JP6344630B2 - Circle measurement method using a three-dimensional measuring machine - Google Patents

Description

  The present invention relates to a circle measuring method using a three-dimensional measuring machine.

  Conventionally, a probe head having first driving means (for example, a motor) for rotating the probe around two rotation axes orthogonal to each other, and second driving means for moving the probe head in three axial directions orthogonal to each other (for example, A three-dimensional measuring machine including a motor is known (for example, see Patent Document 1).

  In the three-dimensional measuring machine described in Patent Document 1, the probe head moves based on a pre-programmed measurement path to automatically measure an object to be measured (also referred to as a workpiece).

JP 2010-537184 A

  However, in such a coordinate measuring machine, generally, a plurality of measurement methods (for example, CMM touch, 5-axis head touch, 5-axis & 2-axis head touch) are prepared, and the operator considers various conditions. Thus, an optimal measurement method must be selected from these, and the burden on the operator is large.

  The present invention has been made in view of such circumstances, and without being aware of the difficulty of the operator from a plurality of measurement methods (CMM touch, 5-axis head touch, 5-axis & 2-axis head touch), The purpose is to automatically determine the optimum measurement method.

  In order to achieve the above object, a circle measuring method using a coordinate measuring machine according to the present invention comprises a probe head comprising first driving means for rotating a probe around two rotation axes orthogonal to each other; And a second driving means for moving the probe head in three axis directions orthogonal to each other, and using a CMM touch, a 5-axis head touch, or a 5-axis & 2-axis head touch to automatically measure a circle using a three-dimensional measuring machine In the method, a first step for determining whether or not at least one determination condition is satisfied, and the CMM touch, the 5-axis head touch, and the 5-axis & 2-axis head touch based on a determination result in the first step. And a second step of automatically determining an optimum measurement method from among the above.

  According to the first aspect of the present invention, an optimum measurement method can be obtained without being aware of the difficulty of the operator from among a plurality of measurement methods (CMM touch, 5-axis head touch, 5-axis & 2-axis head touch). Automatic determination can be made.

  This determines whether or not at least one determination condition is satisfied, and automatically determines the optimal measurement method from among the CMM touch, 5-axis head touch, and 5-axis & 2-axis head touch based on the determination result. Is due to.

  The invention described in claim 2 is the invention described in claim 1, further comprising a third step of automatically measuring a circle by the optimum measurement method determined in the second step.

  According to invention of Claim 2, a circle | round | yen (a hole or a cylinder) can be automatically measured with the optimal measuring method automatically determined by the 2nd step.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the determination condition includes a first determination condition, and the first determination condition is an angle formed between a normal line of a measurement plane and a probe posture. Is determined to be greater than a first threshold, and the second step automatically determines that the optimal measurement method is the CMM touch when it is determined by the first step that the first determination condition is satisfied. It is characterized by.

  According to the invention described in claim 3, even when an obstacle exists near the circle (hole or cylinder) to be measured, an appropriate measurement method is automatically determined so that the probe does not collide with the obstacle. can do.

  The invention according to claim 4 is the invention according to claim 1 or 2, wherein the determination condition includes a second determination condition, and the second determination condition includes a radius of a circle to be measured and a probe radius. The condition is that the difference is smaller than a second threshold value, and the second step automatically determines that the optimal measurement method is the CMM touch when it is determined by the first step that the second determination condition is satisfied. It is characterized by that.

  According to the invention described in claim 4, even if the hole (inner diameter) to be measured is small, it is possible to automatically determine an optimal measurement method in which the probe does not collide with an unexpected place.

  The invention according to claim 5 is the invention according to claim 1 or 2, wherein the determination condition includes a third determination condition, wherein the normal of the measurement plane is within a critical angle range. And the second step automatically determines that the optimum measurement method is the 5-axis head touch when it is determined that the third determination condition is satisfied by the first step. To do.

  According to the invention described in claim 5, even when the hole to be measured is within the critical angle range, it is possible to automatically determine an optimal measurement method in which the probe is not swung.

  The invention according to claim 6 is the invention according to claim 1 or 2, wherein the determination condition includes a fourth determination condition, and the fourth determination condition is that a probe posture angle at an approach point is a third threshold value. The second step automatically determines that the optimal measurement method is the 5-axis head touch when the second step determines that the fourth determination condition is satisfied by the first step. And

  According to the sixth aspect of the present invention, there is provided an optimum measurement method that does not cause the probe to fluctuate even when the radius is shorter than the length of the probe (stylus) and does not deteriorate the measurement accuracy. Automatic determination can be made.

