JP2009300200A - Controlling device of probe for shape measurement - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controlling device of a probe for shape measurement which enables the probe to follow a measuring surface at a high speed, while maintaining a low measuring force, and makes high speed and high accuracy measurement, in a shape measuring apparatus. <P>SOLUTION: The controlling device is equipped with an X control mode changeover switch 41 and a Y control mode changeover switch 45. A positional control is performed on one axis and an inclination control on the other, according to the shape of a measuring object or the relation between an X probe inclination angle θX and a Y probe inclination angle θY at the time of measurement. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a probe control device for a shape measuring apparatus that measures the inner surface and hole diameter of a hole having an arbitrary shape, the outer surface of an arbitrary shape, and the like with high accuracy.

  As a shape measuring device for measuring an outer surface, an inner surface, a hole diameter and the like of an arbitrary shape with high accuracy, there is one disclosed in Patent Document 1. The configuration of the shape measurement probe 1 and the measurement point information determination unit described in Patent Document 1 will be described in detail with reference to FIG. In FIG. 4 and other drawings, the Z-axis direction of the orthogonal coordinate system is the vertical direction, and the remaining two axes (X-axis and Y-axis) are the horizontal directions.

  A shape measuring probe (hereinafter simply referred to as a probe) 1 shown in FIG. 4 includes a stylus 4 that comes into contact with a measurement object 2 to be measured, and an oscillating member 6 including an arm 5 having the stylus 4 at the tip thereof. The connecting mechanism 8 is connected to the mounting member 9 so as to be tiltable in any direction regardless of the X-axis direction or the Y-axis direction. The probe 1 has an attachment member 9 attached to the shape measuring device 3. In short, the probe 1 includes the stylus 4 that contacts the measurement surface 2a of the measurement object 2, and can be tilted in both the X-axis direction and the Y-axis direction.

  The measurement point information determination unit 10 includes an optical system 11 for obtaining position information of the measurement point 100, an inclination angle detection unit 12, a stylus position calculation unit 13, a position coordinate measurement unit 14, and an addition unit 15. .

  The measurement laser beam 17 generated by the laser beam generator 16 is split into four by the optical system 11 in order to obtain the three-dimensional coordinate position of the measurement point 100. Specifically, the optical system 11 includes a total of four optical systems including three first optical systems 11 a for X, Y, and Z coordinates and one second optical system 11 b for the tilt angle of the probe 1. Have. Although not shown in the first optical system 11a to detect the position coordinates of the measurement point 100 in the X-axis direction and the Y-axis direction, an X-axis reference plate orthogonal to the X-axis direction and the Y-axis direction are omitted. A Y-axis reference plate orthogonal to.

  The position coordinate measurement unit 14 includes detection units 14 a to 14 c that measure the X coordinate value, the Y coordinate value, and the Z coordinate value at the measurement point 100. Reflected light from the X-axis reference plate is attached to the detector 14a, reflected light from the Y-axis reference plate is attached to the detector 14b, and the swing member 6 of the shape measuring probe 1 is attached to the detector 14c. Reflected light from the mirror 7 is incident.

  The second optical system 11 b includes a light separating unit 18 that guides the reflected light 17 b from the mirror 7 attached to the swing member 6 of the shape measuring probe 1 to the tilt angle detecting unit 12 among the measuring laser light 17. Have.

  The inclination angle detection unit 12 is configured by a photodetector having a light receiving surface 121 that receives the reflected light 17b from the mirror 7 and converts it into an electrical signal. As shown in FIG. 5, the light receiving surface 121 is divided into four light receiving regions 12 a to 12 d that perform photoelectric conversion independently.

  Assuming that the light amounts detected in the light receiving areas 12a to 12e are “A”, “B”, “C”, and “D”, respectively, the stylus calculation unit 13 performs the following operation on the electrical signals obtained from the light receiving areas 12a to 12d. By calculating (A + B) − (C + D), the tilt angle (slope angle of the probe 1) θX of the swinging member 6 in the X-axis direction can be obtained, and (A + D) − (B + C) is calculated. Thus, the inclination angle (inclination angle of the probe 1) θY of the swing member 6 in the Y-axis direction is obtained. Further, the stylus calculation unit 13 obtains the relative displacement in the XYZ axis direction of the stylus 4 with respect to the probe 1 (strictly, the attachment member 9) from the inclination angles θX and θY.

