JP2011203064A - Apparatus and method of measuring rotation angle of rotating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method for measuring a rotation angle of a rotating device, easily and accurately measuring the rotation angle of the rotating device of a machining device, and also reducing measurement time and operation cost.SOLUTION: The rotation angle measuring apparatus 1 is constituted of: an encoder mount 3 provided on a table 2 of the machining device; an encoder 4 mounted on the encoder mount 3; a V-block 6 mounted on a V-block mount 5 attached to the encoder 4; a ball plunger 9, an eccentric displacement gage 10 and a deflection angle displacement gage 11 disposed on a ball plunger mount 8 attached to the rotating device 7; a detecting part 13 for detecting the rotation angle commanded from a rotation angle command device 12 (controller of a machine) to the rotating device 7; and an arithmetic device 14 for processing output signals from the encoder 4, the eccentric displacement gage 10, the deflection angle displacement gage 11 and the detecting part 13.

Description

  The present invention relates to a rotational angle measurement of a rotating device that evaluates the positioning accuracy of a rotational movement axis in a rotating device used for positioning a processing machine or a robot that moves a cutting tool, a laser processing head, a measuring head, an assembly manipulator, and the like. The present invention relates to a device and a rotation angle measuring method.

  In cutting complex processing machines, laser processing machines, measuring / assembling robots, etc., work such as cutting, fusing, welding, measuring, and assembling can be performed by moving and rotating each axis by fixing the workpiece to the table or board surface. Done. In such a positioning device in a processing machine or the like, a specification value is determined for the movement accuracy of each axis, and an inspection is performed at the time of shipment so as to satisfy this specification value. Also, this specification value needs to be maintained during the period of use. However, there may be problems with the movement accuracy due to various factors such as shaft wear and breakage due to long-term use, improper installation during replacement or replacement, or deformation due to weight or resistance load. In order to check and correct the above, accuracy measurement is performed on each axis periodically or appropriately.

  Conventionally, as a method of measuring the rotation angle of the rotary moving shaft of the rotating device, an encoder, a mounting shaft having an outer diameter and a length corresponding to the magnitude of the sliding resistance of the encoder, and a rotation angle error (accuracy) are used. 2. Description of the Related Art An angle indexing accuracy measuring device (rotational angle measuring device) including a calculating unit is known (for example, see Patent Document 1).

  In the angle indexing accuracy measuring device described in Patent Document 1, first, the mounting shaft is fitted into the rotating central portion of the encoder, and then the other end of the mounting shaft is coaxially held on the rotating shaft of the rotating device. . Thereby, the rotation center of an encoder and the rotation center of a rotating apparatus can be made to correspond. Finally, the outer periphery of the encoder is fixed to the processing machine. In this measurement, the strength is maintained by adjusting the outer diameter and length so that the deformation of the mounting shaft caused by the rotational sliding resistance of the encoder does not exceed a specified value. Thereby, the rotation angle actually rotated in the rotating device is precisely transmitted to the encoder, and can be measured with high reproducibility and accuracy.

JP 2008-281468 A

  However, in the angle indexing accuracy measuring apparatus of the above-mentioned Patent Document 1, mounting is performed by aligning the central axis of the mounting shaft with the rotation axis of the encoder (state without eccentricity and declination), and the other end of the mounting shaft is There is a problem that it is necessary to attach the rotating machine to the rotating shaft of the rotating device of the processing machine, and this attachment adjustment work requires a great deal of time. In addition, when high measurement accuracy is required, there is a problem that advanced technology is required.

  In practice, it is difficult to make the two rotation axes completely coincide with each other, and it is difficult to make both the eccentricity and the deflection angle zero. When rotating in this state, stress (deformation) synchronized with the rotation acts on the bearings of the encoder and the like, and a measurement error occurs. In some cases, there was a problem that the bearings and the like were damaged.

  The present invention is intended to solve the above-described problems, and can easily measure the rotation angle of the rotating device of the processing machine with high accuracy, and can reduce the measurement time and the work cost. An object of the present invention is to provide a rotation angle measuring device and a rotation angle measuring method for a rotating device.

