Rotation angle detection system, method and application thereof

Abstract

The present invention relates to a rotation angle detection system, method, and application thereof. The system includes a light source, a beam splitter, a collimating lens, and a CCD receiver; a wedge-shaped wedge and a rotation drive mechanism for driving the wedge-shaped wedge to rotate circumferentially; a reflector and a sway drive mechanism for driving the reflector to sway; and a detection mechanism for detecting the sway angle of the reflector. A light beam emitted by the light source passes through the beam splitter, the collimating lens, and the wedge-shaped wedge in sequence and is incident on the reflector. The sway drive mechanism can drive the reflector to sway and make the reflector perpendicular to the incident light beam. The light beam reflected by the reflector returns along the incident path, and the position of the light spot on the CCD is used to determine whether the reflector is perpendicular to the incident light beam. The circumferential rotation angle of the wedge-shaped wedge is obtained by measuring the sway angle of the reflector through the detection mechanism. The present invention can avoid the shortcomings currently existing in precision rotation angle measurement, such as angle sensor calibration, and achieve continuous measurement, smaller errors, and higher accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of angle measurement characterized by adopting optical methods in physical measurement, and particularly relates to a rotation angle detection system, method and application thereof. Background Art

[0002] Angle sensors used in industrial production, such as circular gratings, time-based grating angle sensors and other systems for measuring rotation angles, require high rotation measurement accuracy within a 360° range. The currently achievable accuracy is 2″ to 3″. In addition, in order to ensure the accuracy of the angle sensor, initial calibration and error detection of the angle sensor are also very important and technically more difficult. The most commonly used method is to use a standard polyhedron (such as a dodecahedron) as a carrier, and fix the circular grating, time-based grating and other angle sensors on the prism in a concentric manner. Please refer to the attached Figure 1 The figure shows an octahedral prism. The prism 200 and the angle sensor 100 are rotated synchronously through a turntable (not shown in the figure), and the surface of the prism is detected using an autocollimator 300 after each rotation. The measured rotation angle is compared with the indication of the angle sensor 100 for calibration. The shortcomings are: 1. The processing of the polyhedron will cause errors in the angles between adjacent faces; 2. Multiple rotations will cause the processing errors between the faces of the polyhedron to accumulate, increasing the errors. Although the self-sealing characteristics of the angle can be used to eliminate the errors, the procedure is cumbersome and time-consuming. Long-term measurement requires a high environmental standard and is prone to introducing additional errors due to factors such as vibration and temperature changes. 3. When the angle sensor is fixed on the prism in a concentric manner, there is an eccentricity problem, which causes the calibrated rotation angle to be inconsistent with the rotation angle indicated by the angle sensor, resulting in eccentricity error. 4. Due to the number of faces of the polyhedron, it can only be calibrated by rotating the corresponding number of degrees (number of times), and the angles of the discrete side faces cannot be continuously measured. 5. The range of the autocollimator is small. Due to the range of the autocollimator, the number of angle segments that can be subdivided during detection is small, making it difficult to expand and improve the detection accuracy under this method. These shortcomings will affect and limit the accuracy of the angle sensor calibration.

[0003] In Chinese patents CN110926367B and CN110940298B, the applicant proposed the optical application principle of normal tracing. This method employs an f-θ angle detection system and uses a double wedge mechanism to adjust the incident light beam onto the surface to be measured, so that the beam is incident on the surface to be measured at normal incidence (vertical). The reflected light path from the surface to be measured returns along the original incident path, achieving normal tracing. The CCD detector performs detection, and the required detection data of the surface to be measured is calculated based on the circumferential rotation data of the two single wedge wedges. Whether this principle can be effectively applied to application scenarios such as angle sensors that require precise angle measurement, and whether it can achieve the best technical results possible and overcome the aforementioned shortcomings, is a technical problem that the applicant is considering solving. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide another rotation angle detection system, method and application thereof, so as to avoid the deficiencies currently existing in precision rotation angle measurement such as angle sensor calibration, and achieve the effect of continuous measurement, smaller error, and conducive to expansion and improvement of detection accuracy.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The rotation angle detection system includes a light source, a beam splitter, a collimating lens and a CCD receiver.