  The adding unit 15 adds the relative displacement of the stylus with respect to the probe 1 obtained by the stylus calculating unit 13 to the X coordinate value, the Y coordinate value, and the Z coordinate value obtained by the detection units 14a to 14c, and XYZ of the measurement point 100 is obtained. Axial position coordinates are calculated.

  In order to perform shape measurement with this type of probe 1, it is necessary to move the stylus 4 along the measurement surface 2 a of the measurement object 2. For example, when the measurement object 2 has a cylindrical shape and the outer circumferential surface thereof is measured once, it is necessary to make the probe 1 make one round around the cylinder while maintaining the state in which the stylus 4 is in contact with the outer circumferential surface. A conventional shape measurement probe control apparatus 200 for realizing such movement of the probe 1 is configured as shown in FIG. 6, for example, and drives the shape measurement probe 1 or the measurement object 2 in the XY directions. As a result, the measurement object 2 is moved on the surface 2a to be measured while maintaining the tilt angles of the probe 1 in the X-axis direction and the Y-axis direction substantially constant.

  The conventional shape measurement probe control apparatus 200 will be described. The operation condition setting unit 20 sets operation conditions including a design formula representing the shape of the measurement object 2, a measurement path, a measurement speed, a target probe tilt angle, and the like. In the position command generation unit 21, those operating conditions, the X actual position Xr detected by the X position detector 26, the Y actual position Yr detected by the Y position detector 32, and the inclination angle detection unit 12 The inclination angle of the probe 1 for shape measurement is determined by the inclination angles (X probe inclination angle θX and Y probe inclination angle θY) of the probe 1 calculated by the inclination angle calculation unit 44 based on the signal. The X target position Xt and the Y target position Yt are calculated and output so as to move along the measurement path while maintaining substantially constant. This process is repeated every fixed target position update cycle. The subtractor 22 calculates the difference between the X target position Xt and the X actual position Xr, and the X position controller 23 outputs a speed command corresponding to the difference to the X speed control amplifier 24. The X speed control amplifier 24 drives the X motor 25 so that the speed of the X stage 27 matches the given speed command. As a result, the X stage 27 is driven to the X target position Xt. The same applies to the driving of the Y stage 33. Since the X target position Xt and the Y target position Yt are updated every fixed period, if the period is set to an appropriate time, the shape measuring probe 1 continuously continues the measurement path while maintaining the tilt angle constant. It will move.

JP 2006-284410 A

  In the conventional shape measurement probe control device as described above, a design equation representing the shape of the measurement object set in advance, a measurement path, a measurement speed, a target probe tilt amount, an X actual position, a Y actual position, and an X From the probe tilt angle and the Y probe tilt angle, the X target position and the Y target position are updated at regular intervals so as to move along the measurement path while maintaining the probe tilt angle substantially constant. That is, both the position and the inclination are controlled simultaneously on both the X axis and the Y axis. Such control has a problem that it is difficult to ensure sufficient followability of the probe to the surface to be measured, and if the probe is moved at a high speed, the probe is separated from the measurement object and cannot be measured. . In addition, if the measurement force applied to the measurement object from the probe is increased, the followability can be secured and the measurement speed can be increased, but there is a problem that the detection accuracy of the probe tilt angle is lowered and the measurement accuracy is lowered. It was.

  The present invention solves the above-described conventional problems, and provides a probe controller for shape measurement that can cause a probe to follow a measurement surface at high speed while maintaining a low measurement force, and realize high-speed and high-precision measurement. The purpose is to provide.

  The present invention includes a stylus that contacts a surface to be measured of a measurement object, and a shape for moving a shape measuring probe that can be tilted in both the X-axis direction and the Y-axis direction along the surface to be measured. An X-axis position controller that drives an X-axis motor to move the shape measuring probe to an arbitrary position in the X-axis direction and a Y-axis motor to drive the shape measuring probe. A Y-axis position controller that moves the X-axis motor to an arbitrary position in the Y-axis direction, an X-axis tilt controller that drives the X-axis motor to move the shape measurement probe to an inclination angle in the X-axis direction, and a Y-axis motor Then, the Y-axis tilt controller that moves the shape measuring probe to the tilt angle in the Y-axis direction, the X-axis motor is driven by the X-axis position controller, and the X-axis tilt controller drives the position control mode. Tilt control mode And the Y-axis motor can be switched between a position control mode driven by the Y-axis position controller and a tilt control mode driven by the Y-axis tilt controller. Provided is a shape measurement probe control device including a mode control unit that sets one of the motor and the Y-axis motor to the tilt control mode when the other is in the position control mode.

