JP4583361B2 - POSITION CORRECTION DEVICE, POSITION CORRECTION METHOD, AND PROGRAM - Google Patents

Description

  The present invention relates to a position correction apparatus, a position correction method, and a program.

  Conventionally, an object (work) to be worked by a working means such as a welding robot is positioned at a predetermined position. However, the correlation between the work and the working means may be shifted due to a shift in the installation position of the working means, a deviation due to the bending of the arm of the working means, or a shift of the work due to the working means directly contacting the work. .

As a technique for correcting these positional deviations, for example, Patent Document 1 is disclosed. In this technique, first, a CCD (Charge Coupled Device) camera is mounted on both of a pair of spot welding gun mounting sites, and marks of the same size are provided on the front and back of the spot position of the workpiece. For each spot position, the CCD camera is moved in the Z direction (direction perpendicular to the work surface at the spot position) so that the image diameters of the marks captured by both CCD cameras are the same, and the amount of movement (Δ This is a technique for correcting only Z).
Japanese Patent No. 3191563

  However, according to Patent Document 1, it is necessary to prepare marks on the workpiece side in advance, and when working at a plurality of locations on the workpiece, it is necessary to correct the work position for each location, which hinders cycle time. To do.

  Therefore, an object of the present invention is to provide a technique for reducing the time required for correcting the position where the work is performed when the work is performed on a plurality of locations on the object.

  In the first aspect of the present invention, a table on which an object is placed with reference to a predetermined position, a first axis and a second axis that are orthogonal to each other in a plane on the table are set, and the object in the first axis direction is set. A distance measuring means for measuring a distance to an object; a working means for performing work on a plurality of locations of the object; a reference distance from the distance measuring means to the object; and a distance from the predetermined position to the distance measuring means. Calculating a difference amount between a distance in the second axis direction and a storage means for storing the position where the working means performs work; a distance to the object measured by the distance measuring means; and the reference distance; And a control means for controlling the position of the working means by correcting the position where the working means works based on the distance in the second axial direction.

  According to the first aspect of the present invention, it is utilized that the object is displaced with respect to a predetermined position. That is, the distance of one point from the distance measuring means to the object is measured, and the movement amount (difference amount) from the original position of the observation point is calculated based on the measured value. From this movement amount and a predetermined position, Control for correcting the working position of the working means is performed based on the distance in the second axis direction to the distance measuring means. For this reason, even if the position for measuring the distance is one point, a plurality of work positions on the object can be corrected. That is, even if there are a plurality of work positions, position correction can be controlled without increasing the amount of calculation.

  According to a second aspect of the present invention, in the first aspect of the present invention, a right triangle having the difference amount as a height and a distance in the second axis direction as a base is set, and the right triangle and the right triangle The correction is performed based on the ratio of sides to the similar triangle.

  According to the second aspect of the present invention, a correction value to be obtained is obtained by replacing the state of displacement with a predetermined position as a reference by a geometrical relationship approximated by a right triangle. That is, the difference amount and a known value (the distance between the distance measuring means and the predetermined position in the second axis direction) are applied to a geometrical relationship approximated by a right triangle, and based on that The amount of correction required when performing work is obtained. For this reason, it is possible to perform accurate processing with a simple calculation.

  A third aspect of the present invention provides the distance measuring device according to the first or second aspect, wherein the distance measuring unit measures the distance based on a time from irradiating the object with light and detecting reflected light. It is a measuring means, and is provided at one measuring position where reflected light can be detected.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the working means is a member attaching means for holding a plurality of members and attaching the members. Moving means movable to a position; optical detection means for optically detecting the attachment position of the member; member holding means for holding the member; switching means for switching between the optical detection means and the member holding means; And a member pushing means for pushing the member in an axial direction substantially coinciding with the optical axis of the optical detection means.

  The invention according to claim 5 is the invention according to claim 4, wherein the working means is a screw tightening means for holding and tightening the screws, and the member pushing means is a rotation for rotating the screws. A driving means is provided, and the screw is tightened by pushing the screw in the axial direction and rotating the screw around the axis.

