JP6474216B2 - Shape measuring apparatus and shape measuring method - Google Patents

Description

  The present invention relates to a shape measuring device and a shape measuring method.

Conventionally, a probe having a probe for measuring an object to be measured, a moving mechanism for moving the probe, and a control device for controlling the moving mechanism are provided, and the object to be measured is moved by moving the probe along the surface of the object to be measured. A shape measuring device for measuring the shape of a measurement object is known (see, for example, Patent Document 1).
The apparatus described in Patent Document 1 is based on design data (NURBS (Non-Uniform Rational B-Spline) data) based on CAD data or the like, and PCC (Parametric Cubic Curves) indicating the movement path of the probe. ) Calculate the curve. The PCC curve is composed of a plurality of PCC segments, and is divided into a plurality of interpolation points for each segment. Then, the scanning measurement is performed substantially along the PCC curve by moving the probe along the linear direction connecting the interpolation point (i) in each segment and the interpolation point (i + 1) with respect to the interpolation point (i).

JP 2014-21004 A

By the way, in the shape measuring apparatus described in Patent Document 1, the PCC curve is based on the design contour (ideal design value tracing trajectory) obtained by subtracting the reference pressing amount E of the probe from the radius R of the probe from the design data. The curve takes into account a predetermined tolerance (Allowed Deviation; AD value). Here, depending on the magnitude of the AD value, a separation error in which the probe is detached from the object to be measured or a push-in error in which the probe push-in amount is exceeded occurs.
The occurrence frequency of the separation error and the push-in error varies depending on the magnitude of the AD value, and the error occurrence frequency can be suppressed by setting the AD value to be small. When the AD value is increased, the error occurrence frequency is increased.

On the other hand, the number of PCC segments constituting the PCC curve, that is, the maximum number of segments that can be set is limited, and if the maximum number of segments is exceeded, an over segment number error occurs.
This segment number over error varies depending on the size of the AD value. If the AD value is set small, the number of segments increases and the frequency of error occurrence increases. If the AD value is set large, the number of segments decreases and an error occurs. Frequency is suppressed.

  As described above, the occurrence frequency of the separation error and the push-in error and the segment number over error both vary depending on the AD value, but the relationship with the AD value is contradictory. For this reason, conventionally, a method of dividing a design contour or the like has been employed as an error countermeasure. However, in this case, there has been a problem that processing when combining measurement results becomes complicated.

  An object of this invention is to provide the shape measuring apparatus and shape measuring method which can suppress complication of a measurement process.

  The shape measuring apparatus of the present invention comprises a probe having a probe at the tip and a moving mechanism for moving the probe along the surface of the object to be measured, and the contact between the probe and the surface of the object to be measured Is a shape measuring device for measuring the shape of the object to be measured, and includes contour setting means for setting a design contour based on the shape data of the object to be measured, and moving the probe along the design contour An allowable error setting means for setting an allowable error to be performed, and a path setting means for setting a design curve that is formed of a plurality of segments along the design outline based on the design outline and the allowable error. Segment number determining means for determining whether or not the number of segments exceeds a predetermined maximum number of segments; position detecting means for detecting the amount of pressing of the measuring element into the object to be measured; and the pressing Error detection means for detecting a measurement error based on the amount, and the allowable error setting means increases the allowable error when the number of segments exceeds the maximum number of segments, and is measured by the error detection means. When an error is detected, the tolerance is reduced.

In the present invention, a design curve (PCC curve) taking into account a predetermined tolerance (AD value) is set for the design contour, the PCC curve is divided into a plurality of segments, and along the divided segments. The scanning measurement is performed by moving the probe.
Here, in the present invention, it is determined whether or not the number of segments (number of segments) is the maximum number of segments by the number of segments determination unit. When the number of segments is the maximum number of segments, the tolerance setting unit Increase the value.
In addition, when the scanning measurement is actually performed, the error detection unit detects a measurement error when the pressing amount of the probe exceeds the allowable range. That is, when the pushing amount is smaller than a predetermined minimum value, a separation error is detected, and when the pushing amount is larger than a predetermined maximum value, a pushing error is detected. The allowable error setting means decreases the AD value when such an error in measurement is detected.
As described above, in the present invention, it is possible to set an optimum AD value that does not cause an error in the number of segments and does not cause a measurement error during measurement. Therefore, it is possible to avoid complication of measurement processing due to division of the design contour.