The invention according to claim 7 is the invention according to claim 1 or 2, wherein the determination condition includes a first determination condition, a second determination condition, a third determination condition, and a fourth determination condition. The determination condition is that the angle between the normal of the measurement plane and the probe posture is larger than the first threshold value. The second determination condition is that the difference between the radius of the circle to be measured and the probe radius is larger than the second threshold value. The third determination condition is a condition that the normal of the measurement plane is within the critical angle range, and the fourth determination condition is that the probe posture angle at the approach point is larger than the third threshold value. The first step is a step of determining whether or not the first determination condition is satisfied, a step of determining whether or not the second determination condition is satisfied, and whether or not the third determination condition is satisfied Step to determine whether And determining whether or not the fourth determination condition is satisfied, wherein the second step is optimal when the first step determines that the first determination condition or the second determination condition is satisfied. When it is automatically determined that the measurement method is the CMM touch and it is determined in the first step that the third determination condition or the fourth determination condition is satisfied, the optimal measurement method is the 5-axis head touch. It is characterized by automatic determination.

  According to the seventh aspect of the present invention, an optimum measurement method can be obtained without being aware of the difficulty of the operator from among a plurality of measurement methods (CMM touch, 5-axis head touch, 5-axis & 2-axis head touch). Automatic determination can be made.

  This is to determine whether or not the first determination condition, the second determination condition, the third determination condition, and the fourth determination condition are satisfied, and based on the determination result, the CMM touch, the 5-axis head touch, and the 5-axis & 2-axis This is because the optimum measurement method is automatically determined from the head touch.

  The invention according to claim 8 is the invention according to claim 7, wherein the first determination condition, the second determination condition, the third determination condition, and the fourth determination condition are not satisfied in the first step. When the determination is made, the optimum measurement method is automatically determined to be the 5-axis & 2-axis Head touch.

  According to the eighth aspect of the present invention, an optimal measurement method can be obtained without being aware of the difficulty of the operator from among a plurality of measurement methods (CMM touch, 5-axis head touch, 5-axis & 2-axis head touch). Automatic determination can be made.

  This is because, when it is determined that the first determination condition, the second determination condition, the third determination condition, and the fourth determination condition are not satisfied, it is automatically determined that the 5-axis & 2-axis Head touch is the optimum measurement method. Is.

  According to the present invention, it is possible to automatically determine an optimum measurement method from a plurality of measurement methods (CMM touch, 5-axis head touch, 5-axis & 2-axis head touch) without being aware of the difficulty of the operator. It becomes possible.

It is a perspective view of the coordinate measuring machine 10 of this embodiment. It is a figure for demonstrating a CMM touch. It is a figure for demonstrating 5-axis Head touch. It is a figure for demonstrating 2 axis | shaft Head touch. 4 is a flowchart for explaining the operation of the coordinate measuring machine 10; It is a flowchart for demonstrating a measuring method automatic determination process. It is a figure showing a mode that it is going to measure the circle | round | yen (inside diameter) by inserting the probe 24a in the hole H1 where the obstruction 34 exists near. It is a figure showing a mode that the probe 24a is inserted in the small hole H2, and it is going to measure a circle | round | yen (inside diameter). (A)-(c) It is a figure showing a mode that the probe 24a (stylus 24b) is inserted in the inclined hole H3, and it is going to measure a circle | round | yen (inside diameter). It is a figure for demonstrating a critical angle. It is a figure showing a mode that the probe 24a is inserted in the hole H4 whose radius is shorter than the length of the probe 24a (stylus 24b), and it is going to measure a circle | round | yen (inside diameter). It is a figure for demonstrating 5 axis | shaft Head touch in 5 axis | shaft & 2 axis | shaft Head touch. It is a figure for demonstrating the 3rd axis | shaft of the measurement plane P and the measurement plane P. FIG. (A) The figure for demonstrating the measurement plane P, (b) It is the table | surface which put together the relationship between a measurement plane and an XYZ axis | shaft.

  A preferred embodiment of a circle measuring method using a coordinate measuring machine according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a coordinate measuring machine 10 according to the present embodiment.

