JP6425009B2 - Three-dimensional measuring machine and shape measuring method using the same - Google Patents

Description

  The present invention relates to a three-dimensional measuring machine and a shape measuring method using the same.

  Conventionally, a probe head provided with a first drive means (for example, a motor) for rotating the probe about two rotation axes orthogonal to each other, and a second drive means (for example, a third drive means for moving the probe head in mutually orthogonal three axial directions) There is known a three-dimensional measurement machine having a so-called five-axis probe head provided with a motor) (see, for example, Patent Document 1).

  In the three-dimensional measuring machine described in Patent Document 1, the automatic measurement of the object to be measured (also referred to as a work) is performed by moving the probe head based on the part-programmed measurement path.

JP-A-2010-537184

  Generally, in a three-dimensional measuring machine having a 5-axis probe head, attitude information of the probe head at the time of measuring an object to be measured is written in a part program. When measuring an object to be measured, a part program is read, and the attitude of the probe head is controlled based on the attitude information.

  However, the attitude information of the probe head written in the part program is described on the premise that the object to be measured is accurately placed on the table. A high precision jig is required to place the object to be measured. Therefore, if a high-precision jig can not be prepared, the object to be measured is placed in an incorrect arrangement state, which causes a problem that the object to be measured can not be accurately measured.

  There is also a demand for measuring another object using a part program that has already been created. At this time, due to the size of the three-dimensional measuring machine, it may be necessary to place the object to be measured in a tilted state. Also in this case, it is determined that the object to be measured is placed in an incorrect arrangement state, and the problem arises that the already created part program can not be used.

  The present invention has been made in view of such circumstances, and does not require a high-precision jig, and even if the placement of the object to be measured is changed, the same part program can be used, as a result. The purpose is to reduce the cost burden of the operator and to improve the productivity.

  A coordinate measuring machine according to one aspect of the present invention moves a probe head provided with a first drive means for rotating a probe about two rotation axes orthogonal to each other, and moves the probe head in three axial directions orthogonal to each other The control means includes a second drive means, a table for placing the object to be measured, a drive controller for driving the first drive means and the second drive means, and a control means for controlling the drive controller. A storage means for storing a part program in which posture information of the probe head is described in a work coordinate system in which an origin setting and an XYZ reference axis are set, and an arrangement state of the object mounted on the table is detected. And setting means for determining a new reference Z-axis for the object to be measured, and then determining a new reference XY-axis to set a new reference XYZ axis and a new origin Correction value acquiring means for acquiring attitude correction values of the probe head in the vertical direction and horizontal direction from the new origin point and the new reference XYZ axis, the origin point and the reference XYZ axis, and the probe head based on the attitude correction value And correcting the attitude of the probe head, converting the attitude information of the probe head from the workpiece coordinate system to the machine coordinate system, executing the part program, and instructing the drive controller.

  Preferably, setting means for setting a new reference XYZ reference axis and setting a new origin determines at least three points of the plane of the object to be measured by the probe head to determine the new reference Z-axis, and the object to be measured Measuring at least two points of the side of the to determine the new reference XY axis.

  According to another aspect of the present invention, there is provided a shape measuring method using a three-dimensional measuring machine, comprising: a probe head comprising a first drive means for rotating a probe about two rotation axes orthogonal to each other; Second drive means for moving in three axial directions, a table for mounting the object to be measured, a drive controller for driving the first drive means and the second drive means, and control means for controlling the drive controller , And the control means stores a part program in which posture information of the probe head is described in a work coordinate system in which origin setting and reference XYZ axes are set. Step and the arrangement state of the object placed on the table are detected to determine a new reference Z-axis for the object, and then a new reference XY axis The attitude of the probe head in the vertical direction and the horizontal direction from the step of determining and setting the new reference XYZ axes and setting the new origin, the new origin, the new reference XYZ axes, and the origin and the reference XYZ reference axes Obtaining a correction value, reading out the part program, correcting the attitude of the probe head based on the attitude correction value, converting the attitude information of the probe head from a workpiece coordinate system to a machine coordinate system, and driving the drive controller And instructing.