In the shape measuring apparatus of the present invention, the design curve is a curve that is offset from the design contour by a value obtained by subtracting the amount of pushing of the probe into the object to be measured from the radius of the probe. When the measurement error is detected by the control unit, the control unit includes a pressing amount adjusting unit that adjusts the pressing amount between a predetermined lower limit value and a predetermined upper limit value, and the allowable error setting unit is controlled by the pressing amount adjusting unit. It is preferable to reduce the allowable error when the adjusted push-in amount reaches the lower limit value or the upper limit value, and when the measurement error is detected by the error detection means.

In the present invention, when the measurement of the probe position is performed and a measurement error is detected, first, the pushing amount is adjusted. In such a configuration, in addition to the setting of the allowable error (AD value) as described above, the measurement error can be eliminated by adjusting the push-in amount of the probe. Also, in the case of avoiding measurement errors by dividing the design contour, as described above, after setting a design curve (PCC curve) and a segment for each divided design contour, the measurement result is obtained after measurement. The process to combine becomes complicated. In the present invention, adjustment is performed so that measurement errors are avoided by adjusting the AD value and the push-in amount, so that the processing complexity due to the division of the design contour can be avoided with a higher probability.
Further, when the AD value is decreased, the number of segments increases, and there is a possibility that an error in the number of segments will occur. On the other hand, in the present invention, before the AD value is decreased, the probe pressing amount is adjusted, and when the measurement error cannot be avoided by adjusting the probe pressing amount, the AD value is decreased. For this reason, generation | occurrence | production of the segment number over error can be suppressed as much as possible.

The shape measuring apparatus according to the present invention further includes a moving speed setting unit that sets a moving speed when the probe is moved, and the moving speed setting unit detects an error by the error detecting unit and adjusts the pushing amount. When the pushing amount adjusted by the means reaches the lower limit value or the upper limit value, the moving speed of the probe is reduced, and the allowable error setting means is configured to reduce the movement speed setting means. It is preferable to reduce the allowable error when the moving speed reaches a predetermined minimum moving speed and when the measurement error is detected by the error detecting means.

In the present invention, similarly to the above-described invention, when a measurement error is detected, the push amount is first adjusted, and when the measurement error is not avoided by adjusting the push amount, the moving speed of the probe is decreased. Decreasing the moving speed of the probe means a measurement time delay. In the present invention , when a measurement error is detected after the push-in amount is adjusted, the moving speed is reduced, so that a delay in measurement time can be avoided as much as possible. Also, in the present invention, adjustment is performed so as to avoid measurement errors by setting tolerances, adjusting the probe push-in amount, and adjusting the probe moving speed, so the process can be complicated by dividing the design contour. It can be avoided as much as possible.
Similarly to the above-described invention, when the AD value is decreased, the number of segments increases, which may cause an over-segment error. On the other hand, in the present invention, the occurrence of the segment number over error can be suppressed as much as possible by adjusting the moving speed of the probe before reducing the AD value.

In the shape measuring apparatus according to the aspect of the invention, the contour setting unit may be configured such that the allowable error set by the allowable error setting unit reaches a predetermined minimum value, and the measurement error is detected by the error detection unit. The design contour is preferably divided.
In the present invention, when the measurement error cannot be avoided by setting the AD value by the allowable error setting unit as described above, the design contour set by the contour setting unit is divided into a plurality. If the design contour is not divided, high-precision shape measurement cannot be performed. However, by dividing the design contour, the number of segments and the length of each segment can be shortened, and the occurrence of segment number over error and measurement error can be suppressed. .

The shape measuring method of the present invention comprises a probe having a probe at the tip and a moving mechanism for moving the probe along the surface of the object to be measured, and the contact between the probe and the surface of the object to be measured Is a shape measuring method in a shape measuring apparatus for measuring the shape of the object to be measured, wherein a design contour based on the shape data of the object to be measured is set and the probe is moved along the design contour A setting step of setting an allowable error that is allowed when the probe is set, and setting a design curve that is formed along a plurality of segments along the design contour based on the design contour and the allowable error, and the position of the probe with measuring a detectable to the position of the probe, a measuring step of detecting a pressing amount of the to be measured of the measuring element, the number of said segments set in the setting step is predetermined And segment number determination step of determining whether or not more than the number of large segments, wherein the error detection step of detecting a measurement error, was performed based on the push amount detected in the measuring step, the setting step, the When the number of segments is determined to exceed the maximum number of segments by the segment number determination step, the tolerance is increased, and when the measurement error is detected by the error detection step, the tolerance is decreased. Features.
In the present invention, similarly to the above-described invention, it is possible to set an optimum allowable error that does not cause an error in the number of segments and does not cause an error during measurement. Therefore, it is possible to avoid complication of measurement processing due to division of the design contour.