  A coordinate measuring machine 10 (CMM: Coordinate Measuring Machine) is a device that moves a probe head 24 and determines spatial coordinates on the surface of an object to be measured (also called a workpiece). Also called a machine. In the present embodiment, a portal moving type coordinate measuring machine 10 will be described as an example. In the coordinate measuring machine 10, there is a method using a machine coordinate system. However, since the work posture needs to be strictly matched with the machine coordinate system and work efficiency is not good, it is usually set on the table 14 in an arbitrary posture. The workpiece coordinate system set on the set workpiece is used.

  As shown in FIG. 1, in the coordinate measuring machine 10, a table 14 is placed on a gantry 12, and a right Y carriage 16R and a left Y carriage 16L are erected on both sides of the table 14, and the right Y carriage The upper part of 16R and the left Y carriage 16L are connected by an X guide 18 to form a portal frame 26. Sliding surfaces in the Y-axis direction are formed on the upper surface and side surfaces of both sides of the table 14, and the right Y carriage 16R and the left Y carriage 16L are provided with air bearings to counter this, and the right Y carriage 16R and the left The Y carriage 16L is movable along with the X guide 18 in the Y-axis direction. Further, the X guide 18 has a sliding surface in the X-axis direction, and an X carriage 20 incorporating an air bearing is provided to be movable in the X-axis direction. Further, the X carriage 20 incorporates an air bearing for guiding in the Z-axis direction, and a Z spindle 22 is movably provided along the Z-axis direction along the air bearing. A probe head 24 is attached to the lower end of the Z spindle 22. The probe head 24 is a probe head (5-axis simultaneous control probe head) provided with a stepless positioning mechanism. The probe-type touch trigger probe 24a (stylus 24b) has two rotation axes AB (see FIG. 1) orthogonal to each other. First drive means (for example, a motor, not shown) that rotates around is provided. According to the probe head 24, faster measurement (probing, that is, an operation for determining coordinate values) can be performed by using only the rotation operation around the rotation axis AB.

  The coordinate measuring machine 10 also moves 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. Driving means (for example, a motor, not shown) is provided.

  Scales are provided in the Y-axis direction of the table 14, the X guide 18, and the Z spindle 22, the right Y carriage 16R has a detection head in the Y axis direction, and the X carriage 20 has detection heads in the X axis direction and the Z axis direction. The three-dimensional coordinate position is detected at the moment when the contact 24c at the tip of the probe 24a (stylus 24b) is attached to the workpiece.

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

  The computer 32 executes software 32a installed therein (including software for confirming measurement operation and confirming measurement results), and includes a measurement path (also referred to as a part program) including coordinate values of target points and intermediate points. And the first driving means and / or the second driving means are controlled (CNC control) via the controller 28 based on the measurement path, and the probe head 24 is automatically moved. Measure workpieces automatically.

  As an automatic measurement method, at least a CMM touch, a 5-axis head touch, a 2-axis head touch, and a 5-axis & 2-axis head touch in combination of a 5-axis head touch and a 2-axis head touch are prepared.

  FIG. 2 is a diagram for explaining the CMM touch.

  The CMM touch is a measurement method that automatically measures a workpiece without rotating the probe 24a (without changing the posture of the probe 24a) and moving the probe head 24 in the XYZ directions.

  As shown in FIG. 2, in the CMM touch, the first driving unit does not rotate the probe 24a and the second driving unit simultaneously moves the probe head 24 in the XYZ directions (simultaneous control of three axes). The step of moving 24a to the approach point (see arrow a1 in FIG. 2), the first driving means does not rotate the probe 24a, and the second driving means simultaneously moves the probe head 24 in the XYZ directions (three axes) (Simultaneous control) by probing the target point (work W) (see arrow b1 in FIG. 2), the first drive means does not rotate the probe 24a, and the second drive means moves the probe head 24 to XYZ. A step (arrow c1 in FIG. 2) of performing a return operation by simultaneously moving in the direction (simultaneous control of three axes). In this operation, for example, the computer 32 (software 32a) issues a command including the target point (coordinate value) and the probing direction to the controller 28, and the controller 28 that receives this command controls the coordinate measuring machine 10. This is realized.

  The approach point is a position (center position in FIG. 2) that is away from the target probing point by the approach distance in the direction of the probing vector. After probing, the probe head 24 returns from the probing point to a position separated by a return amount in the direction of the probing vector (a central position in FIG. 2). The approach distance and the return amount are set in advance.