[0007] The invention also includes a wedge-shaped wedge tip and a rotation drive mechanism for driving the wedge-shaped wedge tip to rotate circumferentially, so as to change the direction of the light beam by rotating the wedge-shaped wedge tip;

[0008] The invention also includes a reflector and a deflection driving mechanism for driving the deflection of the reflector, so as to make the reflector perpendicular to the incident light beam through the deflection;

[0009] Also included is a deflection angle detection mechanism for detecting the deflection angle of the reflector;

[0010] The light beam emitted by the light source passes through the beam splitter, collimating lens, and wedge-shaped tip in sequence. After passing through the wedge-shaped tip, the light beam is incident on the reflector. The deflection drive mechanism can drive the deflection of the reflector and make the reflector perpendicular to the incident light beam. The light beam reflected by the reflector returns along the incident path, passes through the wedge-shaped tip, collimating lens, and beam splitter in sequence, and forms a light spot on the CCD receiver. The position of the light spot formation is used to determine whether the reflector is perpendicular to the incident light beam; the circumferential rotation angle of the wedge-shaped tip is obtained by the deflection angle of the reflector measured by the deflection angle detection mechanism. Specifically, the collimating lens and the CCD receiver constitute an f-θ angle measurement device, which can calculate the angle of the light beam reflected by the reflector by the position of the light spot formation, and determine whether the reflector is perpendicular to the incident light beam by whether the reflected light beam angle is zero; when the reflected light beam angle approaches zero, the reflected light beam returns close to the normal line, and various errors in the optical path system tend to zero. The circumferential rotation angle of the wedge-shaped tip is obtained by the deflection angle of the reflector measured by the deflection angle detection mechanism and the angle measured by the f-θ device.

[0011] To further improve the above technical solution, the roll angle detection mechanism can be a laser interferometer or a roll stage capable of displaying the roll angle. The apex angle of the wedge tip and the range of the roll angle detection mechanism are related to the system's detection accuracy and can be set based on the required detection accuracy. Preferably, when the refractive index of the wedge is 1.5, the apex angle of the wedge tip is 8°, the range of the roll angle detection mechanism is 8°, and the roll measurement accuracy is 0.1", then a 360° rotation angle can achieve detection accuracy better than 2".

[0012] The present invention also relates to a method for detecting the degree of rotation angle, comprising a light source, a beam splitter, a collimating lens and a CCD receiver, and also comprising a wedge-shaped wedge tip and a reflector;

[0013] The light beam emitted by the light source passes through the beam splitter, the collimating lens and the wedge-shaped wedge in sequence, and the light beam after passing through the wedge-shaped wedge is incident on the reflector;

[0014] The wedge-shaped wedge tip can rotate circumferentially and change the direction of the light beam passing through the wedge-shaped wedge tip by the rotation. The reflector can swing and make the reflector perpendicular to the incident light beam by the swing. Specifically, after the wedge-shaped wedge tip rotates circumferentially to change the direction of the light beam passing through the wedge-shaped wedge tip, the angle can be measured by the f-θ device to calculate the swing angle. The swing drive mechanism drives the reflector to swing according to the calculated swing angle and makes the reflector perpendicular to the incident light beam. The process can be repeated and corrected multiple times.

[0015] The light beam reflected by the reflector returns along the incident path, passes through the wedge tip, collimating lens and beam splitter in sequence, and forms a light spot on the CCD receiver. The position of the light spot (the angle measured by the f-θ device) can be used to determine whether the reflector is perpendicular to the incident beam.

[0016] The yaw angle of the reflector is obtained, and the circumferential rotation angle of the wedge tip can be calculated through the yaw angle of the reflector, the top angle of the wedge tip, and the angle measured by the f-θ device.

[0017] Furthermore, two laser interferometers are used to obtain the deflection angle of the reflector.

[0018] The direction of the light beam between the collimating lens and the wedge tip is the Z axis, and the Z axis is horizontal. An X axis and a Y axis are perpendicular to the Z axis, and the X axis is vertical and the Y axis is horizontal.

[0019] When the reflector deflects, one laser interferometer detects the amount of the reflector swinging with the X-axis as the center of rotation and calculates the rotation angle α. Another laser interferometer detects the amount of the reflector swinging with the Y-axis as the center of rotation and calculates the rotation angle β.