  Specifically, the shape measurement probe control device detects an actual position of the shape measurement probe in the X axis direction and an actual position of the shape measurement probe in the Y axis direction. A Y-axis position detector; and an inclination angle calculation unit that calculates a representative inclination angle of the shape measurement probe from the optically detected inclination angle of the shape measurement probe in the X axis direction and the Y axis direction. The X position controller further moves the shape measuring probe to an arbitrary position in the X axis direction according to a difference between an actual position in the X axis direction and a target position in the X axis direction, and moves the Y position. The controller moves the shape measuring probe to an arbitrary position in the Y-axis direction according to the difference between the actual position in the Y-axis direction and the target position in the Y-axis direction, and the X-axis tilt controller Depending on the difference between the representative tilt angle and the target tilt angle The shape measurement probe is moved to an arbitrary inclination angle in the X-axis direction, and the Y-axis inclination controller moves the shape measurement probe in the Y-axis direction according to a difference between the representative inclination angle and the target inclination angle. Move to any tilt angle.

  In the shape measuring probe control device of the present invention, the mode control unit sets one of the X-axis motor and the Y-axis motor as the position control mode and the other as the tilt control mode. That is, position control is performed independently on one axis, and tilt control is performed independently on the other axis (an axis for tilt control and an axis for position control are separate). As a result, the control responsiveness of each of the two axes (X-axis motor and Y-axis motor) can be improved, and the shape measurement probe can be moved following the measurement surface at high speed while maintaining a low measurement force. Can do.

  Specifically, the mode control unit is configured to determine the X-axis motor based on the shape of the measurement object or based on a comparison result of the inclination angles of the X-axis direction and the Y-axis direction of the shape measurement probe. One of the motor and the Y-axis motor is set as the position control mode, and the other is set as the tilt control mode.

  The tilt angle calculation unit is configured to set an axis set in the tilt control mode of the X-axis motor and the Y-axis motor among the optically detected tilt angles in the X-axis direction and the Y-axis direction. The corresponding one is set to the representative inclination angle. Alternatively, the inclination angle calculation unit may set the square root of the square sum of the optically detected inclination angles in the X-axis direction and the Y-axis direction as the representative inclination angle. The tilt angle calculation unit may set the sum of absolute values of the optically detected tilt angles in the X-axis direction and the Y-axis direction as the representative tilt angle.

  According to the probe controller for shape measurement of the present invention, the probe can follow the measurement surface at high speed while maintaining a low measurement force, and shape measurement can be performed at high speed and with high accuracy.

  A probe controller for shape measurement which is an embodiment of the present invention will be described in detail below with reference to FIGS.

  FIG. 1 is a diagram illustrating a configuration of a shape measuring probe control apparatus 300 according to an embodiment of the present invention. In this embodiment, a shape measuring probe (hereinafter simply referred to as a probe) 1 showing only the inclination angle detector 12 in FIG. 1 is assumed to be shown in FIGS. 4 and 5. In the following description, FIGS. 4 and 5 are also referred to. 4 and 5 are incorporated in the description of the present embodiment. However, the probe 1 that is an object of the present invention is not limited to that shown in FIGS. 4 and 5, and includes at least a stylus that contacts the surface to be measured of the measurement object, and in either the X-axis direction or the Y-axis direction. As long as it can also be tilted.

  Hereinafter, the shape measuring probe control apparatus 300 will be described in detail.

  In the operating condition setting unit 20 of FIG. 1, operating conditions including a design formula representing the shape of the measurement object 2, a measurement path, a measurement speed, a measurement acceleration, and a target probe tilt angle θt are set. The target probe inclination angle θt is an inclination angle with respect to the Z-axis direction that the stylus 4 of the probe 1 should maintain while the stylus 4 is moving (scanning) on the surface 2a to be measured.

