is no difference between the position of the reference calibration object measured by the three-dimensional shape measuring apparatus and the position of the measurement target calibration object. On the other hand, if there is a positioning error in the three-dimensional shape measuring apparatus, when the reference calibration object positioning the three-dimensional shape measuring apparatus to a position or an object from a measured object calibrated measured, the position of the three coordinate axes A deviation and / or a rotational deviation on each coordinate axis has occurred, and the difference can be detected as a positioning coordinate error and / or a rotational deviation.
The detection of the positioning coordinate error and / or rotational deviation will be described including the functions and operations of the constituent elements of the present invention. First, for the reference calibration object, the first image data acquisition unit acquires three-dimensional image data related to the reference calibration object. This three-dimensional image data is expressed in a three-dimensional coordinate system related to the three-dimensional shape measuring apparatus. The first parameter calculation means defines at least one straight line for each dimension based on the acquired three-dimensional image data relating to the reference calibration object for comparison with the position of the measurement target calibration object. The reference calibration object straight line definition parameter and the coordinate value of the fixed point specified by the reference calibration object are calculated. In order to calculate the coordinate values of the reference calibration object and the fixed point, an identification parameter stored in the storage means for identifying the reference calibration object is used. Further, the first coordinate conversion function calculation means is configured to measure the three-dimensional shape in order to obtain a coordinate value of a coordinate system equivalent to the coordinate system at the time of comparison with the position of the calibration object to be measured. A reference calibration object coordinate conversion function for converting the coordinate value of the three-dimensional coordinate system related to the apparatus into the coordinate value of the conversion coordinate system is calculated. In this conversion coordinate system, the coordinate values of the three-dimensional coordinate system related to the three-dimensional shape measuring apparatus are stored in the storage means, and the directions of the three straight lines corresponding to the respective dimensions defined by the reference calibration object straight line definition parameters are stored in the storage means. This is a coordinate system in which the orientation of the three straight lines corresponding to each dimension defined by the straight line definition parameter relating to the reference calibration object is matched, and the origin coordinates of the three-dimensional coordinate system relating to the multi-degree-of-freedom robot are the origin coordinates. The calculation of the reference calibration object coordinate conversion function includes the reference calibration object straight line definition parameter calculated by the first parameter calculation means, the straight line definition parameter related to the reference calibration object stored in the storage means, and the storage. The origin position relation parameter stored in the means is used. Then, the first coordinate conversion means converts the coordinate value of the fixed point specified by the reference calibration object calculated by the first parameter calculation means to the conversion coordinates using the calculated reference calibration object coordinate conversion function. The coordinate value of the system is converted into the coordinate value of the reference fixed point.
On the other hand, with respect to the measurement target calibration object, the second image data acquisition unit acquires three-dimensional image data regarding the measurement target calibration object. This three-dimensional image data is also expressed in a three-dimensional coordinate system related to the three-dimensional shape measuring apparatus. The second parameter calculation means defines at least one straight line for each dimension based on the acquired three-dimensional image data regarding the calibration object to be measured for comparison with the position of the reference calibration object. The object-to-be-calibrated object straight line definition parameter for the measurement object and the coordinate value of the fixed point specified by the object to be measured are calculated. In order to calculate the coordinate values of the measurement target calibration object and the fixed point, identification parameters stored in the storage means for identifying the measurement target calibration object are used. Further, the second coordinate conversion function calculating means relates to a three-dimensional shape measuring apparatus in order to obtain a coordinate value of a coordinate system equivalent to the coordinate system at the time of comparison with the position of the reference calibration object. An object coordinate conversion function for calibration of an object to be measured for converting the coordinate value of the three-dimensional coordinate system into the coordinate value of the conversion coordinate system is calculated. In this conversion coordinate system, the coordinate values of the three-dimensional coordinate system relating to the three-dimensional shape measuring apparatus are stored in the storage means, and the directions of the three straight lines corresponding to the respective dimensions defined by the calibration target object straight line definition parameters are stored in the storage means. Coordinates that match the orientation of the three straight lines corresponding to each dimension defined by the straight line definition parameters for the calibration object to be measured and that have the origin coordinates of the three-dimensional coordinate system for the multi-degree-of-freedom robot as the origin coordinates It is a system. It should be noted that the object-to-be-measured object coordinate conversion function is calculated by the second parameter calculating unit, the object-to-be-measured object straight line definition parameter, which is stored in the storage unit and is related to the object to be measured. The straight line definition parameter and the origin position relation parameter stored in the storage means are used. Then, the second coordinate conversion means uses the calculated object calibration object coordinate conversion function to calculate the coordinate value of the fixed point specified by the object to be measured calibration calculated by the second parameter calculation means. Is converted to the coordinate value of the conversion coordinate system to obtain the coordinate value of the fixed point to be measured.
By such calculation, the fixed point related to the reference calibration object and the fixed point related to the measurement target calibration object are represented by the coordinate values of the equivalent conversion coordinate system. Accordingly, with respect to the positioning coordinate error, the coordinate error calculation means is coordinate-converted by the first coordinate conversion means and each coordinate value of the measurement target fixed point of the conversion coordinate system coordinate-converted by the second coordinate conversion means. The difference from each coordinate value of the reference fixed point of the converted coordinate system is calculated as a positioning coordinate error. Further, with respect to the rotation deviation, the rotation deviation calculation means uses the object coordinate conversion function for calibration of the measurement target and the object coordinate conversion function for reference calibration for the measurement target calibration by the second image data acquisition means. A deviation between the direction of the three-dimensional shape measuring apparatus when the three-dimensional image data of the object is acquired and the direction of the three-dimensional shape measuring apparatus designated by the moving means is calculated as a rotational deviation.
Thus, the calibration object in the calibration fixture, three-dimensional shape of the respective calibration objects are accurately measured by the three-dimensional shape measuring apparatus, it was based on the measurement data each fixed point coordinates Ru are accurately calculated Therefore, it is not necessary to manufacture each calibration object and the calibration jig itself with high accuracy, and it is not necessary to precisely position the calibration jig if the arrangement position of the calibration jig is within the movable range of the support mechanism. For this reason, the cost for correcting the positioning error in the multi-degree-of-freedom robot can be suppressed, and the work of arranging the calibration jig can be simplified. As a result, the positioning error can be detected with high work efficiency while maintaining the accuracy of the positioning error correction in the multi-degree-of-freedom robot.

Another feature of the present invention is that, in the positioning error correction apparatus for the multi-degree-of-freedom robot, a three-dimensional shape measuring apparatus using the moving means is provided for each of the calibration objects other than the reference calibration object. Movement, acquisition of three-dimensional image data by the second image data acquisition means, calculation of a measurement target straight line definition parameter and coordinate values by the second parameter calculation means, second coordinate conversion function calculation means The object coordinate conversion function for calibrating the object to be measured is calculated by the above, coordinate conversion by the second coordinate conversion means, calculation of positioning coordinate error by the positioning coordinate error calculation means, and calculation of rotational deviation by the rotational deviation calculation means Repetitive control means (S442), positioning coordinate error calculated by the positioning coordinate error calculating means, Correction data storage means (S436) for storing correction data for correcting rotational deviation calculated by the rolling deviation calculation means in the storage means in correspondence with each of the plurality of calibration objects other than the reference calibration object. , S440) .

According to another feature of the present invention configured as described above, the repetitive control unit moves the three-dimensional shape measuring apparatus by the moving unit with respect to each of the plurality of calibration objects other than the reference calibration object. Acquisition of three-dimensional image data by image data acquisition means, calculation of calibration target object straight line definition parameters and coordinate values by second parameter calculation means, measurement target object calibration coordinates by second coordinate transformation function calculation means The conversion function is calculated, the coordinate conversion is performed by the second coordinate conversion means, the positioning coordinate error is calculated by the positioning coordinate error calculation means, and the rotation deviation is calculated by the rotation deviation calculation means. Then, the correction data storage means uses a plurality of calibrations other than the reference calibration object as correction data for correcting the positioning coordinate error calculated by the positioning coordinate error calculation means and the rotation deviation calculated by the rotation deviation calculation means. It is stored in the storage means corresponding to each object. Therefore, when moving the three-dimensional shape measuring apparatus to a plurality of destination, it is possible to position the three-dimensional shape measuring apparatus using the compensation data corresponding to the positions of the plurality of destination. In this case, for example, by interpolation from the calculated compensation data for each position of the object to be measured for calibration object, it may calculate the compensation data that corresponds to a position that is positioned in the three-dimensional shape measurement device. As a result, since the positioning error in the multi-degree-of-freedom robot can be corrected by the correction amount corresponding to the position where the three-dimensional shape measuring apparatus is positioned, the tip of the multi-degree-of-freedom robot can be positioned with higher accuracy. it can.

  The present invention can be implemented not only as an apparatus invention but also as a method invention.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a basic configuration of an articulated robot provided with a positioning error correction apparatus of the present invention.

  This articulated robot includes an arm support mechanism 20 that is fixed on the base 10 and that freely displaces the tip portion within the measurement target space, and a three-dimensional shape measuring device 30 attached to the tip portion of the arm support mechanism 20. I have. The arm support mechanism 20 includes a fixed base 21, a rotation base 22, a first arm 23, a second arm 24, a third arm 25 and a fourth arm 26.

  The fixed base 21 is formed in a cylindrical shape and is vertically fixed on the base 10 at the lower end thereof. The rotating base 22 is formed in a disk shape, and is assembled on the upper surface of the fixed base 21 so as to be rotatable around the axis of the fixed base 21. The rotary base 22 is driven to rotate around the axis of the fixed base 21 by a servo motor 21 a provided in the fixed base 21. The first arm 23 is assembled to a connecting portion 22a provided on the upper surface of the rotating base 22 at a connecting portion 23a provided at the base end thereof so as to be rotatable around an axis perpendicular to the axial direction of the rotating base 22. ing. The first arm 23 is rotationally driven around an axis perpendicular to the axial direction of the rotary base 22 by a servo motor 23b provided in the connecting portions 22a and 23a.

  The second arm 24 is assembled at a connecting portion 24 a provided at the base end thereof to a connecting portion 23 c provided at the distal end of the first arm 23 so as to be rotatable about an axis perpendicular to the axial direction of the first arm 23. ing. The second arm 24 is rotationally driven around an axis perpendicular to the axial direction of the first arm 23 by a servo motor 24b provided in the connecting portions 23c and 24a. The third arm 25 is assembled at a connecting portion 25 a provided at the base end thereof to a connecting portion 24 c provided at the distal end of the second arm 24 so as to be rotatable about an axis perpendicular to the axial direction of the second arm 24. ing. The third arm 25 is rotationally driven about an axis perpendicular to the axial direction of the second arm 24 by a servo motor 25b provided in the connecting portions 24c and 25a.

  The fourth arm 26 is assembled at a connecting portion 26 a provided at the base end thereof to a connecting portion 25 c provided at the distal end of the third arm 25 so as to be rotatable about an axis perpendicular to the axial direction of the third arm 25. ing. The third arm 25 is rotationally driven around an axis perpendicular to the axial direction of the third arm 25 by a servo motor 26b provided in the connecting portions 25c and 26a. A three-dimensional shape measuring device 30 is attached to the distal end portion of the fourth arm 26 via a fixing member 27 so as to be rotatable about the axis of the fourth arm 26 and detachable. The fixing member 27 is fixed to the bottom surface or the side surface of the rectangular housing of the three-dimensional shape measuring apparatus 30. Further, the fixing member 27 is provided with a servo motor 27 a, and the fixing member 27 is rotationally driven around the axis of the fourth arm 26.

  The three-dimensional shape measuring apparatus 30 measures the three-dimensional shape of an object located on the front side of the object and outputs information representing the measured three-dimensional shape. In this embodiment, laser light is used. The three-dimensional shape of an object is measured according to a triangulation method. In the present embodiment, laser light is used. However, other light may be used as long as the surface shape of the three-dimensional object can be measured and the reflectance and color can be identified.

  In this three-dimensional shape measuring apparatus 30, a virtual plane that is substantially perpendicular to the traveling direction of the laser light emitted from the laser light source toward the object is assumed, and the X-axis direction and Y that are orthogonal to each other on the virtual plane are assumed. A large number of minute areas divided along the axial direction are assumed. The three-dimensional shape measuring apparatus 30 sequentially irradiates the plurality of minute areas with laser light, and sequentially detects the distance to the object surface defined by the minute areas as reflected in the Z-axis direction by reflected light from the object. Information on X, Y, and Z coordinates representing each divided area position obtained by dividing the surface of the object into minute areas is obtained, and the shape of the object surface facing the three-dimensional shape measuring apparatus 30 is measured.

  Therefore, the three-dimensional shape measuring apparatus 30 includes an X-axis direction scanner that changes the direction of the emitted laser light in the X-axis direction, a Y-axis direction scanner that changes the direction of the emitted laser light in the Y-axis direction, A distance detector that receives reflected laser light reflected from the surface and detects the distance to the object surface. The X-axis direction scanner and the Y-axis direction scanner may be any mechanism that can change the optical path of the laser beam emitted from the laser light source independently in the X-axis direction and the Y-axis direction. Rotating around the axis in the direction and the Y-axis direction by an electric motor, or rotating the galvanometer mirror provided in the optical path of the emitted laser light and changing the direction around the axes in the X-axis direction and the Y-axis direction by the electric motor Can be used. As the distance detector, a plurality of imaging lenses such as an imaging lens that condenses the reflected laser light reflected on the object surface and rotates following the optical path of the emitted laser light, and a CCD that receives the condensed laser light are used. It is possible to use a mechanism for detecting the distance to the object surface based on the light receiving position of the reflected laser beam by the line sensor.

  Therefore, such a three-dimensional shape measuring apparatus 30 uses the reference of the emitted laser light by the X-axis direction scanner as information on the X, Y, and Z coordinates representing the divided area positions obtained by dividing the surface of the object into minute areas. The inclination θx in the X-axis direction with respect to the direction, the inclination θy in the Y-axis direction with respect to the reference direction of the laser beam emitted by the Y-axis direction scanner, and the distance Lz to the object surface by the distance detector are the virtual X-axis. Are output for each of a number of minute areas divided along the direction and the Y-axis direction. More specifically, the inclinations θx and θy in the X-axis and Y-axis directions are rotation angles from the reference position of the electric motor. Further, the distance Lz to the object surface is the light receiving position of the reflected laser beam in the line sensor. The three-dimensional shape measuring apparatus 30 described above is an example, and any three-dimensional shape measuring apparatus can be used, such as one using millimeter waves or ultrasonic waves instead of laser light.

  A controller 41 and a three-dimensional image processing device 42 are connected to the three-dimensional shape measuring device 30. The controller 41 is connected to the servo motors 21a, 23b, 24b, 25b, 26b, 27a and the three-dimensional image processing device 42 in addition to the three-dimensional shape measuring device 30, and from a keyboard including a plurality of operators. The operations of the three-dimensional shape measuring device 30, the servo motors 21a, 23b, 24b, 25b, 26b, 27a and the three-dimensional image processing device 42 are controlled in accordance with instructions from the input device 43.

  The controller 41 defines a geometric configuration of each arm such as an angle between the arms, a twist angle between the arms, a distance between the arms, and a length of each arm when the arm support mechanism 20 is in the basic posture. Basic posture information is set. Then, the controller 41 is a rotation base for positioning the distal end portion at the positioning position (including the orientation of the distal end portion) of the distal end portion of the arm support mechanism 20 instructed from the input device 43 or the three-dimensional image processing device 42. The rotation angle of 22, each angle between the first arm 23 to the fourth arm 26, and the rotation angle in the axial direction of the fourth arm are respectively calculated using the basic posture information, and each of the rotation angles corresponding to these rotation angles is calculated. Control values for controlling the servo motors 21a, 23b, 24b, 25b, 26b, 27a are calculated. In addition, when the arm tip position information representing the positioning position (including the direction of the tip portion) of the tip portion of the arm support mechanism 20 is input from the input device 43, the controller 41 three-dimensionally displays the arm tip position information. This is supplied to the image processing measurement device 42. The position of the tip of the fourth arm 26 and the orientation of the tip indicated by the arm tip position information are expressed in a three-dimensional coordinate system with a predetermined point at the fixed portion of the fixed base 21 to the base 10 as the origin. It is represented by a certain reference coordinate system.

  The three-dimensional image processing device 42 is constituted by a computer device and executes each program shown in FIGS. 7, 8, 9, 11, 17, and 20, whereby arm tip position information and a three-dimensional shape supplied from the controller 41. The information representing the three-dimensional shape from the measuring device 30, specifically, the tilt θx in the X-axis direction, the tilt θy in the Y-axis direction, and the distance Lz to the object surface are input, and the tip of the fourth arm 26 3D image data that can be displayed by viewing the three-dimensional shape of an object located in the measurement target space from an arbitrary direction is calculated. A display device 44 is connected to the three-dimensional image processing device 42. The display device 44 includes a liquid crystal display, a plasma display, a CRT display, or the like, and performs measurement based on the execution process of each program executed by the three-dimensional image processing device 42 and three-dimensional image data generated by the execution of each program. The three-dimensional shape of the object located in the target space is displayed.

  Next, the operation of the articulated robot configured as described above will be described. The operator prepares a calibration jig 50 for correcting the positioning error for detecting the difference between the tip position of the fourth arm 26 instructed by the controller 41 and the actual tip position of the fourth arm 26. As shown in FIG. 2A, the calibration jig 50 is configured by supporting a plurality of spheres 51 as calibration objects on a calibration object support base 52. Each sphere 51 is made of a material having a relatively small mass such as resin or polystyrene, and the three spheres 51 constitute one sphere set 53. There are 16 sets of the spheres 53 in total, which are equally arranged and supported in the calibration object support base 52. Each diameter of the sphere 51 is formed with a predetermined diameter (25 mm in the present embodiment) as a guide, but the range of the dimensional tolerance is wide and the sphere 51 is formed to have a different diameter.

  The calibration object support base 52 is formed by dividing the inside of a square-shaped frame body 52a into four square-shaped regions by a support bar 52b formed in a cross shape. In each of the four divided areas, two wires 52c and 52d are stretched in the vertical and horizontal directions of the frame 52a, respectively, and the three wires 52c and 52d are located near the intersections of the three wires 52c and 52d. A sphere set 53 composed of two spheres 51 is arranged. Specifically, two spheres 51 each penetrating the wire 52d are arranged on both sides of the intersection of the wire 52c and the wire 52d, and one sphere 51 penetrating the wire 52c is arranged on the upper side of the same intersection in the drawing. It is made to support in the frame 52a.