  The invention according to claim 6 sets a first axis and a second axis orthogonal to each other in a plane on the table in a state where the object is placed on the table with a predetermined position as a reference, and the first axis A distance measurement procedure for measuring a distance to the object in a direction by a distance measurement means, a distance measured in the distance measurement procedure, and a difference amount between a reference distance from the distance measurement means to the object, A calculation procedure for calculating a position at which the working means for performing work on a plurality of locations of the object is based on the difference amount and the distance in the second axis direction from the predetermined position to the distance measuring means; And a control procedure for controlling a position at which the working means performs work based on the procedure.

  The invention according to claim 7 sets a base for placing an object on the basis of a predetermined position, and a first axis and a second axis orthogonal to each other in a plane on the base, and the object in the first axis direction. A distance measuring means for measuring a distance to an object; a working means for performing work on a plurality of locations of the object; a reference distance from the distance measuring means to the object; and a distance from the predetermined position to the distance measuring means. An amount of difference between the distance to the object measured by the distance measuring means and the reference distance in a position correction apparatus comprising a distance in the second axis direction and a storage means for storing a position where the working means performs work Is a program for correcting the position where the working means performs work based on the difference amount and the distance in the second axial direction, and causing the position to function as a control means for controlling the position of the working means. .

  According to the first aspect of the present invention, when working on a plurality of locations of an object, all the positions where the work is performed are corrected by measuring the distance at one location, so that the time required for correction can be reduced. it can.

  According to the second aspect of the present invention, since the correction calculation of the position where the work is performed is formalized, the time required for correction can be further reduced.

  According to the third aspect of the present invention, since it is not necessary to provide a surface on which the distance measuring means can detect the reflected light for each position where the work is performed, a simple configuration can be achieved. In addition, since it is not necessary to provide a plurality of distance measuring means, an inexpensive and simple configuration can be achieved. In addition, since it is not necessary to provide the distance measuring means in the working means, the working means can be reduced in weight, and the construction can be made inexpensive and simple.

  According to the fourth aspect of the present invention, when the members are attached to a plurality of locations of the object, the work means holds the plurality of members, so that the work route and the work time can be shortened. Further, since the attachment position of the member can be detected by the optical detection means, the attachment accuracy is improved, and the quality of the object can be improved. In addition, since the optical axis of the optical detection means and the axis from which the member pushing means pushes the member substantially coincide, correction calculation of the attachment position of the member can be simplified.

  According to the fifth aspect of the present invention, when the screws are tightened at a plurality of positions of the object, the working means holds the plurality of screws, so that the work route and the working time can be shortened.

  According to the sixth aspect of the present invention, when the work is performed on a plurality of locations of the object, all the positions where the work is performed are corrected by measuring the distance at one location, and therefore the time required for the correction can be reduced. it can.

  According to the seventh aspect of the present invention, in the case where work is performed on a plurality of locations on the object, all the positions where the work is performed are corrected by measuring the distance at one location, so that the time required for correction can be reduced. it can.

  In this embodiment, an example in which a screw tightening operation is performed in a process of attaching a side airbag (an example of a member) to a vehicle body (an example of an object) of an automobile.

(Configuration of the embodiment)
Hereinafter, a configuration example of the position correction apparatus will be described with reference to FIGS. 1 to 6. FIG. 1 is an exploded view of a work station S that performs screw tightening work, a vehicle body B, and a transport hanger 10 that transports the vehicle body B to the work station. The work station S includes a seating conveyance path D2 and a work device W (an example of a position correction device) that can move back and forth along the seating conveyance path D2.

  A rack 21 having teeth that mesh with a pinion gear, which will be described later, and rails 29 are laid on both sides of the rack 21 in the seating conveyance path D2. The work device W includes a vehicle body transport carriage 20 that can move the rack 21 back and forth by a pinion gear, and a fastening jig transport carriage that is connected to the vehicle body transport carriage 20 and can be moved back and forth by a slide guide 31 on a rail 29. 30.