[0020] The circumferential rotation angle of the wedge tip is calculated by using the values of α or β or α and β, in combination with the top angle of the wedge tip and the angle measured by the f-θ device.

[0021] Furthermore, the circumferential rotation angle range of the wedge-shaped wedge tip is 360°, and the circumferential rotation angle range of the wedge-shaped wedge tip is equally divided into four regions;

[0022] In the same area, when the incident light beam on the reflector is close to the X-axis, the circumferential rotation angle of the wedge tip is calculated by combining the β value with the top angle of the wedge tip and the angle measured by the f-θ device;

[0023] When the light beam incident on the reflector is close to the Y-axis, the circumferential rotation angle of the wedge tip is calculated using the α value combined with the top angle of the wedge tip and the angle measured by the f-θ device.

[0024] The present invention also relates to the application of the aforementioned rotation angle detection system, wherein the part to be calibrated, the rotation angle of which needs to be detected, is synchronously rotated and arranged on the wedge-shaped wedge tip.

[0025] The light beam emitted by the light source passes through the beam splitter, collimating lens and wedge tip in sequence and then is incident on the reflector;

[0026] The reflector is driven to deflect by a deflection driving mechanism so that the reflector is perpendicular to the incident light beam, and the deflection angle detection mechanism obtains the deflection angle of the reflector;

[0027] The wedge-shaped wedge is driven by a rotary drive mechanism to rotate a certain angle and then stop. The direction of the light beam passing through the wedge-shaped wedge changes, and the calibration object rotates synchronously with the wedge-shaped wedge. The angle measured by the f-θ device deviates from zero, and the light beam reflected by the reflector deviates from the normal direction. The angle measurement error of the f-θ device is large.

[0028] The reflector is again driven to yaw by the yaw drive mechanism so that the reflector is perpendicular to the incident light beam, and the yaw angle detection mechanism obtains the yaw angle of the reflector. Specifically, the yaw angle is calculated based on the angle measured by the f-θ device, and the yaw angle of the reflector is set. The reflector will be close to perpendicular to the incident light beam, and the reflected light beam will return nearly along its original path. The errors introduced by each optical element tend to zero. The yaw angle detection mechanism obtains the yaw angle of the reflector and the accurate f-θ device measurement angle.

[0029] By obtaining the deflection angle of the reflector twice, combined with the top angle of the wedge wedge and the angle measured by the f-θ device, the change in the direction of the light beam before and after the wedge wedge is rotated can be calculated, and then the circumferential rotation angle of the wedge wedge can be obtained, which corresponds to the rotation angle of the part to be calibrated.

[0030] Furthermore, the part to be calibrated is an angle sensor, and the angle sensor is synchronously rotated and sleeved on the wedge-shaped wedge tip;

[0031] The angle sensor is calibrated by comparing the rotation angle reading of the angle sensor with the calculated circumferential rotation angle of the wedge tip.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The rotation angle detection system of the present invention uses the normal tracing principle in reverse, and calculates the circumferential rotation angle of the wedge wedge tip through the deflection angle of the reflector; the circumferential rotation angle of the wedge wedge tip is not restricted, and the measurement of any rotation angle within 360° can be achieved, that is, continuous measurement, and the corresponding circumferential rotation angle value can be calculated through the deflection angle of the reflector; fewer errors are introduced, and there is no prism working surface processing error and cumulative error in the multi-faceted prism method detection.

[0034] 2. The rotation angle detection system of the present invention is suitable for the calibration of high-precision angle measuring instruments such as circular gratings and time grating angle sensors. The part to be calibrated is synchronously rotated and mounted on the wedge tip, and there is no eccentricity error. When in use, the misalignment only causes the azimuth deviation of the light beam, but does not cause deviation in the angle change.