  Note that the three spheres 51 in each sphere set 53 are arranged at substantially equal intervals. Note that the range in which the spherical body set 53 is arranged in the calibration object support base 52 is within the movable range of the arm support mechanism 20, and the workpiece WK that is a measurement target measured by the three-dimensional shape measuring apparatus 30. It is set according to the size. That is, the sphere set 53 is arranged so as to cover the range in which the three-dimensional shape measuring apparatus 30 needs to be moved in order to measure the workpiece WK. Therefore, the size of the calibration object support base 52 is also set within the range in which the sphere set 53 is arranged. In this case, the size of the calibration object support base 52 may be formed in a size corresponding to the movable range of the three-dimensional shape measuring apparatus 30, or the size of the calibration object support base 52 may be larger than the movable range. It may be formed small and the calibration jig 50 may be moved within the movable range to cover the same range.

  The calibration object support base 52 is fixed to the bottom plate 55 via a column 54. As shown in FIG. 2B, the column 54 is integrally formed by coaxially arranging cylindrical bodies 54a, 54b, 54c, and 54d formed with four different outer diameters, and has a small outer diameter. The cylindrical body is assembled so as to be housed in a cylindrical body having a larger outer diameter. That is, the column 54 is formed to be extendable and contractable in the axial direction. The upper surface of the column 54, specifically, the upper surface of the cylindrical body 54a is fixed to the lower surface of the cross portion of the support bar 52b of the calibration object support base 52 via a connecting portion capable of changing the angle. The lower surface of the cylindrical body 54, specifically, the lower surface of the cylindrical body 54 d is fixed to the center of the upper surface of the bottom plate 55, and the column 54 supports the calibration object support base 52 so that it can be displaced in the axial direction of the column 54. That is, the calibration object support base 52 can be displaced in the vertical direction, the calibration object support base 52 can be set to an appropriate inclination angle, the range in which the sphere set 53 is arranged is moved in the vertical direction, The angle of the plane on which the sphere set 53 is arranged can be changed.

  The vertical position of the calibration object support base 52 can be detected by a sensor or a scale attached to the support column 54. The bottom plate 55 is made of a square plate material and supports a support column 54 that is fixed to the center of the upper surface. Casters 56 are respectively provided at four corners on the bottom surface of the bottom plate 55, and the calibration jig 50 can be moved to an arbitrary position. 2A shows the calibration jig 50 with the column 54 contracted, and FIG. 2B shows the calibration jig 50 with the column 54 extended.

  The operator performs an operation of acquiring calibration object information in the calibration jig 50 configured as described above. The calibration object information includes a sphere center (center coordinate) of each sphere 51 for each sphere set 53, a sphere radius, a distance between the centers of each sphere 51, and fixed points that are the center points of the three spheres 51. Specifically, the operator measures each sphere 51 using the three-dimensional measuring machine 60 shown in FIG. The three-dimensional measuring machine 60 is a measuring machine that can three-dimensionally measure the coordinate position and the size of an object located in the measurement target space, and includes a measuring unit 61, a controller 62, and a coordinate calculation processing device. 63, an input device 64 and a display device 65. The measuring unit 61 is supported on the surface of the measurement target placed on the base 66 by an arm 67 and a column 68 so as to be slidable in the three axial directions of the X-axis direction, the Y-axis direction, and the Z-axis direction. The probe 69 being in contact is brought into contact, and measurement coordinate information representing each coordinate value at the contact point is output to the coordinate calculation processing device 63.

  A controller 62 and a coordinate calculation processing device 63 are connected to the measurement unit 61. The controller 62 controls the operation of the measuring unit 61 in accordance with an instruction from the input device 64 formed of a keyboard. In addition, the controller 62 controls the operation of the coordinate calculation processing device 63 in accordance with an instruction from the input device 64, and supplies data input by the input device 64 to the coordinate calculation processing device 63. The coordinate calculation processing device 63 is constituted by a computer device, and executes various predetermined values of measurement values using measurement coordinate information output from the measurement unit 61 and data supplied from the controller 62 by executing a predetermined program. The calculation is performed and the result is output to the display device 65. The display device 65 is composed of a liquid crystal display or the like, and displays the calculation process and calculation results by the coordinate calculation processing device 63, respectively.

  In the measurement target space on the base 66 of the three-dimensional measuring machine 60 configured as described above, the operator sets the calibration jig 50 with the column 54 contracted as shown in FIG. 64 is instructed to acquire calibration object information. The calibration object information acquisition instruction is transmitted to the coordinate calculation processing device 63 via the controller 62, and the coordinate calculation processing device 63 starts execution of the calibration object information acquisition program shown in FIG. 4 in step S100. In step S102, the operator waits for the input of the feature to be measured. When the operator operates the input device 64 to input the characteristics of the sphere 51 to be measured, the input information is supplied to the coordinate calculation processing device 63 via the controller 62. Here, the characteristic of the measurement target is data indicating that each sphere 51 as the measurement target is a sphere in the present embodiment. Note that if the previously input characteristics of the measurement target are not changed, the process of step S102 may be skipped. After the processing in step S102, the coordinate calculation processing device 63 waits for input of measurement coordinate information for each sphere set 53 by the measurement unit 61 in step S104.

On the other hand, the operator operates the probe 69 of the measuring unit 61 to bring the surfaces of the spheres 51 in any one of the sphere sets 53 to be measured into contact with each other at four locations. In this case, the operator inputs a number (1 to N) for distinguishing each sphere set 53 for each sphere set 53 and measures each sphere set 53. As a result, the measurement unit 61 transmits four sets of measurement coordinate information (each point is represented by coordinate values x, y, z) corresponding to the four contact points for each sphere 51 to the coordinate calculation processing device 63. Output. The measurement coordinate information is a measurement machine coordinate system that is a coordinate system related to the three-dimensional measurement machine 60. In the present embodiment, the measurement coordinate information is X, Y, Z having a predetermined point on the base 66 as an origin. It is a coordinate value in the three-dimensional coordinates. In step S106, the coordinate calculation processing device 63 uses the four sets of measurement coordinate information for each sphere 51 to determine the sphere center coordinates C _mA , C _mB , C _mC, and sphere of each sphere 51 to be measured. The radii R _mA , R _mB , and R _mC are calculated (“m” represents the measuring machine coordinate system). Specifically, since the surface of the sphere is represented by the following equation 1, the calculation is performed by substituting the four sets of measurement coordinate information into X, Y, and Z of the following equation 1, respectively, and solving simultaneous equations. . In the following formula 1, a, b, and c are unknown numbers representing the center coordinates of the sphere, and d is an unknown number representing the radius of the sphere.

That is, in the process of step S106, four sets of measurement coordinate information measured for one sphere 51 are substituted into the left side of Equation 1 for each measurement coordinate information to create four simultaneous equations. Then, a, b, c, and d are calculated by solving the simultaneous equations. Thereby, the coordinate values (X, Y, Z) representing the center position of the sphere 51 are calculated as a, b, c, and the radius of the sphere 51 is calculated as d. After executing the processing for calculating the sphere center coordinates C _m and the sphere radius R _m of these spheres 51 for the three spheres 51, the process proceeds to step S108. In the present embodiment, the probe 69 is brought into contact with one sphere 51 at four locations to acquire measurement coordinate information. However, the probe 69 is brought into contact with five or more locations to obtain high precision including correction. The calculation of the spherical center coordinates C _m and the spherical radius R _m may be performed. In addition, the measurement coordinate information is acquired a plurality of times for one sphere 51 and the sphere center coordinates C _m and the sphere radius R _m are calculated. The sphere center coordinates C _m and the sphere radius R calculated each time are calculated. _m and may be an average value, respectively as a sphere center coordinates C _m and the sphere radius R _m. Thereby, the sphere center coordinates C _m and the sphere radius R _m of the sphere 51 can be calculated with higher accuracy.

Next, the coordinate calculation processing device 63 calculates the distances L _mAB , L _mBC , and L _mCA between the spheres 51 in step S108. The distance _L mAB between the spherical bodies _51, L _{MBC, L mCA} is another sphere center coordinates _C mA for each sphere 51 calculated at the step _S106, C _mB, a linear distance between the _{C mC.} Next, the coordinate computing unit 63, at step S110, it calculates the fixed point coordinate _{T m.} The fixed point coordinate T _m is a coordinate value representing the center position where the three spheres 51 in the sphere set 53 are arranged. The fixed point coordinates T _m are expressed by the following formulas 2 X _A , X _B , X _C , Y _A , Y _B , Y _C , Z _A , Z _B , Z _C, and the spherical center coordinates C _mA , C of each sphere 51. Each coordinate value (CX _mA , CY _mA , CZ _mA ) (CX _mB , CY _mB , CZ _mB ) (CX _mC , CY _mC , CZ _mC ) of _mB and C _mC is substituted and calculated.

  Next, the coordinate calculation processing device 63 determines whether or not measurement has been performed for all the sphere sets 53 in step S112. In this determination, if all the sphere sets 53 have not been measured, it is determined as “No”, the process returns to step S104, and the measurement process is continued for the sphere set 53 that has not been measured yet. On the other hand, when the measurement is performed for all the sphere sets 53, it is determined as “Yes” and the process proceeds to step S114. In step S114, the coordinate calculation processing device 63 inquires of the operator whether to change the position of the sphere set 53 in the height direction and perform the measurement process of each sphere set 53 again. This is because the calibration object of the sphere set 53 is substantially uniformly within the height direction range corresponding to the height direction range in which the arm support mechanism 20 is moved to measure the workpiece WK placed on the base 10. This is for acquiring information. Therefore, when the measurement process of the sphere 53 is necessary again at a position in a different height direction, the operator inputs information indicating that the measurement process is continued by operating the input device 64 to the coordinate calculation processing device 63. . In response to this instruction, the coordinate calculation processing device 63 determines “Yes” in step S114, returns to step S104, and executes each process of measuring the sphere set 53 again. In this case, the operator changes the height of the calibration object support base 52 to a necessary height by extending and contracting the support 54 of the calibration jig 50.

On the other hand, when the calibration object information of the sphere set 53 is acquired approximately evenly within the height direction range corresponding to the height direction range in which the arm support mechanism 20 is movable, the operator inputs the input device 64. Is input to the coordinate calculation processing device 63 to end the measurement process. In response to this instruction, the coordinate calculation processing device 63 makes a “No” determination at step S114, proceeds to step S116, and ends the execution of the calibration object information acquisition program at step S116. . Thereby, as shown in FIG. 5, the coordinate calculation processing device 63 includes the sphere center coordinates C _m and the sphere radius R _m of each sphere 51 for each sphere set 53 (1 to N), and the center-to-center distance of each sphere 51. L _m and fixed point coordinates T _m of the sphere set 53 are stored. Of these calibration object information, the sphere center coordinates C _m are the straight line definition parameters according to the present invention, the sphere radius R _m and the distance L _m between the spheres 51 are the identification parameters according to the present invention, fixed point coordinate T _m of a sphere set 53 is fixed point according to the present invention. Then, the operator removes the calibration jig 50 from the base 66 of the three-dimensional measuring machine 60 and finishes the calibration object information acquisition operation. If the calibration object information is known, the calibration object information acquisition process by executing this calibration object information acquisition program is not necessary.

  Next, the operator inputs the calibration object information calculated by executing the calibration object information acquisition program to the three-dimensional image processing device 42 in the articulated robot. Specifically, the coordinate calculation processing device 63 of the three-dimensional measuring machine 60 and the three-dimensional image processing device 42 are connected by a signal cable or the like, and the object information for calibration is transferred from the coordinate calculation processing device 63 to the three-dimensional image processing device 42. input. As a method of inputting the calibration object information to the three-dimensional image processing device 42, in addition to using the signal cable, a method of inputting by an input operation by an operator via the input device 43, or a coordinate calculation processing device 63. Is input to the three-dimensional image processing apparatus 42 via another recording medium (for example, FD, portable flash memory device, etc.).

  Next, the operator converts the three-dimensional image data represented by the camera coordinate system, which is the coordinate system related to the three-dimensional shape measuring apparatus 30, into the three-dimensional image represented by the arm coordinate system, which is the coordinate system related to the arm support mechanism 20. A coordinate conversion function CA for converting to data is calculated. Here, the camera coordinate system is a coordinate system related to the three-dimensional shape measuring apparatus 30 and includes three coordinate axes (X axis, Y axis, Z axis) orthogonal to each other, and a specific point of the three-dimensional shape measuring apparatus 30 as an origin. This is a three-dimensional coordinate system. The arm coordinate system is a coordinate system related to the mounting portion of the three-dimensional shape measuring apparatus 30 and includes three coordinate axes (X axis, Y axis, Z axis) corresponding to the camera coordinate system. 3 is a three-dimensional coordinate system having a predetermined position at the tip of the fourth arm 26 as an attachment portion for attaching to the arm support mechanism 20. The predetermined position of the tip of the fourth arm 26 is specifically the point of the tip of the fourth arm 26 on the axis of the fourth arm 26.

  First, as shown in FIG. 6, the operator attaches the base 71 of the probe 70 to the tip of the fourth arm 26 instead of the three-dimensional shape measuring apparatus 30. The probe 70 is configured by attaching one end of a stylus 72 formed in a needle shape to a base 71 via a connecting portion 73. The connecting portion 73 supports the distal end portion of the stylus 72 so as to be freely displaceable about two axes orthogonal to the base portion 71 (in the arrow direction in the drawing). The probe 70 is electrically connected to the three-dimensional image processing device 42. When the tip of the stylus 72 comes into contact with any object, a signal indicating the contact and the biaxial direction of the connecting portion 73 are displayed. A signal representing each rotation angle is output to the three-dimensional image processing device 42. In this probe 70, the rotation center position of the connecting portion 73 with respect to a predetermined position of the base portion 71 and the position of the distal end portion of the stylus 72 with respect to the rotation center position of the connecting portion 73 are recognized by the operator, and three-dimensional image processing is performed. It is stored in advance in the memory device of the device 42.

  Next, the worker places a reference sphere 80 for acquiring a coordinate conversion function at a preset position on the base 10. The reference sphere 80 is formed in a true sphere and functions as a reference object for determining a fixed point in the measurement target space. The reference sphere 80 is fixed on a base portion 81 formed in a trapezoid shape via a columnar support portion 82 and is disposed at an appropriate height from the upper surface of the base 10. In the present embodiment, the reference sphere 80 is arranged on the base 10 via the base portion 81 and the support portion 82, but the reference sphere 80 may be directly arranged on the base 10.

  Next, the operator operates the input device 43 to instruct the three-dimensional image processing device 42 to execute the reference sphere measurement program shown in FIG. In response to this instruction, the three-dimensional image processing apparatus 42 starts execution of the reference sphere measurement program in step S200, and measures the reference sphere 80 by the probe 70 in step S202. The reference sphere 80 is measured by bringing the tip of the stylus 72 of the probe 70 into contact with the reference sphere 80. First, the three-dimensional image processing device 42 contacts the tip of the stylus 72 with the reference sphere 80. For this purpose, the display device 44 displays a range of positions that the tip of the arm support mechanism 20 should take. The range of the position to be taken by the tip of the arm support mechanism 20 is stored in advance in the memory device of the three-dimensional image processing device 42. The operator operates the input device 43 while confirming the range of the position to be taken by the tip of the arm support mechanism 20 displayed on the display device 44, and moves the tip of the arm support mechanism 20 within the same range. . In this case, the operator changes the direction of the tip of the stylus 72 to the reference sphere 80 so that the tip of the stylus 72 of the probe 70 does not contact the reference sphere 80 due to the movement of the tip of the arm support mechanism 20. Is directed in the opposite direction, and then the input device 43 is operated to input arm tip position information to the controller 41.

  Next, the operator manually operates the stylus 72 to bring the tip of the stylus 72 into contact with the surface of the reference sphere 80. In this case, a signal representing the contact of the tip of the stylus 72 and a signal representing the rotation angle of the connecting portion 73 in the biaxial direction are output from the probe 70 to the three-dimensional image processing device 42. The three-dimensional image processing device 42 responds to the signal representing the contact of the distal end portion of the stylus 72 with each input rotation angle of the connecting portion 73 in the biaxial direction, the input arm tip position information, and the predetermined base 71 position. The contact point of the reference sphere 80 at the distal end portion of the stylus 72 is determined using the length to the rotation center of the connection portion 73 with respect to the position and the length to the distal end portion of the stylus 72 with respect to the rotation center position of the connection portion 73. A coordinate value of a reference coordinate system which is a coordinate system to be expressed and is a coordinate system related to the base 10 is calculated. The reference coordinate system is composed of the three coordinate axes (X axis, Y axis, Z axis) corresponding to the camera coordinate system as described above, and a predetermined point at the fixed portion of the fixed base 21 to the base 10 is set as the origin. Is a three-dimensional coordinate system. The operator changes the position of the distal end portion of the arm support mechanism 20 four times, brings the stylus 72 of the probe 70 into contact with the reference sphere 80 at each position, and coordinates of the coordinates of each contact point in the reference coordinate system. Values are calculated for each contact point, and four sets of coordinate data corresponding to the four contact points are stored in the three-dimensional image processing device 42.

  After the process of step S204, the three-dimensional image processing apparatus 42 is a coordinate representing the center position of the reference sphere 80 and the coordinates of the reference coordinate system (hereinafter referred to as center coordinates (x ″, y ″, z ″) in step S206. )) Using the calculated four sets of coordinate data, in which the four sets of coordinate data are substituted into X, Y, and Z of the above equation 1 representing the surface of the sphere. Then, the center coordinates (x ″, y ″, z ″) of the reference sphere 80 are calculated by calculating the values of a, b, and c. Next, the three-dimensional image processing apparatus 42 stores the calculated center coordinates (x ″, y ″, z ″) as coordinates representing a fixed point of the reference sphere 80 in step S208, and then in step S210. In the present embodiment, the probe 70 is brought into contact with the reference sphere 80 at four locations, but the contact with the reference sphere 80 is performed at five or more locations, and high accuracy including correction is performed. In addition, when the radius d of the reference sphere 80 is known, the center coordinates of the reference sphere 80 can be obtained even if the number of contact points is three.

