JP7223939B2 - Shape measuring machine and its control method - Google Patents

Description

The present invention relates to a shape measuring machine that measures the shape of a workpiece without contact and a control method thereof.

2. Description of the Related Art A shape measuring machine is known for non-contact measurement of various shapes such as roundness, cylindricity and squareness of a columnar or cylindrical work.

For example, Patent Literature 1 describes a shape measuring machine that includes a light source, an interferometer, a sensor head, and a rotating mechanism. The light source outputs measurement light. The interferometer outputs the measurement light input from the light source to the sensor head, and the reference light which is part of the measurement light reflected by the reflection surface different from the work and the reflected light of the measurement light reflected by the work. Detect interference signals of light and The sensor head is arranged at a position facing the surface to be measured (outer peripheral surface or inner peripheral surface) of the workpiece, emits the measurement light input from the interferometer toward the surface to be measured, and Output the reflected light to the interferometer. The rotating mechanism rotates the work irradiated with the measurement light.

As described above, the shape measuring machine described in Patent Document 1 continuously emits the measurement light from the sensor head and detects the interference signal with the interferometer while rotating the workpiece by the rotation mechanism. The roundness and cylindricity of the workpiece are calculated based on the detection result of the interference signal.

JP 2011-220816 A

By the way, when using the shape measuring machine described in Patent Document 1 to measure the shape of the work such as roundness at a plurality of positions (multiple cross sections) along the longitudinal direction of the work, the sensor head is placed at a plurality of positions in order. In addition, it is necessary to emit the measurement light from the sensor head and detect the interference signal by the interferometer while rotating the workpiece for each of a plurality of positions. Furthermore, when measuring the squareness of a work, the upper surface of the work is also the surface to be measured in addition to the outer peripheral surface of the work, so it is necessary to change the posture of the sensor head. Therefore, the shape measuring machine described in Patent Document 1 has a problem that it takes time to measure the shape.

Therefore, it is conceivable to provide a shape measuring machine with a plurality of sets of sensor heads and interferometers so that the shape measuring machine can measure the shape at each of a plurality of positions in parallel. In this case, since the shape measuring machine can be multi-sensored, the measuring time can be shortened. However, in this case, it is necessary to provide a plurality of interferometers, and the interferometers are expensive, which significantly increases the manufacturing cost of the shape measuring machine. In addition, there is a possibility that the measurement accuracy of the shape measurement may deteriorate due to variations in the measurement accuracy of each interferometer.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shape measuring machine capable of measuring the shape of a workpiece at low cost and at high speed, and a method of controlling the same.

A shape measuring machine for achieving the object of the present invention is a shape measuring machine for measuring the shape of a workpiece in a non-contact manner. is a part of the measurement light reflected by different reflecting surfaces, an interferometer for detecting interference signals of the reference light, and a plurality of sensor heads arranged at mutually different positions, and the measurement light from the interferometer is A plurality of sensor heads that emit measurement light toward a workpiece and output reflected light reflected by the workpiece to an interferometer when an input is received, and the plurality of sensor heads are sequentially connected to the interferometer one by one. and a relative movement mechanism for relatively moving the workpiece and the plurality of sensor heads, wherein the optical switch is connected while the relative movement is being performed by the relative movement mechanism. Repeat switching.

According to this shape measuring machine, the shape measuring machine can be multi-sensored without providing an interferometer for each sensor head.

In the shape measuring machine according to another aspect of the present invention, the plurality of sensor heads intermittently scan different workpiece scanning ranges for each sensor head with measurement light while the relative movement mechanism performs the relative movement, A shape calculation unit is provided for calculating the shape of the work based on the detection result of the interference signal for each sensor head by the interferometer. As a result, the shape measuring machine can be multi-sensored without providing an interferometer for each sensor head.

In the shape measuring machine according to another aspect of the present invention, the number of samplings of the interference signal for each scanning range required for the shape calculation by the shape calculation section is Q, and the relative movement by the relative movement mechanism is completed. When the time is t, the number of sensor heads is N, and the sampling speed of the interferometer is V, the sampling speed satisfies V≧Q×N/t, and the optical switch switches at a switching speed corresponding to the sampling speed. Switch connection. As a result, the necessary number of interference signals for calculating the shape of the workpiece can be obtained for each scanning range.

In a shape measuring machine according to another aspect of the present invention, the relative movement mechanism comprises a rotary table on which a columnar or cylindrical workpiece is placed and which rotates around a rotation axis, and the rotary table rotates around the rotation axis. a rotating mechanism that rotates the rotating table at least once, the rotating mechanism rotating the rotating table at least once. In between, a plurality of sensor heads intermittently scan with measurement light a scanning range along the circumferential direction of the outer peripheral surface, where the positions in the axial direction are different for each sensor head, and the shape computing unit At least one of the roundness and the cylindricity of the work for each scanning range of the work is calculated based on the detection result of the interference signal for each sensor head by the interferometer. Thereby, the roundness and/or cylindricity of the workpiece can be measured at low cost and at high speed.

A shape measuring machine according to another aspect of the present invention includes a position adjusting mechanism for adjusting the axial position of each sensor head. This makes it possible to measure the shape of the workpiece at a desired axial position.

In the shape measuring machine according to another aspect of the present invention, the shape calculation unit calculates the inclination of the work placed on the rotary table based on the detection result of the interference signal for each sensor head by the interferometer, and calculates the shape. A tilting mechanism is provided for tilting the rotary table and correcting the tilt based on the result of tilt calculation by the unit. As a result, it is possible to correct the inclination of the workpiece at low cost and at high speed.

In a shape measuring machine according to another aspect of the present invention, the relative movement mechanism comprises a rotary table on which a columnar or cylindrical workpiece is placed and which rotates around a rotation axis, and the rotary table rotates around the rotation axis. a rotating mechanism for rotating the work, a plurality of first sensor heads arranged at positions facing the outer peripheral surface of the work and at different positions in the axial direction of the rotating shaft; and second sensor heads arranged at opposing positions, wherein the plurality of first sensor heads cover a scanning range along the circumferential direction of the outer peripheral surface while the rotating mechanism rotates the rotary table at least once. The first scanning range, which is a first scanning range in which the positions in the axial direction are different for each of the first sensor heads, is intermittently scanned with the measurement light. The sensor head intermittently scans the second scanning range, which is a circular scanning range on the upper surface, with the measurement light, and the shape calculation unit detects interference signals for each of the first sensor head and the second sensor head using an interferometer. Based on the results, the squareness of the workpiece is calculated. As a result, it is possible to measure the squareness of the workpiece at low cost and at high speed.

A control method of a shape measuring machine for achieving the object of the present invention is to output measurement light, and to produce measurement light reflected by a work and measurement light reflected by a reflecting surface different from the work. An interferometer that detects the interference signal of the reference beam, which is a part, and a plurality of sensor heads arranged at different positions. A method for controlling a shape measuring machine comprising a plurality of sensor heads that emit light toward the workpiece and output reflected light reflected by the workpiece to an interferometer, wherein the plurality of sensor heads are sequentially connected to the interferometer one by one. A connection switching step for switching the connection to be connected, and a relative movement step for relatively moving the workpiece and the plurality of sensor heads. repeatedly.