[0035] 3. In the rotation angle detection system and method of the present invention, the acquisition of the swing angle of the reflector can have a larger range based on the currently available detection method, which allows the top angle of the wedge-shaped wedge to be selected to be larger. Therefore, in the detection of the swing angle of the reflector, the angle can be subdivided into more parts. Under the same accuracy, a higher measurement accuracy of the circumferential rotation angle of the wedge-shaped wedge can be obtained, which has good scalability for improving the detection accuracy of the rotation angle of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1This is a schematic diagram of the structure of the current circular grating calibration method mentioned in the background technology;

[0037] Figure 2 is a structural diagram of a rotation angle detection system according to a specific embodiment;

[0038] Figure 3 It is a structural schematic diagram of a rotation angle detection system applied to angle sensor calibration in a specific embodiment;

[0039] Figure 4 In the specific embodiment, the range is [-π / 4,π / 4] Error estimate plot;

[0040] Figure 5 In the specific embodiment, the range is [π / 4, 3π / 4] Error estimate plot;

[0041] Figure 6 In the specific embodiment, the range is [3π / 4, 5π / 4] Error estimate plot;

[0042] Figure 7 In the specific embodiment, the range is [5π / 4, 7π / 4] Error estimate plot;

[0043] Among them, there are a light source 1, a beam splitter 2, a collimating lens 3, a wedge tip 4, a reflector 5, a CCD receiver 6, an angle sensor 100, a prism 200, and an autocollimator 300. DETAILED DESCRIPTION

[0044] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0045] See Figure 2 , a rotation angle detection system of a specific embodiment includes a light source 1, a beam splitter 2, a collimating lens 3 and a CCD receiver 6;

[0046] The invention also includes a wedge-shaped wedge tip 4 and a rotation drive mechanism (not shown in the figure) for driving the wedge-shaped wedge tip 4 to rotate circumferentially, so as to change the direction of the light beam by rotating the wedge-shaped wedge tip 4;

[0047] The device further comprises a reflector 5 and a deflection driving mechanism (not shown in the figure) for driving the deflection of the reflector 5, so as to make the reflector 5 perpendicular to the incident light beam by deflection;

[0048] It also includes a deflection angle detection mechanism (not shown in the figure) for detecting the deflection angle of the reflector 5;

[0049] The light beam emitted by the light source 1 is reflected by the beam splitter 2 and passes through the collimating lens 3 and the wedge-shaped tip 4 in sequence. After passing through the wedge-shaped tip 4, the direction of the light beam changes, deviates from the optical axis and is incident on the reflector 5. The yaw drive mechanism can drive the reflector 5 to yaw and make the reflector 5 perpendicular to the incident light beam. The light beam reflected by the reflector 5 returns along the original incident path, passes through the wedge-shaped tip 4, the collimating lens 3 and the beam splitter 2 in sequence, and forms a light spot on the CCD receiver 6. The position of the light spot is used to determine whether the reflector 5 is perpendicular to the incident light beam; specifically, the collimating lens 3 and the CCD receiver 6 form an f-θ angle measuring device for measuring angles, and the angle measured by the f-θ device is used to determine whether the reflector 5 is perpendicular to the incident light beam; the circumferential rotation angle of the wedge-shaped tip 4 can be calculated by combining the yaw angle of the reflector 5 measured by the yaw angle detection mechanism with the top angle of the wedge-shaped tip 4 and the angle measured by the f-θ device.

[0050] The rotation angle detection system of the embodiment uses the normal tracing principle in reverse, and calculates the circumferential rotation angle of the wedge-shaped wedge tip 4 through the deflection angle of the reflector 5, which has good technical effects: ① The circumferential rotation angle of the wedge-shaped wedge tip 4 is not restricted, and the measurement of any rotation angle within 360° can be achieved, that is, continuous measurement, and the corresponding circumferential rotation angle value can be calculated through the deflection angle of the reflector 5; ② Fewer errors are introduced, and there is no prism working surface processing error and cumulative error in the multi-faceted prism method detection. Only the physical value of the vertex angle of the wedge-shaped wedge tip 4 is introduced, but in the calculation process, since the introduced vertex angle is unchanged, it can be to be ignored; ③ If the part to be calibrated is synchronously rotated and placed on the wedge-shaped wedge 4, there is no eccentricity error. In this system, the eccentricity only causes the azimuth deviation of the light beam, and does not cause the deviation of the angle change; ④ Under the mode of this system, for the acquisition of the swing angle of the reflector 5, based on the currently available detection method, a larger range can be obtained, which corresponds to the fact that the top angle of the wedge-shaped wedge 4 can be selected to be larger, so that in the detection of the swing angle of the reflector 5, the number of angle subdivisions can be more, and under the same accuracy, a higher measurement accuracy of the circumferential rotation angle of the wedge-shaped wedge 4 can be obtained, which greatly expands and improves the detection accuracy of the rotation angle of this system.