  Next, as shown in FIG. 1, the operator removes the probe 70 from the distal end portion of the fourth arm 26 and enables the three-dimensional shape measuring device 30 to rotate around the axis of the fourth arm 26 at the distal end portion. Assemble. Then, the input device 43 is operated to instruct the three-dimensional image processing device 42 to execute the coordinate conversion function calculation program shown in FIG. In response to this instruction, the three-dimensional image processing apparatus 42 starts execution of the coordinate conversion function calculation program in step S300, and measures the reference sphere 80 by the three-dimensional shape measuring apparatus 30 in step 302. Specifically, the operator operates the input device 43 to move the three-dimensional shape measuring device 30 to a position where the reference sphere 80 can be measured, and measures the reference sphere 80. The measurement of the reference sphere 80 is performed from three different measurement positions, and the arm tip position information and information representing the three-dimensional shape of the reference sphere 80 are stored in the three-dimensional image processing device 42 for each measurement position. The

  In this case, as described above, the arm tip position information is information input to the three-dimensional image processing device 42 by the operator via the input device 43, and is a coordinate representing the origin of the arm coordinate system based on the reference coordinate system ( xd 1, yd 1, zd 1), (xd 2, yd 2, zd 2), (xd 3, yd 3, zd 3), and the X axis of the reference coordinate system when the direction of the coordinate axis of the reference coordinate system is the direction of the coordinate axis of the arm coordinate system, The rotation angles (α1, β1, γ1), (α2, β2, γ2), (α3, β3, γ3) around the Y axis and the Z axis. The information representing the three-dimensional shape of the reference sphere 80 is information relating to the XYZ coordinates (specifically, the inclination θx, θy and distance Lz). Then, in step S302, the three-dimensional image processing device 42 determines the three-dimensional shape data representing the three-dimensional shape of the reference sphere 80 at each measurement position based on the stored information representing the three-dimensional shape of the reference sphere 80. Each group of 3D image data is calculated. In this case, the three-dimensional image data is represented by a coordinate system related to the three-dimensional shape measuring apparatus 30, that is, a camera coordinate system. When the 3D image data includes unnecessary 3D image data related to an object other than the reference sphere 80 (for example, the base 10 or the like), the 3D image processing device 42 has a 3D shape. Along with information on the XYZ coordinates from the measuring device 30, data on the received light amount of the line sensor or data on the ratio of the received light amount to the emitted light amount is input, and in step S302, the received light amount or received light amount is emitted. A process for removing the unnecessary three-dimensional image data from the data of the ratio with respect to the amount of light is also executed.

  Next, in step S304, the three-dimensional image processing apparatus 42 substitutes the calculated three-dimensional image data for each measurement position into X, Y, and Z of the above equation 1, and uses the least square method. By calculating a, b, and c, center coordinates (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3) for each measurement position of the reference sphere 80 are obtained. The three-dimensional image data of the reference sphere 80 for each measurement position is distinguished using the arm tip position information input from the input device 43.

  Next, in step S306, the three-dimensional image processing device 42 calculates the center coordinates of the reference sphere 80 in the arm coordinate system. Specifically, the three-dimensional image processing device 42 has center coordinates (x ″, y ″, z ″) in the reference coordinate system of the reference sphere 80 stored in the memory device by executing the reference sphere measurement program shown in FIG. And arm tip position information input in step S302, specifically, coordinates (xd1, yd1, zd1), (xd2, yd2, zd2), (xd3) representing the origin of the arm coordinate system based on the reference coordinate system. , Yd3, zd3) and rotation angles (α1, β1, γ1), (about the X, Y, and Z axes of the reference coordinate system when the direction of the coordinate axes of the reference coordinate system is changed to the coordinate axis direction of the arm coordinate system. α2, β2, γ2), (α3, β3, γ3) are substituted into the following equations 3 and 4, respectively, to obtain the center coordinates of the reference sphere 80 and the center coordinates (x′1, y ′) in the arm coordinate system. 1, z'1), (x'2, y'2, z'2), (x'3, y'3, z'3) are calculated.

  Equations (3) and (4) above represent the coordinates (x, y, z) of one point in the first coordinate system made up of XYZ coordinates, the origin of the first coordinate system as the X-axis direction, the Y-axis direction, and the Z-axis. Coordinates of the same point in the second coordinate system (a, b, c are moved in the axial direction and the first coordinate system is rotated by xθ, yθ, zθ around the X, Y, and Z axes, respectively) x ′, y ′, z ′). In the calculation of step S306, the coordinate values x, y, z in the above equation 3 are the center coordinates of the reference sphere 80 and the center coordinates (x ″, y ″, z ″) of the reference coordinate system. The coordinate values x ′, y ′, and z ′ in the above equation 3 are the center coordinates of the reference sphere 80 and the center coordinates (x ′ according to the arm coordinate system). , y ′, z ′) corresponding to the X, Y, and Z coordinate values of the equation 3. The values a, b, and c in Equation 3 are information input from the input device 43 by the operator in step S302. Α, β, γ corresponding to the origin coordinates (xd1, yd1, zd1), (xd2, yd2, zd2), (xd3, yd3, zd3) of the arm coordinate system by the reference coordinate system Indicates the direction of the coordinate axis of the reference coordinate system, which is information input by the operator from the input device 43 in step S302, as the coordinate axis of the arm coordinate system. Reference coordinate system X axis when the direction, Y-axis and the rotation angle of the Z axis (α1, β1, γ1), (α2, β2, γ2), (α3, β3, γ3) corresponding to.

  Next, in step S308, the three-dimensional image processing apparatus 42 obtains the center coordinates (x1, y1, z1), (x2, y2) for each measurement position of the reference sphere 80 of the camera coordinate system calculated by the process of step S304. , z2), (x3, y3, z3) and the center coordinates (x′1, y′1, z′1), (x′2, y) of the reference sphere 80 of the arm coordinate system calculated by the processing of step S308. A coordinate conversion function CA from the camera coordinate system to the arm coordinate system is calculated using '2, z'2) and (x'3, y'3, z'3).

  Prior to the calculation of this coordinate conversion function CA, this type of coordinate conversion will be briefly described. First, the first coordinate system composed of XYZ coordinates and the first coordinate system are rotated by xθ, yθ, zθ around the X, Y, and Z axes, respectively, and the origin of the first coordinate system Is assumed to be a second coordinate system that is moved by a, b, and c in the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively. Also in this case, if the coordinate of one point in the first coordinate system is (x, y, z) and the coordinate of the same point in the second coordinate system is (x ′, y ′, z ′), the following equation 5 is established. In addition, the matrix M in the equation 5 is represented by the following equation 6.

The calculation of the coordinate transformation function CA in step S308 is performed by calculating the matrix values g ₁₁ , g ₁₂ , g ₁₃ , g ₂₁ , g ₂₂ , g ₂₃ , g ₃₁ , g ₃₂ , g ₃₃ and the matrix in the above formulas 5 and 6. Means that the values a, b, c are calculated. In this case, the camera coordinate system of the present embodiment corresponds to the first coordinate system, and the arm coordinate system corresponds to the second coordinate system. Therefore, the center coordinates (x1, y1, z1), (x2, y2, z2), (x3, y3, z3) of the reference sphere 80 in the camera coordinate system for each measurement position, and the reference sphere 80 in the arm coordinate system. The central coordinates (x′1, y′1, z′1), (x′2, y′2, z′2), and (x′3, y′3, z′3) of When applied, the following relationships 7 to 9 are established.

  When the above Equation 7 is modified, the following simultaneous equations of Equation 10 are established.

  Here, the normal vector of the plane including the fixed point coordinates (x1, y1, z1), (x2, y2, z2), (x3, y3, z3) is (α, β, γ), and the fixed point coordinates (x ′ 1, y′1, z′1), (x′2, y′2, z′2), (x′3, y′3, z′3) and the normal vector of the plane including (α ′, If β ′ and γ ′), the following equation 11 is established if the magnitudes and directions of the two normal vectors are the same. The matrix M in the equation 11 is expressed by the above equation 6.

  The normal vector of the plane including the fixed point coordinates (x1, y1, z1), (x2, y2, z2), (x3, y3, z3) is directed from (x2, y2, z2) to (x1, y1, z1) The normal vector (α, β, γ) is expressed by the following equation (12), assuming that the vector is a vector formed by the outer product of the vector and the vector from (x3, y3, z3) to (x2, y2, z2).

  Similarly, the vector (α ′, β ′, γ ′) is expressed by the following equation (13).

  Substituting Equation 12 and Equation 13 into Equation 11 yields Equation 14 below.

  If the first equation of the above equation 14 is added to the above equation 10, the following simultaneous equations of the following equation 15 are obtained.

The matrix values g ₁₁ , g ₁₂ , and g ₁₃ can be calculated by solving the simultaneous equations of Formula 15. Also, the above equations 8 and 9 are also transformed into the simultaneous equations of the above equation 10, and the matrix value g ₂₁ is obtained by solving the simultaneous equations obtained by adding the second and third equations of the above equation 14, respectively. , G ₂₂ , g ₂₃ and matrix values g ₃₁ , g ₃₂ , g ₃₃ can be calculated. Then, by substituting these calculated matrix values into the above formulas 7 to 9, matrix values a, b, and c can be calculated. Thereby, the coordinate conversion function CA for converting the coordinate value (x, y, z) in the camera coordinate system into the coordinate value (x ′, y ′, z ′) in the arm coordinate system is calculated.

Next, at step S310, the matrix value _g 11 of a coordinate transformation function CA that the _{calculated, g 12, g 13, g} 21, g 22, g 23, g 31, g 32, g 33, a, b, c Is stored in the memory device of the three-dimensional image processing device 42, and in step S312, the execution of the coordinate transformation function calculation program is terminated. Then, the worker removes the reference sphere 80 from the base 10 and finishes the operation of acquiring the coordinate conversion function CA.

  Next, the operator performs an operation of acquiring a correction data group for correcting a difference between the tip position of the fourth arm 26 instructed by the controller 41 and the actual tip position of the fourth arm 26. Specifically, the operator places the calibration jig 50 at an appropriate position on the base 10 and expands / contracts the support column 54 in the vertical direction to set the height of the calibration object support base 52 to the calibration. The height is set to one of the heights set in S104 of the object information acquisition program. Then, the operator operates the input device 43 to instruct the three-dimensional image processing device 42 to execute the correction data group acquisition program shown in FIG. In response to this instruction, the three-dimensional image processing apparatus 42 starts executing the correction data group acquisition program in step S400, and sets the reference position in step S402.

  In setting the reference position, as shown in FIG. 10, the operator selects an arbitrary sphere set 53 among the N sphere sets 53 in the calibration jig 50 as the reference sphere set, and operates the input device 43. The three-dimensional shape measuring apparatus 30 is positioned at a position facing the reference sphere set, and the same position is set as a reference position. As a result, the three-dimensional image processing device 42 stores coordinates representing a predetermined position of the tip of the fourth arm 26, that is, coordinates representing the origin of the arm coordinate system by the reference coordinate system as the reference position, A rotation angle representing the orientation of each coordinate axis of the arm coordinate system with respect to the coordinate axis of the reference coordinate system is stored as a reference rotation angle. In addition, the operator operates the input device 43 and, among the calibration object information for each sphere set 53 stored in the three-dimensional image processing device 42, the calibration object information regarding the sphere set selected as the reference sphere set. Numbers (1 to N) are designated as reference sphere set information.

  Next, in step S404, the three-dimensional image processing device 42 measures the reference sphere set three-dimensionally. The three-dimensional image processing device 42 controls the operation of the three-dimensional shape measuring device 30 in response to an instruction to start measurement by the operator, and starts measuring the reference sphere set facing the three-dimensional shape measuring device 30. . The three-dimensional shape measurement device 30 outputs information representing the three-dimensional shape of the reference sphere set located in the measurement target space to the three-dimensional image processing device 42. In other words, information (specifically, inclinations θx, θy and distance Lz) regarding the XYZ coordinates representing the divided area positions obtained by dividing the surface of the reference sphere set into minute areas is given to the three-dimensional image processing device 42. Output. Then, in step S404, the three-dimensional image processing device 42, based on the information about the XYZ coordinates output from the three-dimensional shape measuring device 30, in the same manner as in step S302, Three-dimensional image data including a three-dimensional shape data group representing a three-dimensional shape is calculated. In this case, the three-dimensional image data is represented by a coordinate system related to the three-dimensional shape measuring apparatus 30, that is, a camera coordinate system. In addition to the reference sphere set, the 3D image data also includes 3D image data representing the surface shape of other objects existing around the reference sphere set such as the wires 53c and 53d and other sphere sets 53. It is.

  Next, in step S406, the three-dimensional image processing device 42 extracts three-dimensional image data representing the three-dimensional shape of the calibration object, that is, the sphere 51, from the three-dimensional image data calculated in step S404. To do. Specifically, execution of the calibration object extraction subprogram shown in FIG. 11 is started in step S500, and input of characteristics of the calibration object is awaited in step S502. When the operator inputs the characteristics of the calibration object via the input device 43, the input information is supplied to the three-dimensional image processing device. In this case, the feature of the calibration object is data indicating that the sphere 51 that is the calibration object is a sphere. If it is already input that the calibration object is a sphere, the process of step S502 may be skipped.

  Next, in step S504, the three-dimensional image processing apparatus 42 calculates the radius of the sphere in the calibration object information corresponding to the input feature of the calibration object and the number relating to the sphere set 53 input in step S402. Is used to execute unit block and search block size setting processing. In this embodiment, the radius of the sphere is about 12.5 mm, that is, about 25 mm in diameter. The unit block is the minimum block for moving the search block in order to specify the position of the sphere 51 that is the calibration object. In this embodiment, the unit block is formed in a cube, but may have other shapes such as a rectangular parallelepiped. . Further, the size of the unit block is set to be small to some extent so that it can be confirmed that a part of the sphere 51 exists. The search block is used for specifying a position where the sphere 51 is included, and is formed in a cube in the present embodiment, but may be another shape such as a rectangular parallelepiped. The size of this search block can be set to be as small as possible while including all of the spheres 51. However, being able to include the sphere 51 means including all of the unit blocks including a part of the sphere 51.

  In this embodiment, since the diameter of the sphere 51 is about 25 mm, the length of one side of the cube is set to 4 mm as the unit block size and the size of the search block is 1 mm. A side length of 32 mm is set. According to this, the search block includes 8 × 8 × 8 unit blocks, 24 mm of 25 mm in diameter is completely included in 6 unit blocks, and the remaining 1 mm is 1 or 2 It is included in the unit block. FIG. 12 is a perspective view showing the relationship between the unit block and the search block. Further, in this step S504, the unit block and the search block size are set. However, if the sphere 51 is not changed, the preset unit block and search block size may be used as they are. The process of step S504 is not necessary.

  Next, the three-dimensional image processing apparatus 32 executes search area blocking processing in step S506. The search area blocking process is a process of dividing an area that may contain the sphere 51 in the measurement target space into unit blocks. Basically, based on the three-dimensional image data related to the sphere 51, the space where the three-dimensional image data exists in the measurement target space is three-dimensionally divided into unit blocks. The division is performed by a method of arranging unit blocks along the coordinate axes of the X, Y, and Z coordinates. FIG. 13 is a two-dimensional conceptual diagram showing a result of performing this processing based on the three-dimensional image data related to the reference sphere set placed in the measurement target space of FIG. FIG. 13 shows the size of the unit block larger than the actual size for easy understanding. In FIG. 13, a two-dot chain line indicates a boundary (measurement target region) in the measurement target space. Each unit block BL after division is represented by coordinates (i, j, k) using positions i, j, k in the X, Y, and Z directions. However, each value of i, j, and k is an integer. Note that, in the search area blocking processing in step S506, a continuous area where the sphere 51 does not exist, that is, a continuous area that does not include the three-dimensional image data related to the sphere 51 is excluded from the divided area by the unit block. You may make it perform the division | segmentation by a unit block over the whole area | region.

  Next, in step S508, the three-dimensional image processing apparatus 42 checks whether there is a predetermined number or more of three-dimensional image data for each unit block divided by the processing in step S506. Then, a unit block having a predetermined number or more of three-dimensional image data is extracted. FIGS. 14A to 14D are conceptual diagrams when the extracted unit blocks are viewed from the Z-axis direction with a viewpoint on the three-dimensional shape measuring apparatus 30. However, the outer frame corresponds to the search block, and is a unit block from which hatched portions are extracted.

  Next, the three-dimensional image processing apparatus 32 detects a search block position that may include the sphere 51 in step S510. In this search block position detection process, the search block set by the process of step S504 in the region divided into unit blocks by the process of step S506, with the unit block as a unit, the X axis, the Y axis, and the Z axis Move sequentially in the direction. Then, for each movement, the number of unit blocks included in the search block after movement and extracted by the process of step S508 is calculated. If the number of unit blocks is within a predetermined range, the same position is detected as the corresponding search block position. FIGS. 15A to 15D are conceptual diagrams two-dimensionally showing the movement state of the search block.

  In this case, since the sphere 51 is a sphere, it is located on the side facing the 3D shape measuring device 30 and 3D image data can be obtained, and located on the side not facing the 3D shape measuring device 30. Since the ratio of the places where the dimensional image data cannot be obtained is substantially the same, the number of unit blocks included in the search block is set if the diameter of the sphere is specified. As a result, if the sphere shown in FIG. 14A is the sphere 51, the sphere having a diameter smaller than that of the sphere 51 as shown in FIG. 14B is excluded as the number of unit blocks is outside the predetermined range. Can do.

  However, in the case of a sphere having a diameter larger than the sphere 51 as shown in FIG. 14C, the number of unit blocks extracted depending on the position of the search block may fall within a predetermined range. Detected as In addition, as shown in FIG. 11D, when a frame 52a that is an object other than the sphere 51 is included in the search block, the number of unit blocks may be detected as being within a predetermined range. For this reason, instead of or in addition to the number of unit blocks including a predetermined number or more of the three-dimensional image data, objects other than the sphere 51 may be excluded if the corresponding search block position is extracted based on the distribution of the unit blocks. it can.

  Specifically, as shown in FIG. 14, when the search block is viewed from the three-dimensional shape measuring apparatus 30 (that is, viewed from the Z-axis direction), the location where the unit block is extracted on any surface in the Z-axis direction As a unit block extracted in the plane of the X and Y axes, the search block position is detected on the condition that the number extracted in each column of the unit blocks in the plane of the X and Y axes is within the set number range. That's fine. In this way, if FIG. 14A shows a sphere 51, a sphere having a diameter different from that of the sphere 51 as shown in FIGS. 14B and 14C, or as shown in FIG. 14D. An object such as a frame 52a other than the sphere 51 can be excluded as the number extracted in each column of unit blocks on the plane of the X and Y axes is outside the set number range. Further, it is a condition that the unit blocks obtained by extracting the objects detected in the processing in the X, Z plane or the Y, Z plane in each row in the X, Y axis plane unit block are distributed in a circular shape. If the additional detection is performed, it is possible to exclude those detected because the cylinder or the cone has the same diameter and the central axis faces the Z-axis direction.

