Method and apparatus for acquiring geometric error of rotating shaft
By combining a ring encoder and an optical read head, the problem of accurately acquiring the geometric error of the rotating shaft was solved, enabling precise error measurement and correction, and improving the accuracy of the rotating shaft.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- IND TECH RES INST
- Filing Date
- 2021-12-03
- Publication Date
- 2026-07-24
AI Technical Summary
Existing technologies struggle to accurately measure the geometric errors of rotating shafts, especially in precision machinery, which affects the shaft's precision.
By using a combination of a ring encoder and multiple optical read heads, the rotation angle error and runout error of the rotating shaft are obtained by reading the angle values on the ring encoder at different angles of the rotating shaft, calculating parameters such as deviation distance, azimuth angle, and assembly angle deviation.
It enables precise measurement of the geometric error of the rotating shaft, provides a basis for quality inspection and correction, and improves the accuracy of the rotating shaft.
Smart Images
Figure CN116202445B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method and apparatus for obtaining the geometric error of a rotating shaft. Background Technology
[0002] Rotary shafts are widely used in various power machinery and machine tools. Especially in precision machinery, the accuracy of rotary shafts is paramount. Therefore, developing methods and equipment for obtaining the geometric errors of rotary shafts is a crucial research topic. Summary of the Invention
[0003] This invention relates to a method and apparatus for obtaining the geometric error of a rotating shaft, which can obtain the geometric error of the rotating shaft.
[0004] According to an embodiment of the present invention, a method for obtaining the geometric error of a rotating shaft includes the following steps: A ring encoder is mounted on a rotating shaft, and a first optical reader and a second optical reader are mounted around the ring encoder. The ring encoder is rotated with the rotating shaft, and the first and second optical readers simultaneously read multiple angle values on the ring encoder corresponding to the rotating shaft rotating to multiple angles. Based on the angle values read by the first optical reader, the deviation distance and azimuth angle of the center point of the ring encoder relative to the central axis of the rotating shaft when the rotating shaft rotates 0 degrees are obtained. Based on the angle values read by the first and second optical readers, a first assembly angle deviation of the first optical reader and a second assembly angle deviation of the second optical reader are obtained. Based on the angle values, the first assembly angle deviation, and the second assembly angle deviation, the rotation angle error of the rotating shaft at each angle is obtained. Based on the angle values, the radius of the ring encoder, the rotation angle error, the first assembly angle deviation, and the second assembly angle deviation, the rotational runout error of the rotating shaft at each angle is obtained.
[0005] According to an embodiment of the present invention, a device for acquiring the geometric error of a rotating shaft includes a ring encoder, a first optical reader, and a second optical reader. The ring encoder is mounted on a rotating shaft. The first and second optical readers are mounted around the ring encoder. The ring encoder is rotated with the rotating shaft, and the first and second optical readers simultaneously read multiple angle values on the ring encoder corresponding to the rotating shaft rotating to multiple angles. Based on the angle values read by the first optical reader, a deviation distance and azimuth angle of a center point of the ring encoder relative to a central axis of the rotating shaft when the rotating shaft rotates 0 degrees are obtained. Based on the angle values read by the first and second optical readers, a first assembly angle deviation of the first optical reader and a second assembly angle deviation of the second optical reader are obtained. Based on the angle values, the first assembly angle deviation, and the second assembly angle deviation, a rotation angle error of the rotating shaft at each angle is obtained. Based on the angle values, the radius of the ring encoder, the rotation angle error, the first assembly angle deviation, and the second assembly angle deviation, a rotational runout error of the rotating shaft at each angle is obtained.
[0006] In the method and apparatus for obtaining the geometric error of a rotating shaft according to an embodiment of the present invention, the rotation angle error and the rotational runout error of the rotating shaft can be obtained. Attached Figure Description
[0007] Figure 1 This is a schematic diagram of a device for obtaining the geometric error of a rotating shaft according to an embodiment of the present invention.
[0008] Figure 2 This is a flowchart of a method for obtaining the geometric error of a rotating shaft according to an embodiment of the present invention.
[0009] Figure 3 This describes the deviation distance and azimuth angle of the center point of the ring encoder relative to the central axis of the rotating shaft.