  The vehicle transport cart 20 includes a hydraulic lifting device 23 at the top. The elevating device 23 includes an elevating stage 22 (an example of a table) provided horizontally on the upper portion thereof. An orthogonal XY axis (an example of a first axis and a second axis orthogonal to each other in the plane) is set in the plane of the elevating stage 22. In addition, a predetermined position of the vehicle transport cart 20 includes a fitting hole 24 (an example of a predetermined position) serving as a reference position of the vehicle body, a cylinder 25 that supports the fitting hole 24 and is driven up and down, and a rack. And a motor 27 that is engaged with the motor 21 and rotates the pinion gear.

  On the other hand, above the work station S, a vehicle suspension transport path D1 and a transport hanger 10 are provided. A chain 11 is laid in the vehicle body suspension conveyance path D1. The transport hanger 10 can move back and forth on the chain 11. The transport hanger 10 includes a pair of trolleys 15 on the front and back in the transport direction, and a pair of hanger arms 14 on the left and right in the transport direction. The transport hanger 10 moves while being pulled by the chain 11 by the trolley 15.

  The hanger arm 14 includes a seating plate 12 provided at a corresponding position on the front wheel rear lower surface and the rear wheel front lower surface of the vehicle body B, and a pair of upper and lower fitting pins 13 provided at the front end of the front seating plate 12. ing. The upper pins of the fitting pins 13 are fitted into holes H provided at two left and right positions on the lower surface of the front seat foot of the vehicle body B. The reason why the hole H is provided only in the front portion of the vehicle body B is to deal with vehicle bodies having different shapes. The vehicle body B is held by the transport hanger 10 in a state where the upper pin of the fitting pin 13 is fitted in the hole H, and is conveyed to the work station S. When the transport hanger 10 reaches a predetermined position of the work station S, the transport hanger 10 is connected to the work device W while holding the vehicle body B.

  Hereinafter, this connection operation will be described with reference to FIGS. FIG. 2 is a side view of the vehicle body B, the transport hanger 10, and the work device W. FIG. 3 is a front view of the vehicle body B, the transport hanger 10, and the work device W. When the transport hanger 10 holding the vehicle body B reaches the point A in FIG. 2, the fitting hole 24 provided at a predetermined position of the vehicle transport cart 20 shown in FIG. 3 moves upward by the action of the cylinder 25. . Then, the lower pins of the fitting pins 13 provided in the transport hanger 10 are connected by being fitted into the fitting holes 24. However, the vehicle body B is caused by a slight error between the pin diameter of the upper pin of the fitting pin 13 and the hole diameter of the hole H or a slight error between the pin diameter of the lower pin of the fitting pin 13 and the hole diameter of the fitting hole 24. The rear part of the back and forth swings to the left and right, causing misalignment. At this time, the positional deviation amount of the rear part of the vehicle body B is about 5 mm at the maximum.

  Further, the transport hanger 10 is lifted by the action of the cylinder 25 and is released from the engagement of the chain 11 laid on the vehicle body hanging transport path D1. On the other hand, the lifting device 23 raises the vehicle body B from the height T placed on the transport hanger 10 to a predetermined height T ′. Thus, the correlation position between the tightening jig for performing the tightening operation of the screw and the vehicle body B is positioned. Thereafter, while a tightening jig, which will be described later, is performing the tightening operation of the screw, the transport hanger 10 moves to the point A ′ following the self-running of the vehicle transport cart 20. The vehicle transport cart 20 includes a pinion gear 26 connected to a motor 27 on its lower surface, and a roller 28 that supports the vehicle transport cart 20 and rotates back and forth. The pinion gear 26 is engaged with the rack 21 laid on the seating conveyance path D2. Accordingly, the vehicle transport cart 20 can accurately move between the points A and A ′. When the vehicle transport cart 20 reaches the point A ′, the connection between the transport hanger 10 and the work device W is released. The work device W whose connection has been released returns to the point A and waits until the next vehicle body comes.

  Hereinafter, details of the working device W will be described with reference to FIGS. In FIG. 1, a tightening jig transport carriage 30 has a laser range finder 50 (an example of distance measuring means) for measuring the distance to the vehicle body B at the upper portion thereof, and a tightening jig for tightening screws. Two tools 32a and 32b (an example of a working means, a member attaching means, and a screw tightening means) and a control device 40 (an example of a control means) for controlling them are provided.