  Next, in step S512, the three-dimensional image processing device 42 determines whether or not the three-dimensional image data included in the search block at the position detected by the processing in step S510 matches the shape of the sphere 51. When it is determined that they match, a 3D image data extraction process for extracting 3D image data in the search block is performed.

  Specifically, all the three-dimensional image data (X, Y, Z coordinate values) in the corresponding search block are respectively substituted into X, Y, Z on the left side of the above equation 1 representing a sphere, The unknowns a, b, c, and d are calculated using the least square method. In this case, a, b, and c represent the x, y, and z coordinate values of the sphere center represented by the three-dimensional image data, respectively, and d represents the radius of the sphere. Next, for each 3D image data (X, Y, Z coordinate value) in the corresponding search block, the 3D image data (X, Y, Z coordinate value) and the calculated values a, b, By substituting c into Equation 1, a value d (distance from the center of the sphere) is calculated for each three-dimensional image data. The difference between the calculated value d (the radius of the sphere) and the diameter of the input sphere 51 divided by “2”, that is, the radius of the sphere 51 is within a predetermined discriminant value, and each three-dimensional If the deviation of the distance from the sphere center of the image data is within a predetermined discriminant value, the three-dimensional image data in the search block agrees and the sphere center (X, Y, Z based on the three-dimensional image data is matched. Coordinate value) and radius d of the sphere are stored as extracted sphere data. On the other hand, if the difference or deviation is not within a predetermined discriminant value, the extracted sphere data is not stored because the 3D image data in the search block does not match. After the process of step S512, the execution of the calibration object extraction subprogram is terminated in step S514, and the process returns to step S408 of the correction data group acquisition program.

Next, in step S408, the three-dimensional image processing device 42 extracts extracted sphere data related to the three spheres 51 constituting the reference sphere set from the stored extracted sphere data. Processing for extracting the reference sphere set ing from the processing of the next sub-step 1-3.

Sub-step 1: The spheres that match the radii R _mA , R _mB , R _{mC of the} three spheres 51 constituting the reference sphere set in the reference sphere set information stored in the three-dimensional image processing device 42 within a predetermined discriminant value. Extracted sphere data having a radius d is extracted. In this case, as described above, the diameter of each sphere 51 is set to approximately 25 mm, but the diameter of each sphere 52 is different from each other. For this reason, if the extracted sphere data having the radius d of the sphere that coincides with the radius R _mA , R _mB , R _mC of each of the three spheres 51 in the reference sphere set information within a predetermined discrimination value is extracted, the reference sphere set is obtained. Extracted sphere data respectively corresponding to the three spheres 51 constituting the image can be extracted.

Sub-step 2: The center-to-center distance L of the sphere 51 represented by each extracted sphere data is calculated using each sphere center (X, Y, Z coordinate values) in the extracted sphere data extracted in sub-step 1, respectively. A combination of two spheres 51 having the calculated center distance L within a predetermined range is extracted. Here, “within a predetermined range” refers to a range of distances that substantially match the distances between the centers of the three spheres 51 constituting the sphere set 53. Thereby, the combination of the spheres 51 between the other sphere sets 53 can be removed. Then, among the extracted combinations of the two spheres 51, the center distance L that matches the three center distances L _mAB , L _mBC , and L _mCA of each sphere 51 in the reference sphere set information within a predetermined discrimination value. A combination of two spheres 51 having _{c 1} , L _c2 and L _c3 (“c” represents a camera coordinate system) is further extracted. As a result, three extracted sphere data representing the three spheres 51 constituting the reference sphere set are extracted.

Sub-step 3: Specify which of the three spheres 51 in the reference sphere set each of the three extracted sphere data corresponds to, and store the three extracted sphere data specified as the reference sphere data. Each extracted sphere data is specified using the radius d of each of the three spheres in the extracted sphere data and the center distances L _c1 , L _c2 , and L _c3 of the sphere 51 represented by the extracted sphere data. Note that the sphere center coordinates C _cA , C _cB , and C _cC of the three spheres in the extracted sphere data correspond to the reference calibration object straight line definition parameter according to the present invention.

Next, in step S410, the three-dimensional image processing device 42 uses the coordinate values represented by the camera coordinate system, which is the coordinate system related to the three-dimensional shape measuring device 30, and sets the orientation of each coordinate axis of the camera coordinate system to three-dimensional. Coordinate conversion function for coordinate conversion to the coordinate value of the CM coordinate system, which is the coordinate system in which the origin coordinate is made the origin coordinate of the arm coordinate system by matching the direction of each coordinate axis of the measurement machine coordinate system which is the coordinate system related to the measurement machine 60 Gd _CM is calculated. Specifically, the coordinate values of the sphere center coordinates C _cA , C _cB , C _cC of each sphere 51 in the reference sphere data representing the three spheres 51 constituting the reference sphere set extracted in step S408. (CX _cA , CY _cA , CZ _cA ) (CX _cB , CY _cB , CZ _cB ) (CX _cC , CY _cC , CZ _cC ), and 3 corresponding to the spherical center coordinates C _cA , C _cB , C _cC , respectively. The coordinate values of the sphere center coordinates C _mA , C _mB , C _mC of each sphere 51 in the reference sphere set information stored in the two-dimensional image processing device 42 are (CX _mA , CY _mA , CZ _mA ) (CX _mB , CY _{mB, CZ mB) (CX mC} , CY mC, CZ mC) and if the sphere center _{C mA} vector toward the spherical center _{C mB} from _{V CMAB,} spheres Center _{C mA} from the sphere center _{C mC-going} vector _{V CMAC,} the sphere center _{C cA} from the sphere center _{C cB-going} vector _{V CcAB,} vector _{V CCAC} directed from the sphere center _{C cA} a sphere center _{C cC} are each below the number 16 It is represented by the formula shown.

The vector V _Cm by the outer product of the vector V _CmAB and the vector V _CmAC in the above _equation 16 and the vector V _Cc by the outer product of the vector V _CcAB and the vector V _CcAC are expressed by the following equation 17 in each coordinate system.

Further, an equation for converting a vector (α _C , β _C , γ _C ) in the camera coordinate system into a vector (α _M , β _M , γ _M ) in the measuring machine coordinate system is expressed by the following equation (18). . In the following formula 18, M is a coordinate conversion function.

Substituting the coordinate components of the vectors V _CcAB , V _CcAC , and V _Cc in the equations shown in the equations 16 and 17 into (α _C , β _C , γ _C ) in the equation shown in the equation 18, the equation 18 Substituting the coordinate components of the vectors V _CmAB , V _CmAC , and V _Cm in the equations shown in Equation 16 and Equation 17 into (α _M , β _M , γ _M ) in the equation shown in FIG. There are three simultaneous equations.

The values g _{11 to} g ₃₃ of the coordinate transformation function M can be calculated by solving the three simultaneous equations shown in the above equation 19. This coordinate conversion function M is the rotation part Md _CM of the coordinate axis in the coordinate conversion function Gd _CM for converting the coordinate value represented by the camera coordinate system into the coordinate value by the CM coordinate system. The origin coordinate movement part is the same as the origin coordinate movement part (a, b, c in Equation 5 above) of the coordinate conversion function CA calculated by executing the coordinate conversion function calculation program. However, the coordinate transformation in this case, after the movement of the origin coordinate, for performing rotation of the coordinate axes, the coordinate transformation function Gd _CM is Ru formula der represented by Equation 3.

Next, three-dimensional image processing apparatus 42, at step S412, calculates a reference fixed point coordinates _{Td CM} in CM coordinate system. The reference fixed point coordinate Td _CM is a coordinate value representing the reference fixed point coordinate Td representing the center position on the arrangement of the three spheres 51 constituting the reference sphere set by the CM coordinate system. The reference fixed point coordinates Td _C representing the reference fixed point coordinates Td by the camera coordinate system are coordinate values (CX) of the sphere center coordinates C _cA , C _cB , C _cC of the three spheres 51 as shown in the following equation 20. _cA , CY _cA , CZ _cA ) (CX _cB , CY _cB , CZ _cB ) (CX _cC , CY _cC , CZ _cC ) can be averaged for each coordinate value.

Then, the reference fixed point coordinates Td _CM in the CM coordinate system can be calculated by performing coordinate conversion of the fixed point coordinates Td _C calculated by the equation shown in the equation 20 using the coordinate conversion function Gd _CM calculated in step S410. it can. Next, in step S414, the three-dimensional image processing device 42 converts the coordinate values of the sphere center coordinates of the three spheres 51 constituting the reference sphere set into coordinate values based on the reference coordinate system that is a coordinate system related to the articulated robot. Convert coordinates. Specifically, the coordinate values of the sphere center coordinates C _cA , C _cB , C _cC of the three spheres 51 in the reference sphere data are converted by the coordinate conversion function CA calculated by the execution of the coordinate conversion function calculation program. The coordinates are converted into coordinate values of the sphere center coordinates C _aA , C _aB , and C _aC (“a” represents the arm coordinate system) represented by the arm coordinate system. Then, the three-dimensional image processing device 42 converts the coordinate values of the spherical center coordinates C _aA , C _aB , and C _aC represented by the arm coordinate system into coordinate values in the reference coordinate system. In this case, the coordinates of the origin of the arm coordinate system in the reference coordinate system and the rotation angle representing the orientation of each coordinate axis of the arm coordinate system with respect to the coordinate axis of the reference coordinate system are stored in step S402, so the three-dimensional image processing apparatus 42 substitutes the coordinates of this origin into a, b, c of the above equation 3 and the rotation angle into α, β, γ of the above equation 4, and the coordinates of the sphere center represented by the arm coordinate system as the above equation 3. By substituting x ', y', and z 'of the above equation and calculating x, y, and z of Equation 3, the spherical center coordinates C _dA , C _dB , and C _dC in the reference coordinate system ("d" is the reference coordinate Ru can be calculated representing the system).

Next, in step S416, the three-dimensional image processing apparatus 42 uses the coordinate values represented by the reference coordinate system, which is a coordinate system related to the articulated robot, and sets the orientation of each coordinate axis of the reference coordinate system to the three-dimensional measuring machine 60. A coordinate conversion function G _DM for coordinate conversion to coordinate values of the DM coordinate system, which is a coordinate system that is matched with the orientation of each coordinate axis of the measuring machine coordinate system, which is a coordinate system related to, is calculated. Specifically, the coordinate values (CX _dA , CY _{dA) of the} sphere center coordinates C _dA , C _dB , C _dC of the three spheres 51 constituting the reference sphere set in the reference coordinate system calculated in step S414. , CZ _dA ) (CX _dB , CY _dB , CZ _dB ) (CX _dC , CY _dC , CZ _dC ) are the coordinates of the sphere center coordinates C _cA , C _cB , C _cC of each sphere 51 in the above _equations 16 to 19. Values (CX _cA , CY _cA , CZ _cA ) (CX _cB , CY _cB , CZ _cB ) (CX _cC , CY _cC , CZ _cC ), which correspond to the spherical center coordinates C _dA , C _dB , and C _dC , respectively. each sphere center coordinates _C mA of the spherical bodies 51 in the reference sphere set information stored in the dimension image processing apparatus _42, C _mB, the coordinate values of _{C mC (CX} mA, CY _{m , CZ mA) (CX mB,} CY mB, CZ mB) (CX mC, CY mC, if _{CZ mC),} similarly to the calculation of the rotating part of the coordinate axis of the coordinate transformation function _{Gd CM} at the step S410, the number of The coordinate conversion function G _DM can be calculated using 16 to Equation 19.

Next, in step S418, the three-dimensional image processing device 42 calculates the coordinates Td _dm of the reference fixed point in the DM coordinate system. Specifically, the coordinate values (CX _dA , CY _dA , CZ _dA ) (CX _dB , CY _dB ) of the sphere center coordinates C _dA , C _dB , C _dC transformed into the reference coordinate system in step S414 are described. By substituting CZ _dB ) (CX _dC , CY _dC , CZ _cC ) into the equation shown in Equation 21 below, the coordinate Td _d of the reference fixed point in the reference coordinate system is calculated.

Then, to calculate the coordinates Td _dm reference fixed point in the DM coordinate system by multiplying the calculated coordinates transformation function G _DM in the in coordinate Td _d step S416 of the reference fixed point calculated by the equation shown in the equation 21 be able to. In this case, the reference fixed point coordinate Td _d in the reference coordinate system is stored together with the reference fixed point coordinate Td _dm in the DM coordinate system for use in processing to be described later.

Next, in step S420, the three-dimensional image processing apparatus 42 waits for designation of a sphere set to be the next measurement target. The operator operates the input device 43 to input a sphere set number i (i = 1 to N) (see FIG. 5) representing the sphere set 53 to be measured next. In this case, the sphere set 53 designated as the next measurement target is a sphere set other than the reference sphere set, and is a measurement target sphere set for measuring the positional relationship with respect to the reference sphere set. In step S422, the three-dimensional image processing apparatus 42 moves the three-dimensional shape measuring apparatus 30 to a position facing the measurement target sphere set specified in step S420. In this case, the coordinate value in the reference coordinate system of the position to move the three-dimensional shape measuring apparatus 30 (that is, the position to move the tip of the arm support mechanism 20) is calculated by the following sub-step 1 to sub-step 3. Ru is.

Substep 1: Calculate the fixed point coordinates Tn _dm (n = 1) of the sphere set to be measured in the DM coordinate system. Specifically, as shown in the following Equation 22, among the calibration object information stored in the three-dimensional image processing device 42, the coordinate value (TX _m) of the fixed point coordinate T _m corresponding to the measurement target sphere set. , _TY m, the TZ _m), respective coordinate values of the fixed point coordinates Td _m in the reference sphere set information designated from among the calibration object information _{(TdX m,} TdY _m, the difference between the TDZ _m), the step Calculation is performed by adding to the coordinate values (TdX _dm , TdY _dm , TdZ _dm ) of the coordinates Td _dm of the reference fixed point in the DM coordinate system calculated in S418. In this case, fixed point coordinate T _m and fixed point coordinates Td _m stored in the three-dimensional image processing apparatus 42 are represented by the measuring machine coordinate system, but fixed point coordinates T1 _dm is represented by DM coordinate system, measured Since the machine coordinate system and the DM coordinate system have the same direction of the coordinate axes, these coordinate values can be added and subtracted for calculation.

Substep 2: a coordinate conversion of fixed point coordinates T1 _d represented by the reference coordinate system the fixed point coordinates T1 _dm represented by DM coordinate system. More specifically, the conversion by multiplying the coordinate transformation function _{G MD} is an inverse function (inverse) of the coordinate transformation function _{G DM} calculated in the step S416 to the fixed point coordinates _{T1 dm.} Here, the coordinate transformation function G _DM converts the coordinate value represented by the reference coordinate system into the coordinate value of the DM coordinate system in which the direction of each coordinate axis in the reference coordinate system is matched with the direction of each coordinate axis in the measuring machine coordinate system. a conversion function for coordinate transformation, the coordinate transformation function G _MD is an inverse function of the coordinate transformation function G _DM will coordinate transformation coordinate value expressed by the DM coordinate system into coordinate values by the original reference coordinate system Is a conversion function.

Sub-step 3: The coordinate values (X1 _d , Y1 _d , Z1 _d ) in the reference coordinate system for moving the three-dimensional shape measuring apparatus 30 are calculated. Specifically, as shown in Equation 23 below, each coordinate value (T1X _d , T1Y _{d )} of the fixed point coordinate T1 _d of the sphere set 53 that is the next measurement target in the reference coordinate system converted in the sub-step 2 is used. , T1Z _d ) and the coordinate values (TdX _d , TdY _d , TdZ _d ) of the reference fixed point coordinates Td _d in the reference coordinate system stored in step S418, the three-dimensional image processing is performed in step S402. coordinate value in the reference coordinate system of the origin of the arm coordinate system stored in the device 42, i.e., the position of the reference coordinate system of the origin of the arm coordinate system at the time of the reference sphere set was measured (reference position) each coordinates of BP _d Calculation is performed by adding to the values (BPX _d , BPY _d , BPZ _d ). In this case, since the fixed point coordinates T1 _d , the reference fixed point coordinates Td _d and the reference position coordinates BP _d are all represented by the reference coordinate system, they can be calculated by adding and subtracting coordinate values.

  Next, in step S424, the three-dimensional image processing device 42 performs three-dimensional measurement of the measurement target sphere set. The three-dimensional measurement of the measurement target sphere set is the same as in step S404. That is, the three-dimensional image processing device 42 controls the operation of the three-dimensional shape measuring device 30 in response to an instruction to start measurement by the operator, and a sphere set 53 (measured object) facing the three-dimensional shape measuring device 30. The measurement of the target sphere set) is started. The three-dimensional shape measurement apparatus 30 outputs information representing the three-dimensional shape of the sphere set 53 located in the measurement target space to the three-dimensional image processing apparatus 42. Then, in the same manner as in step S302, based on the information about the XYZ coordinates output from the three-dimensional shape measuring apparatus 30, a three-dimensional image composed of a three-dimensional shape data group representing the three-dimensional shape of the sphere set 53. Calculate the data. Note that this three-dimensional image data is represented by a camera coordinate system. The three-dimensional image data represents the surface shape of other objects existing around the sphere set 53 as the measurement target, such as the wires 53c and 53d and other sphere sets 53, in addition to the sphere set to be measured. Dimensional image data is also included.

  Next, in step S426, the three-dimensional image processing device 42 extracts three-dimensional image data representing the three-dimensional shape of the sphere 51 from the three-dimensional image data calculated in step S424. The extraction process of the three-dimensional image data representing the sphere 51 is performed by executing the calibration object extraction subprogram shown in FIG. In steps S502 and S504 in the calibration object extraction subprogram, the calibration object feature, unit block size, and search block size executed in step S406 may be used. Skip each step. By the processing in step S426, three-dimensional image data representing the three-dimensional shape of the sphere 51 including the three spheres 51 constituting the sphere set 53 that is the measurement target is extracted as extracted sphere data.

Next, in step S428, the three-dimensional image processing device 42 extracts extracted sphere data related to the three spheres 51 constituting the measurement target sphere set from the extracted extracted sphere data. Processing of extracting the object to be measured spheres set, similarly to the step S408, ing from the processing of the next sub-step 1-3.

Sub-step 1: Among the calibration object information stored in the three-dimensional image processing device 42, each radius R _mA , of the sphere set 53 input in step 420, that is, the three spheres 51 constituting the measurement target sphere set, Extracted sphere data having a radius d of a sphere that matches R _mB and R _mC within a predetermined discriminant value is extracted.