INDUSTRIAL APPLICABILITY According to the present invention, workpiece shape measurement can be performed at low cost and at high speed.

1 is a perspective view of a shape measuring machine according to a first embodiment that measures the shape of a columnar or cylindrical work in a non-contact manner; FIG. 1 is a block diagram of an interferometer and controller; FIG. FIG. 5 is an explanatory diagram for explaining a scanning range of measurement light for each sensor head with respect to an outer peripheral surface of a work; FIG. 5 is an explanatory diagram for explaining calibration of the angular positional relationship of each sensor head by a calibration unit; 4 is a flow chart showing the flow of processing for measuring the roundness and cylindricity of a workpiece by a shape measuring machine. FIG. 5 is a perspective view of a shape measuring machine of a second embodiment; FIG. 11 is an explanatory diagram for explaining calibration of the height position of each sensor head by the calibration unit of the second embodiment; FIG. 11 is a perspective view of a shape measuring machine according to a third embodiment; FIG. 5 is an explanatory diagram for explaining the calculation of the tilt of the work by the shape calculator and the correction of the tilt of the work by the tilt mechanism; FIG. 4 is an explanatory diagram for explaining a state before tilt correction of a work by a tilt mechanism and a state after tilt correction; FIG. 11 is a perspective view of a shape measuring machine according to a fourth embodiment; FIG. 12 is an explanatory diagram for explaining calibration of the positional relationship between the height positions of the first sensor heads by the calibration unit of the fourth embodiment; FIG. 12 is an explanatory diagram for explaining calibration of the positional relationship between the height positions of the first sensor head and the second sensor head by the calibration unit of the fourth embodiment; FIG. 11 is a block diagram showing a modification of the interferometer;

[First embodiment]
FIG. 1 is a perspective view of a shape measuring machine 10 of a first embodiment for measuring the shape of a columnar or cylindrical work W without contact. As shown in FIG. 1, the shape measuring machine 10 measures various shapes of a cylindrical or cylindrical work W such as roundness, cylindricity, and squareness (such as surface roughness and contour shape). (including surface texture) can be measured. In the first embodiment, measurement of the circularity and cylindricity of the workpiece W will be described as an example.

The shape measuring machine 10 includes a base (not shown), a rotating table 12 , a rotating mechanism 14 , three sensor heads 16 , an interferometer 18 , an optical switch 20 and a controller 22 .

The turntable 12 is provided on a base (not shown) so as to be rotatable around a rotation axis C passing through its center. A workpiece W is placed on the upper surface of the rotary table 12 . The workpiece W is placed on the upper surface of the workpiece W so that its center axis coincides with the rotation axis C (including approximately coincidence; the same shall apply hereinafter).

An annular scale 24 is provided on the outer peripheral surface of the rotary table 12 along the circumferential direction. The scale 24 is provided with grid graduations (not shown). An optical sensor 26 is provided at a position facing the scale 24 .

The optical sensor 26 detects grid graduations on the scale 24 and outputs the detection signal to the control device 22 . Based on the detection signal output from the optical sensor 26, the rotation amount (rotation angle), rotation direction, rotation speed, etc. of the turntable 12 can be detected. An optical sensor 26 may be provided on the outer peripheral surface of the rotary table 12, and the scale 24 may be provided at a position where the optical sensor 26 can read the grid scale.

The rotation mechanism 14 is composed of a motor and a drive transmission mechanism (not shown), and rotates the rotation table 12 around the rotation axis C under the control of the control device 22 . As a result, the workpiece W is rotated (relatively moved) around the rotation axis C with respect to each sensor head 16, which will be described later. Therefore, the rotation mechanism 14 functions as a relative movement mechanism of the invention.

Each sensor head 16 is arranged at a position facing the outer peripheral surface of the work W and at different positions in the vertical direction (corresponding to the axial direction of the rotating shaft C). Note that the number of sensor heads 16 may be two or four or more. Further, the sensor head 16 in this specification also includes a light emitting end (which is also an incident end of the reflected light L3 described later) that emits the measuring light L1 to the work W to be described later. Therefore, for example, the end portion of each optical waveguide 28 described later may function as the sensor head 16 in some cases.

Each sensor head 16 is connected to the optical switch 20 via a separate optical waveguide 28 (eg, fiber optic cable). Each sensor head 16 emits the measurement light L1 toward the outer peripheral surface of the workpiece W when the measurement light L1 is input from the interferometer 18 described later via the optical switch 20 and the like described later.

Further, each sensor head 16 receives the reflected light L3 of the measuring light L1 reflected (specularly reflected) by the outer peripheral surface, which is the surface to be measured of the workpiece W, and transmits the measuring light L1 through the optical waveguide 28 and the light beam. Output to interferometer 18 via switch 20 . The specular reflection here means reflecting the measurement light L1 toward the sensor head 16 from which it is emitted.

FIG. 2 is a block diagram of interferometer 18 and controller 22 . As shown in FIG. 2 and FIG. 1 already described, the interferometer 18 includes a light source 30, a splitter 32, a reference optical path 34, a measurement optical path 36, a mixer 38, a signal detection section 40, an optical waveguide 42 connecting these sections, and the like. It has

Various known light sources such as a halogen lamp, a light emitting diode, or a laser light source are used as the light source 30 , and the light source 30 outputs measurement light L<b>1 toward the splitter 32 . Note that the light source 30 may be provided outside the interferometer 18 .

Splitter 32 connects to light source 30, reference beam path 34, and measurement beam path 36, respectively. The splitter 32 splits a portion of the measurement light L1 input from the light source 30 and outputs the split light to the reference light path 34 as the reference light L2. Also, the splitter 32 outputs the rest of the measurement light L1 to the measurement light path 36 .

The reference optical path 34 is provided with a first collimator 46 , a prism reflector 48 , a corner reflector 50 , a moving stage 52 and a second collimator 54 .

The first collimator 46 emits the reference light L2 input from the splitter 32 toward the prism reflector 48 as parallel rays. The prism reflector 48 reflects the reference light L2 input from the first collimator 46 toward the corner reflector 50 and reflects the reference light L2 incident from the corner reflector 50 toward the second collimator 54 .

The corner reflector 50 functions as a reflecting surface of the present invention and is arranged on the optical path of the reference light L2 reflected by the prism reflector 48 . The corner reflector 50 reflects the reference light L2 incident from the prism reflector 48 toward the prism reflector 48 again.

A moving stage 52 is attached to the corner reflector 50 . The moving stage 52 reciprocates the corner reflector 50 along a direction parallel to the optical path of the reference light L2 reflected by the prism reflector 48. As shown in FIG. Thereby, the optical path length difference between the measurement light L1 and the reference light L2 can be changed with time.

