TWI791343B - Obtaining method and obtaining apparatus for geometric error of rotation axis - Google Patents

Abstract

An obtaining method and an obtaining apparatus for geometric error of rotation axis are provided. The obtaining method for geometric error includes the following steps. An encoding ring is installed on a rotating shaft, and a first optical pickup head and a second optical pickup head are installed around the encoding ring. The encoding ring is rotated by the rotating shaft, and a deviation distance and an azimuth angle of the center point of the encoding ring relative to the center axis of the rotating shaft when the rotating shaft rotates 0 degrees is obtained according to the angle value read by the first optical pickup head. Obtain a first assembly angle deviation of the first optical pickup head and a second assembly angle deviation of the second optical pickup head. Obtain the rotation angle error of the rotation axis when it rotates to various angles. Obtain the rotational yaw error of the rotating shaft when it rotates to various angles.

Description

Acquisition method and equipment for geometric error of rotating shaft

The present invention relates to a geometric error acquisition method and acquisition device, and in particular to a rotational axis geometric error acquisition method and acquisition device.

Rotary shafts are widely used in various power machinery and machine tools. Especially in precision machinery, the accuracy of the rotating axis is even more important. Therefore, it is an important subject to develop a method and equipment for obtaining the geometric error of the rotating shaft.

The invention provides a method and equipment for obtaining the geometric error of the rotating shaft, which can obtain the geometric error of the rotating shaft.

A method for obtaining the geometric error of the rotating shaft in the present invention includes the following steps. The ring encoder is installed on the rotating shaft, and the first optical pickup head and the second optical pickup head are installed around the ring encoder. The ring encoder is rotated by the rotating shaft, and the first optical reading head and the second optical reading head simultaneously read multiple angle values on the ring encoder when the rotating shaft rotates to multiple angles. According to the first optical read head The read angle value is used to obtain the deviation distance and azimuth angle of the center point of the ring encoder relative to the central axis of the rotary shaft when the rotary shaft rotates 0 degrees. The first assembly angle deviation of the first optical pickup head and the second assembly angle deviation of the second optical pickup head are obtained according to the angle values read by the first optical pickup head and the second optical pickup head. According to the angle value, the first assembly angle deviation and the second assembly angle deviation, the rotation angle error when the rotating shaft rotates to each angle is obtained. According to the angle value, the radius of the ring encoder, the rotation angle error, the first assembly angle deviation and the second assembly angle deviation, the rotation deflection error when the rotation shaft rotates to each angle is obtained.

A device for obtaining the geometric error of the rotating shaft of the present invention includes a ring encoder, a first optical pickup head and a second optical pickup head. Ring encoders are used for mounting on a rotating shaft. The first optical pickup head and the second optical pickup head are installed around the ring encoder. Wherein, the ring encoder is rotated by the rotating shaft, and the first optical reading head and the second optical reading head simultaneously read multiple angle values on the ring encoder when the rotating shaft rotates to multiple angles. According to the angle value read by the first optical reading head, a deviation distance and an azimuth angle of a center point of the ring encoder relative to a central axis of the rotation shaft when the rotation shaft rotates 0 degrees are obtained. A first assembly angle deviation of the first optical pickup head and a second assembly angle deviation of the second optical pickup head are acquired according to the angle values read by the first optical pickup head and the second optical pickup head. According to the angle value, the first assembly angle deviation and the second assembly angle deviation, a rotation angle error when the rotating shaft rotates to each angle is obtained. According to the angle value, the radius of the ring encoder, the rotation angle error, the first assembly angle deviation and the second assembly angle deviation, a rotation yaw error when the rotating shaft rotates to each angle is obtained.

Based on the above, in the acquisition method and acquisition device of the geometric error of the rotating shaft in the present invention, the rotational angle error of the rotating shaft and the rotational yaw error of the rotating shaft can be obtained.