Sub-step 2: Using the sphere center (X, Y, Z coordinate values) in the extracted sphere data extracted in sub-step 1, the center-to-center distance L of the sphere 51 represented by each extracted sphere data is calculated. A combination of two spheres 51 in which the center-to-center distance L is within a predetermined range is extracted. Here, the predetermined range is a range of distances that substantially coincide with the distances between the centers of the three spheres 51 constituting the sphere set 53. Thereby, the combination of the spheres 51 between the other sphere sets 53 can be removed. Then, from the extracted combination of the two spheres 51, the centers that coincide with the three center distances L _mAB , L _mBC , and L _mCA between the spheres 51 in the measurement target sphere set within a predetermined discrimination value. A combination of two spheres 51 having inter-distances L _c1 , L _c2 , and L _c3 is further extracted. As a result, three extracted sphere data representing the three spheres 51 constituting the measurement target sphere set are extracted.

Sub-step 3: It is specified which of the three extracted sphere data the three extracted sphere data correspond to the three spheres 51 in the measurement target sphere set, and the three extracted sphere data thus specified are measured object sphere data. Remember as. Each extracted sphere data is specified using the radius d of each of the three spheres in the extracted sphere data and the center distances L _c1 , L _c2 , and L _c3 of the sphere 51 represented by the extracted sphere data. Note that the sphere center coordinates C _cA , C _cB , and C _cC of the three spheres in the extracted sphere data correspond to the measurement object calibration object straight line definition parameters according to the present invention.

Next, three-dimensional image processing apparatus 42, at step S430, calculates a coordinate transformation function _{Gs CM.} The coordinate conversion function Gs _CM is a coordinate value expressed by a camera coordinate system, which is a coordinate system related to the three-dimensional shape measuring apparatus 30, and a direction of each coordinate axis of the camera coordinate system is a coordinate machine related to the three-dimensional measurement device 60. This is a coordinate conversion function for converting the coordinates into the coordinate values of the CM coordinate system, which is the coordinate system in which the origin coordinates are made the origin coordinates of the arm coordinate system by matching the direction of each coordinate axis of the coordinate system, and the coordinate conversion function in step S410 the same coordinate transformation function and gd _CM. In this case, the coordinate values of the sphere center coordinates C _cA , C _cB , C _cC of each sphere 51 in the measurement target sphere data extracted in step S428 are represented by (CX _cA , CY _cA , CZ _cA ) (CX _cB ). , CY _cB , CZ _cB ) (CX _cC , CY _cC , CZ _cC ), and the calibration object information stored in the three-dimensional image processing device 42 corresponding to the spherical center coordinates C _cA , C _cB , C _cC respectively. Each coordinate value of each sphere center coordinate C _mA , C _mB , C _mC of each sphere 51 is expressed as (CX _mA , CY _mA , CZ _mA ) (CX _mB , CY _mB , CZ _mB ) (CX _mC , CY _mC , CZ _mC). ), The rotation part Ms _CM of the coordinate axis of the coordinate conversion function Gs _CM can be calculated in the same manner as in step S410. The moving parts of the same origin coordinates and the step S410 is a mobile part of the origin coordinate of the coordinate transformation function CA, coordinate transformation function Gd _CM is Ru formula der represented by Equation 3.

Next, in step S432, the three-dimensional image processing device 42 calculates a measurement target fixed point coordinate T1 _cm representing the fixed point coordinate T1 of the measurement target sphere set in the CM coordinate system. The coordinate values of the sphere center coordinates C _cA , C _cB , C _cC of the three spheres 51 constituting the measurement target sphere set are expressed as (CX _cA , CY _cA , CZ _cA ) (CX _cB , CY _cB , CZ _cB ). Assuming that (CX _cC , CY _cC , CZ _cC ), the fixed point coordinate T1 _c in the camera coordinate system can be calculated by the equation shown in the above equation 20 in the same manner as in step S412. Then, the measurement target fixed point coordinate T1 _CM in the CM coordinate system is calculated by performing coordinate conversion of the fixed point coordinate T1 _c calculated by the equation shown in the above equation 20 by the coordinate conversion function Gs _CM calculated in step S430. It is Ru can.

Next, the three-dimensional image processing device 42 calculates a positioning error E _Ccm in step S434. The positioning error E _Ccm is the difference between the position of the movement destination of the three-dimensional shape measuring apparatus 30 indicated by the controller 41 and the position where the three-dimensional shape measuring apparatus 30 is actually positioned, and is indicated by the controller 41. This is the difference between the coordinates of the destination of the tip of the fourth arm 26 and the coordinates of the position where the tip of the fourth arm 26 is actually positioned. This positioning error E _Ccm is calculated from the coordinate values (T1X _cm , T1Y _cm , T1Z _cm ) of the measurement target fixed point coordinates T1 _cm of the measurement target sphere set in the CM coordinate system as shown in the following equation 24 Is calculated by subtracting the coordinate values (TdX _cm , TdY _cm , TdZ _cm ) of the reference fixed point coordinates Td _cm of the reference sphere set at.

In this case, the CM coordinate system is a coordinate system in which the direction of the coordinate axis coincides with the direction of the coordinate axis of the measuring machine coordinate system and the origin coordinate is set to the origin coordinate of the arm coordinate system, and moves with the movement of the three-dimensional shape measuring apparatus 30. It is a coordinate system. Therefore, if there is no difference between the position of the movement destination of the 3D shape measuring apparatus 30 instructed by the controller 41 and the position where the 3D shape measuring apparatus 30 is actually positioned, that is, the 3D shape measuring apparatus. If 30 is accurately positioned, the position of the movement destination of the three-dimensional shape measuring apparatus 30 instructed by the controller 41 in step S422 goes from the reference fixed point in the reference sphere set to the fixed point in the measurement target sphere set. Since the position is moved from the reference position by the vector, the positioning error E _Ccm is “0”.

On the other hand, when the three-dimensional shape measuring apparatus 30 is not accurately positioned, the movement destination position of the three-dimensional shape measuring apparatus 30 indicated by the controller 41 and the position where the three-dimensional shape measuring apparatus 30 is actually positioned are A difference occurs between the two, and the difference becomes a positioning error E _Ccm . In this case, the reference fixed point coordinate Td _c in the camera coordinate system and the measurement target fixed point coordinate T1 _c are not directly compared, and the reference fixed point coordinate Td _CM and the measurement target fixed point coordinate T1 _CM in the CM coordinate system are compared. This is for discriminating whether or not the positioning error of the three-dimensional shape measuring apparatus 30 is caused by a deviation related to the direction of the three-dimensional shape measuring apparatus 30. Next, the three-dimensional image processing apparatus 42 multiplies the positioning error E _Ccm calculated by the equation shown in the above equation 24 by a coordinate conversion function G _MD that is an inverse function of the coordinate conversion function G _DM calculated in step S416. Then, the positioning error E _Ccm is coordinate-converted into a positioning error E _Cd represented by the reference coordinate system.

Next, the three-dimensional image processing apparatus 42 stores the coordinate correction data RD in step S436. The coordinate correction data RD is a correction value for correcting the positioning error E _Cd . Specifically, a value obtained by reversing the sign of the positioning error E _Cd represented by the reference coordinate system is stored as the coordinate correction data RD. Next, three-dimensional image processing apparatus 42, at step S438, calculates a rotational deviation _{E D.} The rotational deviation E _D is the difference between the direction of the three-dimensional shape measuring apparatus 30 instructed by the controller 41 and the direction of the three-dimensional shape measuring apparatus 30 when the three-dimensional shape measuring apparatus 30 is actually positioned. In other words, the direction of the coordinate axis of the arm coordinate system at the movement destination of the tip of the fourth arm 26 instructed by the controller 41, and when the tip of the fourth arm 26 is actually positioned. This is a deviation from the direction of the coordinate axis of the arm coordinate system. Specifically, rotation of the coordinate axes of the coordinate transformation function _{Gd CM} that is an inverse function with rotating parts _{Ms MC} calculated in the step S410 of rotating parts _{Ms CM} axes of the coordinate transformation function _{Gs CM} calculated at the step S430 calculating a multiplication value of the partial _{Md CM} as rotational deviation _{E D.}

Rotating part Ms _CM axes of the coordinate transformation function Gs _CM calculated at the step S430, the coordinates for the three-dimensional shape measurement device 30 for definitive a three-dimensional shape measurement device 30 upon positioning to face the object to be measured spheres set The coordinate value represented by the camera coordinate system is a CM coordinate system in which the direction of each coordinate axis of the camera coordinate system is made to coincide with the direction of each coordinate axis of the measurement machine coordinate system which is the coordinate system related to the three-dimensional measuring machine 60. Rotation part Ms _MC which is a rotation part of the coordinate conversion function for coordinate conversion, and is a rotation part Ms _CM of the coordinate axis of the coordinate conversion function Gs _CM. The rotation part Ms _MC is a coordinate value of the CM coordinate system. This is the rotation part of the coordinate conversion function Gs _MC for converting the coordinates to. The rotation portion Md _CM axes of the coordinate transformation function Gd _CM calculated at the step S410, the coordinate values of the camera coordinate system at the time of positioning the three-dimensional shape measurement device 30 to face the reference sphere set CM It is a rotating part of a coordinate conversion function for converting coordinates into coordinate values of a coordinate system.

The rotation deviation E _D, since it regarded as coordinate transformation function for the vector value by the camera coordinate system in the actual measured position vector values of the camera coordinate system at the measuring points to the ideal , the vector value measuring instrument coordinate system by multiplying the rotating part Md _CM coordinate transformation into a vector value of the camera coordinate system at the measuring points to the ideal function Gd _CM, rotating parts Ms _MC further coordinate transformation function Gs _MC , The rotation deviation E _D can be expressed by a value (Ms _MC · Md _CM ) obtained by multiplying the rotation parts of the two coordinate transformation functions. it can. In this case, the coordinate conversion function Gs _CM and the coordinate conversion function Gd _CM are the same function as long as there is no change in the direction of the coordinate axis of the camera coordinate system before and after the positioning of the three-dimensional shape measuring apparatus 30. In other words, coordinate transformation function _{Gd CM} rotating part _{Md CM} coordinate transformation function _{Gs CM} rotating parts _Ms inverse function at a rotating part _{Ms MC} multiplies the value of the _{CM (Ms} MC · _{Md CM)} is the coordinate axes of the camera coordinate system if there is no change in direction "1", there will be no rotational deviation E _D.

Then, the rotational deviation E _D is because it is rotation offset E _D in the camera coordinate system, it is necessary to calculate the rotational deviation E _D the arm coordinate system to obtain the correction function. Rotation offset E _D the arm coordinate system, when the vector value by the arm coordinate system to the vector values of the camera coordinate system, since it regarded to be the value of the previous rotational deviation E _D, rotating in the camera coordinate system shift left by multiplying the rotational portion _{M CA} axes of the coordinate transformation function CA of E _D, it may be multiplied by the inverse function _{M AC} of the rotating portion _{M CA} on the right. Thus, rotational deviation ED the arm coordinate _system, the _{M CA · Ms MC · Md CM} · M AC.

Next, in step S440, the three-dimensional image processing device 42 stores the rotational deviation correction function RG. Rotation offset correction function RG is a function for correcting the rotational deviation E _D. Specifically, stored with the coordinate correction data RD as an inverse function _{((M CA · Ms MC ·} Md CM · M AC) -1) was calculated by the rotational shift correction function RG of the rotational deviation _{E D.} The rotation deviation correction function RG corresponds to the rotation deviation correction data according to the present invention.

  Next, in step S442, the three-dimensional image processing apparatus 42 selects all the sphere sets 53 other than the sphere set 53 designated as the reference sphere set at the height of the calibration object support base 52 when the reference sphere set is selected. It is determined whether or not three-dimensional measurement and correction data have been calculated for all sphere sets 53 at heights other than the height of the calibration object support base 52 when the reference sphere set is selected. To do. In this determination process, the three-dimensional image processing device 42 continues to determine “No” until the three-dimensional measurement and correction data calculation is executed for the measurement target sphere set, and repeatedly executes each process from step S420. To do. In this case, the operator can calculate the three-dimensional measurement and correction data for the measurement target sphere set out of the heights set in S104 of the calibration object information acquisition program. Set to an unexecuted height.

  On the other hand, when the three-dimensional measurement and the calculation of the correction data are executed for all the measurement target sphere sets at the height of all the calibration object support bases 52, “Yes” is determined in the same determination, and step S444 is performed. Then, the execution of the correction data group acquisition program is terminated. As a result, as shown in FIG. 16, from the coordinate correction data RD and the rotation deviation correction function RG for each measurement position of the (N−1) measurement target sphere sets excluding the sphere set 53 designated as the reference sphere set. A correction data group is stored in the memory device of the three-dimensional image processing device 42.

  After executing the correction data group acquisition program, the operator removes the calibration jig 50 from the base 10 and places the workpiece WK as the measurement object on the base 10. Then, the input device 43 is operated to instruct the display of the three-dimensional shape of the work WK. In response to this, the three-dimensional image processing apparatus 42 starts execution of the three-dimensional shape display program shown in FIG. 17 in step S600, and measures the workpiece WK in step S602. Waiting for input of position information representing 30 measurement positions. In this case, the input position information includes the coordinate values (X, Y, Z) of the three coordinate axes in the reference coordinate system and the respective coordinate axes for changing the direction of the coordinate axes to the coordinate axis direction of the arm coordinate system. Rotation angles (Xθ, Yθ, Zθ). Therefore, the operator inputs the position information for measuring the workpiece WK to the three-dimensional image processing device 42 by operating the input device 43. The three-dimensional image processing device 42 recognizes the coordinate value in the input position information as the measurement position WSP and the rotation angle as the rotation angle WSR.

  Next, in step S604, the three-dimensional image processing device 42 corrects the input position information to position the three-dimensional shape measuring device 30 (coordinate values) and the three-dimensional shape measuring device 30 after positioning. Calculate the direction (rotation angle). The correction of the position information is performed using the correction data group acquired by the correction data group acquisition program. First, the three-dimensional image processing device 42 corrects the coordinate value in the position information and calculates the position where the three-dimensional shape measuring device 30 is positioned. First, the three-dimensional image processing device 42 extracts four correction data in the vicinity of the measurement position input in step S602 from the correction data group calculated for each measurement target sphere set of the calibration jig 50. . Specifically, as shown in FIG. 18, the measurement positions KSP1 to KSP8 of the eight measurement target sphere sets in the correction data group surrounding the measurement position WSP input in step S602 are extracted. Of the extracted eight measurement positions KSP1 to KSP8, the correction data corresponding to the measurement position KSP1 that is the measurement positions KSP1 to KSP8 closest to the measurement position WSP and the three measurement positions KSP2 and KSP3 adjacent to the measurement position KSP1 , KSP5, three correction data corresponding to each are extracted.

Next, the three-dimensional image processing device 42 calculates correction data RD ′ corresponding to the measurement position WSP input in step S602, using each coordinate correction data RD in the four extracted correction data. Specifically, as shown in the following formula 25, the coordinate values (X _WSP , Y _WSP , Z _WSP ) of the measurement position _WSP , and the coordinate values (X _KSP1 , Y _KSP1 , X) of the measurement positions KSP1, KSP2, KSP3, _KSP5 , _ZKSP1 ) ( _XKSP2 , _YKSP2 , _ZKSP2 ) ( _XKSP3 , _YKSP3 , _ZKSP3 ) ( _XKSP5 , _YKSP5 , _ZKSP5 ) and respective correction positions corresponding to the measurement positions KSP1, KSP2, KSP3, KSP5 Using each coordinate value ( _XRD1d , _YRD1d , _ZRD1d ) ( _XRD2d , _YRD2d , _ZRD2d ) ( _XRD3d , _YRD3d , _ZRD3d ) ( _XRD5d , _YRD5d , _ZRD5d ) of the data RD Calculate by interpolation for each coordinate axis. The coordinate values (X _RD′d , Y _RD′d , Z _RD′d ) of the correction data RD ′ for each coordinate axis calculated by the following _{equation 25} are visually represented as shown in FIG.

Then, the three-dimensional image processing device 42 calculates the position where the three-dimensional shape measuring device 30 is positioned by adding the calculated correction data RD ′ to each coordinate value at the measurement position WSP input in step S602. Next, the three-dimensional image processing device 42 corrects the rotation angle of each coordinate axis in the position information and calculates the orientation of the three-dimensional shape measuring device 30. The three-dimensional image processing apparatus 42 obtains a 3 × 3 determinant obtained by substituting the rotation angle WSR at the measurement position WSP for the rotation deviation correction function RG in the correction data corresponding to the extracted measurement position KSP1 into the equation 4. The rotation angle WSR ′ is calculated from the 3 × 3 determinant obtained as a result of the multiplication, and the direction of the three-dimensional shape measuring apparatus 30 is calculated. In this case, rotational deviation E _D of the coordinate axes in the arm coordinate system, since a very small shift in comparison to the positioning error E _Cd, rotation of the coordinate axes in the position information by the rotational shift correction function RG corresponding to the measurement position KSP1 The corner can be corrected. In order to correct the rotation angle of each coordinate axis in the position information with higher accuracy, the rotation angle of each coordinate axis should be corrected using an interpolation method in the same manner as the correction of the coordinate value in the position information. That's fine.

  Next, in step S606, the three-dimensional image processing apparatus 42 moves the three-dimensional shape measuring apparatus 30 to the measurement position corrected in step S604 in the direction corrected in step S604. As a result, the three-dimensional shape measuring apparatus 30 is positioned at the rotation angle WSR specified at the measurement position WSP specified at step S602. In step S608, the three-dimensional image processing device 42 waits for input of measurement information representing the three-dimensional shape of the workpiece WK. The three-dimensional shape measuring device 30 is controlled by the controller 41 to start measuring the three-dimensional shape of the workpiece WK, and outputs information representing the three-dimensional shape of the workpiece WK to the three-dimensional image processing device 42. That is, the three-dimensional image processing device 42 obtains information (specifically, inclinations θx, θy, and distance Lz) regarding the XYZ coordinates representing the divided area positions obtained by dividing the surface of the work WK into minute areas. Enter each. Then, the three-dimensional image processing device 42 is based on the three-dimensional shape data group representing the three-dimensional shape of the workpiece WK at each measurement position based on the input information about the XYZ coordinates from the three-dimensional shape measurement device 30. Each of the three-dimensional image data is calculated. In this case, the three-dimensional image data is represented by a coordinate system related to the three-dimensional shape measuring apparatus 30, that is, a camera coordinate system.