  In the CMM touch, the probing direction is a direction from the center of the circle toward a target point (also referred to as a probing point).

  FIG. 3 is a diagram for explaining the 5-axis head touch.

  The 5-axis head touch is a measurement method in which the workpiece is automatically measured by rotating the probe 24a and moving the probe head 24 in the XYZ directions.

  As shown in FIG. 3, in the 5-axis head touch, the first driving means simultaneously rotates the probe 24a around the rotation axis AB, and the second driving means simultaneously moves the probe head 24 in the XYZ directions (5 (Simultaneous control of the axes), the step of moving the probe 24a to the approach point (see arrow a2 in FIG. 3), the first driving means simultaneously rotates the probe 24a around the rotation axis AB (simultaneous control of two axes), In addition, the second driving means does not move the probe head 24, thereby probing the target point (work W) (see arrow b2 in FIG. 3), and the first driving means moves the probe 24a around the rotation axis AB. A step of performing a return operation by simultaneously rotating (two-axis simultaneous control) and not moving the probe head 24 by the second driving means (see arrow c2 in FIG. 3). ) And it contains a.

  In the 5-axis head touch, the approach point is finely adjusted in order to probe the target point.

  FIG. 4 is a diagram for explaining the biaxial head touch.

  In the biaxial head touch, the workpiece is automatically measured by rotating the probe 24a and not moving the probe head 24 in a state where the rotation center of the probe head 24 is positioned on the extension line of the circle center to be measured. This is a measurement method.

  As shown in FIG. 4, in the biaxial head touch, the first driving means rotates the probe 24a around the rotation axis AB, and the second driving means does not move the probe head 24, so that the probe 24a is approached. The step of moving to the point (see arrow a3 in FIG. 4), the first driving means rotates the probe 24a around the rotation axis AB, and the second driving means does not move the probe head 24, so that the target point A step of probing (work W) (see an arrow b3 in FIG. 4), the first driving unit rotates the probe 24a around the rotation axis AB, and the second driving unit does not move the probe head 24. And a step of performing a return operation (see arrow c3 in FIG. 4).

  In the 2-axis head touch, in order to probe the target point, the approach point is finely adjusted when the first point is moved.

  Next, the operation of the coordinate measuring machine 10 configured as described above will be described.

  FIG. 5 is a flowchart for explaining the operation of the coordinate measuring machine 10.

  First, the operator instructs automatic circle measurement from the computer 32 or the like (step S10).

  Next, the operator inputs design value information (information for specifying the circle (hole or cylinder) to be measured) of the circle (hole or cylinder) to be measured (step S12). The design value information is input by operating the joystick to move the probe head 24, inserting the probe 24a into the hole to be measured, and instructing three points (three-point touch). When the input of design value information (three-point instruction) in step S12 is completed, the probe 24a is inserted into the hole to be measured. The design value information may be input by instructing on CAD (by instructing based on CAD drawing data).

  Next, the operator sequentially indicates the number of measurement points and the measurement range (whether the circle to be measured is a complete circle or an arc) from the computer 32 or the like (steps S14 and S16), and then The automatic measurement start is instructed (step S18).

  When the automatic measurement start is instructed, the computer 32 executes the software 32a installed therein, thereby executing the measurement method automatic determination process (step S20). In addition, the computer 32 executes the software 32a installed therein, thereby automatically generating a measurement path (also referred to as a part program) including the coordinate values of target points and intermediate points.

  FIG. 6 is a flowchart for explaining the measurement method automatic determination processing.

  The following processing is realized mainly by the computer 32 executing the software 32a installed therein.

  First, the measurement direction of a circle is determined (step S200). This is a process for determining whether the circle to be measured is the “inner diameter” of the hole or the “outer diameter” of the cylinder. Since this is a known process, its description is omitted.

  FIG. 7 is a diagram illustrating a state in which a probe (24a) is inserted into a hole H1 where an obstacle 34 exists nearby and a circle (inner diameter) is being measured.

  Generally, when measuring a circle (inner diameter or outer diameter), it is desirable that the probe be in a normal direction (normal direction of the measurement plane) with respect to the circle to be measured.

  However, in the situation shown in FIG. 7, if the probe 24a is in the normal direction (normal direction of the measurement plane P) with respect to the circle to be measured, the probe 24a may collide with the obstacle 34. .