50: axis of rotation

100: Obtaining equipment for the geometric error of the rotary axis

110: ring encoder

R1: the first optical read head

R2: Second optical read head

R3: The third optical read head

R4: The fourth optical read head

R5: fifth optical read head

S110~S160: steps

θ : nominal rotation angle value

e : deviation distance

φ : Azimuth

R : the distance between the central axis and the first optical reading head

O' : center point

O : point

ρ: radius of the ring encoder

FIG. 1 is a schematic diagram of a device for acquiring geometric errors of a rotating shaft according to an embodiment of the present invention.

FIG. 2 is a flow chart of a method for obtaining a geometric error of a rotating shaft according to an embodiment of the present invention.

Fig. 3 illustrates the deviation distance and azimuth angle of the center point of the ring encoder relative to the central axis of the rotating shaft.

FIG. 4 shows the difference between the angle value read by each optical pickup head and the rotation angle when the rotation axis rotates to various angles.

Fig. 5 shows the difference between the actual rotation angle and the ideal rotation angle when the rotation shaft rotates to various angles.

FIG. 6 shows the components of the yaw error on the X-axis and the Y-axis when the rotating shaft rotates to various angles.

FIG. 1 is a schematic diagram of a device for acquiring geometric errors of a rotating shaft according to an embodiment of the present invention. Please refer to Fig. 1, the acquisition of the geometric error of the rotating shaft of the present embodiment The fetching device 100 includes a ring encoder 110 and a first optical pickup head R1 and a second optical pickup head R2. The ring encoder 110 is used for installing on a rotating shaft 50 . The first optical pickup head R1 and the second optical pickup head R2 are installed around the ring encoder 110 . The ring encoder 110 fixed on it is driven by the rotating shaft 50 to rotate, and the first optical read head R1 and the second optical read head R2 are used to read the angle value on the ring encoder 110, which can be analyzed and Acquire more than 50 geometric errors of the rotating shaft. Therefore, it can be used to detect whether the quality of the rotating shaft 50 meets the requirements, and can be used as a calibration basis for the subsequent application of the rotating shaft 50 .

In this embodiment, the acquisition device 100 of the geometric error of the rotation axis further includes a third optical pickup head R3, a fourth optical pickup head R4 and a fifth optical pickup head R5, installed on the ring-shaped around the encoder 110. The preset installation angles of the first optical pickup head R1, the second optical pickup head R2, the third optical pickup head R3, the fourth optical pickup head R4 and the fifth optical pickup head R5 are respectively 0 degrees and 72 degrees. degrees, 144 degrees, 216 degrees and 288 degrees. Thereby, using the first optical pickup head R1, the second optical pickup head R2, the third optical pickup head R3, the fourth optical pickup head R4 and the fifth optical pickup head R5 to obtain the rotating shaft 50 Rotation angle error and rotation yaw error at various angles. It should be noted that, although the following description is based on the use of five optical reading heads, only two optical reading heads can also be used in the method and device for obtaining the geometric error of the rotating shaft in the present invention Instead, get the geometric error for the same item. When two optical pickup heads are used, the preset installation angles of the two optical pickup heads can be 0 degree and 90 degree respectively, but the present invention is not limited thereto.

Fig. 2 is the acquisition of the geometric error of the rotating shaft according to an embodiment of the present invention Flowchart of the method. Please refer to FIG. 1 and FIG. 2 , the method for obtaining the geometric error of the rotating shaft in this embodiment includes the following steps. Firstly, install the ring encoder 110 on the rotating shaft 50 , and install the first optical pickup head R1 and the second optical pickup head R2 around the ring encoder 110 , step S110 .

Next, the ring encoder 110 is rotated by the rotating shaft 50 , that is, the ring encoder 110 is driven by the rotating shaft 50 to rotate accordingly. During the rotation process, the first optical pickup head R1 and the second optical pickup head R2 simultaneously read multiple angle values on the ring encoder 110 corresponding to the rotating shaft 50 rotating to multiple angles, step S120 . Since the assembly angles of the first optical pickup head R1 and the second optical pickup head R2 are different, the angle values read by the first optical pickup head R1 and the second optical pickup head R2 in this embodiment are theoretically equal to There is a difference of 72 degrees.