The whole schematic diagram which shows the three-dimensional measuring apparatus which is the shape measuring apparatus of one Embodiment which concerns on this invention. The block diagram which shows schematic structure of the three-dimensional measuring apparatus of this embodiment. The figure which shows an example of the design data in this embodiment, a PCC curve, the movement locus | trajectory of a probe (measuring element), and a locus | trajectory error. The flowchart which shows the error avoidance method at the time of moving the probe in the shape measuring method of this embodiment according to the surface of a to-be-measured object.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.
[Schematic configuration of CMM]
FIG. 1 is an overall schematic diagram showing a coordinate measuring machine 1 which is a shape measuring apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a schematic configuration of the coordinate measuring machine 1.
In FIG. 1, the upper direction is defined as the + Z-axis direction, and two axes orthogonal to the Z-axis are described as the X-axis and the Y-axis, respectively. The machine coordinate system is defined by the X-axis direction, the Y-axis direction, and the Z-axis direction. The same applies to the following drawings.
As shown in FIG. 1, the coordinate measuring machine 1 instructs the motion controller 3 through a coordinate measuring machine body 2, a motion controller 3 that performs drive control of the coordinate measuring machine body 2, and an operation lever. And a host computer 5 for manually operating the coordinate measuring machine main body 2 and for giving a predetermined command to the motion controller 3 and executing arithmetic processing.

[Configuration of CMM body]
As shown in FIG. 1, the coordinate measuring machine main body 2 includes a probe 21 having a spherical probe 211 </ b> A for measuring an object to be measured, a moving mechanism 22 that holds the probe 21 and moves the probe 21. And a surface plate 23 on which the moving mechanism 22 is erected.
As shown in FIG. 1, the probe 21 includes a stylus 211 having a probe 211A on the distal end side (−Z axis direction side) and a support mechanism 212 that supports the proximal end side (+ Z axis direction side) of the stylus 211. Prepare.

The support mechanism 212 supports the stylus 211 so as to be positioned at a predetermined position by urging the stylus 211 in the X, Y, and Z axis directions. The support mechanism 212 can move the stylus 211 in the X, Y, and Z axis directions within a certain range when an external force is applied, that is, when the probe 211A contacts the object to be measured. It is said.
Although not specifically shown, the support mechanism 212 includes a probe sensor for detecting the position of the stylus 211 in each axial direction.
Each probe sensor is a position sensor that outputs a pulse signal corresponding to the amount of movement of the stylus 211 in each axial direction.

As shown in FIG. 1 or FIG. 2, the moving mechanism 22 holds the probe 21 and allows the probe 21 to move by driving the slide mechanism 24 and the slide mechanism 24. And a mechanism 25.
As shown in FIG. 1, the slide mechanism 24 includes two columns 241 that extend in the + Z-axis direction from both ends of the surface plate 23 in the X-axis direction and are slidable along the Y-axis direction, and each column 241. And a slider that is formed in a cylindrical shape that extends along the Z-axis direction and is slidable along the X-axis direction. 243, and a ram 244 that is inserted into the slider 243 and is slidable along the Z-axis direction inside the slider 243.

  As shown in FIG. 1 or 2, the drive mechanism 25 supports a column 241 on the + X-axis direction side among the columns 241, and slides along the Y-axis direction, and a beam 251Y. X-axis drive unit 251X (FIG. 2) that slides 242 and moves slider 243 along the X-axis direction, and Z-axis drive that slides inside slider 243 and moves ram 244 along the Z-axis direction Part 251Z (FIG. 2).

Although not specifically shown in the X-axis drive unit 251X, the Y-axis drive unit 251Y, and the Z-axis drive unit 251Z, in order to detect the position of the slider 243, each column 241, and the ram 244 in each axial direction. Each of the scale sensors is provided.
Each scale sensor is a position sensor that outputs a pulse signal corresponding to the amount of movement of the slider 243, each column 241, and the ram 244.