[0051] During implementation, the rotation drive mechanism, the yaw drive mechanism, and the yaw angle detection mechanism can all adopt existing technologies. For example, the rotation drive mechanism can be a simple planar rotatable support frame, which is rotatably connected to the wedge-shaped wedge tip 4. The driving source of the rotation can be manual or electric control. For experimental development testing, it can be manually rotated, and for engineering use, automatic control is mostly used. For example, the yaw drive mechanism, as an experimental development test, can be a simple ball joint bracket connected to the back of the reflector 5. The driving source of the yaw can be manual. A more convenient choice can be the existing XYZ multi-dimensional yaw table, which is connected to the back of the reflector 5. That is, it can provide the mechanical structure and power for the yaw movement of the reflector 5. At the same time, the existing yaw table can also display the required XYZ yaw angle, and at the same time has the function of a yaw angle detection mechanism.

[0052] The following will specifically introduce the use of laser interferometers as a deflection angle detection mechanism. The deflection angle of the reflector 5 is obtained by two laser interferometers. When in use, the direction of the light beam between the collimating lens 3 and the wedge-shaped wedge 4 is the Z axis and the Z axis is horizontal. The X axis and the Y axis are perpendicular to the Z axis, the X axis is vertical, and the Y axis is horizontal. When the reflector 5 deflects, one laser interferometer detects the amount of the reflector 5 swinging with the X axis as the rotation center, and calculates the rotation angle α. The other laser interferometer detects the amount of the reflector 5 swinging with the Y axis as the rotation center, and calculates the rotation angle β. The circumferential rotation angle of the wedge-shaped wedge 4 is calculated by using the values of α or β or α and β, combined with the top angle of the wedge-shaped wedge 4 and the angle measured by the f-θ device. Specifically, because the circumferential rotation angle range of the wedge-shaped wedge 4 is 360°, it is preferred to divide the circumferential rotation angle range of the wedge-shaped wedge 4 into four equal regions.

[0053] In the same area, when the light beam incident on the reflector 5 is close to the X-axis, the circumferential rotation angle of the wedge tip 4 is calculated using the β value combined with the top angle of the wedge tip 4 and the angle measured by the f-θ device;

[0054] When the light beam incident on the reflector 5 is close to the Y axis, the circumferential rotation angle of the wedge tip 4 is calculated by combining the α value with the top angle of the wedge tip 4 and the angle measured by the f-θ device.

[0055] When the light beam passes through the wedge (wedge tip 4), it will deviate from the light beam by an angle of θ. The size of the angle θ is determined by the apex angle of the wedge and the refractive index of the wedge material. For example, when the apex angle of the wedge is 100", the refractive index of the wedge material is 1.5, and the light beam angle deviates from the optical axis by 50". When the wedge rotates After the angle, the outgoing light vector can be expressed as:

[0056]

[0057] When the deflection angle of the reflector is zero, the direction vector of the reflected light is:

[0058]

[0059] At this time, the f-θ device measures the angle (η AC ,ζ AC )satisfy:

[0060]

[0061]

[0062] Δη AC , Δζ AC This is the angle measurement error introduced by aberrations and processing errors in the optical system. At this time, the reflector tilt angle α is set to -η AC , β=-ζ AC At this time, the light beam approaches the optical axis and returns along its original path. Due to the angle measurement characteristics of normal tracing, the f-θ device measures the angle η. AC1 →0,ζ AC1 →0, Δη AC1 →0, Δζ AC1 →0.

[0063] At this time, the components of the light vector emitted by the optical wedge satisfy:

[0064]

[0065]

[0066] By accurate (α, β) and (η AC ,ζ AC ) value can be calculated to get the exact angle Since the f-θ device can achieve extremely high angle measurement accuracy by using the normal tracing measurement method, the system measurement error is mainly contributed by the (α, β) angle measured by the deflection system. When the optical wedge is selected, the θ angle is constant, which is easy to understand. When the value is close to 0° or 180°, the α change is insensitive and the measurement accuracy is low. When the value is close to 90° or 270°, the β change is insensitive and the measurement accuracy is low. It can be calculated by formula (5) and (6) The expression of is used to estimate the system error:

[0067]

[0068]