Fig. 3 illustrates the deviation distance and azimuth angle of the center point of the ring encoder relative to the central axis of the rotating shaft. Please refer to FIG. 2 and FIG. 3, then according to the angle value read by the first optical reading head R1, the central point O' of the ring encoder 110 relative to the central axis of the rotating shaft 50 when the rotating shaft 50 rotates 0 degrees is obtained (Fig. In 3, the point O through which the central axis passes is described), the deviation distance e and the azimuth angle φ , step S130. Here, the direction of the line connecting the point O passing through the central axis of the rotating shaft 50 and the first optical pickup head R1 is taken as the X-axis, and the azimuth φ is defined with the X-axis and the point O as references.

是第一光學讀取頭讀取的角度值，θ是標稱旋轉角度值，e是偏差距離，φ是方位角，R是中心軸線與第一光學讀取頭的距離，

FIG. 4 shows the difference between the angle value read by each optical pickup head and the rotation angle when the rotation axis rotates to various angles. Please refer to FIG. 3 and FIG. 4 , for example, the angle value read by the first optical reading head R1 is subtracted from a plurality of nominal rotation angle values of the corresponding rotating shaft 50 to obtain a plurality of measurement angle error values. . For example, when the rotation shaft 50 rotates 0 degrees, that is, when the rotation shaft 50 does not rotate, the angle value read by the first optical reading head R1 is 359 degrees, 59 minutes and 52 seconds. Subtract the nominal rotation angle value of 0 degrees from 359 degrees 59 minutes and 52 seconds to obtain a measurement angle error value of -8 seconds, which is the data in Figure 4 where the vertical axis is -8 seconds and the horizontal axis is 0 degrees point. In this way, the curve corresponding to the first optical pickup head R1 in FIG. 4 is completed. Then, curve fitting is performed on the curve representing the relationship between the measured angle error value and the corresponding nominal rotation angle value, so as to obtain a first trigonometric function related to the nominal rotation angle value. The deviation distance and the azimuth can be obtained by simultaneously solving the obtained first trigonometric function and the following formula one. In this embodiment, the step of performing curve fitting is to use the least square method. In the following formula one,

is the angle value read by the first optical reading head, θ is the nominal rotation angle value, e is the deviation distance, φ is the azimuth angle, R is the distance between the central axis and the first optical reading head,

，因此得出偏差距離e是14.39微米，方位角是0.089度。 In this embodiment, the first trigonometric function obtained by curve fitting according to the curve corresponding to the first optical pickup head R1 in FIG. 4 is

, so the deviation distance e is 14.39 microns, and the azimuth angle is 0.089 degrees.

Next, please refer to FIG. 1 and FIG. 2 , according to the angle values read by the first optical pickup R1 and the second optical pickup R2, the first assembly angle deviation and the second optical pickup R1 of the first optical pickup R1 are obtained. Second assembly angular deviation of read head R2, step S140.

For example, please refer to FIG. 1 and FIG. 4 , the same as the previous steps, the angle value read by the first optical pickup head R1 is subtracted from the multiple nominal rotation angle values of the corresponding rotation shaft 50 to obtain a plurality of first rotation angle values. A measurement angle error value. Then, the relationship between the first measurement angle error value and the corresponding nominal rotation angle value (that is, the curve corresponding to the first optical read head R1 in FIG. related to a first trigonometric function.