[Configuration of motion controller]
As illustrated in FIG. 2, the motion controller 3 includes a command acquisition unit 31, a parameter setting unit 32, a drive control unit 33, a counter unit 34, a position measurement unit 35, and an error detection unit 36. In addition, as shown in FIG. 1, the motion controller 3 is provided with an operation means 4 so that the CMM main body 2 can be manually operated.
The command acquisition unit 31 acquires PCC data for driving the probe 21 from the host computer 5. The PCC data includes a movement path for moving the probe 21.
The parameter setting unit 32 functions as a push-in amount adjusting unit and a moving speed setting unit in the present invention, and sets a speed pattern for moving the probe 21 based on the PCC data. Further, the parameter setting unit 32 adjusts the moving speed (the scanning speed V) of the probe 21 and the push-in amount E when an error is detected by the error detection unit 36.
The drive control unit 33 controls the drive mechanism 25 based on the speed pattern set by the parameter setting unit 32 and moves the probe 21 along the movement path specified by the PCC data.
The counter unit 34 counts the pulse signal output from each scale sensor described above to measure the movement amount of the slide mechanism 24 and counts the pulse signal output from each probe sensor described above to move the stylus 211. Measure the amount.
The position measurement unit 35 detects the position (probe position) of the probe 211A based on the movement amounts of the slide mechanism 24 and the stylus 211 measured by the counter unit 34. Further, the position measuring unit 35 functions as an indentation amount detection unit of the present invention, and calculates the indentation amount of the probe 21 (indentation amount of the measuring element 211A with respect to the object W to be measured) based on the output value from the probe sensor. .
The error detection unit 36 detects measurement errors (detachment error and pressing error) based on the pressing amount of the probe 21 calculated by the position measuring unit 35. That is, a release error is output when the push amount is smaller than the predetermined minimum value, and a push error is output when the push amount is larger than the predetermined maximum value.

[Configuration of host computer]
The host computer 5 includes a CPU (Central Processing Unit), a memory, and the like, and controls the coordinate measuring machine main body 2 by giving a predetermined command to the motion controller 3. The host computer 5 includes input means 61 and output means 62. The input means 61 is for inputting measurement conditions and the like in the coordinate measuring machine 1 to the host computer 5, and the output means 62 is for outputting a measurement result by the coordinate measuring machine 1.
As shown in FIG. 2, the host computer 5 includes an information acquisition unit 51, an outline setting unit 52, an AD setting unit 53, a route setting unit 54, a route determination unit 55, a shape analysis unit 56, and a storage. Part 57.
The information acquisition unit 51 acquires design data (CAD data, NURBS data, etc.) of the workpiece W from a CAD system (not shown).

The contour setting unit 52 is contour setting means of the present invention, and moves the probe 21 along the surface of the workpiece W based on the design data, the radius R of the probe 211A, and the reference pushing amount E of the probe 21. A design contour which is an ideal trajectory for copying the design value is set.
FIG. 3 is a diagram showing an example of the design contour, a part of the PCC curve (design curve) set for the design data in this embodiment, and the actual movement locus of the actual probe 211A in the measurement process.
As shown in FIG. 3, the contour setting unit 52 sets a value obtained by subtracting the reference push amount E from the radius R of the measuring element 211A as an offset amount, and sets a curve moved from the design data in the normal direction by the offset amount. Set as.
The AD setting unit 53 is an allowable error setting unit of the present invention, and sets an allowable error (AD value) of the trajectory when the probe 21 is actually moved with respect to the design contour.
The route setting unit 54 is a route setting unit of the present invention, and calculates a PCC curve (design curve) based on the design contour and the AD value. This PCC curve is composed of a plurality of segments, and these segments are divided by interpolation points. In actual scanning measurement, the probe 21 is moved along a straight line (interpolation straight line (i)) connecting the interpolation point (i) and the interpolation point (i + 1) corresponding to the interpolation point (i).
The route determination unit 55 is a segment determination unit of the present invention, and determines whether or not the number of segments (number of segments) included in the PCC curve set by the route setting unit 54 is equal to or less than a predetermined maximum number of segments. . For example, the ratio of the set number of segments to the maximum number of segments is calculated, and it is determined whether or not it is 100% or less.
The shape analysis unit 56 calculates the surface shape data of the object to be measured based on the measurement data output from the motion controller 3, and performs shape analysis to obtain errors, distortions, and the like of the calculated surface shape data of the object to be measured.
The storage unit 57 stores various data used by the host computer 5, design data related to the shape of the workpiece W, and the like.