  In the command generation unit 40, each condition set by the operation condition setting unit 20, the X actual position Xr detected by the X position detector 26, the Y actual position Yr detected by the Y position detector 32, The X probe tilt angle θX and the Y probe tilt angle θY obtained by the tilt angle calculation unit 44 using the signals detected by the tilt angle detection unit 12 are input. The command generation unit 40 determines an axis for performing tilt control and an axis for performing position control among these X and Y axes from these inputs. In response to this determination, the command generator 40 outputs the X target position Xt, the Y target position Yt, the target probe tilt angle θt, the X control mode switching signal Mx, and the Y control mode switching signal My. When moving the X stage 27 or the Y stage 33 from one position to another position, if the target position is updated all at once, sudden acceleration and sudden stop occur, so a fixed period is set so that the set measurement speed and measurement acceleration are obtained. The target position is calculated and output every time.

  The inclination angle detection unit 12 is as already described with reference to FIG.

  The inclination angle calculation unit 44 has two functions in this embodiment. As the first function, the tilt angle calculation unit 44 sets the light amounts detected in the light receiving areas 12a to 12e (see FIG. 5) of the tilt angle detection unit 12 to “A”, “B”, and “C”, respectively. And “D”, the inclination angle (X probe inclination angle) θX of the probe 1 in the X-axis direction is obtained by calculating (A + B) − (C + D), and the calculation of (A + D) − (B + C) is performed. By doing so, the inclination angle (Y probe inclination) θY of the probe 1 in the Y-axis direction is obtained. The calculated X and Y probe tilt angles θX and θY are output to the command generator 40. As a second function, the tilt angle calculation unit 44 obtains the representative probe tilt angle θr from the X and Y probe tilt angles θX and θY by any of the following three methods, and performs the X-axis direction and the Y-axis direction. Are output to the subtracters 42 and 46 respectively used for the inclination control.

  The first representative probe tilt angle θr is calculated by using the probe tilt angle of the X axis and Y axis (X motor 25 and Y motor 31) in the tilt control mode as the representative probe tilt angle θr. To do. Specifically, when the X axis (X motor 25) is in the tilt control mode, the absolute value (| (A + B) − (C + D) |) of the X probe tilt angle θX is output as the representative probe tilt angle θr. When the Y axis (Y motor 31) is in the tilt control mode, the absolute value (| (A + D) − (B + C) |) of the Y probe tilt angle θY is output as the representative probe tilt angle θr.

The calculation method of the second representative probe tilt angle θr includes the tilt angle obtained by converting the X and Y probe tilt angles θX and θY into the direction perpendicular to the measured surface 2a, and the square sum of the X and Y probe tilt angles θX and θY. Is the representative probe tilt angle θr. In this case, the representative probe tilt angle θr is expressed by the following formula (1).

  In the third representative probe tilt angle θr calculation method, the sum of absolute values of the X and Y probe tilt angles θX and θY is set as the representative probe tilt angle θr. In this case, the representative probe tilt angle θr is expressed by the following equation (2).

  In the case of the first representative probe tilt angle calculation method, for example, at the stylus position 61 shown in FIG. 2, the Y probe tilt angle θY is substantially zero, but as the stylus position 62 moves, the Y probe tilt angle θY As the stylus position 62 increases, the X probe tilt angle θX and the Y probe tilt angle θY have substantially the same value. The position at which the reflected light strikes the light receiving surface of the tilt angle detection unit 12 at the stylus position 61 is the light receiving position 50 in FIG. 3, and the position at which the reflected light strikes the light receiving surface of the tilt angle detection unit 12 at the stylus position 62. Is the light receiving position 51.

  Actually, since the characteristics of the light receiving regions 12a to 12d of the tilt angle detector 12 cannot be completely linear, if the Y probe tilt angle θY is different even if (A + B) − (C + D) is the same value, An error occurs in the X probe tilt angle θX. That is, the actual X probe tilt angle θX differs between the light receiving position 50 and the light receiving position 51. Since the X position coordinate of the measurement point is obtained from the X coordinate value measured by the position coordinate measurement unit 14 and the X probe inclination angle θX obtained by the inclination angle detection unit 12 and the inclination angle calculation unit 44, the X probe inclination angle θX is obtained. This detection error becomes a measurement error as it is. Since the measurement error increases as the distance from the center of the light receiving surface of the tilt angle detector 12 increases, it is preferable that reflected light strikes a position near the center of the light receiving surface for high-accuracy measurement.