  Preferably, the new reference XYZ reference axis setting and the new origin setting are performed by measuring at least three points of the plane of the object to be measured by the probe head to determine the new reference Z axis; Measuring at least two points on the side of the object to determine the new reference XY axis.

  According to the present invention, a high-precision jig is not required, and even if the placement of the object to be measured is changed, the same part program can be used, thereby reducing the cost burden on the operator and improving productivity. It can be done.

It is a perspective view of a three-dimensional measuring machine. It is an enlarged view of a probe head. It is a block diagram showing an example of composition of a three-dimensional measuring machine. It is a flowchart for demonstrating the operation | movement of a three-dimensional measuring machine. In a three-dimensional measuring machine, it is a perspective view which shows the state which is performing part program processing. It is explanatory drawing for demonstrating a machine coordinate system origin. It is a perspective view which shows the state which set the origin and the reference | standard XYZ axis to the to-be-measured object. It is a perspective view which shows the state which is performing the process which measures the new reference | standard Z-axis of the upper surface of to-be-measured object. It is a perspective view which shows the state which set the new reference | standard Z axis to the to-be-measured object. It is a perspective view which shows the state which set the new reference | standard XY axis to the to-be-measured object. It is a perspective view which shows the state which set the new origin and the new reference | standard XYZ axis to the to-be-measured object.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, in the drawings, portions indicated by the same symbols are similar elements having similar functions.

  Hereinafter, preferred embodiments of a shape measuring method using a coordinate measuring machine according to the present invention will be described with reference to the attached drawings.

  FIG. 1 is a perspective view of a three-dimensional measuring device 10 of the present embodiment. The coordinate measuring machine 10 (CMM: Coordinate Measuring Machine) is a device which moves the probe head 24 to determine the spatial coordinates on the surface of the object to be measured (also called a workpiece). It is also called a machine. In the present embodiment, a portal moving type three-dimensional measurement machine 10 will be described as an example.

  As shown in FIG. 1, the coordinate measuring machine 10 includes a gantry 12, a table 14 (surface plate) on which the gantry 12 is placed, and right Y carriage 16 R and left Y carriage erected on both sides of the table 14. 16L, and an X guide 18 connecting the right Y carriage 16R and the upper portion of the left Y carriage 16L. A portal frame 26 is configured by the right Y carriage 16R, the left Y carriage 16L, and the X guide 18.

  The sliding surfaces are formed in the Y-axis direction on the upper surface and the side surfaces on both sides of the table 14, and the right Y carriage 16R and the left Y carriage 16L are provided with air bearings opposed thereto. The 16R and the left Y carriage 16L are movable in the Y axis direction together with the X guide 18.

  A sliding surface in the X-axis direction is formed on the X-guide 18, and an X-carriage 20 incorporating an air bearing is provided movably in the X-axis direction. The X carriage 20 incorporates an air bearing for guiding in the Z-axis direction. A Z spindle 22 is provided movably in the Z axis direction along an air bearing for Z axis direction guidance.

  A probe head 24 is attached to the lower end of the Z spindle 22. The probe head 24 is a probe head (five-axis simultaneous control probe head) provided with a stepless positioning mechanism, and two rotation axes A or B (FIG. 1) orthogonal to each other of the contact type touch trigger probe 24a (stylus 24b). (See, for example, a motor (not shown)) for rotating about the reference. According to this probe head 24, it is possible to perform faster measurement (probing, that is, an operation to determine coordinate values) by using only the rotational movement around the rotation axis A or B.

  The coordinate measuring machine 10 is provided with a second drive means (for example, a motor, not shown) for moving the probe head 24 in three axial directions (XYZ directions) orthogonal to each other. By moving the portal frame 26, the X carriage 20 and the Z spindle 22 in the respective axial directions by the second driving means, the probe head 24 can be moved in the three axial directions (XYZ directions) orthogonal to each other.