Therefore, when it is determined that the measurement direction of the circle is “inner diameter” (step S200: inner diameter), abs (λ _w λ _po + μ _w μ _po + ν _w ν _po )> φ (hereinafter also referred to as first determination condition) is satisfied. It is determined whether or not (step S202). Where λ _w , μ _w , ν _w are the direction cosines of the third axis of the measurement plane P (normal vector of the third axis of the measurement plane P (see FIG. 13), known), λ _po , μ _po , ν _po Is a cosine in the stylus direction (direction vector (refer to FIG. 13) from the center of the stylus 24b (center of the contactor 24c) to the center of rotation of the probe head 24 (known)), and φ is a determination threshold (for example, 0.9 = cos (25.8 deg)). However, these vectors are assumed to be normalized.

  Note that the third axis of the measurement plane P has the following meaning. In general, when measuring a workpiece, a reference suitable for the workpiece is set. For example, as shown in FIG. 14A, an XY plane, a YZ plane, a ZX plane, an inclined plane, and the like are selected by an operator (or automatically determined by software) depending on the measurement location. . This selected (or discriminated) is the measurement plane. The relationship between the measurement plane and the XYZ axes is as shown in FIG. Here, since the XY plane is selected (or discriminated) as the measurement plane P in advance, the third axis of the measurement plane P is determined from the table shown in FIG. It means the Z axis of the plane.

  The first determination condition is that the normal of the measurement plane P (the normal vector of the third axis of the measurement plane P) and the probe attitude (direction vector from the stylus 24b center (contact 24c center) to the probe head 24 rotation center). The angle formed by is confirmed. When this angle is larger than the determination angle (first threshold), that is, when it is determined that the first determination condition is satisfied (step S202: Yes), the deviation of the probe posture with respect to the measurement plane P is due to the operator's intention. It is determined (that is, it is determined that there is an obstacle), and it is determined that the optimal measurement method is CMM touch (step S204).

  Then, under the conditions specified in steps S10 to S16, the circle (inner diameter of the hole) is automatically measured by the CMM touch determined in step S204 (step S22). This automatic measurement by CMM touch does not rotate the probe 24a (maintaining the posture of the probe 24a (see FIG. 7) at the time when the input of design value information (three-point instruction) in step S12 is completed), and This is performed by moving the probe head 24 in the XYZ directions.

  As described above, as shown in FIG. 7, even when the obstacle 34 is present near the hole H1 to be measured, an optimum measurement method in which the probe 24a does not collide with the obstacle 34 is automatically performed. Can be determined.

  FIG. 8 is a diagram illustrating a state where the probe 24a is inserted into the small hole H2 and an attempt is made to measure a circle (inner diameter).

  Since the tip of the stylus 24b physically has some vibration, if the probe 24a is rotated in the situation shown in FIG. 8, the probe 24a may collide with an unexpected place.

Therefore, when it is determined that the first determination condition is not satisfied (step S202: No), it is determined whether or not (R _cir -R _pb ) <R _diff (hereinafter also referred to as second determination condition) is satisfied (step S202). S206). However, R _cir is the diameter of the measurement target (known), R _pb is the probe radius (known), and R _diff is the determination threshold (for example, 3 mm).

  This second determination condition confirms the difference between the radius of the circle to be measured and the probe radius. When this difference is smaller than the threshold value (second threshold value), that is, when it is determined that the second determination condition is satisfied (step S206: Yes), it is optimal to prevent the probe 24a from colliding with an unexpected location. It is determined that the correct measurement method is CMM touch (step S204).

  Then, under the conditions specified in steps S10 to S16, the circle (inner diameter of the hole) is automatically measured by the CMM touch determined in step S204 (step S22). This automatic measurement by the CMM touch does not rotate the probe 24a (maintaining the posture of the probe 24a (see FIG. 8) when the input of design value information (three-point instruction) in step S12 is completed), and This is performed by moving the probe head 24 in the XYZ directions.

  As described above, as shown in FIG. 8, even when the hole H2 to be measured is small, the optimum measurement method in which the probe 24a does not collide with an unexpected place can be automatically determined.

  FIG. 9C is a diagram illustrating a state in which the probe 24a (stylus 24b) is inserted into the inclined hole H3 and an attempt is made to measure a circle (inner diameter).