  In the case of the second representative probe tilt angle calculation method, assuming that the representative probe tilt angle θr calculated by Equation (1) at the stylus position 62 is X and Y probe tilt angles θX, θY (θX, θY = θr), The position where the reflected light strikes the light receiving surface of the tilt angle detection unit 12 is the light receiving position 52, which is closer to the center of the light receiving surface than the light receiving position 51, so that the error is reduced.

  In the case of the third representative probe tilt angle calculation method, when the representative probe tilt angle θr calculated by the equation (2) at the stylus position 62 is X and Y probe tilt angles θX, θY (θX, θY = θr), The position where the reflected light strikes the light receiving surface of the tilt angle detection unit 12 is the light receiving position 53, and further approaches the center of the light receiving surface, so the error is reduced. However, in this case, since there is a portion where the tilt angle converted in the direction perpendicular to the measurement surface is small, if the measurement speed is increased, the tilt control cannot follow and the stylus 4 moves away from the measurement object 2 and can be measured. It may disappear.

  As described above, the first tilt angle calculation method is used when it is desired to measure at high speed even if the measurement accuracy is slightly low. The third tilt angle is used when it is desired to measure with high accuracy even if the measurement speed is slightly slow. The second tilt angle calculation method is used with the calculation method as an intermediate between them. In either case, the axis for tilt control and the axis for position control are separate, and the tracking capability of tilt control is better than the conventional method using a shape control probe control device, so it is fast and highly accurate. Measurement is possible.

  When the X control mode changeover switch 41 is set to the position of the solid line by the X control mode change signal Mx from the command generation unit 40, the X axis (X motor 25) enters the position control mode, and the X position controller 23 and the X position controller 23 Among the tilt controllers 43, the X position controller 23 is effective. The X position controller 23 outputs an X speed command to the X speed control amplifier 24 in accordance with the difference between the X target position Xt and the X actual position Xr. The X position controller 23 is based on proportional control and is integrated to improve control characteristics. Control and differential control may be added. In order to simplify the explanation, assuming that only proportional control is performed, the X position controller 23 is obtained by multiplying (X target position Xt−X actual position Xr) calculated by the subtractor 22 by the X position proportional gain. The command is output to the X speed control amplifier 24 as a command. The X speed control amplifier 24 drives the X motor 25 for driving the X stage 27 so that the speed of the X stage 27 matches the X speed command. That is, when the X actual position is smaller than the X target position, the X motor 25 is driven in the direction in which the X actual position becomes larger. Conversely, when the X actual position is larger than the X target position, the X actual position is Since the X motor 25 is driven in a decreasing direction, the X actual position is always controlled to substantially coincide with the X target position.

  When the X control mode changeover switch 41 is set to the position of the broken line by the X control mode change signal Mx from the command generation unit 40, the X axis (X motor 25) is in the tilt control mode, and the X position controller 23 and the X position controller 23 Among the tilt controllers 43, the X tilt controller 43 is effective. The X tilt controller 43 outputs an X speed command to the X speed control amplifier 24 in accordance with the difference between the target probe tilt angle θt and the representative probe tilt angle θr, and is based on proportional control to improve control characteristics. Integral control and differential control may be added. For simplicity of explanation, assuming that only proportional control is performed, the X tilt controller 43 is obtained by multiplying (target probe tilt angle θt−representative probe tilt angle θr) calculated by the subtractor 42 by an X tilt proportional gain. An X speed command is output to the X speed control amplifier 24. However, since the control direction changes depending on the positional relationship between the stylus 4 and the measurement object 2, when the X position of the measurement object 2 is on the + side of the X position of the stylus 4, the sign of the X slope proportional gain is +, When the X position of the measurement object 2 is on the − side with respect to the X position of the stylus 4, the sign of the X inclination proportional gain is −. The X speed control amplifier 24 drives the X motor 25 so that the speed of the X stage 27 matches the X speed command. That is, when the representative probe tilt angle is smaller than the target probe tilt angle, the X motor 25 is driven in the direction in which the representative probe tilt angle increases, and conversely, when the representative probe tilt angle is larger than the target probe tilt angle. Since the X motor 25 is driven in a direction in which the representative probe tilt angle becomes smaller, the representative probe tilt angle is always controlled to substantially match the target probe tilt angle.

  Also for the Y axis (Y motor 31 for driving the Y stage 33), the Y control mode changeover switch 45 switches between the position control mode and the tilt control mode in accordance with the Y control mode changeover signal My from the command generation unit 40. Since the operations in the position control mode and the tilt control mode are the same as in the case of X described above, description thereof will be omitted.