The second collimator 54 collects the reference light L2 incident from the prism reflector 48 and outputs this reference light L2 to the mixer 38 .

A circulator 44 is provided in the measuring beam path 36 . The circulator 44 outputs the measurement light L1 input from the splitter 32 toward the optical switch 20 and outputs the reflected light L3 input from the optical switch 20 toward the mixer 38 .

A circulator 44 is connected to the optical switch 20 via an optical waveguide 42, and each sensor head 16 is connected via each optical waveguide 28 described above. The optical switch 20 switches the sensor head 16 connected to the interferometer 18 under the control of a control device 22 which will be described later. As a result, each sensor head 16 irradiates the outer peripheral surface of the workpiece W with the measurement light L1 at different timings (time division), and receives and outputs the reflected light L3 reflected on the outer peripheral surface.

For the mixer 38, for example, an optical mixer is used. The mixer 38 generates an interference signal LS between the reference light L2 input from the reference optical path 34 and the reflected light L3 from each sensor head 16 input from the measurement optical path 36 . The mixer 38 then outputs the interference signal LS for each sensor head 16 to the signal detection section 40 .

For the signal detection unit 40, for example, various photoelectric conversion devices such as a photodiode, a phototube, and a photomultiplier tube (image pickup devices are also possible) are used. Under the control of the control device 22 , the signal detection unit 40 converts the interference signal LS for each sensor head 16 input from the mixer 38 into an electrical signal and outputs the electrical signal to the control device 22 .

Although the rotation (rotation angle) of the rotary table 12 is synchronized with the timing of connection switching of the optical switch 20 and detection of the interference signal LS of the interferometer 18, they do not have to be synchronized.

The control device 22 is, for example, an arithmetic device such as a personal computer, and includes an arithmetic circuit composed of various processors, memories, and the like. Various processors include CPU (Central Processing Unit), GPU (Graphics Processing Unit), ASIC (Application Specific Integrated Circuit), and programmable logic devices [for example, SPLD (Simple Programmable Logic Devices), CPLD (Complex Programmable Logic Device), and FPGAs (Field Programmable Gate Arrays)]. Various functions of the control device 22 may be realized by one processor, or may be realized by a plurality of processors of the same type or different types.

The control device 22 centrally controls the operation of each part of the shape measuring machine 10 such as the rotation mechanism 14 , the optical switch 20 and the signal detection part 40 . Further, based on the detection result of the interference signal LS for each sensor head 16 input from the signal detection unit 40, the control device 22 controls the roundness of each scanning range 70 of the workpiece W and the A cylindricity (hereinafter abbreviated as “circularity of the workpiece W, etc.” as appropriate) is calculated.

The control device 22 functions as an interferometer control section 60, a drive control section 62, a switch control section 64, a shape calculation section 66, and a calibration section 68 by executing a control program (not shown).

The interferometer controller 60 controls the operation of each part of the interferometer 18 . The interferometer control unit 60 operates the interferometer 18 when an operation for starting measurement such as the roundness of the work W is input to an operation unit (not shown). Specifically, the interferometer control unit 60 always causes the light source 30 to emit the measurement light L1 and always reciprocates the moving stage 52 .

The drive control unit 62 controls driving of the rotation mechanism 14 , that is, controls rotation of the turntable 12 . The drive control unit 62 drives the rotation mechanism 14 to rotate the rotation table 12 about the rotation axis C in response to an operation to start measuring the roundness of the work W and the like. At this time, the drive control unit 62 rotates the turntable 12 at least once based on the detection signal input from the optical sensor 26 . As a result, each sensor head 16 can scan the outer peripheral surface of the work W with the measurement light L1 along the circumferential direction one or more times.

The switch control unit 64 controls switching of the optical switch 20 , that is, switching of the sensor head 16 connected to the interferometer 18 , in response to an operation to start measurement of the roundness of the work W and the like. The switch control unit 64 controls the optical switch 20 to switch the connection to sequentially connect each sensor head 16 to the interferometer 18 while the rotation table 12 is being rotated by the rotation mechanism 14 . repeatedly.

FIG. 3 is an explanatory diagram for explaining the scanning range 70 of the measurement light L1 for each sensor head 16 with respect to the outer peripheral surface of the work W. As shown in FIG. Here, the measurement point P in FIG. 3 indicates the incident position of the measurement light L1 incident on the surface to be measured (here, the outer peripheral surface) of the workpiece W, and also indicates the reflection position of the reflected light L3 of the measurement light L1. . In FIG. 3, only a portion of the measurement points P for each sensor head 16 (for each scanning range 70) is shown in order to prevent complication of the drawing.

As shown in FIG. 3, the optical switch 20 repeatedly performs the above-described connection switching while the rotary table 12 is rotating, so that the sensor heads 16 can rotate the rotating work W at different timings (in a time division manner). measurement light L1 is intermittently irradiated onto the outer peripheral surface (each measuring point P) of the , and reflected light L3 reflected by this outer peripheral surface (each measuring point P) is intermittently received and output. Intermittent (also referred to as intermittent) here means discontinuous, and includes both regular intervals and non-regular intervals.

In this way, each sensor head 16 scans three circular (including substantially circular) scanning ranges 70 along the circumferential direction of the outer peripheral surface of the work W, and each sensor head 16 scans at a position in the vertical direction. Three scanning ranges 70 having different height positions are intermittently and simultaneously scanned with the measurement light L1. As a result, the detection result of the interference signal LS for each measurement point P in each scanning range 70 is input from the interferometer 18 (signal detection unit 40 ) to the shape calculation unit 66 .

Returning to FIG. 2, the shape calculation unit 66, when measuring the roundness of the work W, based on the detection result of the interference signal LS for each measurement point P in the individual scanning range 70 input from the signal detection unit 40, The circularity and the cylindricity of the workpiece W for each scanning range 70 of the outer peripheral surface of the workpiece W are calculated.

Note that the shape calculation unit 66 acquires position information for each sensor head 16 in advance. This positional information includes, for example, the relationship between the angular positions of the sensor heads 16 in the direction around the rotation axis C (hereinafter referred to as the angular positional relationship) and the height position of each sensor head 16. included.

First, the shape calculator 66 calculates the distance between the measurement point P and the sensor head 16 at the time when the measurement light L1 is incident based on the detection result of the interference signal LS for each measurement point P in the scanning range 70. is performed for each measurement point P for each scanning range 70 (for each sensor head 16). Since a specific distance detection method is a known technique, a specific description is omitted here.

Next, the shape calculation unit 66 calculates the relative unevenness of each measurement point P (peripheral surface) for each scanning range 70 based on the calculation result of the distance calculation processing for each scanning range 70, thereby scanning the workpiece W. The circularity of each range 70 is calculated, and the cylindricity of the workpiece W is calculated. The method of calculating the roundness and the cylindricity (for example, interpolation processing and fitting processing) is a known technique, so a detailed description thereof will be omitted. Also, the shape calculator 66 may calculate only one of the circularity and the cylindricity instead of calculating both.