In addition, the angle value read by the second optical pickup head R2 is subtracted from a plurality of nominal rotation angle values of the corresponding rotation axis and a preset angle between the first optical pickup head R1 and the second optical pickup head R2 Obtain a plurality of second measurement angle error values based on the difference values. For example, when the rotating shaft 50 rotates 0 degrees, that is, when the rotating shaft 50 does not rotate, the angle value read by the second optical reading head R2 is 73 degrees, 59 minutes and 35 seconds. Subtract the nominal rotation angle value of 0 degrees from 73 degrees, 59 minutes and 35 seconds and the preset angle difference of 72 degrees between the first optical reading head R1 and the second optical reading head R2 to obtain a measurement of 95 seconds The angle error value, that is, the data points in Figure 4 where the vertical axis is 95 seconds and the horizontal axis is 0 degrees. In this way, the curve corresponding to the second optical pickup head R2 in FIG. 4 is completed.

Then, curve fitting is performed on the curve representing the relationship between the second measured angle error value and the corresponding nominal rotation angle value, so as to obtain a second trigonometric function related to the nominal rotation angle value. Here, taking 0 degree as the actual installation angle of the first optical pickup R1, the actual installation angle of the second optical pickup R2 is an offset angle value that makes the second trigonometric function coincide with the first trigonometric function , for example 72.07 degrees here. And, take 0 degree as the first assembly angle deviation of the first optical pickup head R1, and The second assembly angle deviation (for example, 0.07 degrees) is obtained by subtracting the default installation angle (for example, 72 degrees) of the second optical pickup head R2 from the offset angle value (for example, 72.07 degrees). For example, the third assembly angle deviation of the third optical pickup head R3 is 0.01 degrees, the fourth assembly angle deviation of the fourth optical pickup head R4 is 0.03 degrees, and the fifth assembly angle deviation of the fifth optical pickup head R5 is 0.01 degrees. The deviation is 0.07 degrees.

Fig. 5 shows the difference between the actual rotation angle and the ideal rotation angle when the rotation shaft rotates to various angles. Referring to FIG. 2 and FIG. 5 , according to the angle value, the first assembly angle deviation and the second assembly angle deviation, the rotation angle error when the rotating shaft 50 is rotated to each angle is acquired, step S150 .

For example, when the rotation axis rotates 50° to various angles, the angle value read by the second optical pickup R2 is subtracted from the preset installation angle of the second optical pickup R2 and the second assembly angle deviation, and The angle values read by the first optical reading head R1 are averaged to obtain the rotation angle error when the rotation shaft 50 rotates to various angles. In fact, the angle value read by the first optical pickup head R1 will also subtract the preset installation angle of the first optical pickup head R1 and the first assembly angle deviation, but because the preset installation angle of the first optical pickup head R1 Both the installation angle and the first assembly angle deviation are 0, so the angle value read directly by the first optical reading head R1 and the angle value read by the second optical reading head R2 minus the second optical reading head R2 The default installation angle and the value after the second assembly angle deviation are averaged. In this embodiment, because five optical pickups are installed, except the angle value read by the first optical pickup R1 and the angle value read by the second optical pickup R2 minus the second optical pickup In addition to the preset installation angle of R2 and the value after the deviation of the second assembly angle, the angle read by the third optical reading head R3 is also added The value after subtracting the preset installation angle of the third optical reading head R3 and the deviation of the third assembly angle, the value of the angle read by the fourth optical reading head R4 minus the preset installation angle of the fourth optical reading head R4 Angle and the value after the deviation of the fourth assembly angle and the value of the angle read by the fifth optical reading head R5 minus the preset installation angle of the fifth optical reading head R5 and the value after the deviation of the fifth assembly angle, and then take the average value. The average value is the rotation angle error of the rotation shaft 50 , and the relationship between the rotation angle error and the rotation angle of the rotation shaft 50 when the rotation shaft 50 rotates to various angles is shown in the curve in FIG. 5 .

FIG. 6 shows the components of the yaw error on the X-axis and the Y-axis when the rotating shaft rotates to various angles. Please refer to FIG. 3 and FIG. 6, according to the angle value, the radius of the ring encoder, the rotation angle error, the first assembly angle deviation and the second assembly angle deviation to obtain the rotation deflection error of the rotation shaft 50 when it rotates to various angles , step S160.