  The laser range finder 50 measures the distance based on the time from irradiating the vehicle body B with pulsed light to detecting reflected light. Therefore, it is preferable that the vehicle body to be measured has a plane capable of detecting reflected light. Therefore, the measurement position is set to the vicinity of the rear part of the rear wheel where the amount of positional deviation is maximum (an example of a measurement position where reflected light can be detected). The distance measurement direction is the Y-axis direction shown in FIG. 1 (an example of measuring the distance in the first axis direction).

  Two fastening jigs 32a and 32b are arranged on both sides of the vehicle body B (only the front side is shown). The tightening jigs on both sides work in synchronization. The fastening jig 32a is in charge of fastening a screw of a side airbag attached to the upper portion of the front seat. On the other hand, the fastening jig 32b is in charge of fastening a screw of a side airbag attached to the upper part of the rear seat. The tightening jigs 32a and 32b hold a plurality of screws, and move to the position of one screw hole (the position where the work is performed, an example of the member mounting position) according to the work path calculated by the control means 40. The operation of tightening the screw and moving to the next screw hole is repeated.

  The details of the tip of the fastening jig 32a will be described with reference to FIGS. 4 and 5 (the fastening jig 32b is the same and is omitted). The tightening jig 32a includes an articulated arm (an example of moving means) 306 for moving to the position of the screw hole, a blanket 301 connected to the articulated arm 306, and a CCD camera 60a that detects the position of the screw hole. (An example of an optical detection means), a clamping socket 34a (an example of a member holding means) for holding a screw, and a socket folder 220 (an example of a switching means) that can be switched by rotating the CCD camera 60a and the clamping socket 34a. And a tightening nut runner 400 (an example of an extruding means) that extrudes a screw in an axial direction substantially coinciding with the optical axis of the CCD camera 60a.

  The multi-joint arm 306 includes a servo motor at each joint. On the other hand, the position of the screw hole is specified by XYZ coordinates. The work path is calculated from the positions of the designated screw holes. According to this work path, each servo motor provided in the articulated arm 306 is driven.

  A pair of blankets 301 connected to the articulated arm 306 are provided on the left and right sides of the tightening nut runner 400 to support the tightening tool. The socket folder 220 connected to the blanket 301 has a circular shape that can be rotationally driven. The socket folder 220 has a CCD camera 60a and a plurality of fastening sockets 34a arranged at equal intervals on the circumference thereof. The socket folder 220 includes a socket switching servomotor 36 that is a rotational drive source. When the socket folder 220 switches from the CCD camera 60a to the clamping socket 34a, the axis S from which the clamping nut runner 400 pushes the clamping socket 34a substantially coincides with the optical axis O of the CCD camera 60a (see FIG. 5). .

  The CCD camera 60a is an infrared monochrome CCD camera having about 500,000 pixels or more. The CCD camera 60a includes a ring illumination of an infrared LED (light emitting diode) around the lens. Therefore, the CCD camera 60a can obtain a good image quality even on a dark surface or a metal surface on which reflected light is easily scattered. Further, the CCD camera 60a includes a camera link that can transfer at a maximum of 1.6 gigabits / second using LVDS (low voltage operation transmission) as a communication interface.

  The tightening socket 34a includes a socket 231 into which a screw N is inserted at the tip thereof, a socket bit portion 232, a floating mechanism 233, a socket feed mechanism 234, a socket return mechanism 235, a joint portion 236, and a rotating shaft 237. It has. The socket bit part 232 is a magnetic body and has a configuration in which screws can be smoothly supplied from a supply mechanism. Moreover, the socket bit part 232 is detachable and can be replaced with a socket having a different diameter. The floating mechanism 233 includes a spring 233a and presses the socket 231 forward and absorbs an overload on the screw N caused by being pressed by the tightening nut runner 400. The socket feed mechanism 234 includes a ball spline 234a, and causes the rotary shaft 237 to linearly move and transmit a rotational force. Thereby, the rotating shaft 237 moves back and forth and rotates, and the socket 231 moves back and forth via the rotating shaft 237 and rotates. The socket return mechanism 235 includes a spring 235a, and after tightening the screw N, when the tightening nut runner 400 is retracted (rightward in FIG. 5), the socket 231 is retracted accordingly. The joint portion 236 is disposed behind the tightening socket 34a (right direction in FIG. 5), is coupled to the rotating portion 410 of the tightening nut runner 400, and transmits the rotational force of the rotating portion 410 to the rotating shaft 237.