[Operation of CMM]
Next, the operation of the coordinate measuring machine 1 as described above will be described.
FIG. 4 is a flowchart showing an error avoidance method when the probe 21 is moved along the surface of the workpiece W in the shape measurement method of the present embodiment.
In the present embodiment, when measuring the surface shape of the workpiece W, the information acquisition unit 51 of the host computer 5 receives NURBS (Non-Uniform Rational B-Spline: setting data of the workpiece W from the CAD system. (Non-uniform rational B-spline) data is acquired (step S1).
Next, the contour setting unit 52 calculates (sets) a design contour based on the acquired design data (step S2). Specifically, as described above, when the radius of the measuring element 211A is R and the reference pushing amount is E, the offset amount is calculated as RE. Then, as shown in FIG. 3, a curve obtained by offsetting the curve of the design data in the normal direction by the calculated offset amount is set as the design contour.
Further, the AD setting unit 53 sets the AD value to a default value (for example, 0.1 mm) (step S3), and sets the AD setting flag (AD_FLAG) to 0 (step S4). The AD setting flag is flag data indicating a mode for changing the AD value. In the present embodiment, when the AD setting flag is “0”, the AD increasing mode for increasing the AD value is “1”. In some cases, an AD reduction mode for reducing the AD value is shown.

Thereafter, the path setting unit 54 executes PCC calculation to generate PCC data (PCC curve) (step S5).
Specifically, the route setting unit 54 calculates a PCC curve based on the design contour and the AD value. Here, the AD value is the maximum allowable deviation when the design contour is converted into a PCC curve, and the path setting unit 54 offsets the PCC curve offset in the normal direction of the design contour by a predetermined dimension based on the AD value. calculate. As described above, the PCC curve includes a plurality of interpolation points, and the PCC curve is divided into a plurality of segments by these interpolation points.
Then, the path determination unit 55 calculates the ratio of the number of segments to the maximum number of segments (segment number rate (%)), and determines whether it is 100% or less (step S6).

If it is determined as “No” in step S <b> 6, a segment number over error is output by the path determination unit 55. In this case, the AD setting unit 53 determines whether or not the AD setting flag is “1” (whether or not the AD reduction mode is set) (step S7).
If it is determined “No” in step S7, the AD setting unit 53 determines whether or not the AD value is a predetermined maximum AD value (step S8).
If it is determined “No” in step S8, the AD setting unit 53 increases the AD value by a predetermined value (step S9). The value to be increased may be a preset value, or the AD value may be calculated such that the segment number rate is 100% or less with reference to the segment number rate. Thereafter, the process returns to step S5, the PCC data is recalculated, and the movement path of the probe 21 is reset.
On the other hand, if “Yes” is determined in step S7 and step S8, the process proceeds to step S19 described later.
If it is determined as “Yes” in step S <b> 6 (when the segment rate is determined to be 100% or less), the set PCC data is output to the motion controller 3.

When the motion controller 3 receives a measurement command including PCC data from the command acquisition unit 31, the parameter setting unit 32 determines a speed pattern for moving the probe 21 along the PCC data. As a speed pattern setting method, for example, a well-known method disclosed in Japanese Patent Application Laid-Open No. 2014-21004 is cited. In this case, a measurement speed value is included in a measurement command output from the host computer 5. Just keep it.
Then, the motion controller 3 controls the drive mechanism 25 of the coordinate measuring machine main body 2 to move the probe 21 along each segment of the PCC data with the set speed pattern. That is, the scanning shape measurement is performed (step S10).

In step S10, the position measurement unit 35 takes in the movement amounts of the slide mechanism 24 and the stylus 211 measured by the counter unit 34 at a constant sampling interval, for example. Then, the position measuring unit 35 calculates the probe position and the pushing amount of the probe 21 (the pushing amount of the measuring element 211A into the workpiece W) based on the taken movement amounts of the slide mechanism 24 and the stylus 211. . For example, when the probe sensor output value is (Px, Py, Pz), the push amount is calculated as (Px ² + Py ² + Pz ² ) ^1/2 .