[0010] Figure 4 It is the difference between the angle value read by each optical reading head when the rotating axis rotates to various angles and the rotation angle.
[0011] Figure 5 It is the difference between the actual rotation angle and the ideal rotation angle when the rotating shaft rotates to various angles.
[0012] Figure 6 It represents the runout error along the X and Y axes when the rotating shaft rotates to various angles. Detailed Implementation
[0013] Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same element symbols are used in the drawings and description to denote the same or similar parts.
[0014] Figure 1 This is a schematic diagram of a device for obtaining the geometric error of a rotating shaft according to an embodiment of the present invention. Please refer to... Figure 1 The rotating shaft geometric error acquisition device 100 of this embodiment includes a ring encoder 110, a first optical reader R1, and a second optical reader R2. The ring encoder 110 is mounted on a rotating shaft 50. The first optical reader R1 and the second optical reader R2 are mounted around the ring encoder 110. By rotating the ring encoder 110 fixed thereon with the rotating shaft 50, and by reading the angle values on the ring encoder 110 with the first optical reader R1 and the second optical reader R2, various geometric errors of the rotating shaft 50 can be analyzed and acquired. Therefore, it can be used to detect whether the quality of the rotating shaft 50 meets the requirements, and can serve as a basis for correction when using the rotating shaft 50 in subsequent applications.
[0015] In the rotating shaft geometric error acquisition device 100 of this embodiment, a third optical reader R3, a fourth optical reader R4, and a fifth optical reader R5 are further included, which are installed around the ring encoder 110. The preset installation angles of the first optical reader R1, the second optical reader R2, the third optical reader R3, the fourth optical reader R4, and the fifth optical reader R5 are 0 degrees, 72 degrees, 144 degrees, 216 degrees, and 288 degrees, respectively. Thus, the rotation angle error and rotational runout error of the rotating shaft 50 when rotated to various angles are acquired using the first optical reader R1, the second optical reader R2, the third optical reader R3, the fourth optical reader R4, and the fifth optical reader R5. It should be noted that although the following description assumes the use of five optical readers, in the rotating shaft geometric error acquisition method and acquisition device of the present invention, the same geometric error can also be acquired using only two optical readers. When using two optical read heads, the default installation angles of the two optical read heads can be 0 degrees and 90 degrees respectively, but this invention is not limited to this.
[0016] Figure 2 This is a flowchart of a method for obtaining the geometric error of a rotating shaft according to an embodiment of the present invention. Please refer to... Figure 1 and Figure 2 The method for obtaining the geometric error of the rotating shaft in this embodiment includes the following steps. First, a ring encoder 110 is installed on the rotating shaft 50, and a first optical read head R1 and a second optical read head R2 are installed around the ring encoder 110, step S110.
[0017] Next, the ring encoder 110 is rotated by the rotating shaft 50, meaning the ring encoder 110 is driven to rotate by the rotating shaft 50. During the rotation, the first optical reading head R1 and the second optical reading head R2 simultaneously read multiple angle values on the ring encoder 110 corresponding to the rotating shaft 50 rotating to multiple angles, step S120. Because the assembly angles of the first optical reading head R1 and the second optical reading head R2 are different, the angle values read by the first optical reading head R1 and the second optical reading head R2 in this embodiment theoretically have a difference of 72 degrees.
[0018] Figure 3 This describes 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... Figure 2 and Figure 3 Then, based on the angle value read by the first optical reading head R1, the center 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. Figure 3 (Explained using point O through which the central axis passes) The deviation distance e and azimuth angle φ, step S130. Here, the connection direction between point O through which the central axis of the rotation axis 50 passes and the first optical reading head R1 is taken as the X-axis, and the azimuth angle φ is defined using the X-axis and point O as reference references.