For example, after subtracting the azimuth angle of the center point O' of the ring encoder 110 relative to the central axis of the rotation shaft 50 and the corresponding rotation angle error from the angle value read by the first optical reading head R1, it is multiplied by 2πρ Divided by 360 degrees and multiplied by the sine of the actual installation angle of the first optical pickup head R1 to obtain a first X-axis yaw error when the rotation axis 50 rotates to various angles, multiplied by 2πρ divided by 360 degrees and Multiply the cosine value of the actual installation angle of the first optical pickup head R1 to obtain a first Y-axis yaw error when the rotating shaft 50 rotates to various angles. where ρ is the radius of the ring encoder.

In addition, after subtracting the azimuth angle of the center point O' of the ring encoder 110 relative to the central axis of the rotation shaft 50 and the corresponding rotation angle error from the angle value read by the second optical reading head R2, it is multiplied by 2πρ and divided by 360 degrees and multiplied by the sine of the actual installation angle of the second optical pickup head R2 to obtain a second X-axis yaw error when the rotation axis 50 rotates to each angle, multiplied by 2πρ divided by 360 degrees and multiplied by The cosine value of the actual installation angle of the second optical pickup head R2 is used to obtain a second Y-axis yaw error when the rotation axis 50 rotates to various angles. At the same time, the respective X-axis yaw errors and Y-axis yaw errors of the third optical pickup head R3 , the fourth optical pickup head R4 , and the fifth optical pickup head R5 are obtained in the same manner.

Then, the X-axis yaw errors of all read heads (for example, the first X-axis yaw error and the second X-axis yaw error when there are only two read heads) are obtained according to the rotation angle of the corresponding rotation axis 50 average, and calculate the Y-axis yaw errors of all read heads (for example, the first Y-axis yaw error and the second Y-axis yaw error when there are only two read heads) according to the rotation angle of the corresponding rotation axis 50 The average is taken to obtain the X-axis component and the Y-axis component of the rotation yaw error when the rotation axis rotates to various angles, as shown in FIG. 6 , for example.

To sum up, in the acquisition method and acquisition device of the geometric error of the rotating shaft of the present invention, the deviation distance and azimuth angle of the center point of the ring encoder and the assembly angle deviation of the optical reading head are first acquired, and then the deviation can be obtained Rotational angle error of the rotary axis and rotational yaw error of the rotary axis. Therefore, the quality of the rotating shaft can be detected, and can be used as a calibration basis for the subsequent application of the rotating shaft. Moreover, because the assembly deviation of the ring encoder is acquired first, the acquired rotational angle error of the rotary shaft and the rotational yaw error of the rotary shaft are more accurate.

S110~S160: steps

Claims (5)

A method for obtaining a geometric error of a rotating shaft, comprising: installing a ring encoder on a rotating shaft, and installing a first optical reading head and a second optical reading head around the ring encoder; The rotary shaft rotates the ring encoder, and the first optical read head and the second optical read head simultaneously read multiple angles on the ring encoder when the rotary shaft rotates to multiple angles value; according to the angle values read by the first optical reading head, a deviation distance and an azimuth of a center point of the ring encoder relative to a central axis of the rotation shaft when the rotation shaft rotates 0 degrees are obtained angle; according to the angle values read by the first optical pickup head and the second optical pickup head, a first assembly angle deviation of the first optical pickup head and a deviation of the second optical pickup head are obtained a second assembly angle deviation; according to the angle values, the first assembly angle deviation and the second assembly angle deviation, a rotation angle error of the rotating shaft when rotating to various angles is obtained; and according to the angle values, The radius of the ring encoder, the rotation angle errors, the first assembly angle deviation and the second assembly angle deviation obtain a rotation yaw error when the rotation shaft rotates to various angles, wherein the first The angle values read by the optical reading head are subtracted from the corresponding multiple nominal rotation angle values of the rotating shaft to obtain multiple measurement angle error values, and these measurement angle error values are compared with the corresponding standard rotation angle values. Curve fitting is performed on the relationship between the nominal rotation angle values to obtain a first trigonometric function related to these nominal rotation angle values, and the deviation distance and the azimuth angle are obtained according to the first trigonometric function and formula 1, wherein

is the angle values read by the first optical reading head, θ is the nominal rotation angle values, e is the deviation distance, φ is the azimuth angle, R is the central axis and the first optical reading head head distance,