  The tightening nut runner 400 pushes the tightening socket 34a (leftward in FIG. 5) as a drive mechanism, a gas pressure type feed cylinder 38, a piston rod 311 that slides back and forth in the feed cylinder 38, and a guide for the piston rod 311. A pair of right and left slide guides 313 and slide struts 312 sliding back and forth in the slide guide 313 are provided. Side portions of the feed cylinder 38 and the slide guide 313 are fixed to the blanket 301. Further, as a driving mechanism for rotating the screw N, a tightening nut runner servo motor 37 (an example of a rotation driving means), a rotating shaft 411 connected to the tightening nut runner servo motor 37, and a rotation connected to the rotating shaft 411. Part 410 is provided. The tightening nut runner 400 uses these drive mechanisms to push the screw N in a predetermined axial direction and rotate it around a predetermined axis.

  FIG. 6A is a schematic block diagram of the control device 40. The control device 40 includes a CPU (central processing unit) 42 that performs overall control of the work device W, a ROM (read-only storage device) 43 (an example of a storage unit) that stores data and programs necessary for control, Random Access Memory (RAM) 44 that expands data and programs from the ROM 43 and is used as a work area of the CPU 42, a user interface 41 that is a display / input means, and a RS-232C (Recommended Standard 232) that communicates with a laser rangefinder. version C) 48, an image capture circuit 47 for inputting an image from a CCD camera, an Ethernet (registered trademark) 46 communicating with a fastening jig, and an I / O (input / output) 45 as an input / output interface. ing.

  The ROM 43 is a reference distance from the laser range finder 50 to the vehicle body B (an example of a reference distance, hereinafter referred to as “reference distance”) and an X-axis direction from the fitting hole 24 to the laser range finder 50. The distance (an example of the distance in the second axis direction; hereinafter referred to as “distance in the X axis direction”) and the position coordinates of the screw holes are stored (hereinafter referred to as “reference data”).

  The user interface 41 is a serial communication interface that connects a touch panel monitor, a keyboard, a mouse, and the like. RS-232C48 is also a serial communication interface. The RS-232C 48 outputs a distance measurement command to the laser rangefinder 50 and inputs the measured distance.

  The image capture circuit 47 includes a camera link as a communication interface. The image capture circuit 47 inputs images from the CCD cameras 60a and 60b via the camera link and stores them in the frame buffer.

  The Ethernet (registered trademark) 46 is a CSMA / CD (carrier sense multiple access / collision detection method) communication control circuit, and is connected to a LAN (local communication network). On the other hand, the fastening jigs 32a and 32b are also connected to the LAN. The Ethernet (registered trademark) 46 communicates control data with the fastening jigs 32a and 32b. The control data includes, for example, a servo motor identifier, a pulse generation frequency, a servo motor operation / stop flag, and the like.

  FIG. 6B is a schematic block diagram of the fastening jig 32a (the circuit of the fastening jig 32b is the same). The tightening jig 32a includes a plurality of servo motors 35a, 35b, 35c,... For driving each joint of the multi-joint arm 306 (see FIG. 4) in the XYZ axial directions and around the respective axes, and a socket folder 220 (see FIG. 4), a socket switching servo motor 36 for rotating the drive, a tightening nut runner servo motor 37 for rotating the tightening socket 34a (see FIGS. 4 and 5) for tightening the screw, and a gas pressure type pushing out the tightening socket 34a. A feed cylinder 38, a drive circuit 39 for driving and controlling them, an Ethernet (registered trademark) 33 which is a CSMA / CD communication control circuit, and a CCD camera 60a for detecting the position of a screw hole are provided.