In this embodiment, the scanning range 70 corresponding to each sensor head 16 is intermittently scanned with the measurement light L1. It is necessary to set the number of measurement points P for each to a certain number or more. Therefore, the interferometer 18 used is one capable of sampling at a higher speed than the rotational speed of the rotary table 12 .

Specifically, the number of samplings of the interference signal LS for each scanning range 70 necessary for calculating the roundness and cylindricity of the workpiece W is set to Q [points (pt)], and the rotation of the rotary table 12 by the rotary mechanism 14 ( For example, let t(s) be the time required to complete one rotation), let N be the number of sensor heads 16, and let V [points (pt)/s] be the sampling rate of the interferometer 18 . In this case, an interferometer 18 whose sampling rate satisfies V≧Q×N/t is used. Also, as the optical switch 20, one that performs the above-described connection switching at a switching speed corresponding to the sampling speed of the interferometer 18 is used.

For example, in this embodiment, an interferometer 18 having a sampling rate satisfying V=1000 (pt/s) and an optical switch 20 having a switching speed corresponding to this sampling rate are used. Further, the rotation speed R of the turntable 12 in this embodiment is 4 rpm (0.067 rps), in other words, the rotation speed at which the turntable 12 makes one rotation at t=15 seconds (s). Also, the number of sensor heads 16 in this embodiment is N=3. In this case, as shown in (1) or (2) of the following [Formula 1] formula, sampling of 5000 (pt) measurement points P for each scanning range 70 in one rotation of the rotary table 12 is possible.

In the evaluation of the roundness, for example, a Gaussian filter (low-pass filter) is used, whose cutoff value is a cycle in which the number of peaks per round of each scanning range 70 is 50. Therefore, if 5000 (pt) measurement points P can be sampled for each scanning range 70, it is possible to sufficiently evaluate roundness and the like.

The calibration unit 68 calibrates the position information (angular positional relationship, etc.) for each sensor head 16 described above.

FIG. 4 is an explanatory diagram for explaining calibration of the angular positional relationship of each sensor head 16 by the calibration unit 68. As shown in FIG. As shown in FIG. 4 and FIG. 2 already described, when calibrating the angular positional relationship of each sensor head 16, a jig 72 (also referred to as a reference workpiece) for calibrating the angular positional relationship is set on the rotary table 12. be done. The jig 72 has a columnar shape extending in the vertical direction, and a notch 72a extending in the vertical direction is formed on the outer peripheral surface thereof.

After the jig 72 is set on the rotary table 12 , when a calibration start operation is input to the operation unit (not shown), the interferometer control unit 60 operates the interferometer 18 and the drive control unit 62 operates the rotation mechanism 14 . It is driven to rotate the rotary table 12 once. Further, the switch control unit 64 repeatedly performs connection switching by the optical switch 20 while the rotary table 12 is rotating. As a result, the outer peripheral surface of the jig 72 is scanned by the measurement light L1 emitted from each sensor head 16 along the circumferential direction by one turn.

Furthermore, according to this scanning, the detection result of the interference signal LS for each angular position (0° to 360°) of the rotary table 12 for each sensor head 16 is input from the interferometer 18 to the shape calculation unit 66. be. The shape calculation unit 66 calculates the distance from the sensor head 16 to the outer peripheral surface of the jig 72 at each angular position for each sensor head 16 and outputs the calculation result to the calibration unit 68 .

Next, the calibration unit 68 detects the angular position corresponding to the notch 72a (hereinafter referred to as the notch angular position) for each sensor head 16 based on the distance calculation result of each angular position for each sensor head 16 . Then, the calibration unit 68 calculates the measured value of the angular positional relationship of each sensor head 16 based on the detection result of the notch angular position of each sensor head 16, thereby calculating the angular positional relationship of each sensor head 16 obtained in advance. (design value, etc.).

It should be noted that the measured value of the height position of each sensor head 16 can be obtained by using a distance measuring sensor (not shown) or the like. Therefore, the calibration unit 68 calibrates the previously obtained height position (design value, etc.) of each sensor head 16 based on the actually measured value of the height position of each sensor head 16 .

The calibration of the position information for each sensor head 16 by the calibration unit 68 is periodically performed at a predetermined timing. The already-described shape calculation unit 66 calculates the position coordinates of each measurement point P for each of the above-described scanning range 70 using the post-calibration position information of each sensor head 16 . Thereby, in the present embodiment, the circularity and cylindricity of the workpiece W can be calculated with higher accuracy.

The shape calculator 66 of the first embodiment calculates the circularity and cylindricity of the workpiece W based on the detection results of the interference signal LS for each measurement point P in the scanning range 70. Measurements other than circularity, etc., can also be performed at the same time. For example, the shape calculation unit 66 calculates the distance calculation result (radius information of the workpiece W) for each scanning range 70, and the position information of the sensor head 16 (here, the distance information from the rotation axis C to each sensor head 16). ), etc., the cross-sectional shape of each scanning range 70 of the workpiece W is measured by a known method.

Further, in this case, the calculation result (radius information of the work W) of the distance calculation process for each scanning range 70 is calibrated. Specifically, the rotating mechanism 14 rotates the rotary table 12 by one turn or more in a state in which a cylindrical diameter masterwork having a radius of "r1" is placed on the rotary table 12, and each scanning range by the interferometer 18 Detection of the interference signal LS for each measurement point P of 70 and the above-described distance calculation processing for each scanning range 70 by the shape calculation unit 66 are performed. Thereby, the shape calculator 66 can calculate the radius "r2" of the circular cross-sectional shape for each scanning range 70 using the method of least squares or the like.

Next, for each sensor head 16 (scanning range 70), the calibration unit 68 calculates the above-described difference "r1-r2", which is the difference between the design value "r1" and the measured value "r2" of the radius of the diameter masterwork. The calculation result of distance calculation processing (radius information of work W) is offset. As a result, the distance from the rotation axis C to each measurement point P can be accurately calculated for each scanning range 70, so the cross-sectional shape of the work W can be measured for each scanning range 70 with high accuracy.

[Action of shape measuring machine]
FIG. 5 is a flow chart showing the control method of the shape measuring machine 10 having the above configuration, particularly the flow of the process of measuring the roundness and cylindricity of the workpiece W by the shape measuring machine 10 . As shown in FIG. 5, the operator sets the workpiece W to be measured on the rotary table 12 (step S1), and then inputs an operation to start measurement such as roundness to an operation unit (not shown). Thereby, the control device 22 functions as an interferometer control section 60, a drive control section 62, a switch control section 64, a shape calculation section 66, and the like. Note that the optical switch 20 connects one of the sensor heads 16 to the interferometer 18 at the time of inputting the measurement start operation.