  In order to solve the above-described problems, a rotation angle measurement device for a rotation device according to the present invention includes a detection unit that detects a rotation angle commanded to the rotation device of a processing machine having the rotation device, and a rotation angle of the rotation device. An encoder for measurement, a ball plunger attached to one of the rotating shafts of the rotating device and the rotating shaft of the encoder, and a V block attached to the other rotating shaft and in contact with the tip of the ball plunger And an arithmetic unit that calculates the accuracy of the rotation angle of the rotation device based on the commanded rotation angle and the rotation angle measured by the encoder.

  Further, in the rotation angle measurement method of the rotation device of the present invention, when the rotation angle is commanded to the rotation device by the rotation angle command device of the processing machine having the rotation device, and the rotation angle of the rotation device is measured by the encoder, The ball plunger attached to one of the rotating shafts of the rotating device and the encoder is brought into contact with the V block attached to the other rotating shaft, and the commanded rotation angle and the encoder The accuracy of the rotation angle of the rotating device is calculated from the measured rotation angle.

  According to the rotation angle measurement device and the rotation angle measurement method of the rotation device according to the present invention, there is no need to fix the rotation device and the rotation angle measurement device, and therefore, no advanced adjustment technology is required and high accuracy is achieved. The rotation angle can be measured. Further, the measurement can be performed without damaging the bearing, and the measurement work time can be shortened.

FIG. 3 is a perspective view schematically showing a configuration of a rotation angle measurement device of the rotation device in the first embodiment. FIG. 3 is an enlarged perspective view of the V block of the rotation angle measuring device of the rotating device according to Embodiment 1 and the tip of the ball plunger. It is a figure which shows the relationship between eccentricity of two rotating shafts, and a deflection angle. FIG. 6 is a diagram illustrating a procedure of a rotation angle measurement method for the rotation device according to the first embodiment. It is sectional drawing which shows the shape of V block of the rotation angle measuring apparatus of the rotating apparatus in Embodiment 1. FIG.

  Hereinafter, a rotation angle measuring device for a rotating device according to an embodiment of the present invention will be described with reference to FIGS.

Embodiment 1 FIG.
FIG. 1 is a perspective view schematically showing a configuration of a rotation angle measuring device of the rotating device according to the first embodiment. FIG. 2 is an enlarged perspective view of the V block of the rotation angle measuring device of the rotating device and the tip of the ball plunger.

1 and 2, a rotation angle measuring device 1 includes an encoder mounting base 3 provided on a table 2 of a processing machine, an encoder 4 mounted on the encoder mounting base 3, and an X axis of the encoder 4. An adjustment screw 3X for adjusting the angle of the direction, an adjustment screw 3Y for adjusting the angle of the encoder 4 in the Y-axis direction, a fulcrum 3H for angle adjustment, a V block mounting base 5 attached to the rotary shaft 4C of the encoder 4, V block 6 mounted on V block mounting base 5, plunger mounting base 8 attached to rotating shaft 7C of rotating device 7, ball plunger 9 installed on plunger mounting base 8, and eccentric displacement meter 10, declination displacement meter 11, detection unit 13 for detecting the rotation angle commanded to rotation device 7 from rotation angle command device 12 (control device for processing machine), encoder 4, eccentric displacement meter 10, deflection It is composed of an arithmetic unit 14 for processing the output signal from the displacement meter 11 and the detector 13.

  Further, the encoder 4 is moved and adjusted in the angles of the X axis and the Y axis by the adjusting screw 3X and the adjusting screw 3Y, respectively. The ball plunger 9 is movable in parallel with the rotating shaft 7C of the rotating device 7, and the tip spherical surface portion 9T of the ball plunger 9 is brought into contact with the V groove portion 6V of the V block 6 with a constant pressure in the Z-axis direction. The eccentric displacement meter 10 is in contact with the eccentricity measuring surface 5L of the V block mounting base 5, and the eccentric displacement meter 11 is in contact with the eccentricity measuring surface 5S of the V block mounting base 5. Here, the valley line 6 </ b> L of the V block 6 is set so as to intersect the rotating shaft 4 </ b> C of the encoder 4 on the extension line. When the ball plunger 9 is pressed and abutted against the V groove 6V of the V block 6 and the rotating shaft 7C of the rotating device 7 is rotated, the rotational motion of the rotating device 7 is transmitted to the encoder 4 and the rotation of the encoder 4 is rotated. The shaft 4C is rotated.