  The drive circuit 39 includes a microcomputer (hereinafter referred to as “microcomputer”), a clock oscillator, a regulator, a switch, a capacitor, and the like. The drive circuit 39 receives the control data received by the Ethernet (registered trademark) 33, and outputs a drive current having a designated pulse generation frequency to a designated servo motor.

(Operation of the embodiment)
Hereinafter, an example of operation in this configuration will be described with reference to FIGS.

  FIG. 9 is a flowchart of a program for controlling the fastening jigs 32a and 32b. When the work is started (step S700), the reference data is read from the ROM 43 (step S701). The actual distance to the vehicle body is measured (step S702), and the position coordinates of all screw holes are corrected based on the difference between the reference distance and the actual distance (step S703). The work path is calculated (step S704), and the following steps are repeated until the number of tightened screws reaches the total number of screws (step S705). When moving to the work position (step S706), the center coordinates of the screw hole are measured from the image acquired by the CCD camera (step S707). The working position is further moved so that the center coordinate of the screw hole becomes the center coordinate of the image (step S708), and the screw socket is switched to the fastening socket that holds the screw (step S709). The fastening socket is pushed out (step S710), and the screw is tightened (step S711). When the number of tightened screws reaches the total number of screws (step S705), the operation exits from the loop and ends (step S712). The program for executing this flowchart can be provided not only by communication means but also by storing it in a recording medium such as a CDROM.

  FIG. 8A is a diagram illustrating a method of correcting the position coordinates of the screw hole in step S703 of FIG. A vehicle body indicated by a dotted line in the figure is an actual vehicle body position, and a vehicle body indicated by a solid line is a reference vehicle body position. As shown in the figure, the XY axes are set with the X coordinate of the fitting hole 24 set to zero.

The difference amount a ₀ between the reference distance and the actual distance is a ₀ = L ₁ −L ₀ . The distance in the X-axis direction is _{b 0.} The high Satoshi sides of difference amount a _0, sets the right-angled triangle and bottom sides of the distance b ₀ in the X-axis direction. Based on the ratio of the sides of this right triangle and its similar triangle, the Y coordinate of the positions of all screw holes is corrected. For example, if there are four screw holes and the respective X coordinates are b ₁ , b ₂ , b ₃ , and b ₄ , the correction amounts of the Y coordinates are a ₁ = a ₀ × b ₁ / b ₀ , a _{2, respectively.} = a _{a 0 × b 2 / b 0} , a 3 = a 0 × b 3 / b 0, a 4 = a 0 × b 4 / b 0.

  FIG. 7 is a conceptual diagram when the CCD camera captures a screw hole in step S707 of FIG. The program in FIG. 9 corrects lens distortion for the image G acquired by the CCD camera. Next, the image G is binarized and labeled, and the flatness (major axis-minor axis / major axis) of the labeled object is calculated. Next, an object having a flatness of 0 (becomes a screw hole C) is searched. After detecting the screw hole, the center coordinate of the screw hole C is measured. In step S708, the work position is moved so that the center coordinate of the screw hole C becomes the center coordinate O of the image G.

(Comparative example of embodiment)
A comparative example to which the present invention is not applied will be described below with reference to FIGS. The comparative example is an example in which the laser rangefinder is configured at the tip of the fastening jig.

  In this example, the ROM serving as the storage means stores a reference distance from the laser rangefinder to the vehicle body (hereinafter referred to as “reference distance in the comparative example”) and screw hole position coordinates. (Hereinafter referred to as “reference data in a comparative example”). Other configurations are the same as in the embodiment.

  FIG. 11 is a flowchart of a program for controlling the fastening jig in the comparative example. When the work is started (step S900), the reference data in the comparative example is read (step S901). The work path is calculated (step S902), and the following steps are repeated until the number of tightened screws reaches the total number of screws (step S903). When moving to the work position (step S904), the actual distance to the vehicle body is measured (step S905), and the position of the CCD camera is corrected based on the difference between the reference distance and the actual distance in the comparative example (step S906). The center coordinate of the screw hole is measured from the image acquired by the CCD camera (step S907). The working position is further moved so that the center coordinate of the screw hole becomes the center coordinate of the image (step S908), and the screw socket is switched to a fastening socket that holds the screw (step S909). The tightening socket is pushed out (step S910), and the screw is tightened (step S911). When the number of tightened screws reaches the total number of screws (step S903), the operation exits from the loop and ends (step S912).