Then, the drive control unit 62 drives the rotation mechanism 14 to start rotating the turntable 12 (step S2). As a result, the rotary table 12 and the workpiece W are integrally rotated about the rotary axis C. As shown in FIG. Based on the detection signal input from the optical sensor 26, the drive control unit 62 continues to rotate the turntable 12 until the turntable 12 rotates by a predetermined amount of rotation (at least one rotation) (step NO in S3). Note that steps S2 and S3 correspond to the relative movement step of the present invention.

At the same time, interferometer controller 60 operates interferometer 18 . As a result, the measurement light L1 is emitted from the sensor head 16 connected to the interferometer 18 via the optical switch 20 toward the outer peripheral surface of the workpiece W, and is reflected at the measuring point P on the outer peripheral surface. Light L3 is incident on the original sensor head 16 (step S4). Then, an interference signal LS of the reference light L2 and the reflected light L3 is generated within the interferometer 18, and this interference signal LS is detected by the signal detector 40 (step S5). As a result, the detection result of the interference signal LS is output from the signal detector 40 to the shape calculator 66 .

Then, the switch control unit 64 controls the optical switch 20 to switch the sensor head 16 connected to the interferometer 18 (NO in step S6, step S7). After this switching, the processes of steps S4 and S5 described above are executed again.

Thereafter, the switch control unit 64 controls the optical switch 20 to sequentially connect each sensor head 16 to the interferometer 18 while the rotation table 12 is being rotated by the rotation mechanism 14 . Connection switching is repeatedly executed (NO in step S6, step S7, corresponding to the connection switching step of the present invention). As a result, each sensor head 16 intermittently scans a different scanning range 70 for each sensor head 16 with the measurement light L1 at mutually different timings (time sharing).

Further, each time the connection switching of the optical switch 20 is executed, the processes of steps S4 and S5 are repeatedly executed. Thereby, the detection result of the interference signal LS for each measurement point P in each scanning range 70 is input from the interferometer 18 to the shape calculation unit 66 .

When the rotation of the rotary table 12 by the rotation mechanism 14, that is, the rotation of the workpiece W is completed (YES in steps S2 and S6), the shape calculation unit 66 performs the measurement for each measurement point P in the scanning range 70 input from the interferometer 18. Based on the detection result of the interference signal LS, as described above, the roundness and the cylindricity of the work W for each scanning range 70 of the work W are calculated (step S8).

[Effect of this embodiment]
As described above, in this embodiment, while the rotary table 12 is rotating, the connection switching by the optical switch 20 is repeatedly executed to operate each sensor head 16 in a time-divisional manner, thereby allowing a plurality of different workpieces W to be scanned. can be intermittently and simultaneously scanned with the measurement light L1. Since this eliminates the need to provide an interferometer 18 for each sensor head 16, the shape measuring machine 10 can be made into a multi-sensor at low cost. Further, the shape of the workpiece W can be measured in a shorter time than when the height position of one sensor head 16 is adjusted and each scanning range 70 (the number of cross sections) is scanned with the measurement light L1. Furthermore, the measurement speed is higher than when measuring the same number of scanning ranges 70 (number of cross sections) with one sensor head 16 . As a result, the shape measurement of the workpiece W can be performed at low cost and at high speed.

Further, in this embodiment, since the plurality of sensor heads 16 scan different scanning ranges 70 with the measuring light L1, only one sensor head 16 is arranged for each scanning range 70 to be measured. Shape measurements can be performed. As a result, even if the number of scanning ranges 70 increases, the increase in the number of sensor heads 16 can be minimized, so the shape measuring machine 10 can be constructed at low cost.

Furthermore, in this embodiment, since the interference signal LS is detected by one (common) interferometer 18 for each sensor head 16, the measurement accuracy of each interferometer 18 is reduced as in the case of using a plurality of interferometers 18 simultaneously. The problem of variation does not occur, and the measurement accuracy of the shape measurement of the work W can be improved.

[Second embodiment]
FIG. 6 is a perspective view of the shape measuring machine 10 of the second embodiment. Although the position of each sensor head 16 is fixed in the shape measuring machine 10 of the first embodiment, the height position of each sensor head 16 can be individually adjusted in the shape measuring machine 10 of the second embodiment. The configuration of the shape measuring machine 10 of the second embodiment is basically the same as that of the shape measuring machine 10 of the first embodiment, except that three position adjusting mechanisms 76 are provided. For this reason, the same reference numerals are given to the same functions or configurations as those of the first embodiment, and the description thereof will be omitted.

Each position adjustment mechanism 76 is individually provided for each sensor head 16 . Each position adjusting mechanism 76 is, for example, a known linear motor mechanism, and includes a vertically extending guide 76a and a mover 76b (also referred to as a carriage) held vertically movably by the guide 76a. Prepare. One sensor head 16 is provided for each mover 76b. Since the detailed configuration of the linear motor mechanism is a well-known technology, detailed description thereof will be omitted. Further, as the position adjusting mechanism 76, various linear drive mechanisms such as a ball screw mechanism may be used instead of the linear motor mechanism.

The driving of each position adjusting mechanism 76 is controlled by the drive control section 62 described above. The drive control unit 62 individually adjusts the height position of each sensor head 16 by driving each position adjustment mechanism 76 according to the position adjustment operation of each sensor head 16 input to an operation unit (not shown). do. Thereby, the height position of each scanning range 70 on the outer peripheral surface of the work W can be arbitrarily adjusted.

FIG. 7 is an explanatory diagram for explaining calibration of the height position of each sensor head 16 by the calibration unit 68 of the second embodiment. Other calibration of each sensor head 16 (such as calibration of the angular positional relationship) is basically the same as that of the first embodiment, so the description is omitted here.

As shown in FIG. 7, when calibrating the height position of each sensor head 16, a jig 78 (also referred to as a reference work) for calibrating the height position is set on the rotary table 12. As shown in FIG. This jig 78 has a cylindrical shape extending in the vertical direction.

After the jig 78 is set on the rotary table 12, when a calibration start operation is input to the operation unit (not shown), the interferometer control unit 60 operates the interferometer 18, and the drive control unit 62 operates each position adjustment mechanism. 76 is driven to move each sensor head 16 vertically. Further, the switch control unit 64 causes the optical switch 20 to repeatedly switch the connection while each sensor head 16 is moving. As a result, the outer peripheral surface of the jig 78 is simultaneously scanned in the vertical direction by the measurement light L1 emitted from each sensor head 16 .

Furthermore, according to this scanning, the interferometer 18 sends the shape calculator 66 the detection results of the interference signal LS for each of the plurality of measurement points P along the vertical direction of the outer peripheral surface of the jig 78 for each sensor head 16. is entered. As a result, the shape calculation unit 66 performs the above-described distance calculation processing for each sensor head 16 (calculation of the distance between the measurement point P and the sensor head 16 at the time when the measurement light L1 is incident on each measurement point P). processing) is performed, and the calculation result is output to the calibration unit 68 .