[0019] Figure 4 This is the difference between the angle value read by each optical reader head when the rotating axis rotates to various angles and the rotation angle itself. Please refer to... Figure 3 and Figure 4 For example, multiple measurement angle error values are obtained by subtracting multiple nominal rotation angle values of the corresponding rotating shaft 50 from the angle value read by the first optical reading head R1. For instance, when the rotating shaft 50 rotates 0 degrees, that is, when the rotating shaft 50 does not rotate, the angle value read by the first optical reading head R1 is 359 degrees 59 minutes 52 seconds. Subtracting the nominal rotation angle value of 0 degrees at this time from 359 degrees 59 minutes 52 seconds yields a measurement angle error value of -8 seconds. Figure 4 Data points with -8 seconds on the vertical axis and 0 degrees on the horizontal axis. Complete this process. Figure 4 The curve corresponding to the first optical reading head R1 is then fitted. This curve, representing the relationship between the measured angle error value and the corresponding nominal rotation angle value, is then fitted to obtain a first trigonometric function related to the nominal rotation angle value. The deviation distance and azimuth angle are obtained by simultaneously solving the obtained first trigonometric function and the following equation. In this embodiment, the curve fitting step uses the least squares method. In the following equation, It is the angle value read by the first optical reading head. This is the nominal rotation angle value, e is the deviation distance, φ is the azimuth angle, and R is the distance between the central axis and the first optical readout head.
[0020] Formula 1: .
[0021] In this embodiment, according to Figure 4 The curve corresponding to the first optical read head R1 in the curve, and the first trigonometric function obtained by curve fitting is Therefore, the deviation distance e is 14.39 micrometers and the azimuth angle is 0.089 degrees.
[0022] Next, please refer to Figure 1 and Figure 2 Step S140: Obtain the first assembly angle deviation of the first optical reading head R1 and the second assembly angle deviation of the second optical reading head R2 based on the angle values read by the first optical reading head R1 and the second optical reading head R2.
[0023] For example, please refer to Figure 1 and Figure 4 Similar to the steps described above, multiple first measurement angle error values are obtained by subtracting the corresponding nominal rotation angle values of the rotating axis 50 from the angle value read by the first optical reading head R1. Then, the relationship between the first measurement angle error values and the corresponding nominal rotation angle values (i.e., Figure 4 A first trigonometric function related to the nominal rotation angle value is obtained by curve fitting of the curve corresponding to the first optical reading head R1.
[0024] Furthermore, multiple second measurement angle error values are obtained by subtracting the corresponding nominal rotation angle values of the rotating shaft and a preset angle difference between the first optical reading head R1 and the second optical reading head R2 from the angle value read by the second optical reading head R2. 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. Subtracting the nominal rotation angle value of 0 degrees and the preset angle difference of 72 degrees between the first optical reading head R1 and the second optical reading head R2 from 73 degrees 59 minutes and 35 seconds yields a measurement angle error value of 95 seconds, which is... Figure 4 The data points are set with 95 seconds on the vertical axis and 0 degrees on the horizontal axis. This method completes the process. Figure 4 The curve corresponding to the second optical read head R2.
[0025] Then, the curve representing the relationship between the second measured angle error value and the corresponding nominal rotation angle value is curve-fitted to obtain a second trigonometric function related to the nominal rotation angle value. Here, 0 degrees is taken as the actual installation angle of the first optical reader R1, and the actual installation angle of the second optical reader R2 is an offset angle value that makes the second trigonometric function coincide with the first trigonometric function, which is, for example, 72.07 degrees. Furthermore, 0 degrees is taken as the first assembly angle deviation of the first optical reader R1, and the offset angle value (for example, 72.07 degrees) is subtracted from the preset installation angle of the second optical reader R2 (for example, 72 degrees) to obtain the second assembly angle deviation (for example, 0.07 degrees). For example, the third assembly angle deviation of the third optical reader R3 is 0.01 degrees, the fourth assembly angle deviation of the fourth optical reader R4 is 0.03 degrees, and the fifth assembly angle deviation of the fifth optical reader R5 is 0.07 degrees.
[0026] Figure 5 This is the difference between the actual rotation angle and the ideal rotation angle when the axis of rotation reaches various angles. Please refer to... Figure 2 and Figure 5 The rotation angle error of the rotating shaft 50 when rotating to various angles is obtained based on the angle value, the first assembly angle deviation and the second assembly angle deviation, step S150.