  FIG. 10 is a conceptual diagram when the CCD camera captures a screw hole in steps S905 to S907 in FIG. When the tightening jig 80 moves to the work position, the laser range finder 80b measures the actual distance to the vehicle body. The program in FIG. 11 corrects the distance between the CCD camera 80a and the vehicle body based on the difference between the reference distance and the actual distance in the comparative example. Thereafter, the work position is moved so that the center coordinate of the screw hole C becomes the center coordinate O of the image G. Then, when the screw is tightened and the tightening is completed, the screw moves to the next screw hole.

  Comparing the flowcharts of the embodiment (FIG. 9) and the comparative example (FIG. 11), the comparative example performs the steps of vehicle body distance measurement (step S 905) and camera position correction (step S 906) for the total number of screws. Inhibit. Further, the comparative example needs to have a surface capable of detecting reflected light at all work positions. Further, since it is necessary to provide a laser range finder for all the fastening jigs, the construction of the fastening jigs becomes complicated, the weight increases, and the cost also increases. However, the embodiment also solves such a problem.

(Other embodiments)
Below, the modification of above-mentioned embodiment is described.

  The object is not limited to the vehicle body B shown in the embodiment, and may be a stationary body. For example, a motorcycle, a generator, a tiller, a snowplow, a ship, an aircraft, a train, a robot, or the like may be used.

  Further, the platform is not limited to the elevating stage 22 shown in the embodiment, but may be any planar platform on which an object can be placed.

  Further, the distance measuring means is not limited to the laser range finder 50 shown in the embodiment, and for example, a stereo camera using the principle of triangulation may be used, or a GPS (Global Positioning System) may be used. Good.

  Further, the working means is not limited to the fastening jigs 32a and 32b shown in the embodiment, and any working means may be used as long as it works on a plurality of locations of the target object. For example, a robot that opens a screw hole, a welding robot, or a crushing robot may be used.

  The working means may be a member attaching means for attaching a member. For example, a robot for attaching a windshield or a robot for attaching a tire may be used.

  The screw may be, for example, a bolt, a nut, a rivet, or a pin.

  The storage means is not limited to the ROM 43 shown in the embodiment, and any storage means that can store information may be used. For example, a semiconductor storage device such as a register, cache memory, and RAM, a magnetic storage device such as a hard disk and a magnetic tape, a floppy disk, a removable disk such as an MO, CDROM, DVD, USB memory, and flash memory Good.

  Moreover, a control means is not restricted to the structure of the control apparatus 40 shown to embodiment. For example, a control device may be provided in the tightening jigs 32a and 32b so that only position correction data is passed to each control device. Further, the position of the object may be corrected instead of correcting the position where the work is performed as in the embodiment.

Further, the correction method of the position where the working means performs work is not limited to FIG. 8A shown in the embodiment. FIG. 8B is a diagram showing another correction method. It can be approximated that the rear portion of the vehicle body B is displaced on the circumference around the fitting hole 24. Therefore, the correction amount may be calculated from a trigonometric function in a circle centered on the fitting hole 24. Specifically, a right triangle having a right angle between the sides of a ₀ and b ₀ is set. Then, assuming that the opposite angle of the side having the length a ₀ is θ, θ = atan (a ₀ / b ₀ ), so that the center coordinates of the four screw holes are (b ₁ cos θ, b ₁ sin θ), respectively. , (B ₂ cos θ, b ₂ sin θ), (b ₃ cos θ, b ₃ sin θ), and (b ₄ cos θ, b ₄ sin θ). This correction method can improve the correction accuracy.

  Further, the switching means is not limited to the rotary type such as the socket folder 220 shown in FIG.

  INDUSTRIAL APPLICABILITY The present invention can be used for a position correction apparatus including a working unit that performs work on a plurality of locations of an object and a program for controlling them.