  Next, in step S610, the three-dimensional image processing device 42 determines whether or not the workpiece WK has been measured from three different measurement positions. This is because it is necessary to measure the workpiece WK from at least three different positions in order to generate three-dimensional image data that can be displayed by viewing the workpiece WK from an arbitrary direction. Therefore, in this determination process, it is determined “No” until the workpiece WK is measured from three different measurement positions, and the process returns to step S602, and the workpiece WK measurement process is executed again. On the other hand, in the same determination process, when the workpiece WK is measured from three different measurement positions, it is determined as “Yes” and the process proceeds to step S612. Note that the measurement of the workpiece WK is not limited to the above-described three positions, and may be performed from four or more positions. According to this, it is possible to measure a three-dimensional shape with higher accuracy. .

  Next, in step S612, the three-dimensional image processing device 42 combines the three-dimensional image data for each of the three measurement positions into a set of three-dimensional shape data groups. In this case, the three-dimensional image data for each measurement position is converted from the three-dimensional image data based on the camera coordinate system to the three-dimensional image data based on the reference coordinate system by a predetermined coordinate conversion function, and then a set of three-dimensional shape data. Is synthesized. In this synthesis, since the three-dimensional image data at all measurement positions is represented by coordinate values in a reference coordinate system that is the same coordinate system, the part of the workpiece WK that is not measured at each measurement position (the three-dimensional shape at each measurement position) The three-dimensional image data representing the outer surface of the workpiece WK located on the back side with respect to the measuring device 30 is complemented to generate a set of data groups.

  Next, in step S614, the three-dimensional image processing device 42 causes the display device 44 to display the three-dimensional shape of the workpiece WK using the synthesized three-dimensional shape data group. In step S616, the three-dimensional image processing device 42 ends the execution of the three-dimensional shape display program. In the display of the three-dimensional shape of the workpiece WK, the operator can instruct the display direction of the workpiece WK by operating the input device 43. The controller 41 and the three-dimensional image processing device 42 are displayed on the display device 44. The display direction of the displayed work WK is changed. Thereby, the three-dimensional shape which looked at the workpiece | work WK from arbitrary directions can be displayed.

  If a new work WK is placed on the base 10 and the display of the work WK is instructed as described above, the new work WK can be arbitrarily set in the same manner as described above by executing the three-dimensional shape display program. The three-dimensional shape viewed from the direction can be displayed on the display device 44. Therefore, once the correction data group is acquired, it is possible to display the three-dimensional shape on the display device 44 by changing the workpiece WK one after another.

As can be understood from the above description of the operation, according to the embodiment, in the calibration jig 50 including the 16 sphere sets 53, one sphere set 53 at one height of the calibration object support base 52 is provided. A reference sphere set and other sphere sets, specifically, other sphere sets 53 at the same height of the calibration object support base 52 and all sphere sets at other heights of the calibration object support base 52. Three-dimensional shape measurement is performed by the three-dimensional shape measuring apparatus 30 using 53 as a measurement target sphere set. In this case, the three-dimensional shape measurement device 30 is positioned in the object to be measured spheres set according to the positional relationship of each fixed point coordinate T _m in the calibration object information with respect to the reference sphere set. Therefore, if there is no positioning error in the three-dimensional shape measuring apparatus 30, the position of the reference fixed point coordinate Td _cm of the reference sphere set measured by the three-dimensional shape measuring apparatus 30 and the measured target fixed point coordinates TN of each measured target sphere set. _There is no difference from the _cm position. On the other hand, if there is a difference between the position of the reference fixed point coordinate Td _cm of the reference sphere set and the position of the measured target fixed point coordinate TN _cm of each measured sphere set, the reference sphere set was measured. When the three-dimensional shape measuring device 30 is positioned from the position to each sphere set to be measured, a positional deviation on the three coordinate axes and / or a rotational deviation on the respective coordinate axes are generated, and the difference is determined as the positioning coordinate. it can be detected as an error _{E Cd} and / or rotational displacement _{E D.} That is, the sphere set 53 in the calibration jig 50 is obtained by accurately measuring the three-dimensional shape of each calibration object by the three-dimensional shape measuring apparatus 30 of the sphere 51 by the three-dimensional shape measuring apparatus 30, and based on the measurement data. Since the coordinates of the fixed point are accurately calculated and the positional relationship of each calibration object is stored in the storage means, it is not necessary to manufacture and arrange each sphere 51 and each sphere set 53 with high accuracy, and calibration If the arrangement position of the tool 50 is also within the movable range of the arm support mechanism 20, it is not necessary to position it precisely. For this reason, the cost for correcting the positioning error in the articulated robot can be suppressed, and the work of arranging the calibration jig 50 can be simplified. As a result, the positioning error can be detected with high work efficiency while maintaining the accuracy of the positioning error correction in the multi-joint robot.

Further, the coordinate correction data RD and the rotation deviation correction function RG are calculated according to the position of each measurement target sphere set with respect to the reference sphere set. When the three-dimensional shape measuring apparatus 30 is moved, the three-dimensional shape measuring apparatus 30 is positioned using the coordinate correction data RD and the rotation deviation correction function RG corresponding to the position of the movement destination. In this case, the coordinate correction data RD is calculated by an interpolation method according to the position of the movement destination of the three-dimensional shape measuring apparatus 30. As a result, it can correct | amend with the correction amount according to the position where the three-dimensional shape measuring apparatus 30 is positioned, and can position the three-dimensional shape measuring apparatus 30 with higher precision.
(Second Embodiment)

A second embodiment of the present invention will be described. In the first embodiment, the sphere set 53 including the three spheres 51 is used as the calibration object constituting the calibration jig 50. However, if at least one straight line can be defined for each dimension in three dimensions, that is, coordinates If the conversion function Gd _cm and the coordinate conversion function Gs _cm can be defined, for example, the calibration jig 50 can be configured using a calibration object formed in a cube or a rectangular parallelepiped instead of the spherical shape in the sphere 51. In the calibration jig 50 ′ shown in FIG. 19, a rectangular parallelepiped 51 ′ is used instead of the sphere 51 as a calibration object. The rectangular parallelepiped 51 'is fixed to each intersection part of the wire 52c and the wire 52d in the calibration object support base 52, specifically, to each of the 16 intersection parts. In this case, each rectangular parallelepiped 51 ′ is fixed in a direction in which any three surfaces adjacent to each other among the six surfaces constituting the rectangular parallelepiped 51 ′ can be measured by the three-dimensional shape measuring apparatus 30. That is, one vertex of the rectangular parallelepiped 51 ′ is fixed so as to face the three-dimensional shape measuring apparatus 30. The configuration of other parts in the calibration jig 50 ′ is the same as that of the calibration jig 50. The process of correcting the positioning error in the articulated robot using the calibration jig 50 ′ is substantially the same as the process of correcting the positioning error using the calibration jig 50 in the first embodiment. Therefore, only processing steps different from those in the first embodiment will be described.

  First, execution of the calibration object information acquisition program will be described. The calibration object information in the calibration jig 50 ′ configured as described above includes three adjacent cuboids 51 ′ adjacent to each other for each of the 16 cuboids 51 ′ and for each height of the calibration object support base 52. It is composed of a normal vector of the surfaces in the surface, an angle between the surfaces, a length of a common side in the surfaces, and a fixed point that is an intersection of the surfaces. First, the operator operates the input device 64 after setting the calibration jig 50 ′ in the measurement target space on the base 66 of the three-dimensional measuring machine 60 with the column 54 contracted in the same manner as described above. The coordinate calculation processing device 63 is instructed to acquire the calibration object information. In response to this instruction, the coordinate calculation processing device 63 starts execution of the calibration object information acquisition program shown in FIG. 20, which is the same program as the calibration object information acquisition program shown in FIG. In step S702, the operator waits for the input of the feature to be measured. In the process of step S702, the worker inputs information indicating that the measurement target is a rectangular parallelepiped.

  Next, the coordinate calculation processing device 63 waits for input of measurement coordinate information for each rectangular parallelepiped 51 'by the measurement unit 61 in step S704. In the process of step S704, as shown in FIG. 21, the operator operates the probe 69 of the measurement unit 61, and each of the three surfaces A, B, and C adjacent to each other in one rectangular parallelepiped 51 ′. 3 points each on the surface. As a result, the measurement unit 61 obtains three sets of measurement coordinate information corresponding to the three contact points for each of the three measurement surfaces A, B, and C (each point is represented by coordinate values x, y, and z). The data is output to the coordinate calculation processing device 63.

Next, in step S706, the coordinate calculation processing device 63 uses the three sets of measurement coordinate information measured for each of the three measurement surfaces A, B, and C, and uses the measurement coordinate information on each measurement surface A, B, and C. Each normal vector is calculated. Specifically, for each measurement plane A, B, C, three sets of measurement coordinate information are substituted into the left side of the plane equation shown in the following equation 26, and a, b, c are calculated from the three simultaneous equations. Thus, the respective plane equations of the three measurement surfaces are obtained. The vectors having a, b, and c as vector components in these plane equations are the normal vectors in the three measurement planes A, B, and C, respectively. Then, the vector components a, b, c of the respective normal vectors are substituted into the following equation 27 to obtain vector components α _m , β _m , V _mC of normal vectors V _mA , V _mB , V _mC having a size of “1”. γ _m is calculated.

Next, the coordinate calculation processing device 63 calculates each angle between the measurement surfaces A, B, and C in step S708. The angles between the measurement surfaces A, B, and C are calculated as angles between the normal vectors on the measurement surfaces A, B, and C adjacent to each other. Specifically, each component (α _mA , β _mA , γ _mA ), (α _mB , β _mB , γ _mB ), (α _mC , β _mC , γ) of the normal vectors V _mA , V _mB , V _{mC. mC)} of, by substituting each expression on the right of the dot product representing each component of the two normal vectors to the following equation 28 to calculate the angle theta. Thereby, the angles θ _AB , θ _BC , and θ _CA between the three measurement surfaces A, B, and C are calculated.

Next, the coordinate computing unit 63, at step S710, it calculates the fixed point coordinate _{T m} of a rectangular parallelepiped 51 '. The fixed point coordinate _Tm is calculated as the intersection of the three measurement surfaces A, B, and C. Specifically, the calculation is performed by solving simultaneous equations of the three planes of the measurement surfaces in step S706. Next, the coordinate computing unit 63, at step S712, 3 one measuring plane A, B, the length _L mAB each common edge in _C, L _MBC, calculates the _{L mCA.} In this case, the operator operates the probe 69 of the measuring unit 61, the three vertices _T mAB adjacent the fixed point coordinate _{T m} of a rectangular parallelepiped 51 _', T _MBC, is contacted with _{T mCA.} Thereby, the measurement unit 61 coordinates three sets of measurement coordinate information (each point is represented by coordinate values x, y, and z) corresponding to the contact points of the three vertices T _mAB , T _mBC , and T _mCA. The data is output to the calculation processing device 63. The coordinate computing unit 63, coordinate values of the fixed point coordinate _{T m} and each vertex _{T mAB,} T _MBC, using the measurement coordinate information of _{T mCA,} fixed point coordinate _{T m} and each vertex _{T mAB, T MBC,} T The distance to _mCA is calculated respectively.

  Next, the coordinate calculation processing device 63 determines whether or not measurement has been performed for all the rectangular parallelepipeds 51 ′ in step S <b> 714. In this determination, if all the rectangular parallelepipeds 51 'are not measured, it is determined as "No" and the process returns to step S704, and the measurement processing is continued for the rectangular parallelepiped 51' that has not yet been measured. On the other hand, if the measurement is performed for all the rectangular parallelepipeds 51 ′, it is determined as “Yes” and the process proceeds to step S <b> 716. In step S716, as in step S114, the coordinate calculation processing device 63 inquires of the operator whether to change the position of the sphere set 53 in the height direction and perform the measurement process for each sphere set 53 again. . In this case, when the measurement process of the sphere 53 is necessary again at a position in a different height direction, the operator inputs information indicating that the measurement process is continued by operating the input device 64 to the coordinate calculation processing device 63. To do. In response to this instruction, the coordinate calculation processing device 63 determines “Yes” in step S716, returns to step S704, and executes each process for measuring the sphere set 53 again. In this case, the operator changes the height of the calibration object support base 52 to a necessary height by extending and contracting the support 54 of the calibration jig 50.

On the other hand, when the calibration object information of the sphere set 53 is acquired approximately evenly within the height direction range corresponding to the height direction range in which the arm support mechanism 20 is movable, the operator inputs the input device 64. Is input to the coordinate calculation processing device 63 to end the measurement process. In response to this instruction, the coordinate calculation processing device 63 makes a “No” determination at step S716, proceeds to step S718, and ends the execution of the calibration object information acquisition program at step S718. . Thereby, as shown in FIG. 22, the coordinate calculation processing device 63 has normal vectors V _mA , V of the three measurement surfaces A, B, C in each cuboid 51 ′ for each cuboid 51 ′ (1 to N). _{mB, V mC,} the angle theta _mAB between the respective measuring _surface, θ mBC, θ _mCA, the length _L mAB common sides of the _{faces, L mBC,} L _mCA and fixed point coordinates T is the intersection of the surfaces Each _m is stored. Of these calibration object information, the normal vectors V _mA , V _mB , and V _mC are straight line defining parameters according to the present invention, and the angles θ _mAB , θ _mBC , θ _mCA between the measurement surfaces and The common side lengths L _mAB , L _mBC , and L _{mCA on the surface} are identification parameters _according to the present invention, and the fixed point coordinate T _m that is the intersection of the surfaces is the fixed point according to the present invention. If the calibration object information is known, the calibration object information acquisition process by executing this calibration object information acquisition program is not necessary.

  Next, execution of the correction data acquisition program will be described. In step S402 in the correction data acquisition program shown in FIG. 9, the operator selects an arbitrary rectangular parallelepiped 51 ′ as the reference rectangular parallelepiped 51 ′ among the N rectangular parallelepipeds 51 ′ in the calibration jig 50 ′, and places it at a position facing the reference rectangular parallelepiped. The three-dimensional shape measuring apparatus 30 is positioned. In this case, the vertex of each rectangular parallelepiped 51 'is opposed to the three-dimensional shape measuring apparatus 30, that is, three surfaces of the rectangular parallelepiped 51' constituting the same vertex are facing. In step S402, the operator uses the calibration object information numbers (1-N) for the cuboid 51 ′ selected as the reference cuboid among the calibration object information stored in the three-dimensional image processing apparatus 42 as the reference cuboid. Specify as information. In step S404, the three-dimensional image processing apparatus 42 measures the reference cuboid three-dimensionally. In this case, the three-dimensional image data representing the three-dimensional shape of the reference rectangular parallelepiped is data representing three surfaces facing the three-dimensional shape measuring apparatus 30, that is, three measurement surfaces A, B, and C.

  In step S406, the 3D image processing apparatus 42 extracts 3D image data related to the rectangular parallelepiped 51 'from the 3D image data calculated in step S404. This three-dimensional image data extraction process for the rectangular parallelepiped 51 'is executed by the calibration object extraction subprogram shown in FIG. In step S502, the three-dimensional image processing apparatus 42 inputs data indicating that the shape is a specific polyhedron (rectangular solid) as a feature of the calibration object. Next, in the process of extracting the position of the search block in step S510, the number of unit blocks extracted in the central plane of the search block is continuously present in a straight line more than a predetermined number, On the surface, the position of the search block is extracted on the condition that the number of extracted unit blocks is a predetermined number or less.

  Next, the process of extracting 3D image data related to the calibration object in step S512 is changed to the process shown below. In this case, in order to extract the three-dimensional image data relating to one plane of the calibration object, that is, the rectangular parallelepiped 51 ′, the three-dimensional image data representing the point closest to the three-dimensional shape measuring apparatus 30 and the three points nearby. The two-dimensional image data (X, Y, Z coordinate values) are respectively substituted into x, y, z on the left side of the equation (26), which is a plane equation, and the unknowns a, b, c are calculated using the least square method. . Next, the distance between the plane represented by the above equation 26 using the calculated unknowns a, b, and c and the point represented by each substituted three-dimensional image data is calculated. If all the calculated distances are within a predetermined discrimination value, a plane including all these three-dimensional image data is defined. On the other hand, if each of the calculated distances is not within a predetermined discriminant value, a plurality of 3D image data respectively representing a point at a position different from the 3D image data used for the calculation of the plane and its neighboring points are obtained. And performs the process related to the definition of the plane as described above. These processes are repeated until a plane is defined. Note that even if all the calculated distances are not within the predetermined discriminant value, if there are a very small number of 3D image data regarding distances that are not within the discriminant value, the remaining three-dimensional image data excluding these few 3D image data are excluded. A plane may be defined by three-dimensional image data.

  If a plane is defined, the distance between the point represented by the other three-dimensional image data in the corresponding search block and the plane represented by the above equation 26 is calculated, and this distance is a predetermined discriminant value. Three-dimensional image data regarding the points within is acquired as being in the plane. Then, the obtained three-dimensional image data is again substituted into x, y, and z on the left side of the above equation (26), which is a plane equation, and the unknowns a, b, and c are calculated using the least squares method. Three-dimensional image data relating to a point whose distance from the plane using unknowns a, b, and c calculated at the point represented by the three-dimensional image data is within a predetermined discrimination value is acquired. Next, 3D image data corresponding to the periphery of the plane is acquired from the acquired 3D image data, and the length of one side of the plane is calculated using the acquired 3D image data. Then, the difference between the calculated length of one side and the length of the side input as the feature of the calibration object at the time of the process of step S502 is calculated, and if the calculated difference is within a predetermined determination value, It is determined that there is a possibility that the three-dimensional image data in the search block match, and another plane described later is defined. On the other hand, if the difference is not within the predetermined discriminant value, the 3D image data in the search block is not matched and the 3D image data is discarded. In this case, there is no 3D image data representing the 3D shape of the calibration object in the search block.

  When it is determined that there is a possibility as described above, the three-dimensional image data that is not acquired in the corresponding search block is also used for acquiring the three-dimensional image data related to the other two planes. The acquisition process of the three-dimensional image data regarding the plane is executed. With respect to the other planes, three-dimensional image data that is not included in the defined plane is extracted from the three-dimensional image data representing the points existing in the vicinity of the defined plane, and the plane is determined in the same manner as the definition of the plane. 3D image data representing points belonging to the defined plane is acquired. Then, from the acquired three-dimensional image data, three-dimensional image data corresponding to the periphery of the plane is acquired in the same manner as described above, and the length of one side of the plane is determined using the acquired three-dimensional image data. calculate. Then, the difference between the calculated length of one side and the length of the side input at the time of the processing of step S502 is calculated, and if the calculated difference is within a predetermined discriminant value, the 3D in the search block is calculated. It is determined that the image data may match, and the angles of the two planes in the three planes obtained are calculated. Specifically, two normal vectors (a1, b1, c1) and (a2, b2, c2) determined by a, b, and c in the plane equation are converted into normal vectors of size “1” according to the above equation (27). α1, β1, γ1) and (α2, β2, γ2) are substituted into the right side of Equation 28 to calculate the angle θ. If the difference between three angles of the two planes and the angle determined by the characteristics of the calibration object (90 degrees because it is a rectangular parallelepiped) is within the discriminant value, it is determined that the three-dimensional image data in the search block match. . As a result, three-dimensional image data representing the rectangular parallelepiped 51 'is extracted.