  Here, a portion constituted by the encoder mounting base 3, the encoder 4, the V block mounting base 5, the V block 6, and its accessory parts is referred to as an encoder unit 15. A portion constituted by the plunger mounting base 8, the ball plunger 9, the eccentric displacement meter 10, the deflection displacement meter 11 and its accessory parts is referred to as a ball plunger unit 16. Further, a portion constituted by the detection unit 13 and the arithmetic device 14 is referred to as an arithmetic processing unit 17.

  In actual measurement, first, a rotation angle is commanded from the rotation angle command device 12 to the rotation device 7 and is input to the arithmetic device 14 via the detection unit 13. The actual rotation angle signal measured by the encoder 4 is input, and the arithmetic unit 14 calculates the error of the rotation angle of the rotation device 7 based on the two basic signals (actual rotation angle and command rotation angle). To do. Further, the arithmetic unit 14 refers to the eccentricity signal input from the eccentric displacement meter 10 and the eccentricity signal input from the eccentric displacement meter 11 to determine the error due to eccentricity and deviation. Calculated and the actual rotation angle is corrected. Thereby, in the rotating device used for positioning of the processing machine, the positioning accuracy of the rotary moving shaft can be evaluated.

  FIG. 3 shows the relationship between the eccentricity and the deviation angle between the rotating shaft 7C of the rotating device 7 and the rotating shaft 4C of the encoder 4. Eccentricity refers to the translational displacement of these two rotational axes, FIG. 3A shows the amount of eccentricity 18, and the eccentricity refers to the angular displacement of these two rotational axes. The deviation amount 19 is shown in FIG. The measurement of the rotation angle of the rotation device 7 is desirably performed in the state where there is no eccentricity or deviation angle shown in FIG.

  Next, the operation of the rotation angle measuring apparatus according to the first embodiment will be described with reference to the operation procedure of FIGS.

[Mounting and adjustment]
First, the encoder unit 15 is installed on the table 2, and the rotating shaft 4C of the encoder 4 is made to substantially coincide with the rotating shaft 7C of the rotating device 7 (step S1). This can be easily adjusted by relatively moving the table 2 by means of an X and Y direction moving device of a processing machine (not shown).

  Next, the ball plunger unit 16 is attached to the rotating device 7 of the processing machine (step S2). This attachment does not require adjustment and can be easily performed.

  Further, the spherical surface of the tip 9T of the ball plunger 9 is pressed against the V block 6 (step S3). This can be easily performed by moving the rotating device 7 by the Z-direction moving device of the processing machine.

  FIG. 2 shows details of the contact state between the ball plunger 9 and the V block 6. The eccentric displacement meter 10 detects the position of the side surface 5L of the V block mounting base 5. The declination displacement meter 11 detects the position of the upper surface 5S of the V block mounting base 5.

  The rotation of the rotating shaft 7 </ b> C of the rotating device 7 is transmitted to the rotating shaft 4 </ b> C of the encoder 4 through contact between the spherical surface of the tip 9 </ b> T of the ball plunger 9 and the V groove 6 </ b> V of the V block 6. The trough line 6L of the V block 6 faces the rotating shaft 4C of the encoder 4, and the tip 9T of the ball plunger 9 is in contact with the V block 6 with an appropriate pressing force. In this rotation, the position in the rotation direction is limited by the contact between the spherical surface of the tip 9T of the ball plunger 9 and the two inclined surfaces of the V groove 6V of the V block 6, so that the rotation shaft 7C of the rotation device 7 rotates. Is accurately communicated. Note that the valley line 6 </ b> L of the V block 6 can accurately transmit the rotation of the rotation shaft 7 </ b> C of the rotating device 7 to the encoder 4 even if it is not strictly directed to the rotation shaft 4 </ b> C of the encoder 4.