Wherein, the angle values read by the first optical read head are subtracted from the corresponding multiple nominal rotation angle values of the rotation axis to obtain multiple first measurement angle error values, and these first quantities Curve fitting is performed on the relationship between the angle measurement error value and the corresponding nominal rotation angle values to obtain a first trigonometric function related to the nominal rotation angle values, and the second optical reading head reads the Subtracting a plurality of nominal rotation angle values of the corresponding rotation axis and a preset angle difference between the first optical pickup head and the second optical pickup head from the angle values to obtain a plurality of second measurement angles Error value, the relationship between these second measurement angle error values and the corresponding nominal rotation angle values is subjected to curve fitting to obtain a second trigonometric function related to these nominal rotation angle values, with a value of 0 degrees As the actual installation angle of the first optical pick-up head, the actual installation angle of the second optical pick-up head is an offset angle value that makes the second trigonometric function coincide with the first trigonometric function, and is defined as 0 degrees as the first assembly angle deviation, and subtract the offset angle value from the preset installation angle of the second optical pickup head to obtain the second assembly angle deviation, wherein when the rotation axis rotates to various angles , after subtracting the preset installation angle of the second optical reading head and the second assembly angle deviation from the angle value read by the second optical reading head, it is obtained from the angle value read by the first optical reading head average to obtain the rotation angle error when the rotation axis rotates to various angles, wherein when the rotation axis rotates to various angles, the angle value read by the first optical read head is subtracted from the azimuth angle and the corresponding After the rotation angle error, multiplied by 2πρ divided by 360 degrees and multiplied by the sine and cosine values of the actual installation angle of the first optical read head, to obtain a first when the rotation axis rotates to each angle The X-axis yaw error and a first Y-axis yaw error, ρ is the radius of the ring encoder, and the angle value read by the second optical read head is subtracted from the azimuth angle and the corresponding rotation angle error Afterwards, multiply by 2πρ divided by 360 degrees and multiply by the sine and cosine of the actual installation angle of the second optical pickup head to obtain a second X-axis yaw error when the rotation axis rotates to various angles and a second Y-axis yaw error, average the corresponding first X-axis yaw error and the second X-axis yaw error, and combine the corresponding first Y-axis yaw error and the second Y-axis yaw error The axis yaw error is averaged to obtain the X-axis component and the Y-axis component of the rotation yaw error when the rotation axis rotates to various angles. The method for obtaining the geometric error of the rotating shaft as described in Claim 1, wherein the step of performing curve fitting is to use the least square method. A device for acquiring geometric errors of a rotating shaft, comprising: a ring encoder installed on a rotating shaft; and a first optical reading head and a second optical reading head installed on the ring encoder , where the ring encoder is rotated with the rotation axis, and the ring code corresponding to the rotation axis is read by the first optical reading head and the second optical reading head simultaneously when the rotation axis rotates to multiple angles A plurality of angle values on the encoder; according to the angle values read by the first optical reading head, the position of a center point of the ring encoder relative to a central axis of the rotation shaft when the rotation shaft rotates 0 degrees is obtained a deviation distance and an azimuth angle; according to the angle values read by the first optical pickup head and the second optical pickup head, a first assembly angle deviation and the first assembly angle deviation of the first optical pickup head are obtained A second assembly angle deviation of the two optical pick-up heads; according to the angle values, the first assembly angle deviation and the second assembly angle deviation, a rotation angle error of the rotating shaft when rotating to various angles is obtained; and According to the angle values, the radius of the ring encoder, the rotation angle errors, the first assembly angle deviation and the second assembly angle deviation, a rotation yaw error when the rotation shaft rotates to various angles is obtained , where the angle values read by the first optical reading head are subtracted from the corresponding multiple nominal rotation angle values of the rotating shaft to obtain multiple measurement angle error values, and these measurement angle error values Perform curve fitting on the relationship with the corresponding nominal rotation angle values to obtain a first trigonometric function related to the nominal rotation angle values, and obtain the deviation distance and The azimuth, where