  Next, in step S408, the three-dimensional image processing device 42 extracts three-dimensional image data representing the reference rectangular parallelepiped from the three-dimensional image data representing the extracted rectangular parallelepiped 51 '. The process of extracting the three-dimensional image data representing the reference cuboid includes the following sub-steps 1 to 3.

Sub-step 1: Solving simultaneous equations of three planes corresponding to the three measurement surfaces A, B, and C defined in the extraction of the three-dimensional image data representing the rectangular parallelepiped, and the intersection of the measurement surfaces A, B, and C Is calculated as a fixed point coordinate _Tc . Next, 3D image data common to the two measurement surfaces is extracted from the 3D image data related to the rectangular parallelepiped 51 ′. That is, the three-dimensional image data common to the two measurement surfaces is three-dimensional image data representing one side formed by the two measurement surfaces. Specifically, three simultaneous equations composed of two plane equations among the three plane equations are formed, and three-dimensional image data satisfying each of the three simultaneous equations is extracted. These three sets of simultaneous equations correspond to three sides formed by any two measurement surfaces of the three measurement surfaces A, B, and C. Therefore, the three-dimensional image data satisfying the three sets of simultaneous equations is three-dimensional image data representing the three sides. Of the three sets of three-dimensional image data corresponding to these three sides, the distance between the calculated fixed point coordinate _Tc and the farthest three-dimensional image data and the identified point coordinate _Tc is calculated. Thereby, the lengths L _cAB , L _cBC , and L _cCA of the three sides are calculated. The processes of these sub-steps 1 are executed for all the extracted rectangular parallelepipeds 51 ′.

Sub-step 2: Three-dimensional image data representing the reference rectangular parallelepiped is extracted from the three-dimensional image data representing the rectangular parallelepiped 51 'extracted in step S408. Specifically, the calculated per cuboid 51 'three sides of length _{L cAB, L cBC, L cCA} the three sides of the reference rectangular information stored in the three-dimensional image processing apparatus 42 the length _{L CAB,} L _CBC, the difference between _{L CCA} to extract three-dimensional image data regarding the rectangular parallelepiped 51 'which is within a predetermined determination value. In this case, when three-dimensional image data relating to two or more rectangular parallelepipeds 51 ′ is extracted, three angles θ calculated in extracting three-dimensional image data representing each of the two or more extracted rectangular parallelepipeds 51 ′ are extracted. Three-dimensional related to the rectangular parallelepiped 51 ′ in which the differences between _cAB , θ _cBC , θ _cCA and the three angles θ _mAB , θ _mBC , θ _mCA in the reference rectangular parallelepiped information stored in the three-dimensional image processing device 42 are within a predetermined discriminant value. Image data is further extracted. Then, among the sub-step 2 in-calculated fixed point coordinates T _c, fixed point coordinates T _c representing the reference parallelepiped is stored as a reference fixed point coordinates Td _c.

Sub-step 3: The normal vectors V _a , V _b , and V _c of the three measurement surfaces A, B, and C in the cuboid 51 ′ extracted as the reference cuboid are the normal vectors V _mA , V _mB , and the reference cuboid information, Which of the V _mCs corresponds is specified, and the specified normal vectors V _a , V _b , and V _c are stored as normal vectors V _cA , V _cB , and V _cC . The normal vectors V _a , V _b , and V _c are identified by the three side lengths L _cAB , L _cBC , and L _cCA calculated for each cuboid 51 ′ and the three side lengths L in the reference cuboid information. _cAB , L _cBC , and L _cCA are used. If the normal vectors V _a , V _b , and V _c cannot be specified by the lengths of these three sides, they are further specified by using the angles of the measurement surfaces A, B, and C in the sub-step 2. To do. The specified normal vectors V _cA , V _cB , and V _cC are stored as normal vectors having a magnitude calculated when extracting three-dimensional image data representing a rectangular parallelepiped.

Next, three-dimensional image processing apparatus 42, at step S410, calculates a coordinate transformation function _{G CM.} In the calculation of the coordinate transformation function _{G CM,} vector _V CMAB in the number _16, V _CmAB, respectively _{V Cm} normal vector _{V mA, V mB,} and _{V mC, V} in the same number 16 _{CcAB, V CcAB,} V _{Cc Are} the normal vectors V _cA , V _cB , and V _cC , respectively, to calculate the rotation part M _CM of the coordinate axis of the coordinate conversion function G _CM . The moving parts of the origin coordinate is a mobile part of the origin coordinate of the coordinate transformation function CA, the coordinate transformation function G _CM is a formula represented by Equation 3. The coordinate transformation function _{G CM} shall be the same as the coordinate transformation function _{Gd CM.} In step S412, the reference fixed point coordinates Td _d stored in the sub-step 2 are multiplied by the coordinate conversion function Gd _CM to calculate the reference fixed point coordinates Td _d represented by the CM coordinate system.

Next, in step S414, the three-dimensional image processing apparatus 42 normal vectors V _CA , V _CB , V _CC of the three measurement surfaces A, B, C in the reference rectangular parallelepiped specified in the sub-step 3. _Are coordinate-converted into normal vectors V _dA , V _dB , and V _dC in a reference coordinate system that is a coordinate system related to the articulated robot. Specifically, the normal vectors V _CA , V _CB , and V _CC are multiplied by the rotation part M _CA of the coordinate axis of the coordinate conversion function CA calculated by executing the coordinate conversion function calculation program, thereby normal vectors in the arm coordinate system. Coordinates are converted to V _aA , V _aB , and V _aC . The three-dimensional image processing device 42 is input from the input device 43 and represents the coordinates of the origin of the arm tip coordinate system in the stored reference coordinate system and the orientation of each coordinate axis of the arm coordinate system with respect to the coordinate axis of the reference coordinate system. The normal vectors V _aA , V _aB , and V _aC are converted into normal vectors V _dA , V _dB , and V _dC in the reference coordinate system by the rotation part M of the coordinate axis of the coordinate conversion function according to Equation 3 and Equation 4 using the rotation angle. Convert coordinates to.

Next, the three-dimensional image processing apparatus 42 calculates the coordinate conversion function G _DM in step S416. In the calculation of the coordinate transformation function _{G DM,} vector _V CMAB in the number _16, V _CmAB, respectively _{V Cm} normal vector _{V mA, V mB,} and _{V mC, V} in the same number 16 _{CcAB, V CcAB,} V _Cc the normal vector _V dA _{respectively,} V _dB, calculates a coordinate transformation function _{G DM} as _{V dC.} Next, in step S418, the three-dimensional image processing device 42 calculates a reference fixed point coordinate Td _DM in the DM coordinate system. More specifically, the coordinate transformation to the reference fixed point coordinates Td _a of the arm coordinate system by multiplying the coordinate transformation function CA based fixed point coordinates Td _c stored in the sub-step 3, the reference fixed point coordinates Td _a And the number using the rotation angle representing the coordinates of the origin of the arm coordinate system in the reference coordinate system stored from the input device 43 and the orientation of each coordinate axis of the arm coordinate system with respect to the coordinate axis of the reference coordinate system the coordinate transformation function according to 4 coordinate transformation to the reference fixed point coordinates Td _d in the reference coordinate system. Then, by multiplying the coordinate transformation function _{G DM} calculated in the step 416 to the reference fixed point coordinates Td _d to calculate the reference fixed point coordinates _{Td DM} in DM coordinate system.

  After the process of step S418, the three-dimensional image processing apparatus 42 has a rectangular parallelepiped 51 'other than the reference rectangular parallelepiped 51', specifically, the height of the calibration object support base 52 when the reference rectangular parallelepiped is selected. Steps S420 to S420 with respect to all the rectangular parallelepipeds 53 'other than the rectangular parallelepiped 51' designated as the reference rectangular parallelepiped and all the rectangular parallelepipeds 53 'at a height other than the height of the calibration object support base 52 when the reference rectangular parallelepiped is selected. By executing the same process as each process of S444, a correction data group including the coordinate correction data RD and the rotation deviation correction function RG is calculated. Then, the measurement and display processing of the three-dimensional shape of the workpiece WK is executed while correcting the positioning position of the three-dimensional shape measuring apparatus 30 in the same manner as described above.

  Furthermore, the present invention is not limited to the first and second embodiments described above, and various modifications can be made without departing from the object of the present invention. Hereinafter, modified examples will be described.

In each of the above embodiments, in step S438 in the correction data group acquisition program shown in FIG. 9, the three-dimensional shape measuring apparatus 30 is the next measurement target sphere set without changing the orientation of the three-dimensional shape measuring apparatus 30. 53 (or, the rectangular parallelepiped 51 'is the next measurement object) showing a processing procedure of calculating the rotational shift E _D in the case of moving to. This is because each sphere set 53 (or each rectangular parallelepiped 51 ′) is arranged in substantially the same plane in the calibration jig support base 52, so that the three-dimensional shape measuring apparatus 30 is the sphere set 53 that is the next measurement target. When moving to (or the rectangular parallelepiped 51 ′ which is the next measurement target), the three-dimensional shape measuring apparatus 30 is positioned by changing only the coordinate values without changing the direction of the three-dimensional shape measuring apparatus 30. Because. Therefore, when the sphere set 53 (or cuboid 51 ′) is not arranged in the same plane, the direction of the three-dimensional shape measuring apparatus 30 is changed, and specifically, the sphere set 53 (or cuboid). 51 ′) must be positioned on the sphere set 53 (or the rectangular parallelepiped 51 ′ that is the next measurement target) that is the next measurement target. In this case, in step 438, it calculates a rotational deviation E _D in consideration of the amount of change of changing the three-dimensional shape measuring apparatus 30 orientation.

The reference rotation angle component gd stored in step S402, that is, the rotation angle component gd of each coordinate axis of the arm coordinate system when the three-dimensional shape measuring apparatus 30 is positioned in the reference sphere set with respect to the coordinate axis of the reference coordinate system is used. gd ₁₁ , gd ₁₂ , gd ₁₃ , gd ₂₁ , gd ₂₂ , gd ₂₃ , gd ₃₁ , gd ₃₂ , and gd ₃₃ are used, and the three-dimensional shape measuring apparatus 30 is a sphere set 53 (or next measurement) that is the next measurement target. The rotational component gs of the rotation angle of the arm support mechanism 20 for positioning the target rectangular parallelepiped 51 ′) is gs ₁₁ , gs ₁₂ , gs ₁₃ , gs ₂₁ , gs ₂₂ , gs ₂₃ , gs ₃₁ , gs ₃₂ , gs _33. Then, the conversion coefficient gds for converting the reference rotation angle component gd into the rotation angle component gs is expressed by the following Expression 29.

The rotation deviation E _D, since it regarded as coordinate transformation function for the vector value by the arm coordinate system of the actual measured position vector value by the arm coordinate system at the measuring points to the ideal The vector value by the arm coordinate system at the ideal measurement target position is multiplied by gds ⁻¹ which is the inverse function of the coordinate conversion function gds to obtain the vector value by the coordinate system at the reference position. Then, this vector value is multiplied by the value Md _CM · M _AC of the rotation part Md _CM of the coordinate axis of the coordinate conversion function Gd _CM and the inverse function M _AC (M _CA ⁻¹ ) of the rotation part M _CA of the coordinate axis of the coordinate conversion function CA. was the vector value multiplied measuring machine coordinate system, further multiplies the multiplied value _M CA · _{Ms MC} of the rotating portion _{M CA} axes of rotating parts _{Ms MC} and coordinate transformation function CA the coordinate axes of the coordinate transformation function _{Gs MC} Assuming that the vector value is based on the arm coordinate system at the measurement target position, the rotational deviation E _D is (M _CA · Ms _MC · Md _CM · M _AC · gds ^-1 ) multiplied by three coordinate conversion functions. The rotational shift correction function RG in step S440 is to become the inverse function of the rotational displacement _{E D ((M CA · Ms} MC · Md CM · M AC · gds -1) -1).

In the first embodiment, one sphere set 53 is constituted by the three spheres 51. However, if at least one straight line can be defined for each dimension in three dimensions, that is, the coordinate transformation function Gd _cm and the coordinate transformation function. If Gs _cm can be defined and one fixed point can be specified by each sphere 51, the number of spheres 51 constituting the sphere set 53 is not limited. Further, in order to identify each sphere 51, respectively, although the radius R _m of each sphere 51 is constructed by varying each does not able to identify each limited thereto as long each sphere 51. For example, the reflectance of the surface of each sphere 51 may be varied. Alternatively, an object having a shape other than a sphere including a sphere may be used as the sphere 51 and may be identified by the shape of each sphere 51.

In the first embodiment, each sphere set is identified using the radius R _m of each sphere 51 in each sphere set 53 and the distance L _m between the spheres. In the second embodiment, each side of it is configured so as to identify each rectangular 51 'by the length L _m and the angle theta _m between the measurement surface, do not each calibration object may be identified respectively as being limited thereto if possible. For example, identification may be performed by making the reflectance of each surface of the calibration object different, the shape of each calibration object, and the like.

  In the first embodiment, three spheres 51 are used as calibration objects, and in the second embodiment, one rectangular parallelepiped 51 ′ is used as a calibration object. At least one straight line is provided for each dimension in three dimensions. The calibration object is not limited to this as long as it can be defined and one fixed point can be specified for the calibration object. For example, it may be a polyhedron other than a rectangular parallelepiped, an elliptic cylinder having a cross section parallel to the bottom surface, an elliptical cone whose cross section parallel to the bottom surface is an ellipse, or an elliptical sphere having a cross section perpendicular to the major axis. Furthermore, an object having three or more marks on the surface, an object having three or more minute portions having different reflectances, or an object on which a figure having three or more vertices is drawn may be used.

  In the first embodiment and the second embodiment, the calibration object is configured using the sixteen spherical body sets 53 and the rectangular parallelepiped 51 ', but the invention is not limited to this. The number and arrangement of these calibration objects are appropriately set according to the range in which the three-dimensional shape measuring apparatus 30 is movable and the positioning accuracy of the three-dimensional shape measuring apparatus 30. In the first and second embodiments, the calibration object is measured by changing the height of the calibration object support base 52 and the calibration object information is acquired. However, the correction must be strictly performed. If there is no, the horizontal direction of the calibration object support base 52 is set parallel to the X-axis direction of the reference coordinate system, the height of the calibration object support base 52 is fixed, and the calibration object support base 52 is Calibration object information is acquired at an angle of about 45 degrees. Then, after performing the work to acquire the correction data group, assuming a fixed point where the fixed point of each calibration object whose vertical column is the same column is projected in the height direction and the horizontal direction, the correction amount at this fixed point Is the amount of correction at the Z coordinate value of the fixed point, which is based on the assumption that the Z-axis direction, which is the height direction, is the position in the same height direction, and the X-axis and Y-axis directions are assumed to be the same plane position The correction amount may be set as the correction amount at the X coordinate value and the Y coordinate value of the fixed point. FIG. 23 is a view of the calibration object support base 52 as viewed from the side. In the figure, “◯” indicates a fixed point where the correction amount is actually obtained, and “●” indicates a fixed point indicated by “◯”. The fixed point is shown. Further, the number of arranged calibration objects may be increased without changing the range in which the calibration objects are arranged. According to this, the interval at which the coordinate correction data RD and the rotation deviation correction function RG are acquired is narrowed, and more accurate positioning correction can be performed.

  In each of the above embodiments, the three-dimensional shape measuring device 30 is attached to the tip of the arm support mechanism 20 in the articulated robot so as to measure the three-dimensional shape of the workpiece WK. However, the present invention is not limited to this. It is not a thing. That is, the present invention accurately positions the tip of the arm support mechanism 20 in the articulated robot, and if the three-dimensional shape measuring device 30 is attached in the vicinity of the tip, the object to be attached to the tip. Does not matter. For example, a hand that holds an object may be attached to the tip of the arm support mechanism 20 so that the object held by the hand is positioned at a predetermined position. You may comprise so that a part may be attached and welding may be performed to the predetermined position in a workpiece. Also by this, the same effect as the above-mentioned embodiment can be expected.

  In each of the above embodiments, the present invention is applied to an articulated robot as a multi-degree-of-freedom robot. However, the support mechanism has a plurality of degrees of freedom and can attach the three-dimensional shape measuring device 30 to the tip. If it is a multi-degree-of-freedom robot which has, it is not limited to this.

It is the schematic which shows the whole articulated robot provided with the positioning error correction apparatus which concerns on 1st Embodiment of this invention. (A), (B) is the perspective view and front view which show the calibration jig | tool for the positioning error correction which concerns on 1st Embodiment of this invention. It is the schematic which shows the whole three-dimensional measuring machine used for 1st Embodiment of this invention. It is a flowchart of the object information acquisition program for a calibration performed by the three-dimensional measuring machine in the articulated robot of FIG. 6 is a chart showing calibration object information acquired by executing the calibration object information acquisition program of FIG. 5. It is a schematic perspective view which shows the state which assembled | attached the probe to the arm support mechanism of FIG. 3 is a flowchart of a reference sphere measurement program executed by the three-dimensional image processing apparatus in the articulated robot of FIG. 1. It is a flowchart of the coordinate transformation function calculation program performed by the three-dimensional image processing apparatus in the articulated robot of FIG. It is a flowchart of the correction data group acquisition program performed by the three-dimensional image processing apparatus in the articulated robot of FIG. It is explanatory drawing which showed a mode that the calibration jig | tool was measured with the three-dimensional shape measuring apparatus in the articulated robot of FIG. 3 is a flowchart of a calibration object extraction subprogram executed by the three-dimensional image processing apparatus in the articulated robot of FIG. 1. It is a conceptual diagram which shows a detection target object, a unit block, and a search block in three dimensions. It is a conceptual diagram which shows a search area two-dimensionally. (A)-(D) are the conceptual diagrams which show the relationship between a search block and the extracted unit block two-dimensionally. (A)-(D) are the conceptual diagrams which show the movement of the search block within a search area two-dimensionally. FIG. 10 is a chart showing coordinate correction data and a rotational deviation correction function acquired by executing the correction data group acquisition program of FIG. 9. FIG. 3 is a flowchart of a three-dimensional shape display program executed by the three-dimensional image processing apparatus in the articulated robot of FIG. 1. It is explanatory drawing for demonstrating the process of calculating coordinate correction data by the interpolation method. It is a perspective view which shows the calibration jig | tool for a positioning error correction which concerns on 2nd Embodiment of this invention. It is a flowchart of the object information acquisition program for calibration performed by the three-dimensional measuring machine in the articulated robot of FIG. 1 according to the second embodiment of the present invention. FIG. 21 is an explanatory diagram for explaining each position indicated by calibration object information acquired by the calibration object information acquisition program of FIG. 20. 21 is a chart showing calibration object information acquired by executing the calibration object information acquisition program of FIG. 20. It is a side view of the object support base for calibration for explaining the modification of the present invention.