  If the hole to be measured is within the critical angle range, there is a risk that the hole will be swung during measurement with a 2-axis head touch.

  FIG. 10 is a diagram for explaining the critical angle. When measuring a circle (inner diameter), it is desirable to use a two-axis head touch because of merits such as speed / throughput / accuracy. However, as shown in FIG. 10, due to the structure of the probe head 24, there is a narrow region A where the stylus 24b cannot move in the vicinity of the south pole of the hemisphere in a certain angular range.

  As shown in FIGS. 9A and 9B, there is no problem if the angle of the hole H3 to be measured is large to some extent.

  However, as shown in FIG. 9C, when the hole H3 to be measured has an inclination of about 5 to 10 ° with respect to the horizontal plane, the point where the stylus 24b is vertical or nearly vertical cannot move physically, Measurement with 2-axis head touch is not possible. In the present embodiment, this angle range is called a critical angle.

Therefore, when it is determined that the second determination condition is not satisfied (step S206: No), it is determined whether or not ω _l <abs (ν _w ) <ω _h (hereinafter also referred to as third determination condition) is satisfied ( Step S208). Where ν _w is the cosine (known) of the third axis of the measurement plane P, ω _l is the critical angle lower limit (eg 0.985 = cos (10 deg)), and ω _h is the critical angle upper limit (eg 0.996 = cos ( 5deg)).

  The third determination condition confirms whether or not the normal line of the measurement plane P (for example, the angle formed between the normal line of the measurement plane P and the vertical line) is within the critical angle range. If it is within the critical angle range, that is, if it is determined that the third determination condition is satisfied (step S208: Yes), an optimal measurement method can be used in order to prevent skipping during measurement with the 2-axis Head touch. It is determined that the touch is a 5-axis head touch (step S210).

  Then, under the conditions specified in steps S10 to S16, the circle (inner diameter of the hole) is automatically measured by the 5-axis head touch determined in step S210 (step S22).

  As described above, as shown in FIG. 9C, even when the hole H3 to be measured is within the critical angle range, the optimum measurement method in which the probe 24a is not swung is automatically determined. Can do.

  FIG. 11 is a diagram illustrating a state in which the probe 24a is inserted into the hole H4 whose radius is shorter than the length of the probe 24a (stylus 24b) and an attempt is made to measure a circle (inner diameter).

  If the length of the stylus is short with respect to the hole to be measured, there is a risk that it will be missed during measurement with a 2-axis Head touch. Even if the probe is not swung, if the probe head angle at the time of measurement with the two-axis head touch is larger than a certain value, the measurement accuracy may be deteriorated.

Therefore, if it is determined that the third determination condition is not satisfied (step S208: No), whether or not (R _cir -D _ap -R _pb ) / L _pb > ε (hereinafter also referred to as the fourth determination condition) is satisfied. Is determined (step S212). Where R _cir is the diameter of the measurement target (known), D _ap is the approach distance (known), R _pb is the probe radius (known), L _pb is the probe length (known), and ε is the determination threshold (for example, 0.5 = sin (30 deg)).

  The fourth determination condition confirms the probe posture angle at the approach point (for example, an angle formed by a vertical line and a direction vector from the center of the stylus 24b (center of the contactor 24c) toward the rotation center of the probe head 24). When this angle is larger than the determination angle (third threshold), that is, when it is determined that the fourth determination condition is satisfied (step S212: Yes), the measurement accuracy at the time of measurement with the two-axis head touch deteriorates. In order to prevent this, it is determined that the optimal measurement method is the 5-axis head touch (step S210).

  Then, under the conditions specified in steps S10 to S16, the circle (inner diameter of the hole) is automatically measured by the 5-axis head touch determined in step S210 (step S22).

  As described above, as shown in FIG. 11, even if the radius of the hole H4 is shorter than the length of the probe 24a (stylus 24b), the probe 24a is not swung and the measurement accuracy does not deteriorate. An optimum measurement method can be automatically determined.

  On the other hand, when it is determined that the fourth determination condition is not satisfied (step S212: No), that is, it is determined that none of the first determination condition, the second determination condition, the third determination condition, and the fourth determination condition is satisfied. If it is determined that the optimum measurement method is the 5-axis & 2-axis Head touch (step S214).

  Then, under the conditions specified in steps S10 to S16, the circle (inner diameter of the hole) is automatically measured by the 5-axis & 2-axis Head touch determined in step S214 (step S22).