  A scale is provided in the Y-axis direction of the table 14, the X guide 18, and the Z spindle 22. A detection head in the Y-axis direction is attached to the right Y carriage 16R, and a detection head in the X-axis direction and the Z-axis direction is attached to the X carriage 20. Therefore, the contact 24c at the tip of the probe 24a (stylus 24b) At the moment of contact with the measurement object (work), the three-dimensional coordinate position is detected.

  Connected to the coordinate measuring machine 10 is a drive controller 28 for controlling the movement of the coordinate measuring machine 10 and the probe head 24. The drive controller 28 is connected to a computer 32 via a communication interface 30 such as a LAN (TCP / IP). The drive controller 28 is connected to a joystick (not shown) for remotely controlling the movement of the probe head 24. The joystick is provided in an operation box (not shown).

  The computer 32 executes a software program 32a (including an instruction for measurement operation and software for confirming measurement results) installed in the computer 32 to measure the measurement path including the coordinate values of the target point and the midpoint, etc. And control (CNC control) the first drive means and / or the second drive means via the drive controller 28 based on the measurement path, and automatically move the probe head 24. Automatically measure the object to be measured.

  FIG. 2 is an enlarged view of the probe head 24. The probe head 24 is connected to the Z spindle 22. As shown in FIG. 2A, the probe 24a (stylus 24b (contact 24c)) is moved steplessly in the range of the vertical angle ± θ with respect to the rotation axis A (axis perpendicular to the paper surface). be able to. The position of the lowermost point of the stylus 24 b is 0 °, and can be rotationally moved about the rotation axis A from, for example, elevation angle −115 ° (−θ) to elevation angle +115 (+ θ).

  Further, as shown in FIG. 2B, the probe 24a (stylus 24b) can be rotated steplessly around the rotation axis B in the range of horizontal angle ± φ. The horizontal angle ± φ is ± 180 ° and can be freely rotated.

  FIG. 3 is a block diagram showing a configuration example of the three-dimensional measuring device 10. As shown in FIG. The computer 32 comprises a software program 32 a and control means 40. The control unit 40 includes the CPU 42, the storage unit 44, the part program creation unit 46, the part program execution unit 48, the setting unit 50, the correction value acquisition unit 52, the instruction unit 54, and the coordinate conversion unit 56. Have.

  Next, the operation of the three-dimensional measuring machine 10 configured as described above will be described with reference to FIGS. FIG. 4 is a flowchart for explaining the operation of the three-dimensional measuring machine 10.

  First, the object to be measured W1 is placed on the table (step S10).

  While moving the probe head 24 by the drive controller 28, it contacts the measured object W1. Attitude information on the probe head 24 when actually measuring the object to be measured W1 (measurement path including the coordinate values of the target point and the middle point) is obtained as coordinate values based on the machine coordinate system (step S12). For example, as shown in FIG. 5, the contactor 24c of the probe head 24 is brought into contact with the object to be measured W1 to obtain posture information of the probe head 24. Here, the machine coordinate system is a coordinate unique to the three-dimensional measuring machine 10 and mechanically determined, and means a coordinate system determined based on the machine coordinate system origin unique to the three-dimensional measuring machine 10 Do. The probe head 24 moves on the table 14 based on the coordinate values of this machine coordinate system. The machine coordinate system origin is generally set in the upper left corner or lower left corner of the measurement range, as shown in FIG.

  Next, the obtained posture information of the probe head 24 is converted into a workpiece coordinate system based on the workpiece W1. The posture information converted into the work coordinate system is described in the part program, and the part program is stored (step S14).