  The detailed operation of the shape measuring probe control apparatus 300 configured as described above will be described by taking as an example the case of measuring a cylindrical measurement object as shown in FIG. FIG. 2 is a view (XY plane) of a cylindrical measurement object as viewed from above.

  When shape measurement is performed using the shape measurement probe control apparatus 300 shown in FIG. 1, even if the probe 1 side is moved by the X stage 27 and Y stage 33, the measurement object 2 side is moved to the X stage 27 and Y stage 33. However, in the following description, the probe 1 side is moved to facilitate understanding. Further, the probe 1 is assumed to have the structure shown in FIG. 4, and description of the operation in the Z direction is omitted, and the X stage 27 and the Y stage 33 are moved at any Z position to measure the outer surface of the measurement object 2 once. How to do will be described. However, if the stylus can be swung in the XY direction and can be displaced in the Z direction with respect to the probe, the probe 1 can be moved in the Z direction to measure the entire outer surface of the cylindrical measurement object 2. It is.

  First, the operation condition setting unit 20 sets parameters that do not need to be changed during measurement, that is, X velocity, X acceleration, Y velocity, Y acceleration, and target probe tilt angle θt.

  Since the operation of retracting the probe 1 is necessary to install the measurement object 2, both the X control mode changeover switch 41 and the Y control mode changeover switch 45 are set to the solid line positions, that is, the position control mode. In the example of FIG. 2, the X target position is set to a position where there is no problem with the installation of the measurement object 2, the probe 1 is moved to that position, and then the measurement object 2 is installed at substantially the center of the movable range of the probe 1. The probe 1 is moved so that the position in the Y direction is approximately the center of the measurement object 2. The position of the stylus 4 in this state is the stylus position 60 in FIG.

  Next, in the command generator 40, the X target position Xt is updated at regular intervals so that the shape measuring probe 1 moves to the negative side in the X direction at a constant speed (arrow A1 in FIG. 5). In the meantime, the representative probe tilt angle θr is confirmed for each period, and when the value enters a preset range centered on the target probe tilt angle θt, the X control mode changeover switch 41 is moved from the solid line position to the broken line position. By switching, the X axis is switched from the position control mode to the tilt control mode. The position of the stylus 4 in this state is the stylus position 61 in FIG.

  Next, the operation condition setting unit 20 calculates the Y target position Yt so that the position of the stylus 4 is 45 degrees, that is, the stylus position 62 in FIG. Thus, the Y stage 33 moves from the Y position of the stylus position 61 to the Y position of the stylus position 62 (arrow A2 in FIG. 2). During this time, the X stage 27 is in the tilt control mode and moves so that the representative probe tilt angle θr substantially coincides with the target probe tilt angle θt, so that the stylus 4 moves from the stylus position 61 to the stylus position 62 on the outer surface of the measurement object 2. Will move along.

  When the stylus 4 moves to the stylus position 62, the X target position Xt is set to the same value as the current X actual position Xr, and then the X control mode changeover switch 41 is switched to the solid line position to set the X axis to the position control mode. Then, the Y control mode changeover switch 45 is switched to the position of the broken line to set the Y axis to the tilt control mode.

  Next, in the operation condition setting unit 20, the X target position Xt is calculated so that the position of the stylus 4 becomes a position of 135 degrees, that is, the stylus position 63, and is output to the command generation unit 40. As a result, the X stage 27 moves from the X position of the stylus position 62 to the X position of the stylus position 63 (arrow A3 in FIG. 2). During this time, the Y stage 33 is in the tilt control mode and moves so that the representative probe tilt angle θr substantially coincides with the target probe tilt angle θt, so that the stylus 4 moves from the stylus position 62 to the stylus position 63 on the outer surface of the measurement object 2. Will move along.

  When the stylus 4 moves to the stylus position 63, after setting the Y target position Yt to the same value as the current Y actual position Yr, the Y control mode changeover switch 45 is switched to the position of the solid line, and Y is set to the position control mode. The X control mode changeover switch 41 is switched to the position of the broken line to set X to the tilt control mode.