  If the rotary shaft 4C of the encoder 4 and the rotary shaft 7C of the rotating device 7 are completely coincident with each other, even if the rotary shaft 4C and the rotary shaft 7C are rotated, the tip 9T of the V block 6 and the ball plunger 9 is rotated. There is no relative change in the contact position. However, in actuality, it is difficult to achieve perfect coincidence, and a slight movement due to the slight remaining eccentricity and declination occurs. In this case, a deviation occurs in the contact position between the spherical surfaces of the V block 6 and the tip 9T of the ball plunger 9 during rotation of the rotating shaft 7C. This deviation causes the spherical surface to slide and absorb the slope in the radial direction (the direction of the valley line 6L), so that no error occurs in the rotational direction. However, due to the movement of the contact position between the eccentric displacement meter 10 and the side surface 5L of the V block mounting base 5 and the contact position between the declination displacement gauge 11 and the upper surface 5S of the V block mounting base 5, unevenness of the contact surface becomes An error is caused in the measured values of the eccentric displacement meter 10 and the declination displacement meter 11. This can be avoided by simple flattening of the area of the contact surface of the V-block mounting base 5 where the eccentric displacement meter 10 and the declination displacement meter 11 are supposed to move. Is possible. Further, since unnecessary stress is not generated during rotation transmission, no deformation that causes an angle error occurs, and the possibility that the encoder 4 or the like is damaged is reduced.

[Rotation axis adjustment]
When the rotating shaft 7C of the rotating device 7 is rotated, the amount of eccentricity and its direction can be calculated by the computing device 14 from the signal from the eccentric displacement meter 10. Based on the result, the X and Y movement amounts at which the eccentricity 18 becomes zero are calculated, the table 2 is moved by the X and Y movement devices of the processing machine, and the rotary shaft 4C and the rotation device 7 of the encoder 4 are moved. The amount of eccentricity with respect to the rotation shaft 7C is adjusted to be zero (step S4).

Further, when the rotation shaft 7 </ b> C of the rotating device 7 is rotated, the declination amount 19 and its direction can be calculated by the computing device 14 from the signal of the declination displacement meter 11. Based on the result, an angle amount at which the deflection angle amount 19 becomes zero is calculated, and an adjustment screw 3X that adjusts an angle in the X-axis direction of the encoder 4 and an adjustment screw 3Y that adjusts an angle in the Y-axis direction, Adjustment is made so that the deviation angle 19 between the rotating shaft 4C of the encoder 4 and the rotating shaft 7C of the rotating device 7 becomes zero (step S5).
Note that step S4 and step S5 may be processed simultaneously.

  As described above, in the first embodiment, the eccentricity and declination of the encoder 4 and the rotating device 7 are adjusted by attaching the encoder unit 15 and the ball plunger unit 16 to the rotating shaft 4C and the rotating shaft 7C. Adjustments to match can be made. For this reason, since high accuracy is not required for the mounting operation of the rotation angle measuring device 1, the adjusting operation is simple. On the other hand, in the rotating shaft adjustment by the conventional method, the encoder is attached to the rotating device after adjusting until the rotating shaft is sufficiently matched. This is because if the adjustment is not performed, an unreasonable stress is generated on the rotating shaft, resulting in an increase in measurement error or damage to the encoder. For this reason, the conventional method requires a technique and time for the mounting work.

[Measurement of rotation angle]
First, when starting the rotation angle measurement, the rotation shaft 7C of the rotation device 7 is rotated to the rotation origin (zero-degree position), and the value of the encoder 4 is reset. The values of the eccentric displacement meter 10 and the angular displacement meter 11 are also reset. Subsequently, the rotation angle command device 12 rotates the rotation shaft 7C of the rotation device 7 to a predetermined rotation angle. At this time, the rotation angle measurement value (actual rotation angle) signal by the encoder 4, the rotation angle commanded from the rotation angle command device 12 (command rotation angle detected by the detection unit 13), and the eccentricity measurement. The measured value detected by the eccentric displacement meter 10 for measurement and the signal of the measured value detected by the deviation displacement meter 11 for measuring the deflection angle are input (stored) to the arithmetic unit 14 (step S6). This measurement is performed for a predetermined rotation angle and a predetermined number of times (step S7). When all measurements are complete, move on to the next step.

[Calculation of measurement rotation angle]
The command rotation angle commanded by the rotation angle command device 12 stored so far, the measurement value obtained by the eccentric displacement meter 10 for measuring eccentricity, and the measurement obtained by the deflection displacement meter 11 for measuring deflection angle Based on the values, the amount of eccentricity 18 of the rotating shaft 7C of the rotating device 7 and its direction, the amount of angular deviation 19 and its direction are calculated by the arithmetic unit (step S8).

  Based on the value calculated in step S8, the actual rotation angle, which is a measured value of the rotation angle by the encoder 4, is corrected to obtain a corrected actual rotation angle (step 9).