[0069] in is calculated based on α horn, is calculated based on β Angle, Δ is the yaw angle measurement error. Taking the laser interferometer as an example, when the wedge deflection angle θ=4°, the laser interferometer range is 10°, and the measurement error is ±0.1″, [0,2π] is divided into 4 regions [-π / 4,π / 4], [π / 4,3π / 4], [3π / 4,5π / 4], [5π / 4,7π / 4], and α and β are used to estimate The error can be seen in Figure 4-Figure 7 ;

[0070] It can be seen that when the wedge deflection angle θ = 4° and the measurement accuracy is ±0.1 second, the angle measurement error is no more than 2" within the 360° range. When a larger deflection angle θ is used, the range of the deflection angles α and β is larger and the accuracy is higher, then the angle The measurement accuracy is higher. When the α and β ranges are smaller, the measurement accuracy is higher. The higher the measurement accuracy.

[0071] This system can be used to detect the rotation angle of the test piece. Of course, based on the above-mentioned usage results, a more specific scenario is to calibrate the full range of angle sensors such as circular gratings and time gratings. Figure 3 , the angle sensor 100 is synchronously rotated and sleeved on the wedge-shaped wedge tip 4;

[0072] The light beam emitted by the light source 1 passes through the beam splitter 2, the collimating lens 3 and the wedge-shaped wedge 4 in sequence and then is incident on the reflector 5;

[0073] The reflector 5 is driven to deflect by the deflection driving mechanism so that the reflector 5 is perpendicular to the incident light beam, and the deflection angle detection mechanism obtains the deflection angle of the reflector 5;

[0074] The wedge tip 4 is driven by the rotation drive mechanism to rotate circumferentially for a certain angle and then stops. The direction of the light beam passing through the wedge tip 4 changes, and the angle sensor 100 rotates synchronously with the wedge tip 4.

[0075] The reflector 5 is driven to deflect by the deflection driving mechanism again so that the reflector 5 is perpendicular to the incident light beam, and the deflection angle detection mechanism obtains the deflection angle of the reflector 5;

[0076] By obtaining the deflection angle of the reflector 5 twice, combined with the top angle of the wedge tip 4 and the angle measured by the f-θ device, the change in the direction of the light beam before and after the rotation of the wedge tip 4 can be calculated, and then the circumferential rotation angle of the wedge tip 4 can be obtained. The rotation angle reading of the angle sensor 100 is compared with the calculated circumferential rotation angle of the wedge tip 4, so that the angle sensor 100 can be calibrated.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. The rotation angle detection system includes a light source, a beam splitter, a collimating lens, and a CCD receiver, and is characterized by: The invention also includes a wedge-shaped wedge tip and a rotation drive mechanism for driving the wedge-shaped wedge tip to rotate circumferentially, so as to change the direction of the light beam by rotating the wedge-shaped wedge tip; The invention also includes a reflector and a deflection driving mechanism for driving the deflection of the reflector, so as to make the reflector perpendicular to the incident light beam through the deflection; Also included is a deflection angle detection mechanism for detecting the deflection angle of the reflector; The light beam emitted by the light source passes through the beam splitter, collimating lens, and wedge-shaped wedge in sequence. After passing through the wedge-shaped wedge, the light beam is incident on the reflector. The deflection drive mechanism can drive the deflection of the reflector to make the reflector perpendicular to the incident light beam. The light beam reflected by the reflector returns along the incident path, passes through the wedge-shaped wedge, collimating lens, and beam splitter in sequence, and forms a light spot on the CCD receiver. The position of the light spot is used to determine whether the reflector is perpendicular to the incident light beam. The circumferential rotation angle of the wedge-shaped wedge is obtained by the deflection angle of the reflector measured by the deflection angle detection mechanism. The deflection angle of the reflector is obtained by two laser interferometers. The direction of the light beam between the collimating lens and the wedge tip is the Z axis, and the Z axis is horizontal. An X axis and a Y axis are perpendicular to the Z axis, and the X axis is vertical and the Y axis is horizontal. When the reflector deflects, a laser interferometer detects the amount of the reflector's swing with the X-axis as the center of rotation and calculates the rotation angle. α Another laser interferometer detects the swing of the reflector with the Y axis as the rotation center and calculates the rotation angle β , pass α or β or α and β The value is combined with the top angle of the wedge wedge tip to calculate the circumferential rotation angle of the wedge wedge tip; The circumferential rotation angle range of the wedge-shaped wedge tip is 360°, which is divided into four equal areas; In the same area, when the incident light beam to the reflector is close to the X axis, β The value is combined with the top angle of the wedge wedge tip to calculate the circumferential rotation angle of the wedge wedge tip; When the incident light beam to the reflector is close to the Y axis, α The value is combined with the top angle of the wedge tip to calculate the circumferential rotation angle of the wedge tip.