In the measurement process of step S10, the error detection unit 36 determines whether a measurement error has occurred based on the calculated push amount of the probe 21. For example, the error detection unit 36 detects a separation error when the pushing amount E = (Px ² + Py ² + Pz ² ) ^1/2 <0.05 mm, and the pushing amount E = (Px ² + Py ² + Pz ² ) ^{1 / 2} > Push-in error is detected when 0.7 mm.
The drive control unit 33 of the motion controller 3 monitors whether or not the measurement error (detachment error and push-in error) as described above is detected by the error detection unit 36 in the measurement process of step S10, and whether or not the measurement is successful. Is determined (step S11).
When it is determined as “Yes” in step S11 (when no measurement error is detected), the measurement result is output to the host computer 5, and the shape analysis unit 56 of the host computer 5 performs the shape analysis processing of the workpiece W. Is performed, and the measurement process is terminated.

On the other hand, when it is determined as “No” in Step S11 (when a measurement error is detected), the parameter setting unit 32 indicates that the pushing amount E of the probe 21 into the workpiece W is the upper limit value or the lower limit value. Is determined (step S12). If a measurement error is detected during the measurement process in step S10, the determination may be “No” immediately in step S11, and the process may proceed to step S12.
When it is determined as “No” in step S12 (when the pushing amount E is a value between the lower limit value and the upper limit value), the measurement error may be avoided by adjusting the pushing amount E. The parameter setting unit 32 adjusts the push amount E (step S13). For example, when a separation error is detected by the error detection unit 36, the parameter setting unit 32 increases and corrects the push amount E by a predetermined amount and outputs the corrected push amount E to the host computer 5. When the error detection unit 36 detects a pressing error, the parameter setting unit 32 corrects the pressing amount E by a predetermined amount and outputs the corrected pressing amount E to the host computer 5.
Thereafter, the host computer 5 returns to the process of step S5. That is, the route setting unit 54 recalculates the PCC data based on the design contour, the AD value, and the corrected push amount E.

If it is determined as “Yes” in step S12, it is determined that it is impossible to avoid a measurement error by adjusting the push amount E.
In this case, the parameter setting unit 32 determines whether or not the moving speed (the scanning speed V) of the probe 21 can be decelerated (step S14). In step S14, when the scanning speed V of the probe 21 is not the predetermined minimum speed, it is determined that deceleration is possible (step S14; Yes), and the parameter setting unit 32 decelerates the scanning speed V by a predetermined amount (step S14). S15), the scanning speed V that has been decelerated is output to the host computer 5.
Thereafter, the host computer 5 returns to the process of step S5.
In the present embodiment, an example is shown in which the process returns to step S5 after step S15, but the speed pattern for the PCC data may be recalculated by the parameter setting unit 32 and the process may return to step S10.

If it is determined as “No” in step S <b> 14, the motion controller 3 returns to the host computer 5 that an unavoidable measurement error has been detected due to the pushing amount E and the copying speed V. Then, the AD setting unit 53 of the host computer 5 determines whether or not the AD value is a preset minimum AD value (step S16).
If it is determined “No” in step S16, the AD setting unit 53 sets the AD setting flag to AD_FLAG = 1 (AD decrease mode) (step S17). Thereafter, the AD setting unit 53 decreases the AD value by a predetermined value (step S18). The value to be decreased may be a preset value, or the AD value may be calculated in a range where the segment number rate is 100% or less with reference to the segment number rate. Thereafter, the process returns to step S5, the PCC data is recalculated, and the movement path of the probe 21 is reset.

On the other hand, if “Yes” is determined in step S16, or if “Yes” is determined in step S7 and step S8, the AD setting unit 53 sets the AD setting flag to AD_FLAG = 0 (AD increase mode). Set (step S19).
Then, the contour setting unit 52 divides the design contour set in step S2 into N (step S20). The number of divisions is gradually increased by repeatedly performing the process of step S20. For example, when dividing first, the number of divisions is increased, for example, by dividing into two, and performing the processing from step S5 to step S18 again to divide into three.
Thereafter, the pressing amount E, the scanning speed V, and the AD value are returned to the default values (or initial values), and the process returns to step S5.