  Further, an error of the rotation angle is obtained based on the corrected actual rotation angle and the command rotation angle (step 10). Thus, the angle measurement operation by the rotation angle measurement device of the rotation device according to Embodiment 1 is completed. As a result, if there is a rotation angle error exceeding the specification value, adjustment, disassembly repair, etc. may be performed as necessary.

  As described above, according to the rotation angle measuring device and the rotation angle measuring method of the rotating device according to the first embodiment, since the encoder and the rotating device are not directly connected and fixed, the installation / adjustment work is very easy. Not only can this be performed, but the rotation angle of the rotation device is precisely transmitted to the encoder, and the encoder performance can be fully extracted, so that the rotation angle of the rotation device can be measured with high reproducibility and accuracy. Further, since the rotation axes do not completely coincide with each other, the generation of stress (deformation) can be suppressed to be small, and the generation of measurement errors is small. Furthermore, there is a low possibility that the rotation angle measuring device or the processing machine will break down even in the X and Y movement due to an erroneous operation.

  FIG. 3 shows an example of the shape of the V block 6 used in the first embodiment. As the shape of the V block 6, as shown in FIG. 3A, the angle of two inclined surfaces of a general V groove portion 6V is 90 degrees, and the bottom of the V groove portion 6V shown in FIG. In the plane 6B, the angle of the two inclined surfaces of the V-groove portion 6V shown in FIG. 3C is 90 degrees or more, and the angle of the two inclined surfaces of the V-groove portion 6V shown in FIG. Any of them can be used, and any spherical surface can be used as long as the spherical surface of the tip 9T of the ball plunger 9 can come into contact with the two inclined surfaces of the V groove 6V of the V block 6. The shape of the non-contact portion is not particularly specified.

It should be noted that it is difficult to completely match the rotation axis of the both surfaces where the inclined surface of the V groove 6V of the V block 6 and the spherical surface of the tip 9T of the ball plunger 9 are in contact with each other. Relative movement occurs. For this reason, wear occurs by sliding on these contact surfaces. As a countermeasure, for example, the contact surface may be quenched to increase the hardness. As a result, the amount of wear due to contact is reduced, and the rotation angle can be measured with high accuracy over a long period of time.

  Further, the V block 6 may be fixed to the encoder mounting base 3 through a linear motion guide that can move in a straight line precisely in the direction of the valley line 6L. Naturally, in this case, the linear motion direction is the radial direction toward the rotating shaft 4C. With such a configuration, the slight relative displacement caused by the difficulty in completely matching the rotation axes causes the V block 6 and the spherical surface of the tip portion 9T of the ball plunger 9 to move in the valley line 6L direction. Instead of sliding and moving, it is a precise movement of the linear guide. That is, since the contact surface does not move relatively, there is no sliding, the amount of wear is reduced, and highly accurate rotation angle measurement can be performed over a long period of time.

  As described above, in the rotation angle measuring device of the rotating device according to the first embodiment, the V block attached to the encoder is brought into contact with the tip of the ball plunger attached to the rotating device, and the rotation angle of the rotating device is determined by the encoder. By calculating the rotation angle error of the rotating device, the rotation angle measuring device can be mounted and adjusted very easily, and the rotating device and the encoder are not directly connected and fixed. Even if the axes do not coincide completely, the occurrence of stress (deformation) can be kept small, the occurrence of measurement errors is small, and the rotation angle of the rotating device can be measured with high reproducibility and accuracy. effective.

  In the first embodiment, the case where the V block 6 is attached to the encoder unit 15 and the ball plunger 9 is attached to the rotating device 7 has been described. Conversely, the ball plunger 9 is attached to the encoder unit 15 and attached to the rotating device 7. Even if the V block 6 is attached, the same effect as in the first embodiment can be expected. What is necessary is just to select an attachment position according to the condition of a processing machine, and what is necessary is just to take the structure suitable for a processing machine.

  In the first embodiment, the eccentric displacement meter 10 and the angular displacement meter 11 are attached to the ball plunger unit 16. However, the eccentric displacement meter 10 and the angular displacement meter 11 are attached to the encoder unit 15. Also, the same effect as in the first embodiment can be expected. In this case, since the wiring of the signal lines can be concentrated on the encoder unit 15, the workability of the wiring is improved.