[0027] For example, when the rotating shaft 50 rotates to various angles, the angle value read by the second optical reading head R2 is subtracted from the preset installation angle and the second assembly angle deviation of the second optical reading head R2, and then averaged with the angle value read by the first optical reading head R1 to obtain the rotation angle error of the rotating shaft 50 when rotating to various angles. In fact, the angle value read by the first optical reading head R1 is also subtracted from the preset installation angle and the first assembly angle deviation of the first optical reading head R1, but since the preset installation angle and the first assembly angle deviation of the first optical reading head R1 are both 0, the average is directly calculated using the angle value read by the first optical reading head R1 and the angle value read by the second optical reading head R2 after subtracting the preset installation angle and the second assembly angle deviation of the second optical reading head R2. In this embodiment, because five optical reading heads are installed, in addition to the angle values read by the first optical reading head R1 and the second optical reading head R2 minus the preset installation angle and the second assembly angle deviation of the second optical reading head R2, the following values are also added: the angle values read by the third optical reading head R3 minus the preset installation angle and the third assembly angle deviation of the third optical reading head R3; the angle values read by the fourth optical reading head R4 minus the preset installation angle and the fourth assembly angle deviation of the fourth optical reading head R4; and the angle values read by the fifth optical reading head R5 minus the preset installation angle and the fifth assembly angle deviation of the fifth optical reading head R5. Then, the average value is taken. This average value is the rotation angle error of the rotating shaft 50, and the relationship between the rotation angle error of the rotating shaft 50 at each rotation angle and the rotation angle of the rotating shaft 50 is as follows: Figure 5 The curve in the figure is shown.
[0028] Figure 6 This refers to the runout error along the X and Y axes as the rotating axis rotates to various angles. Please refer to... Figure 3 and Figure 6 The rotational runout error of the rotating shaft 50 when rotating to various angles is obtained based on the angle value, the radius of the ring encoder, the rotation angle error, the first assembly angle deviation and the second assembly angle deviation, step S160.
[0029] For example, the angle value read by the first optical reader R1 is subtracted from the azimuth angle of the center point O' of the ring encoder 110 relative to the central axis of the rotating shaft 50 and the corresponding rotation angle error. This result is multiplied by 2πρ, divided by 360 degrees, and multiplied by the sine of the actual installation angle of the first optical reader R1 to obtain a first X-axis yaw error when the rotating shaft 50 rotates to various angles. Similarly, 2πρ is multiplied by 2πρ, divided by 360 degrees, and multiplied by the cosine of the actual installation angle of the first optical reader R1 to obtain a first Y-axis yaw error when the rotating shaft 50 rotates to various angles. Here, ρ is the radius of the ring encoder.
[0030] Furthermore, the angle value read by the second optical reader R2 is subtracted from the azimuth angle of the center point O' of the ring encoder 110 relative to the central axis of the rotating shaft 50 and the corresponding rotation angle error. This result is multiplied by 2πρ, divided by 360 degrees, and multiplied by the sine of the actual installation angle of the second optical reader R2 to obtain a second X-axis yaw error when the rotating shaft 50 rotates to various angles. Similarly, the X-axis yaw error of the third optical reader R3, the fourth optical reader R4, and the fifth optical reader R5 are obtained in the same manner.
[0031] Then, the X-axis yaw error of all read heads (e.g., the first X-axis yaw error and the second X-axis yaw error when there are only two read heads) is averaged according to the rotation angle of the corresponding rotation axis 50, and the Y-axis yaw error of all read heads (e.g., the first Y-axis yaw error and the second Y-axis yaw error when there are only two read heads) is averaged according to the rotation angle of the corresponding rotation axis 50, to obtain the X-axis and Y-axis components of the rotational yaw error when the rotation axis rotates to each angle, for example as follows: Figure 6 As shown.
[0032] In summary, in the method and apparatus for obtaining 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 read head are first obtained. Then, the rotation angle error and rotational runout error of the rotating shaft can be obtained. Therefore, the quality of the rotating shaft can be detected and used as a basis for correction when using the rotating shaft in subsequent applications. Furthermore, because the assembly deviation of the ring encoder is obtained first, the obtained rotation angle error and rotational runout error of the rotating shaft are more accurate.