  In this 5-axis & 2-axis head touch, the first target point among the target points is automatically measured by the 5-axis head touch, and the target points after the first target point among the target points are automatically measured by the 2-axis head touch. Performed (step S22). This 5-axis head touch is different from the 5-axis head touch in step S210, and as shown in FIG. 12, the rotation center of the probe head 24 is positioned on the extension line of the center of the hole H5 (circle) to be measured. Done in

  On the other hand, when it is determined in step S200 that the measurement direction of the circle is “outer diameter” (step S200: outer diameter), as in step S202, it is determined whether or not the first determination condition is satisfied.

  If it is determined that the first determination condition is satisfied (step S216: Yes), it is determined that the displacement of the probe posture with respect to the measurement plane P is due to the operator's intention (that is, it is determined that there is an obstacle), and the optimum It is determined that the correct measurement method is CMM touch (step S218).

  Then, under the conditions instructed in steps S10 to S16, the circle (cylinder outer diameter) is automatically measured by the CMM touch determined in step S218. In the automatic measurement by the CMM touch, the probe 24a is not rotated (maintaining the posture of the probe 24a when the design value information input (three-point instruction) is completed in step S12) and the probe head 24 is moved. This is done by moving in the XYZ directions.

  As described above, even when an obstacle exists near the cylinder to be measured, the probe 24a can perform automatic measurement without colliding with the obstacle.

  On the other hand, when it is determined that the first determination condition is not satisfied (step S216: No), it is determined that the optimal measurement method is the 5-axis head touch (step S220).

  Then, under the conditions instructed in steps S10 to S16, the circle (cylinder outer diameter) is automatically measured by the 5-axis head touch determined in step S220 (step S22).

  As described above, according to the circle measuring method using the coordinate measuring machine 10 of the present embodiment, the operator can select from a plurality of measuring methods (CMM touch, 5-axis head touch, 5-axis & 2-axis head touch). Therefore, it is possible to automatically determine the optimum measurement method without being aware of the difficulty.

  This is whether the computer 32 satisfies the at least one determination condition (at least one of the first determination condition to the fourth determination condition) by executing the software 32a installed therein. This is because the optimum measurement method is automatically determined from the CMM touch, the 5-axis head touch, and the 5-axis & 2-axis head touch based on the determination result (steps S200 to S220).

  In addition, according to the circle measuring method using the coordinate measuring machine 10 of the present embodiment, it is possible to perform automatic measurement with the optimum measuring method determined as described above (step S22).

  Next, a modified example will be described.

  In the measurement method automatic determination process shown in FIG. 6, the process in step S202 and the process in step S206 may be interchanged. Further, the process of step S208 and the process of step S212 may be interchanged.

  Further, in the measurement method automatic determination process shown in FIG. 6, it is not essential to include all of steps S202, S206, S208, and S212, and at least one of steps S202, S206, S208, and S212 may be included. That's fine. Even if at least one of steps S202, S206, S208, and S212 is provided and the other steps are omitted, a plurality of measurement methods (CMM touch, 5-axis head touch, 5-axis & 2-axis head, as in the above embodiment). It is possible to automatically determine the optimum measurement method from the touch) without being aware of the difficulty of the operator.

  The above embodiment is merely an example in all respects. The present invention is not construed as being limited to these descriptions. The present invention can be implemented in various other forms without departing from the spirit or main features thereof.

  DESCRIPTION OF SYMBOLS 10 ... Three-dimensional measuring machine, 12 ... Stand, 14 ... Table, 16L, 16R ... Y carriage, 18 ... X guide, 20 ... X carriage, 22 ... Spindle, 24 ... Probe head, 24a ... Probe, 24b ... Stylus, 24c ... contacts, 26 ... gate frame, 28 ... controller, 30 ... communication interface, 32 ... computer, 32a ... software, 34 ... obstacle, W ... workpiece

Claims (7)