  Further, the eccentric displacement meter 10 and the declination displacement meter 11 may be separately attached to the encoder unit 15 and the ball plunger unit 16 respectively. What is necessary is just to take the arrangement configuration suitable for the rotation apparatus of the processing machine to apply.

  Also, by using a plurality of eccentric displacement gauges 10 or a plurality of deviation displacement gauges 11, it is possible to improve the measurement accuracy of the eccentricity and the deviation angle, and to correct the actual rotation angle more accurately. is there. The number of displacement meters may be selected according to the required accuracy.

  In the rotating device of the present invention, the rotational angle measuring device and the rotational angle measuring method for simply evaluating the movement positioning accuracy by the rotating device of the processing machine have been described. Specifically, the processing machine includes a cutting tool. Any positioning device such as a processing machine or a robot that moves a laser processing head, a measurement head, an assembly manipulator, or the like that can be positioned by a rotating device can be applied.

  Moreover, in the figure, the same code | symbol shows the same or an equivalent part.

DESCRIPTION OF SYMBOLS 1 Rotation angle measuring device 4 Encoder 4C Encoder rotation shaft 5 V block mounting base 6 V block 6L V block trough line 7 Rotating device 7C Rotating device rotation shaft 8 Plunger mounting base 9 Ball plunger 10 Eccentric displacement meter 11 Deflection angle Displacement meter 13 Detector 14 Computing device 15 Encoder unit 16 Ball plunger unit 17 Arithmetic processing unit

Claims (8)

A detecting unit for detecting a rotation angle commanded to the rotating device of the processing machine having the rotating device;
An encoder for measuring a rotation angle of the rotating device;
A ball plunger attached to one of the rotating shafts of the rotating device and the encoder; and
A V block attached to the other rotating shaft and abutted against the tip of the ball plunger;
A rotation angle measurement device for a rotation device, comprising: an arithmetic device that calculates the accuracy of the rotation angle of the rotation device from the commanded rotation angle and the rotation angle measured by the encoder.   The rotation angle measuring device of the rotating device according to claim 1, wherein the central axis of the ball plunger is located away from the rotating shaft of the rotating device or the rotating shaft of the encoder.   The rotation angle measuring device for a rotating device according to claim 1 or 2, wherein a valley line of the V block is arranged so as to intersect with a rotation axis of the encoder.   The rotation angle measuring device for a rotating device according to any one of claims 1 to 3, wherein the ball plunger is movable so that a central axis thereof and a rotating shaft of the rotating device are kept parallel to each other. .   The ball plunger is attached to a mounting base, and the mounting base includes an eccentric displacement meter that detects an eccentric amount of the rotating shaft of the rotating device with respect to the rotating shaft of the encoder, and a rotating device of the rotating device with respect to the rotating shaft of the encoder. Either or both declination displacement meters for detecting the declination amount of the rotating shaft are mounted, and the accuracy of the rotation angle of the rotator with reference to the decentered amount and / or declination amount detected. The rotation angle measurement device for a rotation device according to any one of claims 1 to 4, wherein the rotation angle measurement device is calculated.   A rotation angle measurement device for a rotation device, wherein the rotation angle of the rotation device is corrected from the measurement result of the accuracy of the rotation angle of the rotation device calculated according to any one of claims 1 to 5.   When the rotation angle is commanded to the rotation device by the control device of the processing machine having the rotation device, and the rotation angle of the rotation device is measured by the encoder, the rotation shaft of either the rotation device or the rotation shaft of the encoder A V-block attached to the other rotating shaft is brought into contact with the ball plunger attached to the other, and the accuracy of the rotational angle of the rotating device is increased by the commanded rotational angle and the rotational angle measured by the encoder. A method for measuring a rotation angle of a rotating device, comprising calculating the rotation angle.   The ball plunger includes an eccentric displacement meter that detects an eccentric amount of the rotating shaft of the rotating device with respect to the rotating shaft of the encoder, and a deviation that detects an amount of deviation of the rotating shaft of the rotating device with respect to the rotating shaft of the encoder. Both or one of the angular displacement meters is attached, and the accuracy of the rotation angle of the rotating device is calculated and the rotation angle is corrected with reference to the detected eccentricity amount and / or the eccentricity amount. The rotation angle measuring method of the rotating device according to claim 7.

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