[Operational effects of this embodiment]
In the coordinate measuring machine 1 of the present embodiment, the contour setting unit 52 sets a design contour based on the design data, and the path setting unit 54 converts the design contour and the AD value set by the AD setting unit 53. Based on this, a PCC curve composed of a plurality of segments is set. Then, the route determination unit 55 determines whether or not the set segment number rate of the PCC curve is 100% or less. The AD setting unit 53 increases the AD value when the segment rate exceeds 100%, and the path setting unit 54 generates PCC data again based on the set AD value. Thereby, the segment number over error can be avoided.
In the measurement process, the position measurement unit 35 calculates the probe position and the push amount of the probe 21, and the error detection unit 36 detects a measurement error based on the push amount of the probe 21. Then, when a measurement error is detected, the AD setting unit 53 decreases the AD value, and the path setting unit 54 generates PCC data again based on the set AD value. Thereby, an appropriate AD value can be set so that a measurement error is avoided.
As described above, in the present embodiment, it is possible to set an optimum AD value that does not cause an error in the number of segments and a measurement error (separation error and push-in error). Therefore, as in the prior art, it is possible to avoid the delay of the measurement time due to the division of the design contour and the reduction of the scanning speed as much as possible, and the coordinate measuring machine 1 can be set to the optimum measurement state.

In the coordinate measuring machine 1 of the present embodiment, when a measurement error is detected by the error detection unit 36, the parameter setting unit 32 adjusts the push amount of the probe 21. The setting unit 53 resets the AD value.
That is, there is a limit in avoiding a measurement error by setting only the AD value, and there is a possibility that the design contour needs to be divided early. On the other hand, in the present embodiment, as described above, in order to avoid measurement errors by both adjusting the push-in amount E of the probe 21 and adjusting the AD value, an aspect that requires division of the design contour occurs. Can be suppressed as much as possible.
In this embodiment, when a measurement error occurs, the push amount of the probe 21 is adjusted before resetting the AD value. When the AD value is decreased, the number of segments to be set increases, and accordingly, a segment number over error may occur. On the other hand, when the adjustment of the push-in amount E of the probe 21 is performed first and the measurement error cannot be avoided by adjusting the push-in amount E of the probe, the AD value is decreased, thereby generating an over-segment error. It can be suppressed as much as possible. Thereby, the coordinate measuring machine 1 can be set to an optimal measurement state earlier.

In the present embodiment, when a measurement error is detected, the push amount E is adjusted, and when the measurement error cannot be avoided by adjusting the push amount E, the scanning speed V is decreased. By reducing the scanning speed V, the measurement time is delayed. However, by adjusting the push amount E first, the possibility that the measurement time is delayed can be reduced as much as possible.
Further, in order to avoid measurement errors by adjusting the push-in amount E of the probe 21, adjusting the scanning speed V, and adjusting the AD value, it is possible to further suppress the occurrence of an aspect that requires division of the design contour. be able to.
Further, as described above, resetting the AD value may cause an error in the number of segments. On the other hand, by reducing the scanning speed V before resetting the AD value, it is possible to suppress the occurrence of the segment number over error.
Furthermore, after setting the scanning speed V, the measurement process may be performed by returning to the measurement process in step S10. In this case, the process of resetting the AD value and recalculating the PCC data can be omitted.

  In this embodiment, when the measurement error cannot be avoided by adjusting the push-in amount E of the probe 21, setting the scanning speed V, and setting the AD value, the set contour is divided. For this reason, when a measurement error cannot be avoided, measurement is not performed and measurement processing is performed based on PCC data for each divided setting contour. In this case, complicated processing occurs in combining the measurement results, but the shape of the object to be measured can be measured with high accuracy.

[Other Embodiments]
It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  For example, in the above embodiment, when a measurement error occurs, adjustment of the probe push-in amount E and deceleration of the scanning speed V are performed, but any of these processes may not be performed, and the AD value Measurement errors may be avoided only by setting.

In the above embodiment, when the measurement error occurs, the AD value is decreased when the measurement error cannot be avoided after adjusting the push-in amount E and decelerating the scanning speed V. However, the present invention is not limited to this. For example, when a measurement error occurs, after adjusting the push-in amount E, if the measurement error cannot be avoided, the AD value is decreased, and if the measurement error cannot be avoided, the scanning speed V is reduced. You may implement. Thereby, the delay of the measurement time due to the decrease in the scanning speed V can be further suppressed.
Further, before adjusting the push-in amount, the AD value may be decreased to avoid measurement errors.