A probe head having first driving means for rotating the probe around two rotation axes orthogonal to each other; and a second driving means for moving the probe head in three axial directions orthogonal to each other, and a CMM touch or In a circle measuring method using a coordinate measuring machine that automatically measures a workpiece with a 5-axis head touch,
A first step for determining whether or not at least one determination condition is satisfied;
A second step of automatically determining an optimal measurement method from among the CMM touch and the 5-axis Head touch based on the determination result in the first step;
A circle measuring method using a three-dimensional measuring machine.   The circle measuring method using the coordinate measuring machine according to claim 1, further comprising a third step of automatically measuring a circle by the optimum measuring method determined in the second step. The determination condition includes a first determination condition,
The first determination condition is a condition that an angle formed by the normal of the measurement plane and the probe posture is larger than a first threshold value.
3. The method according to claim 1, wherein the second step automatically determines that the optimal measurement method is the CMM touch when it is determined that the first determination condition is satisfied by the first step. 4. Circle measurement method using three-dimensional measuring machine. The determination condition includes a second determination condition,
The second determination condition is a condition that a difference between a radius of a circle to be measured and a probe radius is smaller than a second threshold value.
3. The method according to claim 1, wherein the second step automatically determines that the optimum measurement method is the CMM touch when it is determined that the second determination condition is satisfied by the first step. 4. Circle measurement method using three-dimensional measuring machine. The determination conditions include a first determination condition, a second determination condition, and a third determination condition,
The first determination condition is a condition that an angle formed by the normal of the measurement plane and the probe posture is larger than a first threshold value.
The second determination condition is a condition that a difference between a radius of a circle to be measured and a probe radius is smaller than a second threshold value.
The third determination condition is a condition that an angle formed by a normal line to a measurement plane and a vertical line is within a critical angle range,
The step of determining whether or not the first determination condition is satisfied, the step of determining whether or not the second determination condition is satisfied, and the step of determining whether or not the third determination condition is satisfied Including
The second step includes
When it is determined by the first step that the first determination condition or the second determination condition is satisfied, the optimum measurement method is automatically determined to be the CMM touch,
If it is determined in the first step that the first determination condition and the second determination condition are not satisfied and the third determination condition is satisfied, it is automatically determined that the optimal measurement method is the 5-axis head touch. A circle measuring method using the coordinate measuring machine according to claim 1 or 2. The determination conditions include a first determination condition, a second determination condition, and a fourth determination condition,
The first determination condition is a condition that an angle formed by the normal of the measurement plane and the probe posture is larger than a first threshold value.
The second determination condition is a condition that a difference between a radius of a circle to be measured and a probe radius is smaller than a second threshold value.
The fourth determination condition is a condition that an angle formed by the vertical line at the approach point and the probe posture is larger than a third threshold value,
The first step includes a step of determining whether or not the first determination condition is satisfied, a step of determining whether or not the second determination condition is satisfied, and a step of determining whether or not the fourth determination condition is satisfied. Including
The second step includes
When it is determined by the first step that the first determination condition or the second determination condition is satisfied, the optimum measurement method is automatically determined to be the CMM touch,
When it is determined in the first step that the first determination condition and the second determination condition are not satisfied and the fourth determination condition is satisfied, it is automatically determined that the optimal measurement method is the 5-axis head touch. A circle measuring method using the coordinate measuring machine according to claim 1 or 2. The determination conditions include a first determination condition, a second determination condition, a third determination condition, and a fourth determination condition,
The first determination condition is a condition that an angle formed by the normal of the measurement plane and the probe posture is larger than a first threshold value.
The second determination condition is a condition that a difference between a radius of a circle to be measured and a probe radius is smaller than a second threshold value.
The third determination condition is a condition that an angle formed by a normal line to a measurement plane and a vertical line is within a critical angle range,
The fourth determination condition is a condition that an angle formed by the vertical line at the approach point and the probe posture is larger than a third threshold value,
The step of determining whether or not the first determination condition is satisfied, the step of determining whether or not the second determination condition is satisfied, and the step of determining whether or not the third determination condition is satisfied And determining whether or not the fourth determination condition is satisfied,
The second step includes
When it is determined by the first step that the first determination condition or the second determination condition is satisfied, the optimum measurement method is automatically determined to be the CMM touch,
When it is determined in the first step that the first determination condition and the second determination condition are not satisfied and the third determination condition is satisfied, it is automatically determined that the optimum measurement method is the 5-axis head touch. ,
When it is determined in the first step that the first determination condition, the second determination condition, and the third determination condition are not satisfied, and the fourth determination condition is satisfied, an optimal measurement method is the 5-axis head touch. The circle measuring method using the coordinate measuring machine according to claim 1, wherein the circle measuring method is automatically determined to be.

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