It is the exploded view of the conveyance hanger 10 which conveys the work station S which performs the bolting operation | work, the vehicle body B, and the vehicle body B to this work station. 2 is a side view of a vehicle body B, a transport hanger 10, and a work device W. FIG. 2 is a front view of a vehicle body B, a transport hanger 10, and a work device W. FIG. It is a perspective view of the front-end | tip part of a clamping jig. It is sectional drawing of the front-end | tip part of a clamping jig. (A) is a schematic block diagram of a control apparatus, (B) is a schematic block diagram of a clamping jig. It is a conceptual diagram when a CCD camera image | photographs a screw hole. (A) is a figure which shows the method of correct | amending the position of a screw hole, (B) is a figure which shows the other correction methods. It is a flowchart of the program which controls a clamping jig. It is a conceptual diagram when the CCD camera in a comparative example images a screw hole. It is a flowchart of the program which controls the clamping jig | tool in a comparative example.

Explanation of symbols

  W ... Working device, 22 ... Elevating stage, 50 ... Laser rangefinder, 32a, 32b ... Fastening jig, 43 ... ROM, 40 ... Control device.

Claims (7)

A platform for placing the object on the basis of a predetermined position;
A distance measuring means for setting a first axis and a second axis perpendicular to each other in a plane on the table, and measuring a distance to the object in the first axis direction;
Working means for working on a plurality of locations of the object;
Storage means for storing a reference distance from the distance measuring means to the object, a distance in the second axis direction from the predetermined position to the distance measuring means, and a position at which the working means performs work;
A difference amount between the distance to the object measured by the distance measuring unit and the reference distance is calculated, and the position where the working unit performs work is corrected based on the difference amount and the distance in the second axis direction. And control means for controlling the position of the working means;
A position correction apparatus comprising: Set the right angle triangle with the difference amount as the height and the distance in the second axis direction as the base,
The position correction apparatus according to claim 1, wherein the correction is performed based on a ratio of sides of the right triangle and a similar triangle of the right triangle.   The distance measuring means is a distance measuring means for measuring a distance based on a time from irradiating the object with light and detecting reflected light, and is provided at one measurement position where the reflected light can be detected. The position correction apparatus according to claim 1 or 2. The working means is a member attaching means for holding a plurality of members and attaching the members,
A movable means that can move to the attachment position of the member, an optical detection means that optically detects the attachment position of the member, a member holding means that holds the member, and the optical detection means and the member holding means can be switched. Switching means; and member pushing means for pushing the member in an axial direction substantially coinciding with the optical axis of the optical detection means;
The position correction apparatus according to any one of claims 1 to 3, further comprising: The working means is a screw fastening means for holding a plurality of screws and fastening the screws,
5. The position according to claim 4, wherein the member pushing means includes rotation driving means for rotating a screw, and the screw is tightened by pushing the screw in the axial direction and rotating around the axis. Correction device. In a state where the object is placed on a table with a predetermined position as a reference, a first axis and a second axis orthogonal to each other in a plane on the table are set, and a distance to the object in the first axis direction is set. A distance measuring procedure for measuring by a distance measuring means;
A difference amount between the distance measured in the distance measurement procedure and a reference distance from the distance measurement unit to the object is obtained, and the difference amount and a distance in the second axis direction from the predetermined position to the distance measurement unit Based on the above, a calculation procedure for calculating the position of the work means for performing work on a plurality of locations of the object,
A control procedure for controlling the position where the working means performs work based on the calculation procedure;
The position correction method characterized by stepping on. A platform for placing the object on the basis of a predetermined position;
A distance measuring means for setting a first axis and a second axis perpendicular to each other in a plane on the table, and measuring a distance to the object in the first axis direction;
Working means for working on a plurality of locations of the object;
Position correction comprising: a reference distance from the distance measurement means to the object; a distance in the second axis direction from the predetermined position to the distance measurement means; and a storage means for storing a position at which the work means performs work. To the device,
A difference amount between the distance to the object measured by the distance measuring unit and the reference distance is calculated, and the position where the working unit performs work is corrected based on the difference amount and the distance in the second axis direction. And a program for functioning as control means for controlling the position of the working means.

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