[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for obtaining the geometric error of a rotating shaft, characterized in that, include: A ring encoder is mounted on a rotating shaft, and a first optical read head and a second optical read head are mounted 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 corresponding to the rotating shaft rotating to multiple angles; Based on the angle values read by the first optical reading head, the deviation distance and azimuth angle of the center point of the ring encoder relative to the central axis of the rotating shaft when the rotating shaft rotates 0 degrees are obtained; The first assembly angle deviation of the first optical reading head and the second assembly angle deviation of the second optical reading head are obtained based on the angle values read by the first optical reading head and the second optical reading head. The rotation angle error of the rotating shaft at each angle is obtained based on these angle values, the first assembly angle deviation, and the second assembly angle deviation; and The rotational runout error of the rotating shaft at various angles is obtained based on these angle values, the radius of the ring encoder, these rotational angle errors, the first assembly angle deviation, and the second assembly angle deviation. The method involves subtracting multiple nominal rotation angle values of the corresponding rotation axis from the angle values read by the first optical reading head to obtain multiple measurement angle error values. A curve fitting is then performed on the relationship between these measurement angle error values and the corresponding nominal rotation angle values to obtain a first trigonometric function related to these nominal rotation angle values. Finally, the deviation distance and the azimuth angle are obtained based on the first trigonometric function and Equation 1. These are the angle values read by the first optical reading head. These are the nominal rotation angle values, e is the deviation distance, φ is the azimuth angle, and R is the distance between the central axis and the first optical readout head. Formula 1: ,in, Multiple first measurement angle error values are obtained by subtracting the corresponding nominal rotation angle values of the rotating axis from the angle values read by the first optical reading head. Curve fitting is then performed on the relationship between these first measurement angle error values and the corresponding nominal rotation angle values to obtain a first trigonometric function related to these nominal rotation angle values. Multiple second measurement angle error values are obtained by subtracting the corresponding nominal rotation angle values of the rotating axis and the default angle difference between the first and second optical reading heads from the angle values read by the second optical reading head. A curve fitting is then performed on the relationship between these second measurement angle error values and the corresponding nominal rotation angle values to obtain a second trigonometric function related to these nominal rotation angle values. Taking 0 degrees as the actual installation angle of the first optical read head, the actual installation angle of the second optical read head is the offset angle value that makes the second trigonometric function coincide with the first trigonometric function, and Using 0 degrees as the first assembly angle deviation, and subtracting the default installation angle of the second optical reading head from this offset angle value, we obtain the second assembly angle deviation. When the rotating shaft rotates to various angles, the angle value read by the second optical reading head is subtracted from the default installation angle of the second optical reading head and the second assembly angle deviation, and then averaged with the angle value read by the first optical reading head to obtain the rotation angle error of the rotating shaft when it rotates to various angles. When the rotating axis rotates to various angles... Subtracting the azimuth angle and the corresponding rotation angle error from the angle value read by the first optical reader, multiplying by 2πρ, dividing by 360 degrees, and then multiplying by the sine and cosine values of the actual installation angle of the first optical reader, yields the first X-axis runout error and the first Y-axis runout error when the rotating shaft rotates to various angles. ρ is the radius of the ring encoder. Subtract the azimuth angle and the corresponding rotation angle error from the angle value read by the second optical reading head, multiply by 2πρ, divide by 360 degrees, and multiply by the sine and cosine values of the actual installation angle of the second optical reading head to obtain the second X-axis yaw error and the second Y-axis yaw error when the rotation axis rotates to various angles. The first X-axis yaw error and the second X-axis yaw error are averaged, and the first Y-axis yaw error and the second Y-axis yaw error are averaged to obtain the X-axis and Y-axis components of the rotational yaw error when the rotation axis rotates to various angles.
2. The method for obtaining the geometric error of a rotating shaft according to claim 1, characterized in that, The curve fitting step involves using the least squares method.