Based on the result of the distance calculation processing for each sensor head 16, the calibration unit 68 determines the boundary position between the upper surface and the outer peripheral surface of the jig 78 (or position of the step) is detected. Next, based on the detected position of each sensor head 16 , the calibration unit 68 sets the detected position of each sensor head 16 as the origin (reference position) of the height position of the sensor head 16 . As a result, a common origin (reference position) defined by the jig 78 is set for all the height positions of the sensor heads 16, and calibration of the height position of each sensor head 16 is completed.

As described above, in the shape measuring machine 10 of the second embodiment, the height position of each sensor head 16 can be adjusted. be able to.

[Third embodiment]
FIG. 8 is a perspective view of the shape measuring machine 10 of the third embodiment. In the shape measuring machine 10 of the first embodiment, the measurement of the roundness and cylindricity of the workpiece W was described as an example. The inclination of the work W above is measured, and the inclination of the work W is corrected based on the measurement result.

Note that the shape measuring machine 10 of the third embodiment has the above-described configuration except that the shape calculation unit 66 of the control device 22 calculates the inclination of the workpiece W placed on the rotary table 12 and that the inclination mechanism 80 is provided. It has basically the same configuration as the shape measuring machine 10 of the first embodiment. For this reason, the same reference numerals are given to the same functions or configurations as those of the first embodiment, and the description thereof will be omitted.

The shape calculator 66 of the third embodiment calculates the circularity and cylindricity of the workpiece W based on the detection results of the interference signal LS at each measurement point P for each sensor head 16 (scanning range 70). The inclination of the workpiece W on the turntable 12 is calculated based on the detection result of the interference signal LS at each measuring point P corresponding to each of the sensor heads 16 .

The tilting mechanism 80 includes an actuator and a drive transmission mechanism (not shown), and tilts the rotary table 12 from a horizontal posture (a posture perpendicular to the vertical direction) under the control of the control device 22 (drive control unit 62). Let

FIG. 9 is an explanatory diagram for explaining the calculation of the tilt of the work W by the shape calculator 66 and the correction of the tilt of the work W by the tilt mechanism 80. As shown in FIG. 10A and 10B are explanatory diagrams for explaining the state before tilt correction of the work W by the tilt mechanism 80 and the state after tilt correction.

As indicated by symbol IXA in FIG. 9, the shape calculator 66 calculates measurement points P corresponding to two sensor heads 16 (two scanning ranges 70) having different height positions in the vertical direction (Z-axis direction). The position coordinates of each measurement point P for each of the two scanning ranges 70 are calculated based on the detection result of the interference signal LS. In FIG. 9, one of the two sensor heads 16 is designated as "sensor 1" and the other is designated as "sensor 2".

Next, as indicated by reference numeral IXB in FIG. 9, the shape calculation unit 66 interpolates the measurement points P for each scanning range 70 based on the calculation results of the position coordinates of each measurement point P for each of the two scanning ranges 70. (Interpolation) is performed to increase the number of measurement points P.

Then, the shape calculator 66 calculates the center position of each measuring point P for each scanning range 70 by the method of least squares or the like, based on the position coordinates of each measuring point P for each scanning range 70 after interpolation.

Here, the vertical direction is the Z-axis direction, the direction perpendicular to the Z-axis direction is the X-axis direction, and the direction perpendicular to both the Z-axis direction and the X-axis direction is the Y-axis direction. As the origin, the position coordinates of the center position 1 corresponding to one of the two scanning ranges 70 are represented by (ΔX1, ΔY1), and the position coordinates of the center position 2 corresponding to the other of the two scanning ranges 70 are represented by (ΔX2, ΔY2 )expressed. Further, the height position of center position 1 is represented by coordinate Z1, and the height position of center position 2 is represented by coordinate Z2. In this case, the shape calculation unit 66 calculates the inclination of the work W in the XZ plane based on the following formula [Equation 2], and calculates the tilt of the work W in the YZ plane based on the following [Equation 3]. The inclination is calculated, and the calculated result of each inclination is output to the drive control section 62 .

As indicated by reference numeral IXC in FIG. 9 and reference characters XA and XB in FIG. The inclination of the workpiece W is corrected by driving the inclination mechanism 80 . As a result, the workpiece W becomes parallel to the vertical direction (Z-axis).

When the inclination of the work W is corrected as described above, the center of the work W may deviate from the rotation axis C due to the shape error of the work W (displacement of cross-sectional shape, etc.). Therefore, it is preferable to repeat the above-described measurement (calculation) and correction of the inclination of the workpiece W a plurality of times. Then, measurement of the roundness and cylindricity of the workpiece W is started in the same manner as in the first embodiment. Thereby, the circularity and cylindricity of the workpiece W can be measured with higher accuracy.

As described above, also in the third embodiment, the two sensor heads 16 are operated at different timings (time division) to intermittently scan two different scanning ranges 70 on the outer peripheral surface of the workpiece W with the measurement light L1. and can be scanned at the same time. Therefore, for the same reason as in the first embodiment, tilt measurement and tilt correction of the work W can be performed at low cost and at high speed.

In the third embodiment, the tilt of the work W is calculated by the shape calculation unit 66, and the tilt of the work W is corrected by the tilt mechanism 80 based on the result of this calculation. may be executed.

Specifically, the shape calculator 66 calculates the position coordinates of the central position of each measurement point P for each scanning range 70 as described above (see symbols IXA and IXB in FIG. 9). Then, based on the calculation result of the position coordinates of the center position of each scanning range 70, the shape calculation unit 66 causes the position coordinates of the center position of each measurement point P to match (substantially match) the rotation axis C for each scanning range 70. ), the position coordinates of each measurement point P are corrected (see symbol IXC in FIG. 9).

In the above-described third embodiment, calculation and correction of the inclination of the work W have been described. The eccentricity of the workpiece W may be corrected by tilting the rotary table 12 by the tilting mechanism 80 based on the above.

Further, although the position of each sensor head 16 is fixed in the third embodiment, the height position of each sensor head 16 may be individually adjustable as in the second embodiment.

[Fourth embodiment]
FIG. 11 is a perspective view of the shape measuring machine 10 of the fourth embodiment. In the shape measuring machine 10 of each of the above embodiments, measurement of the circularity, cylindricity, and inclination of the workpiece W has been described as an example, but the shape measuring machine 10 of the fourth embodiment As a measurement, the squareness of the workpiece W is measured. In this case, both the outer peripheral surface and the upper surface of the work W are the surfaces to be measured.

The shape measuring machine 10 of the fourth embodiment includes one position adjusting mechanism 76 having two first sensor heads 16A, one second sensor head 16B, and a substantially L-shaped mover 76b, and Except for the point that the control device 22 calculates the squareness of the workpiece W, the configuration is basically the same as the shape measuring machine 10 of each of the above-described embodiments. Therefore, the same reference numerals are assigned to the same functions or configurations as those of the above-described embodiments, and the description thereof will be omitted.