is the angle values read by the first optical reading head, θ is the nominal rotation angle values, e is the deviation distance, φ is the azimuth angle, R is the central axis and the first optical reading head head distance,

Wherein, the angle values read by the first optical read head are subtracted from the corresponding multiple nominal rotation angle values of the rotation axis to obtain multiple first measurement angle error values, and these first quantities Curve fitting is performed on the relationship between the angle measurement error value and the corresponding nominal rotation angle values to obtain a first trigonometric function related to the nominal rotation angle values, and the second optical reading head reads the Subtracting a plurality of nominal rotation angle values of the corresponding rotation axis and a preset angle difference between the first optical pickup head and the second optical pickup head from the angle values to obtain a plurality of second measurement angles Error value, the relationship between these second measurement angle error values and the corresponding nominal rotation angle values is subjected to curve fitting to obtain a second trigonometric function related to these nominal rotation angle values, with a value of 0 degrees As the actual installation angle of the first optical pick-up head, the actual installation angle of the second optical pick-up head is an offset angle value that makes the second trigonometric function coincide with the first trigonometric function, and is defined as 0 degrees as the first assembly angle deviation, and subtract the offset angle value from the preset installation angle of the second optical pickup head to obtain the second assembly angle deviation, wherein when the rotation axis rotates to various angles , after subtracting the preset installation angle of the second optical reading head and the second assembly angle deviation from the angle value read by the second optical reading head, it is obtained from the angle value read by the first optical reading head average to obtain the rotation angle error when the rotation axis rotates to various angles, wherein when the rotation axis rotates to various angles, the angle value read by the first optical reading head is subtracted from the azimuth angle and the corresponding After the rotation angle error, multiplied by 2πρ divided by 360 degrees and multiplied by the sine value and cosine value of the actual installation angle of the first optical pickup head, to obtain a first when the rotation axis rotates to each angle The X-axis yaw error and a first Y-axis yaw error, ρ is the radius of the ring encoder, and the angle value read by the second optical read head is subtracted from the azimuth angle and the corresponding rotation angle error Afterwards, multiply by 2πρ divided by 360 degrees and multiply by the sine and cosine of the actual installation angle of the second optical pickup head to obtain a second X-axis yaw error when the rotation axis rotates to various angles and a second Y-axis yaw error, average the corresponding first X-axis yaw error and the second X-axis yaw error, and combine the corresponding first Y-axis yaw error and the second Y-axis yaw error The axis yaw error is averaged to obtain the X-axis component and the Y-axis component of the rotation yaw error when the rotation axis rotates to various angles. The acquisition device of the geometric error of the rotating shaft as described in Claim 3, wherein the step of performing curve fitting is to use the least square method. The acquisition device for the geometric error of the rotating shaft as described in claim 3 further includes a third optical reading head, a fourth optical reading head and a fifth optical reading head, installed on the ring encoder around, wherein the preset installation angles of the first optical pickup head, the second optical pickup head, the third optical pickup head, the fourth optical pickup head and the fifth optical pickup head are respectively 0 degree, 72 degree, 144 degree, 216 degree and 288 degree, and use the first optical pickup head, the second optical pickup head, the third optical pickup head The pickup head, the fourth optical pickup head and the fifth optical pickup head acquire the rotation angle error and the rotation yaw error when the rotation shaft rotates to various angles.

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