3. A device for acquiring the geometric error of a rotating shaft, characterized in that, include: Ring encoder, used for mounting on a rotating shaft; as well as The first optical read head and the second optical read head are mounted 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 corresponding to the rotating shaft rotating to multiple angles; Based on the angle values read by the first optical reading head, the deviation distance and azimuth angle of the center point of the ring encoder relative to the central axis of the rotating shaft when the rotating shaft rotates 0 degrees are obtained; The first assembly angle deviation of the first optical reading head and the second assembly angle deviation of the second optical reading head are obtained based on the angle values read by the first optical reading head and the second optical reading head. The rotation angle error of the rotating shaft at each angle is obtained based on these angle values, the first assembly angle deviation, and the second assembly angle deviation; and The rotational runout error of the rotating shaft at various angles is obtained based on the angle values, the radius of the ring encoder, the rotational angle errors, the first assembly angle deviation, and the second assembly angle deviation. The method is characterized by subtracting multiple nominal rotational angle values of the rotating shaft from the angle values read by the first optical reading head to obtain multiple measured angle error values. Curve fitting is performed on the relationship between these measured angle error values and the corresponding nominal rotational angle values to obtain a first trigonometric function related to the nominal rotational angle values. The deviation distance and the azimuth angle are then obtained based on the first trigonometric function and Equation 1. These are the angle values read by the first optical reading head. These are the nominal rotation angle values, e is the deviation distance, φ is the azimuth angle, and R is the distance between the central axis and the first optical readout head. Formula 1: ,in, Multiple first measurement angle error values are obtained by subtracting the corresponding nominal rotation angle values of the rotating axis from the angle values read by the first optical reading head. Curve fitting is then performed on the relationship between these first measurement angle error values and the corresponding nominal rotation angle values to obtain a first trigonometric function related to these nominal rotation angle values. Multiple second measurement angle error values are obtained by subtracting the corresponding nominal rotation angle values of the rotating axis and the default angle difference between the first and second optical reading heads from the angle values read by the second optical reading head. A curve fitting is then performed on the relationship between these second measurement angle error values and the corresponding nominal rotation angle values to obtain a second trigonometric function related to these nominal rotation angle values. Taking 0 degrees as the actual installation angle of the first optical read head, the actual installation angle of the second optical read head is the offset angle value that makes the second trigonometric function coincide with the first trigonometric function, and Using 0 degrees as the first assembly angle deviation, and subtracting the default installation angle of the second optical reading head from this offset angle value, we obtain the second assembly angle deviation. When the rotating shaft rotates to various angles, the angle value read by the second optical reading head is subtracted from the default installation angle of the second optical reading head and the second assembly angle deviation, and then averaged with the angle value read by the first optical reading head to obtain the rotation angle error of the rotating shaft when it rotates to various angles. When the rotating axis rotates to various angles... Subtracting the azimuth angle and the corresponding rotation angle error from the angle value read by the first optical reader, multiplying by 2πρ, dividing by 360 degrees, and then multiplying by the sine and cosine values of the actual installation angle of the first optical reader, yields the first X-axis runout error and the first Y-axis runout error when the rotating shaft rotates to various angles. ρ is the radius of the ring encoder. Subtract the azimuth angle and the corresponding rotation angle error from the angle value read by the second optical reading head, multiply by 2πρ, divide by 360 degrees, and multiply by the sine and cosine values of the actual installation angle of the second optical reading head to obtain the second X-axis yaw error and the second Y-axis yaw error when the rotation axis rotates to various angles. The first X-axis yaw error and the second X-axis yaw error are averaged, and the first Y-axis yaw error and the second Y-axis yaw error are averaged to obtain the X-axis and Y-axis components of the rotational yaw error when the rotation axis rotates to various angles.
4. The device for obtaining the geometric error of a rotating shaft according to claim 3, characterized in that, The curve fitting step involves using the least squares method.
5. The device for obtaining the geometric error of a rotating shaft according to claim 3, characterized in that, It also includes a third, fourth, and fifth optical reading head, which are installed around the ring encoder. The default installation angles of the first, second, third, fourth, and fifth optical reading heads are 0 degrees, 72 degrees, 144 degrees, 216 degrees, and 288 degrees, respectively. The first, second, third, fourth, and fifth optical reading heads are used to obtain the rotation angle error and rotation runout error of the rotating shaft when it rotates to each angle.