Each of the first sensor heads 16A is provided on the mover 76b so as to face the outer peripheral surface of the work W and to be arranged at different positions in the vertical direction. Each first sensor head 16A emits measurement light L1 input from the interferometer 18 toward the outer peripheral surface of the workpiece W when connected to the interferometer 18 by the optical switch 20 . The reflected light L3 reflected by the outer peripheral surface of the work W is incident on the first sensor head 16A from which it is emitted, and is input to the interferometer 18 via the optical switch 20. FIG.

The second sensor head 16B is provided on the mover 76b at a position facing the upper surface of the workpiece W. As shown in FIG. The second sensor head 16B emits the measurement light L1 input from the interferometer 18 toward the upper surface of the workpiece W when connected to the interferometer 18 by the optical switch 20 . The reflected light L3 reflected by the upper surface of the workpiece W is incident on the second sensor head 16B from which it is emitted, and is input to the interferometer 18 via the optical switch 20. FIG.

The position adjustment mechanism 76 adjusts the height positions of the sensor heads 16A and 16B by vertically moving the mover 76b under the control of the drive control unit 62. FIG.

The optical switch 20 of the fourth embodiment performs connection switching to sequentially connect the sensor heads 16A and 16B to the interferometer 18 under the control of the switch control unit 64 .

The interferometer control unit 60, the drive control unit 62, and the switch control unit 64 of the fourth embodiment operate according to the measurement start operation of the squareness of the workpiece W according to the above-described first embodiment (during measurement of roundness, etc.). ) to perform the same control. As a result, the interferometer 18 is activated, and the rotating mechanism 14 starts rotating the rotating table 12 . Further, while the rotary table 12 is being rotated by the rotary mechanism 14, the optical switch 20 repeatedly performs the connection switching described above.

The optical switch 20 repeatedly performs connection switching while the rotary table 12 is rotating, so that the sensor heads 16 and 16B measure the surfaces (the outer peripheral surface and the upper surface) of the workpiece W at different timings (time division). Scanning is performed intermittently and simultaneously with the measurement light L1.

Specifically, each of the first sensor heads 16A scans two different scanning ranges 70 on the outer peripheral surface of the work W with the measurement light L1, and the second sensor head 16B scans the circular shape ( (including a substantially circular shape) is scanned with the measurement light L1. As a result, the detection result of the interference signal LS for each measurement point P of each first sensor head 16A (scanning range 70) is input from the signal detection unit 40 of the interferometer 18 to the shape calculation unit 66, and The detection result of the interference signal LS for each measurement point P of the two-sensor head 16B (scanning range 71) is input. Therefore, the scanning range 70 of the fourth embodiment corresponds to the first scanning range of the invention, and the scanning range 71 corresponds to the second scanning range of the invention.

The shape calculation unit 66 of the fourth embodiment calculates the interference signal LS for each measurement point P of each sensor head 16A, 16B (scanning ranges 70, 71) input from the signal detection unit 40 when measuring the squareness of the workpiece W. The squareness of the workpiece W is calculated based on the detection result and the positional information of each sensor head 16A, 16B. Since a specific method for calculating the squareness is a known technique, a specific description will be omitted here.

The calibration unit 68 of the fourth embodiment calibrates the position information of each sensor head 16A, 16B, more specifically, the position information used to calculate the squareness of the workpiece W. FIG. This positional information includes at least the positional relationship between the height positions of the sensor heads 16A and 16B.

FIG. 12 is an explanatory diagram for explaining the calibration of the positional relationship between the height positions of the first sensor heads 16A by the calibration unit 68 of the fourth embodiment. FIG. 13 is an explanatory diagram for explaining the calibration of the positional relationship between the height positions of the first sensor head 16A and the second sensor head 16B by the calibration unit 68 of the fourth embodiment.

As shown in FIGS. 12 and 13, when calibrating the vertical positional relationship of the sensor heads 16A and 16B, a jig for calibrating the height position is mounted on the rotary table 12 as in the second embodiment. 78 is set.

After setting the jig 78 on the rotary table 12 , when a calibration start operation is input to an operation unit (not shown), the interferometer control unit 60 operates the interferometer 18 and the drive control unit 62 operates the position adjustment mechanism 76 . to move the sensor heads 16A and 16B vertically. Also, the switch control unit 64 controls the optical switch 20 to repeatedly switch the connection between the sensor heads 16A and 16B. As a result, the outer peripheral surface of the jig 78 is simultaneously scanned in the vertical direction by the measurement light beams L1 emitted from the respective first sensor heads 16A. Further, the measurement light L1 is emitted toward the top surface of the jig 78 from the second sensor head 16B.

The interferometer 18 intermittently inputs the detection results of the interference signal LS for each of the plurality of measurement points P along the vertical direction of the outer peripheral surface of the jig 78 to the shape calculation unit 66 for each first sensor head 16A. be done. Further, the detection result of the interference signal LS corresponding to the measurement point P on the upper surface of the jig 78 facing the second sensor head 16B is intermittently input from the interferometer 18 to the shape calculator 66 . Thereby, the shape calculation section 66 performs the above-described distance calculation processing separately for each of the sensor heads 16A and 16B, and outputs the calculation result to the calibration section 68. FIG.

As shown in FIG. 12, the calibration unit 68 of the fourth embodiment, based on the results of distance calculation processing for each first sensor head 16A, performs the following operations in the same manner as in the calibration of the second embodiment described above (see FIG. 7). The boundary position between the upper surface and the outer peripheral surface of the jig 78 is detected for each first sensor head 16A, and this detected position is set as the origin of the height position of each first sensor head 16A. Thereby, the positional relationship of the height position of each first sensor head 16A is calibrated.

Further, as shown in FIG. 13, the calibration unit 68 sets the origin of the height position of the second sensor head 16B to the height position where the boundary position or the like is detected on one side of each of the first sensor heads 16A (zero Reset. Thereby, the positional relationship of the height position between the first sensor head 16A and the second sensor head 16B is calibrated. This completes the calibration of the positional relationship between the height positions of the sensor heads 16A and 16B.

As described above, in the fourth embodiment as well, the sensor heads 16A and 16B are operated in a time-sharing manner by repeatedly switching the connection by the optical switch 20 while the rotary table 12 is being rotated. A plurality of different scanning ranges 70 and 71 can be intermittently and simultaneously scanned with the measuring light L1. Thereby, the shape measuring machine 10 can be made into a multi-sensor at low cost. In addition, since the sensor heads 16A and 16B do not need to be changed in posture, the squareness of the workpiece W can be measured in a short period of time. As a result, the squareness of the workpiece W can be measured at low cost and at high speed.

In the fourth embodiment, the height position of each sensor head 16A, 16B can be changed, but the height position of each sensor head 16A, 16B may be fixed. Alternatively, the height position of only one of the first sensor heads 16A or the second sensor heads 16B may be fixed. Furthermore, although the first sensor heads 16A are arranged in a row in the vertical direction, they may not be arranged in a row.