Explanation of symbols

WK ... Work, 10 ... Base, 20 ... Arm support mechanism, 21 ... Fixed base, 22 ... Rotary base, 23 ... First arm, 24 ... Second arm, 25 ... Third arm, 26 ... Fourth arm, 30 ... 3D shape measuring device, 41 ... controller, 42 ... 3D image processing device, 43 ... input device, 44 ... display device, 50 ... calibration jig, 51 ... sphere, 51 '... rectangular parallelepiped, 52 ... object support for calibration Base, 52c, 52d ... wire, 53 ... sphere set, 54 ... support, 60 ... three-dimensional measuring machine, 61 ... measuring unit, 62 ... controller, 63 ... coordinate calculation processing device, 69 ... probe, 70 ... probe.

Claims (14)

Positioning error correction device for correcting a positioning error of the tip portion in a multi-degree-of-freedom robot having a support mechanism having a plurality of degrees of freedom and capable of attaching a three-dimensional shape measuring device for measuring the three-dimensional surface shape of an object to the tip portion In
A calibration jig having a plurality of calibration objects that can be distinguished from each other and that can define at least one straight line for each dimension in three dimensions is prepared, and each dimension in each calibration object is prepared A straight line definition parameter for defining a straight line, an identification parameter for identifying each calibration object, and a coordinate value representing the position of each fixed point specified by each calibration object are stored in advance in the storage means. In addition, from the predetermined origin coordinate position of the three-dimensional coordinate system related to the three-dimensional shape measuring apparatus, the tip of the multi-degree-of-freedom robot which is the origin coordinate position of the three-dimensional coordinate system related to the multi-degree-of-freedom robot is determined in advance. The origin position relationship parameter representing the amount of movement to the position is previously stored in the storage means,
The three-dimensional shape measuring apparatus is attached to a tip portion of the support mechanism, and the three-dimensional shape measuring apparatus is configured to measure one of the plurality of calibration objects as a reference calibration object. First image data acquisition means for acquiring three-dimensional image data relating to the measured reference calibration object, expressed in a three-dimensional coordinate system for
For defining at least one straight line for each dimension using the identification parameter stored in the storage unit and related to the reference calibration object based on the acquired 3D image data related to the reference calibration object First parameter calculation means for calculating a reference calibration object straight line definition parameter and a coordinate value of a fixed point specified by the reference calibration object;
Using the calculated reference calibration object straight line definition parameter, the straight line definition parameter related to the reference calibration object stored in the storage unit, and the origin position relation parameter stored in the storage unit, the three-dimensional shape The storage means stores the coordinate values of the three-dimensional coordinate system relating to the measuring device, and the orientations of the three straight lines corresponding to the respective dimensions defined by the calculated reference calibration object straight line definition parameters. The coordinate value of the transformed coordinate system that matches the direction of the three straight lines corresponding to each dimension defined by the straight line definition parameter for the object and uses the origin coordinates of the three-dimensional coordinate system for the multi-degree-of-freedom robot as the origin coordinates First coordinate conversion function calculating means for calculating a reference calibration object coordinate conversion function for converting the coordinates into
Using the calculated reference calibration object coordinate conversion function, the coordinate value of the fixed point specified by the calculated reference calibration object is converted into the coordinate value of the converted coordinate system to obtain the coordinate value of the reference fixed point. 1 coordinate conversion means;
One calibration object other than the reference calibration object designated from the plurality of calibration objects is used as a measurement target calibration object, and the three-dimensional shape measuring apparatus measures the measurement target calibration object. Therefore, the moving position of the three-dimensional shape measuring apparatus is calculated using the coordinate values representing the positions of the fixed points of the reference calibration object and the measurement target calibration object stored in the storage means. Moving means for moving the three-dimensional shape measuring apparatus to the calculated movement position and setting the direction of the three-dimensional shape measuring apparatus to a designated direction;
The moved three-dimensional shape measuring apparatus is caused to measure the measurement object calibration object, and three-dimensional image data related to the measurement target calibration object represented in the three-dimensional coordinate system related to the three-dimensional shape measurement apparatus is acquired. Second image data acquisition means for
Based on the acquired three-dimensional image data relating to the calibration object to be measured, at least one straight line for each dimension is stored using the identification parameter stored in the storage means and related to the calibration object to be measured. Second parameter calculation means for calculating a measurement object straight line definition parameter for defining and a coordinate value of a fixed point specified by the measurement target calibration object;
Using the calculated measurement object calibration object straight line definition parameter, the straight line definition parameter stored in the storage means and related to the measurement target calibration object, and the origin position relationship parameter stored in the storage means, The three-dimensional coordinate values related to the three-dimensional shape measuring apparatus are stored in the storage means, and the directions of the three straight lines corresponding to the dimensions defined by the calculated object straight line definition parameter for calibration to be measured are stored. A conversion in which the origin coordinates of the three-dimensional coordinate system relating to the multi-degree-of-freedom robot are made the origin coordinates by matching the directions of the three straight lines corresponding to the dimensions defined by the straight line definition parameters relating to the calibration object to be measured. Second coordinate conversion function meter for calculating an object coordinate conversion function for calibration of the measurement target object for coordinate conversion into coordinate values of the coordinate system And means,
Using the calculated object-to-be-measured object coordinate conversion function, the coordinate value of the fixed point specified by the calculated object to be measured is coordinate-converted into the converted coordinate system, and the coordinate value of the fixed-point to be measured Second coordinate conversion means,
A positioning coordinate error calculating means for calculating a difference between each coordinate value of the coordinate-converted measurement target fixed point and each coordinate value of the coordinate-converted reference fixed point as a positioning coordinate error;
Using the calculated object coordinate conversion function for the calibration object to be measured and the calculated object coordinate conversion function for the reference calibration, the second image data acquisition means obtains the three-dimensional image data of the object to be measured calibration object. A rotational deviation calculating means for calculating a deviation between the orientation of the three-dimensional shape measuring apparatus when acquired and the orientation of the three-dimensional shape measuring apparatus designated by the moving means as a rotational deviation;
A positioning error correction apparatus for a multi-degree-of-freedom robot, comprising: correction means for correcting the positioning error of the tip based on the calculated positioning error and the calculated rotational deviation. The positioning error correction device for a multi-degree-of-freedom robot according to claim 1,
For each of the plurality of calibration objects other than the reference calibration object, the movement means moves the three-dimensional shape measuring apparatus, the second image data acquisition means obtains three-dimensional image data, the second Measurement object calibration object straight line definition parameter and coordinate value calculation by parameter calculation means, measurement object calibration object coordinate conversion function calculation by second coordinate conversion function calculation means, coordinates by second coordinate conversion means Repetitive control means for performing conversion, calculation of positioning coordinate error by the positioning coordinate error calculating means, and calculation of rotational deviation by the rotational deviation calculating means;
Correction data for correcting the positioning coordinate error calculated by the positioning coordinate error calculating means and the rotational deviation calculated by the rotational deviation calculating means is provided for each of the plurality of calibration objects other than the reference calibration object. A positioning error correction device for a multi-degree-of-freedom robot, comprising correction data storage means for correspondingly storing the data in the storage means. In the positioning error correction apparatus for a multi-degree-of-freedom robot according to claim 1 or 2,
Each of the plurality of calibration objects in the calibration jig constitutes one calibration object by at least three or more objects,
The first parameter calculating means calculates a coordinate value of a fixed point specified by the at least three or more objects constituting the reference calibration object,
The second parameter calculation means is a positioning error correction apparatus for a multi-degree-of-freedom robot that calculates coordinate values of fixed points specified by the at least three or more objects constituting the measurement target calibration object. The positioning error correction device for a multi-degree-of-freedom robot according to claim 3,
Each straight line definition parameter stored in the storage means is a specific point specified by each object for each of the at least three or more objects,
The first parameter calculation means calculates a coordinate value of a specific point specified by each object for each of the at least three or more objects, and calculates a specific point corresponding to each of the calculated objects. Calculate the center position as a fixed point specified by the reference calibration object,
The second parameter calculating means calculates a coordinate value of a specific point specified by each object for each of the at least three or more objects, and the center of the specific point corresponding to each of the calculated objects A positioning error correction apparatus for a multi-degree-of-freedom robot that calculates a position as a fixed point specified by the calibration object to be measured. The positioning error correction device for a multi-degree-of-freedom robot according to claim 4,
Each of the at least three objects is a sphere;
A positioning error correction apparatus for a multi-degree-of-freedom robot, wherein each specific point specified by each object for each of the at least three or more objects is the sphere center of each sphere. In the positioning error correction apparatus for a multi-degree-of-freedom robot according to claim 1 or 2,
Each of the plurality of calibration objects includes a polyhedron and is provided in the calibration jig in a state where at least three of the surfaces constituting the polyhedron can be simultaneously measured by the three-dimensional shape measuring apparatus. ,
Each straight line definition parameter stored in the storage means is a normal vector for each of the at least three surfaces,
The first parameter calculation means calculates a coordinate value of a vertex formed by the at least three surfaces as a fixed point specified by the reference calibration object,
The multi-degree-of-freedom robot positioning error correction device, wherein the second parameter calculation means calculates a coordinate value of a vertex formed by the at least three surfaces as a fixed point specified by the object to be measured. The positioning error correction apparatus for a multi-degree-of-freedom robot according to any one of claims 1 to 6,
The identification parameter is a positioning error correction device for a multi-degree-of-freedom robot, which is the reflectance, shape, size, or arrangement state between the calibration objects on the calibration object. A positioning error correction method for correcting a positioning error of the tip in a multi-degree-of-freedom robot having a support mechanism having a plurality of degrees of freedom and capable of attaching a three-dimensional shape measuring device for measuring a three-dimensional surface shape of an object to the tip. In
A calibration jig having a plurality of calibration objects that can be distinguished from each other and that can define at least one straight line for each dimension in three dimensions is prepared, and each dimension in each calibration object is prepared A straight line definition parameter for defining a straight line, an identification parameter for identifying each calibration object, and a coordinate value representing the position of each fixed point specified by each calibration object are stored in advance in the storage means. In addition, from the predetermined origin coordinate position of the three-dimensional coordinate system related to the three-dimensional shape measuring apparatus, the tip of the multi-degree-of-freedom robot which is the origin coordinate position of the three-dimensional coordinate system related to the multi-degree-of-freedom robot is determined in advance. The origin position relationship parameter representing the amount of movement to the position is previously stored in the storage means,
The three-dimensional shape measuring apparatus is attached to a tip portion of the support mechanism, and the three-dimensional shape measuring apparatus is configured to measure one of the plurality of calibration objects as a reference calibration object. A first image data acquisition step for acquiring three-dimensional image data relating to the measured reference calibration object expressed in a three-dimensional coordinate system for
For defining at least one straight line for each dimension using the identification parameter stored in the storage unit and related to the reference calibration object based on the acquired 3D image data related to the reference calibration object A first parameter calculating step for calculating a reference calibration object straight line definition parameter and a coordinate value of a fixed point specified by the reference calibration object;
Using the calculated reference calibration object straight line definition parameter, the straight line definition parameter related to the reference calibration object stored in the storage unit, and the origin position relation parameter stored in the storage unit, the three-dimensional shape The storage means stores the coordinate values of the three-dimensional coordinate system relating to the measuring device, and the orientations of the three straight lines corresponding to the respective dimensions defined by the calculated reference calibration object straight line definition parameters. The coordinate value of the transformed coordinate system that matches the direction of the three straight lines corresponding to each dimension defined by the straight line definition parameter for the object and uses the origin coordinates of the three-dimensional coordinate system for the multi-degree-of-freedom robot as the origin coordinates A first coordinate transformation function calculating step for calculating a reference calibration object coordinate transformation function for coordinate transformation into
Using the calculated reference calibration object coordinate conversion function, the coordinate value of the fixed point specified by the calculated reference calibration object is converted into the coordinate value of the converted coordinate system to obtain the coordinate value of the reference fixed point. 1 coordinate conversion step;
One calibration object other than the reference calibration object designated from the plurality of calibration objects is used as a measurement target calibration object, and the three-dimensional shape measuring apparatus measures the measurement target calibration object. Therefore, the moving position of the three-dimensional shape measuring apparatus is calculated using the coordinate values representing the positions of the fixed points of the reference calibration object and the measurement target calibration object stored in the storage means. Moving the three-dimensional shape measuring apparatus to the calculated movement position and setting the direction of the three-dimensional shape measuring apparatus to a designated direction;
The moved three-dimensional shape measuring apparatus is caused to measure the measurement object calibration object, and three-dimensional image data related to the measurement target calibration object represented in the three-dimensional coordinate system related to the three-dimensional shape measurement apparatus is acquired. A second image data acquisition step,
Based on the acquired three-dimensional image data relating to the calibration object to be measured, at least one straight line for each dimension is stored using the identification parameter stored in the storage means and related to the calibration object to be measured. A second parameter calculation step of calculating a measurement object straight line definition parameter for defining and a coordinate value of a fixed point specified by the measurement target calibration object;
Using the calculated measurement object calibration object straight line definition parameter, the straight line definition parameter stored in the storage means and related to the measurement target calibration object, and the origin position relationship parameter stored in the storage means, The three-dimensional coordinate values related to the three-dimensional shape measuring apparatus are stored in the storage means, and the directions of the three straight lines corresponding to the dimensions defined by the calculated object straight line definition parameter for calibration to be measured are stored. A conversion in which the origin coordinates of the three-dimensional coordinate system relating to the multi-degree-of-freedom robot are made the origin coordinates by matching the directions of the three straight lines corresponding to the dimensions defined by the straight line definition parameters relating to the calibration object to be measured. Second coordinate conversion function meter for calculating an object coordinate conversion function for calibration of the measurement target object for coordinate conversion into coordinate values of the coordinate system And the step,
Using the calculated object-to-be-measured object coordinate conversion function, the coordinate value of the fixed point specified by the calculated object to be measured is coordinate-converted into the converted coordinate system, and the coordinate value of the fixed-point to be measured A second coordinate conversion step,
A positioning coordinate error calculation step of calculating a difference between each coordinate value of the coordinate-converted measurement target fixed point and each coordinate value of the coordinate-converted reference fixed point as a positioning coordinate error;
Using the calculated object coordinate conversion function for the calibration object to be measured and the calculated object coordinate conversion function for the reference calibration, the second image data acquisition means obtains the three-dimensional image data of the object to be measured calibration object. A rotational deviation calculating step for calculating a deviation between the orientation of the three-dimensional shape measuring apparatus when acquired and the orientation of the three-dimensional shape measuring apparatus designated by the moving means as a rotational deviation;
A positioning error correction method for a multi-degree-of-freedom robot, comprising: a correction step for correcting the positioning error of the tip based on the calculated positioning error and the calculated rotational deviation. The positioning error correction method for a multi-degree-of-freedom robot according to claim 8,
For each of the plurality of calibration objects other than the reference calibration object, the three-dimensional shape measuring apparatus is moved by the moving step, the three-dimensional image data is obtained by the second image data obtaining step, the second Measurement object calibration object straight line definition parameter and coordinate value calculation by parameter calculation step, measurement object calibration object coordinate conversion function calculation by second coordinate conversion function calculation step, coordinate by second coordinate conversion step Repetitive control step for performing conversion, calculation of positioning coordinate error by the positioning coordinate error calculation step, and calculation of rotational deviation by the rotational deviation calculation step;
Correction data for correcting the positioning coordinate error calculated in the positioning coordinate error calculation step and the rotation shift calculated in the rotation shift calculation step are set in each of the plurality of calibration objects other than the reference calibration object. A method for correcting a positioning error of a multi-degree-of-freedom robot, comprising a correction data storage step for storing the correction data in the storage means. The positioning error correction method for a multi-degree-of-freedom robot according to claim 8 or 9,
Each of the plurality of calibration objects in the calibration jig constitutes one calibration object by at least three or more objects,
The first parameter calculating step calculates a coordinate value of a fixed point specified by the at least three objects constituting the reference calibration object,
The second parameter calculation step is a multi-degree-of-freedom robot positioning error correction method of calculating coordinate values of fixed points specified by the at least three or more objects constituting the measurement target calibration object. The positioning error correction method for a multi-degree-of-freedom robot according to claim 10,
Each straight line definition parameter stored in the storage means is a specific point specified by each object for each of the at least three or more objects,
The first parameter calculating step calculates a coordinate value of a specific point specified by each object for each of the at least three or more objects, and calculates a specific point corresponding to each of the calculated objects. Calculate the center position as a fixed point specified by the reference calibration object,
The second parameter calculating step calculates a coordinate value of a specific point specified by each object for each of the at least three or more objects, and the center of the specific point corresponding to each of the calculated objects A positioning error correction method for a multi-degree-of-freedom robot that calculates a position as a fixed point specified by the calibration object to be measured. The positioning error correction method for a multi-degree-of-freedom robot according to claim 11,
Each of the at least three objects is a sphere;
A positioning error correction method for a multi-degree-of-freedom robot in which each specific point specified by each of the at least three or more objects is the sphere center of each sphere. The positioning error correction method for a multi-degree-of-freedom robot according to claim 8 or 9,
Each of the plurality of calibration objects includes a polyhedron and is provided in the calibration jig in a state where at least three of the surfaces constituting the polyhedron can be simultaneously measured by the three-dimensional shape measuring apparatus. ,
Each straight line definition parameter stored in the storage means is a normal vector for each of the at least three surfaces,
The first parameter calculating step calculates a coordinate value of a vertex formed by the at least three surfaces as a fixed point specified by the reference calibration object;
The second parameter calculating step is a multi-degree-of-freedom positioning error correction method for calculating a coordinate value of a vertex formed by the at least three or more faces as a fixed point specified by the object to be measured. The positioning error correction method for a multi-degree-of-freedom robot according to any one of claims 8 to 13,
The identification parameter is a method for correcting a positioning error of a multi-degree-of-freedom robot, which is a reflectance, shape, size, or arrangement state between calibration objects on a calibration object.

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