  In addition, the specific structure for carrying out the present invention can be appropriately changed to other structures and the like within a range in which the object of the present invention can be achieved.

  The present invention can be applied to a shape measuring apparatus that measures the shape of an object to be measured by design value copying based on a design value.

  DESCRIPTION OF SYMBOLS 1 ... Coordinate measuring machine (shape measuring device), 2 ... Coordinate measuring machine main body, 3 ... Motion controller, 5 ... Host computer, 21 ... Probe, 22 ... Moving mechanism, 24 ... Slide mechanism, 25 ... Drive mechanism, 31 ... command acquisition part, 32 ... parameter setting part (pushing amount adjusting means and moving speed setting means), 33 ... drive control part, 34 ... counter part, 35 ... position measuring part (pushing amount detecting means), 36 ... error detecting part (Error detection means), 51 ... information acquisition section, 52 ... contour setting section (contour setting means), 53 ... AD setting section (allowable error setting means), 54 ... path setting section (path setting means), 55 ... path determination Part (number of segments determination means), 211A.

Claims (5)

A probe having a probe at the tip; and a moving mechanism for moving the probe along the surface of the object to be measured; detecting contact between the probe and the surface of the object to be measured; A shape measuring device for measuring the shape of
Contour setting means for setting a design contour based on the shape data of the object to be measured;
An allowable error setting means for setting an allowable error when moving the probe along the design contour;
Path setting means for setting a design curve that is formed along a plurality of segments along the design contour based on the design contour and the tolerance;
Segment number determination means for determining whether or not the number of segments exceeds a predetermined maximum number of segments;
An indentation amount detecting means for detecting an indentation amount of the measuring element into the object to be measured;
An error detection means for detecting a measurement error based on the pushing amount,
The allowable error setting means increases the allowable error when the number of segments exceeds the maximum number of segments, and decreases the allowable error when a measurement error is detected by the error detecting means. Shape measuring device. In the shape measuring apparatus according to claim 1,
The design curve is a curve offset from the design contour by a value obtained by subtracting the pushing amount of the probe into the object to be measured from the radius of the probe.
A pressing amount adjusting means for adjusting the pressing amount between a predetermined lower limit value and a predetermined upper limit value when the measurement error is detected by the error detecting means;
The allowable error setting means is when the pushing amount adjusted by the pushing amount adjusting means reaches the lower limit value or the upper limit value, and when the measurement error is detected by the error detecting means. The shape measuring apparatus, wherein the tolerance is reduced. In the shape measuring apparatus according to claim 2,
Comprising a moving speed setting means for setting a moving speed when moving the probe;
The moving speed setting means is configured to move the probe when the error is detected by the error detecting means and the pushing amount adjusted by the pushing amount adjusting means reaches the lower limit value or the upper limit value. Reduce
The allowable error setting means is when the moving speed of the probe reduced by the moving speed setting means reaches a predetermined minimum moving speed, and when the measurement error is detected by the error detecting means. The shape measuring apparatus, wherein the tolerance is reduced. In the shape measuring device according to any one of claims 1 to 3,
The contour setting means divides the design contour when the allowable error set by the allowable error setting means reaches a predetermined minimum value and the measurement error is detected by the error detection means. A shape measuring device. A probe having a probe at the tip; and a moving mechanism for moving the probe along the surface of the object to be measured; detecting contact between the probe and the surface of the object to be measured; A shape measuring method in a shape measuring apparatus for measuring the shape of
Setting a design contour based on the shape data of the object to be measured, setting an allowable error when moving the probe along the design contour, based on the design contour and the allowable error, A setting process for setting a design curve along a design contour and including a plurality of segments;
A measurement step of detecting the position of the probe to measure the position of the probe, and detecting the amount of pushing of the probe into the object to be measured;
A segment number determination step of determining whether or not the number of segments set in the setting step exceeds a predetermined maximum number of segments;
An error detection step of detecting a measurement error based on the indentation amount detected in the measurement step, and
The setting step increases the allowable error when the number of segments exceeds the maximum number of segments by the number-of-segments determination step and increases the allowable error when the measurement error is detected by the error detection step. A shape measuring method characterized by reducing errors.

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