[others]
In each of the embodiments described above, the interferometer 18 is of the type shown in FIG. 2, but the type of the interferometer 18 is not particularly limited. For example, in FIG. 14, which is a block diagram showing a modification of the interferometer 18, a wavelength swept light source 30A is used as the light source 30, and the light reflected by the end face of each sensor head 16, 16A, 16B or the tip end face of each optical waveguide 28 is measured. An interferometer 18 of a type that uses part of the light L1 as the reference light L2 (see JP-A-2018-084434) may be used. Also in this case, by analyzing the detection result of the interference signal LS between the reference light L2 and the reflected light L3 detected by the interferometer 18 by a known method (see Japanese Patent Laid-Open No. 2018-084434), each of the above The distance from the sensor head 16 to the measurement point P can be calculated as in the embodiment.

In each of the above embodiments, the workpiece rotation type shape measuring machine 10 that measures various shapes of the workpiece W by rotating the rotary table 12 has been described as an example. The present invention can also be applied to a head-rotating shape measuring machine 10 that measures various shapes of a workpiece W by rotating each sensor head 16, 16A, 16B about the axis C. FIG.

In each of the above embodiments, the shape measuring machine 10 rotates the work W or each sensor head 16, 16A, 16B about the rotation axis C to measure the shape such as the roundness of the work W. However, the present invention can be applied to various shape measuring machines 10 that measure various shapes of workpieces W while relatively moving workpieces W of various shapes and sensor heads 16, 16A, and 16B. is. For example, by arranging the sensor head 16 inside the ring-shaped work W, the shape of the inner peripheral surface of the work W can be measured, or by arranging the sensor heads 16 inside and outside the ring-shaped work W, the work can be measured. The shape of the inner and outer peripheral surfaces of W can be measured simultaneously.

DESCRIPTION OF SYMBOLS 10... Shape measuring machine 12... Rotary table 14... Rotating mechanism 16... Sensor head 16A... First sensor head 16B... Second sensor head 18... Interferometer 20... Optical switch 22... Control device 30... Light source 40... Signal detector 60 ... interferometer control section 62 ... drive control section 64 ... switch control section 66 ... shape calculation section 68 ... calibration section 70, 71 ... scanning ranges 72, 78 ... jig 76 ... position adjustment mechanism 80 ... tilt mechanism W ... workpiece L1 ... measurement Light L2...Reference light L3...Reflected light LS...Interference signal

Claims (8)

In a shape measuring machine that measures the shape of a workpiece without contact,
A measurement light is output, and an interference signal between the reflected light of the measurement light reflected by the work and the reference light that is a part of the measurement light reflected by a reflecting surface different from the work is detected. an interferometer that
A plurality of sensor heads arranged at positions different from each other, wherein when the measurement light is input from the interferometer, the measurement light is emitted toward the work and reflected by the work. a plurality of sensor heads that output light to the interferometer;
an optical switch that performs connection switching for sequentially connecting the plurality of sensor heads one by one to the interferometer;
a relative movement mechanism for relatively moving the workpiece and the plurality of sensor heads;
with
The shape measuring machine, wherein the optical switch repeatedly performs the connection switching while the relative movement mechanism is performing the relative movement. While the relative movement mechanism performs the relative movement, the plurality of sensor heads intermittently scans a different scanning range of the workpiece with the measurement light, and
2. The shape measuring machine according to claim 1, further comprising a shape calculation unit that calculates the shape of the workpiece based on the detection result of the interference signal for each of the sensor heads by the interferometer. Let Q be the number of samplings of the interference signal for each scanning range required for the shape calculation unit to calculate the shape of the workpiece, let t be the time required for the relative movement by the relative movement mechanism to complete, and let the sensor where N is the number of heads and V is the sampling rate of the interferometer, the sampling rate satisfies V≧Q×N/t;
3. The shape measuring machine according to claim 2, wherein the optical switch performs connection switching at a switching speed corresponding to the sampling speed. The relative movement mechanism has a rotary table on which the columnar or cylindrical workpiece is placed and rotates around a rotation axis, and a rotation mechanism that rotates the rotary table around the rotation axis,
a plurality of the sensor heads are arranged at positions facing the outer peripheral surface of the work and at different positions in the axial direction of the rotating shaft;
While the rotating mechanism rotates the rotating table at least one time, the plurality of sensor heads are positioned within the scanning range along the circumferential direction of the outer peripheral surface and the positions of the sensor heads in the axial direction are relative to each other. intermittently scanning the different scanning ranges with the measurement light;
2. The shape calculation unit calculates at least one of the circularity of the workpiece for each scanning range and the cylindricity of the workpiece based on the detection result of the interference signal for each sensor head by the interferometer. Or the shape measuring machine according to 3. 5. The shape measuring machine according to claim 4, further comprising a position adjusting mechanism for adjusting the axial position of each sensor head. The shape calculation unit calculates the inclination of the workpiece placed on the rotary table based on the detection result of the interference signal for each sensor head by the interferometer,
6. The shape measuring machine according to claim 4, further comprising a tilting mechanism for tilting the rotary table and correcting the tilt based on the result of calculation of the tilt by the shape calculator. The relative movement mechanism has a rotary table on which the columnar or cylindrical workpiece is placed and rotates around a rotation axis, and a rotation mechanism that rotates the rotary table around the rotation axis,
A plurality of sensor heads are arranged at positions facing the outer peripheral surface of the work and at positions facing the upper surface of the work, and a plurality of first sensor heads arranged at positions different from each other in the axial direction of the rotating shaft. a second sensor head;
While the rotating mechanism rotates the rotating table at least one time, the plurality of first sensor heads rotates in a first scanning range, which is the scanning range along the circumferential direction of the outer peripheral surface, and in the first sensor. intermittently scanning the first scanning range in which the position in the axial direction is different for each head with the measurement light;
While the rotating mechanism rotates the rotary table at least once, the second sensor head intermittently scans a second scanning range, which is the circular scanning range on the upper surface, with the measurement light,
4. The shape measurement according to claim 2 or 3, wherein the shape calculation unit calculates the squareness of the workpiece based on the detection results of the interference signal for each of the first sensor head and the second sensor head by the interferometer. machine. A measurement light is output, and an interference signal between the reflected light of the measurement light reflected by the work and the reference light that is a part of the measurement light reflected by a reflecting surface different from the work is detected. an interferometer;
A plurality of sensor heads arranged at positions different from each other, wherein when the measurement light is input from the interferometer, the measurement light is emitted toward the work and reflected by the work. a plurality of sensor heads that output light to the interferometer;
In a method for controlling a shape measuring machine comprising
a connection switching step of performing connection switching for sequentially connecting the plurality of sensor heads one by one to the interferometer;
a relative movement step of relatively moving the workpiece and the plurality of sensor heads;
has
A control method for a shape measuring machine, wherein the connection switching step is repeatedly executed while the relative movement is being performed in the relative movement step.

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