2. The rotation angle detection system according to claim 1, characterized in that: The yaw angle detection mechanism is a laser interferometer or a yaw table capable of displaying the yaw angle.

3. A method for detecting the degree of rotation angle, comprising a light source, a beam splitter, a collimating lens, and a CCD receiver, characterized in that: Also included is a wedge-shaped wedge tip and reflector; The light beam emitted by the light source passes through the beam splitter, the collimating lens and the wedge-shaped wedge in sequence, and the light beam after passing through the wedge-shaped wedge is incident on the reflector; The wedge-shaped wedge tip can rotate circumferentially and change the direction of the light beam passing through the wedge-shaped wedge tip by rotation, and the reflector can be tilted and tilted to make the reflector perpendicular to the incident light beam. The light beam reflected by the reflector returns along the incident path, passes through the wedge tip, collimating lens and beam splitter in sequence, and forms a light spot on the CCD receiver. The position of the light spot can be used to determine whether the reflector is perpendicular to the incident beam; Obtaining the yaw angle of the reflector, and calculating the circumferential rotation angle of the wedge-shaped wedge through the yaw angle of the reflector and the top angle of the wedge-shaped wedge; The deflection angle of the reflector is obtained by two laser interferometers. The direction of the light beam between the collimating lens and the wedge tip is the Z axis, and the Z axis is horizontal. An X axis and a Y axis are perpendicular to the Z axis, and the X axis is vertical and the Y axis is horizontal. When the reflector deflects, a laser interferometer detects the amount of the reflector's swing with the X-axis as the center of rotation and calculates the rotation angle. α Another laser interferometer detects the swing of the reflector with the Y axis as the rotation center and calculates the rotation angle β , pass α or β or α and β The value is combined with the top angle of the wedge wedge tip to calculate the circumferential rotation angle of the wedge wedge tip; The circumferential rotation angle range of the wedge-shaped wedge tip is 360°, which is divided into four equal areas; In the same area, when the incident light beam to the reflector is close to the X axis, β The value is combined with the top angle of the wedge wedge tip to calculate the circumferential rotation angle of the wedge wedge tip; When the incident light beam to the reflector is close to the Y axis, α The value is combined with the top angle of the wedge tip to calculate the circumferential rotation angle of the wedge tip.

4. The application of the rotation angle detection system as claimed in claim 1, characterized in that: The part to be calibrated whose rotation angle needs to be detected is synchronously rotated and placed on the wedge tip. The light beam emitted by the light source passes through the beam splitter, collimating lens and wedge tip in sequence and then is incident on the reflector; The reflector is driven to deflect by a deflection driving mechanism so that the reflector is perpendicular to the incident light beam, and the deflection angle detection mechanism obtains the deflection angle of the reflector; The wedge-shaped wedge tip is driven by a rotating drive mechanism to rotate circumferentially for a certain angle and then stop. The direction of the light beam passing through the wedge-shaped wedge tip changes, and the calibration object rotates synchronously with the wedge-shaped wedge tip. The reflector is driven to deflect by the deflection driving mechanism again so that the reflector is perpendicular to the incident light beam, and the deflection angle detection mechanism obtains the deflection angle of the reflector; By obtaining the deflection angle of the reflector twice and combining it with the top angle of the wedge wedge, the change in the direction of the light beam before and after the wedge wedge is rotated can be calculated, and then the circumferential rotation angle of the wedge wedge can be obtained, which corresponds to the rotation angle of the part to be calibrated.

5. The application of the rotation angle detection system according to claim 4, characterized in that: The object to be calibrated is an angle sensor, which is synchronously rotated and sleeved on the wedge-shaped wedge tip; The angle sensor is calibrated by comparing the rotation angle reading of the angle sensor with the calculated circumferential rotation angle of the wedge tip.

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