  Thereafter, movement to the stylus position 64 (arrow A4 in FIG. 2), switching of the control mode at the stylus position 64 (X-axis from tilt control to position control, Y-axis from position control to tilt control), to stylus position 65 2 (arrow A5 in FIG. 2), switching of the control mode at the stylus position 65 (X-axis from position control to tilt control, Y-axis from tilt control to position control) and movement to the stylus position 61 (in FIG. 2) Arrow A6) is performed.

  As described above, after moving from the stylus position 60 to the stylus position 61 for the first time, moving around the outer surface of the measurement object 2 and returning to the stylus position 61 again (arrows A1 to A6), the position Measurement is performed from the X coordinate value, the Y coordinate value, and the Z coordinate value measured by the coordinate measuring unit 14, and the X probe tilt angle θX and the Y probe tilt angle θY obtained by the tilt angle detecting unit 12 and the tilt angle calculating unit 44. The X position coordinate, Y position coordinate, and Z position coordinate of the point 100 are obtained.

  Next, another measurement method will be described with reference to FIG. The process from the stylus position 60 to the stylus position 61 (arrow A1) is the same as that described above. Thereafter, in the command generator 40, the Y target position Yt is updated at regular intervals so that the probe 1 moves to the + side in the Y direction at a constant speed. During this period, the X probe tilt angle θX and the Y probe tilt angle θY are compared for each period, and when the Y probe tilt angle θY is larger than the sum of the X probe tilt angle θX and the determination width D, the X target position Xt is After setting the same value as the X actual position Xr, the X control mode switch 41 is switched to the solid line position, the X axis is set to the position control mode, the Y control mode switch 45 is switched to the broken line position, and the Y axis To tilt control mode.

  Since the positional relationship between the stylus 4 and the measurement object 2 can be known from the sign of the Y probe tilt angle θY before the control mode is switched, the sign of the Y tilt proportional gain is set accordingly. Further, since the positional relationship between the stylus 4 and the measurement object 2 can be known from the sign of the X probe tilt angle before the control mode is switched, the shape measurement probe 1 is moved to the measurement object side in the X direction in the command generation unit 40. The X target position is updated at regular intervals so as to move at a constant speed.

  During the movement in the X direction, the X probe tilt angle θX and the Y probe tilt angle θY are compared for each period, and if the X probe tilt angle θX becomes larger than the sum of the Y probe tilt angle θY and the determination width D, the Y target After setting the position Yt to the same value as the current Y actual position Yr, the Y control mode switch 45 is switched to the solid line position, the Y axis is set to the position control mode, and the X control mode switch 41 is set to the broken line position. Switch to the tilt control mode for the X axis.

  The determination width D gives hysteresis to the change in the magnitude relationship between the X probe tilt angle θX and the Y probe tilt angle θY, and the control mode can be switched when the X probe tilt angle θX and the Y probe tilt angle θY are approximately the same. It is intended not to be repeated many times.

  By repeating the above operation, even if the design formula of the measurement object is unknown, the measurement can be performed by making a round along the outer surface of the measurement object 2 from the stylus position 61.

  Regardless of which of the two methods described above, one of the X axis (X motor 25) and the Y axis (Y motor 31) is set to the position control mode, and the other is set to the tilt control mode. That is, position control is performed independently on one of the X axis and the Y axis, and tilt control is performed independently on the other axis (the axis for tilt control and the axis for position control are separate). As a result, the control responsiveness of each of the two axes (X-axis motor 25 and Y-axis motor 31) can be improved, and the probe 1 can be moved following the measurement surface 2a at high speed while maintaining a low measurement force. High-speed and high-precision shape measurement.

  The shape measuring probe control device of the present invention has an effect that high-precision measurement can be performed while causing the probe to follow a measurement object at a high speed with a low measurement force. It can be effectively used for probe control of a shape measuring apparatus that measures the diameter and the shape of the outer surface of an arbitrary shape with high accuracy.