  The part program creation means 46 creates a part program according to an instruction from the CPU 42. The workpiece coordinate system means a coordinate system set to the object to be measured W1 based on the object to be measured W1. As shown in FIG. 7, in the work coordinates, setting of an origin (origin O) with reference to the workpiece W1 and setting of reference XYZ axes are performed. At this time, when the origin O set to the object to be measured W1 does not match, the offset amount between the machine coordinate system origin Om and the origin O is stored. The origin and the reference XYZ axes for the object to be measured W1 are executed by the setting means 50. In the part program, the measurement position of the object to be measured W1, the intermediate point, the movement direction (approach direction) to the measurement position, the posture of the probe head 24, and the like are described as coordinate values of the workpiece coordinate system. Coordinate conversion means 56 converts coordinate values from the machine coordinate system to the work coordinate system according to a command from the CPU 42. In the part program, for example, commands are described in the form of X (), Y (), Z (): I (), J (), K (): A (), B (). X (), Y (), and Z () indicate measurement positions where the contact 24c contacts the object W1. Further, I (), J () and K () indicate the moving direction (approach direction) to the measurement position. A () and B () indicate the vertical angle θ and the horizontal angle φ of the probe head 24. That is, A () and B () indicate the attitude of the probe head 24. The created part program is stored in the storage means 44.

  Next, when the part program described in the work coordinate system is stored, the process proceeds to the step of measuring the object to be measured W2 to be measured. The DUT W2 to be measured is placed on the table 14 (step S16).

  Next, the arrangement of the object to be measured W2 placed on the table 14 is detected, the inclination of the upper surface of the object to be measured W2 is determined, and a new reference Z axis is determined (step S18). For example, as shown in FIG. 8, the attitude of the probe head 24 is changed so that the probe 24a, the stylus 24b, and the contact 24c are parallel to the Z axis and the contact 24c has a vertical angle of 0 °. In this state, the contact 24c is brought into contact with the upper surface of the object to be measured W3 three times. A plane is determined based on the three measured points, and then a new reference Z-axis is determined based on this plane. The angle difference between the reference Z axis of the reference XYZ axes of the workpiece coordinate system set in the part program and the new reference Z axis is determined. That is, the posture correction value in the vertical direction is obtained.

  For example, as a result of measurement, if it is assumed that the X axis is rotated 5 ° around the Y axis (if the new reference Z axis is inclined 5 ° with respect to the reference Z axis), as shown in FIG. The new reference Z axis is required to be inclined, for example, 5 ° with respect to the reference Z axis.

  If this is shown by a transformation matrix, it can be expressed as follows. First, when the workpiece coordinate system is not set to the object to be measured, the transformation matrix is as shown in Expression (1).

  When the upper surface of the object to be measured W2 is measured, a normal vector of the upper surface is obtained. When the new reference Z-axis is inclined 5 ° with respect to the reference Z-axis, a conversion matrix of the new reference Z-axis and the X-axis / Y-axis orthogonal to the new reference Z-axis is Formula (1) is updated to formula (2).

  After the new reference Z-axis is obtained, the new reference XY-axis of the object W2 is obtained (step S20). For example, as shown in FIG. 10, the attitude of the probe head 24 is changed so that the probe 24a, the stylus 24b, and the contact 24c are parallel to the Z axis and the contact 24c has a vertical angle of 0 °. In this state, the contact 24c is brought into contact twice with the side surface of the object to be measured W2. A straight line is determined based on the two measured points, and then, based on the straight line, a new reference X-axis and a new reference Y-axis orthogonal to the new reference X-axis are determined. A new reference XY axis is determined. In the case of equation (2), there is no change in the Y axis.

  The angle difference between the reference X axis of the reference XYZ axes of the workpiece coordinate system set in the part program and the new reference X axis is determined. That is, the horizontal attitude correction value is obtained. Similarly, the angle difference between the reference Y axis of the reference XYZ axis and the new reference Y axis is determined. The new reference X-axis is, for example, 5 ° inclined with respect to the reference X-axis of the reference XYZ reference axis, and the new reference Y-axis is, for example, 5 ° inclined with respect to the reference Y-axis of the reference XYZ reference axis Are required to The determination of the new reference XY axis is performed in the order of the new reference X axis to the new reference Y axis, but may be determined in the order of the new reference Y axis to the new reference X axis.

  When the new reference X axis is rotated 5 ° with respect to the reference X axis in the XY plane, the transformation matrix of the new reference X axis and the new reference Y axis is updated from Expression (2) to Expression (3) .

  After the new reference XYZ axes are determined, a new origin is set to the object W2 to be measured (step S22). For example, as shown in FIG. 11, a new origin and a new reference XYZ axis are set to the object to be measured W2. The new origin and the new reference XYZ axes are set by the setting means 50 according to a command from the CPU 42.

  Next, after the new origin O and the new reference XYZ axes are set, the attitude correction values of the probe head 24 in the vertical direction and the horizontal direction are obtained from the new origin O, the new reference XYZ axes, and the origin O and the reference XYZ axes. . For example, the transformation matrix is obtained by equation (3). Also, the offset amount between the new origin and the origin is obtained. The transformation matrix and the offset amount are obtained as attitude correction values of the probe head 24. The posture correction value is acquired by the correction value acquisition means 52 according to a command from the CPU 42 (step S24).

  Next, the attitude of the probe head 24 is corrected based on the attitude correction value, the attitude information of the probe head is converted to the machine coordinate system, the part program is executed, and the drive controller 28 is instructed (step S26).

  In order for the drive controller 28 to control the probe head 24, coordinate values of the machine coordinate system are required. Posture information of the probe head 24 is described in a part coordinate system in the part program. Therefore, posture information (coordinate values) of the probe head 24 is converted from the workpiece coordinate system to the machine coordinate system. At this time, the posture correction value is added as a value of the machine coordinate system to the posture information (coordinate value) of the probe head 24 converted into the machine coordinate system, and the part program is read out by the command of the CPU 42, part program execution means 48 is executed. The conversion from the work coordinate system to the machine coordinate system is executed by the coordinate conversion means 56 in accordance with a command from the CPU 42.

  Next, measurement of the object to be measured W2 is performed (step S28). The drive controller 28 controls the movement and measurement of the probe head 24 based on the instruction of the part program. The instruction based on the part program is transmitted to the drive controller 28 by the instruction means 54. The measurements from probe head 24 are sent to computer 32. The measurement results are displayed, stored, etc. on the computer 32.

  Next, it is determined whether or not all of the object to be measured W2 has been measured (step S30). While the determination in step S30 is No, the processing from step S16 to step S28 is repeated. If it is determined as Yes in step S30, the measurement of the object to be measured W2 is ended.

  In the present embodiment, the following steps are preferably performed in consideration of the directions of the XYZ axes of the machine coordinate system and the case where they are not parallel to the platen surface.

  In step S12 and step S14, the platen surface is measured by the probe head. Check the Z direction and the X and Y directions, and determine the X, Y and Z coordinates with reference to the surface plate. Based on the design data input to the apparatus in advance, the upper surface normal of the workpiece (reference surface with the normal direction of the Z axis) is measured at three points and set. The normal of the probe head is aligned using a drive mechanism of vertical angle θ and horizontal angle φ in the direction of the work. Perform vector conversion of surface plate normal and work surface normal.

  Next, the X-axis and Y-axis are measured, and the deviation of the work direction in the X direction and Y direction is detected in comparison with the surface of the platen. Finally, deviations in the Z direction and in the X and Y directions are calculated, and a transformation of the work coordinate system is set based on the surface plate coordinate system.

  Here, the machine coordinate system does not necessarily coincide with the surface plate coordinate system. The machine coordinate system is based on the direction of the slide mechanism of the column, but the platen and slide mechanism are not always parallel. In the present embodiment, the surface of the platen is used as a reference, not based on the direction of the slide mechanism. Usually, since the object to be measured (work) is placed on the surface plate and measured, the bottom surface of the object to be measured (work) coincides with the surface of the surface plate. As a result, since the normal direction of the top surface of the object to be measured is set based on the bottom surface of the object to be measured, accurate measurement can be performed. That is, it is possible to measure more accurately by converting the values written in the part program into the work coordinate system with the orientation of the base plate as the reference of the machine coordinate system.