The block diagram which shows the structure of the probe control apparatus for shape measurement in embodiment of this invention. The schematic diagram for demonstrating an example of the shape measurement in the embodiment. The front view which shows the state in which reflected light hits the inclination-angle detector in the same embodiment. The schematic diagram which shows the structure of the probe for shape measurement, and a measurement point information determination part. The front view which shows the state in which reflected light hits an inclination angle detector. The block diagram which shows the structure of the conventional probe controller for shape measurement.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shape measuring probe 2 Measurement object 4 Stylus 5 Arm 6 Swing member 7 Mirror 8 Connection mechanism 9 Mounting member 10 Measuring point information determination part 11 Optical system 11a 1st optical system 11b 2nd optical system 12 Inclination angle detection part 12a- 12d Light receiving area 13 Stylus position calculation unit 14 Position coordinate measurement unit 14a to 14c Detection unit 15 Addition unit 16 Laser light generation unit 17 Laser beam for measurement 17b Reflected light 18 Light separation unit 20 Operating condition setting unit 21 Position command generation unit 22 Subtraction 23 X Position Controller 24 X Speed Control Amplifier 25 X Motor 26 X Position Detector 27 X Stage 28 Subtractor 29 Y Position Controller 30 Y Speed Control Amplifier 31 Y Motor 32 Y Position Detector 33 Y Stage 40 Command Generation Unit 41 X control mode selector switch 42 Subtractor 43 X tilt controller 44 Tilt angle Calculation unit 45 Y control mode switch 46 subtractor 47 Y tilt controller 50-53 receiving position 60-65 stylus position 100 measuring points 121 light-receiving surface

Claims (7)

A shape measuring probe control for moving a shape measuring probe, which is provided with a stylus in contact with the surface to be measured of the object to be measured and can be tilted in both the X axis direction and the Y axis direction, along the surface to be measured. A device,
An X-axis position controller that drives the X-axis motor to move the shape measuring probe to an arbitrary position in the X-axis direction;
A Y-axis position controller for driving the Y-axis motor to move the shape measuring probe to an arbitrary position in the Y-axis direction;
An X-axis tilt controller that drives the X-axis motor to move the shape measuring probe to an tilt angle in the X-axis direction;
A Y-axis tilt controller that drives the Y-axis motor to move the shape measuring probe to a tilt angle in the Y-axis direction;
The X-axis motor can be switched between a position control mode driven by the X-axis position controller and a tilt control mode driven by the X-axis tilt controller, and the Y-axis motor is controlled by the Y-axis position control. The position control mode can be switched between a position control mode driven by a motor and a tilt control mode driven by the Y-axis tilt controller, and one of the X-axis motor and the Y-axis motor is set as the position control mode. And a shape control probe control device, comprising: a mode control unit that sets the other to the tilt control mode. An X-axis position detector for detecting the actual position of the shape measuring probe in the X-axis direction;
A Y-axis position detector for detecting the actual position of the shape measuring probe in the Y-axis direction;
An inclination angle calculation unit that calculates a representative inclination angle of the shape measurement probe from the inclination angles of the X axis direction and the Y axis direction of the shape measurement probe detected optically;
The X position controller moves the shape measuring probe to an arbitrary position in the X axis direction according to a difference between the actual position in the X axis direction and a target position in the X axis direction,
The Y position controller moves the shape measuring probe to an arbitrary position in the Y axis direction according to the difference between the actual position in the Y axis direction and the target position in the Y axis direction,
The X-axis tilt controller moves the shape measuring probe to an arbitrary tilt angle in the X-axis direction according to the difference between the representative tilt angle and the target tilt angle.
The shape measurement probe according to claim 1, wherein the Y axis inclination controller moves the shape measurement probe to an arbitrary inclination angle in the Y axis direction according to a difference between the representative inclination angle and the target inclination angle. Control device.   The mode control unit according to claim 2, wherein the mode control unit sets one of the X-axis motor and the Y-axis motor as the position control mode and the other as the tilt control mode based on the shape of the measurement object. Probe control device for shape measurement   The mode control unit controls one of the X-axis motor and the Y-axis motor in the position control mode based on a comparison result of the tilt angles of the shape measuring probe in the X-axis direction and the Y-axis direction. The shape control probe control device according to claim 2, wherein the other is set to the tilt control mode.   The tilt angle calculation unit is configured to set an axis set in the tilt control mode of the X-axis motor and the Y-axis motor among the optically detected tilt angles in the X-axis direction and the Y-axis direction. 5. The shape measuring probe control device according to claim 2, wherein a corresponding one is set to the representative inclination angle.   The tilt angle calculation unit sets the square root of the square sum of the optically detected tilt angles in the X-axis direction and the Y-axis direction as the representative tilt angle. The probe control device for shape measurement according to 1.   The tilt angle calculation unit sets the sum of absolute values of the tilt angles in the X-axis direction and the Y-axis direction detected optically as the representative tilt angle. The probe control device for shape measurement according to 1.

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