  The above embodiments are merely illustrative in every respect. The present invention is not to be interpreted as being limited by these descriptions. The present invention can be implemented in other various forms without departing from the technical idea or the main features.

  DESCRIPTION OF SYMBOLS 10 ... Three-dimensional measuring machine, 12 ... Mounting frame, 14 ... Table, 16L, 16R ... Y carriage, 18 ... X guide, 20 ... X carriage, 22 ... Spindle, 24 ... Probe head, 24a ... Probe, 24b ... Stylus, 24c ... contactor 26 portal frame 28 controller 30 communication interface 32 computer 32a software program 40 control means 42 CPU 44 storage means 46 part program creation means 48: part program execution means, 50: setting means, 52: correction value acquisition means, 54: instruction means, 56: coordinate conversion means, W1, W2: measured object

Claims (4)

A probe head comprising first driving means for rotating the probe about two rotation axes orthogonal to each other;
Second driving means for moving the probe head in three axial directions orthogonal to each other;
A table on which an object to be measured is placed;
A drive controller for controlling the first drive means and the second drive means;
And d) control means for controlling the drive controller.
The control means
The position information of the probe head is stored in the part program described in the setting of the origin and the work coordinate system in which the reference XYZ axes are set, with the orientation of the table as the reference of the machine coordinates before measuring the object to be measured Storage means,
The arrangement of the object placed on the table is detected to determine a new reference Z axis for the object, and then a new reference XY axis is determined to set a new reference XYZ axis. And setting means for setting a new origin,
Correction value acquiring means for acquiring attitude correction values of the probe head in the vertical direction and the horizontal direction from the new origin point, the new reference XYZ axis, the origin point and the reference XYZ axis;
Instruction means for correcting the attitude of the probe head based on the attitude correction value, converting the attitude information of the probe head from a workpiece coordinate system to a machine coordinate system, executing the part program, and instructing the drive controller ,
Three-dimensional measuring machine equipped with.   The setting means for setting a new reference XYZ axis and setting a new origin measures at least three points of the plane of the object to be measured by the probe head to determine the new reference Z axis, and The three-dimensional measuring machine according to claim 1, further comprising measuring at least two points on a side to determine the new reference XY axis. A probe head comprising first driving means for rotating the probe about two rotation axes orthogonal to each other;
Second driving means for moving the probe head in three axial directions orthogonal to each other;
A table on which an object to be measured is placed;
A drive controller for controlling the first drive means and the second drive means;
And controlling means for controlling the drive controller. A shape measuring method using a three-dimensional measuring machine, comprising:
The control means
The position information of the probe head is measured by the probe head before measuring the object, and the work with the origin set and the reference XYZ axes set with the orientation of the table as a reference of machine coordinates Storing a part program described in a coordinate system;
The arrangement of the object placed on the table is detected to determine a new reference Z axis for the object, and then a new reference XY axis is determined to set a new reference XYZ axis. And setting a new origin,
Obtaining attitude correction values of the probe head in the vertical direction and the horizontal direction from the new origin point and the new reference XYZ axes and the original point and the reference XYZ reference axes;
Reading the part program, correcting the attitude of the probe head based on the attitude correction value, converting the attitude information of the probe head from a workpiece coordinate system to a machine coordinate system, and instructing the drive controller.
Shape measurement method using a three-dimensional measurement machine equipped with   The steps of setting a new reference XYZ axis and setting a new origin point comprise: measuring at least three points of the plane of the object to be measured by the probe head to determine the new reference Z-axis; And measuring at least two points on a side surface to determine the new reference XY axis.

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