A spatial rotation angle detection device and method

Abstract

The application relates to a spatial rotation angle detection device and method, and relates to the technical field of rotation angle detection. The device comprises a light source, a light wedge, a position sensitive element and a collimating lens. The light source is used for emitting a light beam; the light wedge is fixedly arranged on a rotation part to be detected and is used for reflecting and refracting the light beam; the position sensitive element is used for receiving position information of a light spot formed by the collimated light beam; and the collimating lens is arranged between the position sensitive element and the light wedge and is used for collimating the light beam emitted by the light source into parallel collimated light beams and converging the reflected and refracted light beams of the light wedge onto the position sensitive element. Due to the special layout of the light source and the position sensitive element, the device does not need to use a beam splitter or a plane mirror and other optical elements to change the propagation direction of the light beam, so compared with the known three-axis angle measuring device, the device has the advantages of compact structure and high integration, and can realize accurate measurement of spatial three-axis angles under narrow measurement conditions.

Description

Technical Field

[0001] This application relates to the field of rotation angle detection technology, and in particular to a spatial rotation angle detection device and method. Background Technology

[0002] Photoelectric angle measurement technology plays an important role in fields such as geological exploration, surveying, construction engineering, and aerospace. However, since changes in the roll angle of an object do not alter the tilt angle of the optical path and optical axis, current research on photoelectric angle measurement mainly focuses on single-axis and two-axis methods, with three-axis angle measurement technology being relatively uncommon. When measuring the three-axis angles of an object, two two-axis photoelectric autocollimators are typically used for intersection measurement, which has the disadvantages of requiring a large space and being difficult to calibrate.

[0003] In recent years, various solutions have been proposed for the problem of triaxial angle measurement of objects, among which the following are some typical examples: a triaxial angle measurement method combining moiré fringe technology with autocollimation measurement technology; a triaxial angle measurement device based on a combined target reflector; a laser autocollimation triaxial angle measurement method based on a transmission grating and a combined reflector; and a method for triaxial angle measurement using a collimated beam projection dot pattern. The standard error for roll angle measurement is 0.39″, but because this system does not use a reflector, the entire collimation unit must be mounted on the object being measured, which is difficult to achieve when the target size is small.

[0004] The above solutions all have high accuracy, but they all require the use of beam splitters or plane mirrors to change the direction of beam propagation to achieve the purpose of angle measurement. This results in the system being too large in the direction perpendicular to the optical axis, occupying a lot of space, having an insufficiently compact structure, and being unable to achieve high integration. In measurement environments with limited space, such as airborne optoelectronic pods where the space is small, it is difficult to complete the measurement task. Summary of the Invention

[0005] To reduce the space occupied by the measurement environment, this application provides a spatial rotation angle detection device and method.

[0006] Firstly, the spatial rotation angle detection device provided in this application adopts the following technical solution:

[0007] A spatial rotation angle detection device, comprising:

[0008] A light source, used to emit light beams;

[0009] An optical wedge, fixedly mounted on the rotating component under test, is used to reflect and refract the collimated beam.

[0010] A position-sensitive element is used to receive position information of the spot formed by the collimated beam; and

[0011] A self-collimating lens is placed between the position-sensitive element and the optical wedge to collimate the light beam emitted by the light source into a parallel collimated beam and to converge the light beam reflected and refracted by the optical wedge onto the position-sensitive element.

[0012] The position-sensitive element and the light source are both located on the focal plane of the autocollimating lens.

[0013] A further technical solution is that the light source is a laser light source.

[0014] A further technical solution is that the position-sensitive element includes a first position-sensitive detector and a second position-sensitive detector, which are arranged symmetrically with the light source as the center.

[0015] A further technical solution is that the light wedge is a double-sided reflective light wedge, the front surface of the light wedge is coated with a partial reflective film, and the rear surface of the light wedge is coated with a total reflective film; the front surface of the light wedge is the end face of the light wedge facing the light source.

[0016] A further technical solution is that the partially reflective film has the properties of 35% to 41% light reflection and 59% to 65% light transmission.

[0017] A further technical solution is that the position-sensitive element is circular or rectangular, and the area of ​​the light spot formed by the collimated beam is less than one-twentieth of the photosensitive area of ​​the position-sensitive element.

[0018] A further technical solution is that the line connecting the center point of the first position-sensitive detector and the center point of the second position-sensitive detector is parallel to the plane determined by the normal of the front end face and the normal of the rear end face of the optical wedge.

[0019] Secondly, the spatial rotation angle detection method provided in this application adopts the following technical solution:

[0020] A method for detecting spatial rotation angles, applied to any of the spatial rotation angle detection devices described in the first aspect, characterized in that the method comprises:

[0021] List the vector coordinates of the emitted light rays in the initial state of the optical wedge in spatial coordinates; the emitted light rays include the light rays reflected from the optical wedge and the light rays refracted from the optical wedge;

[0022] List the vector coordinates of the emitted ray segment after the optical wedge is rotated by angles a, β, and γ in spatial coordinates; where a, β, and γ are the angles of rotation of the optical wedge along the OX, OY, and OZ axes in spatial coordinates, respectively.

[0023] Based on the vector coordinates of the emitted light segment of the optical wedge in its initial state, the vector coordinates of the emitted light segment after the optical wedge is rotated, and the properties of the autocollimating lens, an expression is derived for the change in the light spot value of the emitted light on the position-sensitive element.

[0024] Based on the expression for the change in light spot value, solve the simultaneous equations for a, β, and γ to obtain the rotation angles of the light wedge in three directions in space.

[0025] A further technical solution involves listing the vector coordinates of the emitted ray segment after the light wedge has been rotated by angles a, β, and γ in spatial coordinates, specifically including:

[0026] Based on the incident beam vector, rotation matrix, and reflection matrix of the front surface of the optical wedge, list the vector coordinates of the beam reflected from the front surface of the optical wedge;

[0027] Based on the refractive index of the optical wedge and Snell's law, list the vector coordinates of the light beam refracted into the front surface of the optical wedge;

[0028] Based on the vector coordinates of the light beam refracted into the front surface of the optical wedge, the reflection matrix and rotation matrix of the rear surface of the optical wedge, list the vector coordinates of the light beam reflected into the rear surface of the optical wedge.

[0029] Based on the vector coordinates of the beam reflected from the rear surface of the optical wedge, the refractive index of the optical wedge, and Snell's law, list the vector coordinates of the beam refracted from the front surface of the optical wedge.

[0030] The vector coordinates of the light beam reflected from the front surface of the optical wedge and the vector coordinates of the light beam refracted from the front surface of the optical wedge are the vector coordinates of the emitted light beam segment after the optical wedge is rotated by angles a, β, and γ in spatial coordinates.

[0031] A further technical solution is that the properties of the autocollimating lens include the focal length of the autocollimating lens.

[0032] In summary, this application includes at least one of the following beneficial technical effects:

[0033] This application employs an optical wedge placed on the component under test. Two position-sensitive elements and the light source are arranged in a confocal configuration, allowing the light beam emitted from the light source to be refracted and reflected by the optical wedge, ultimately falling onto the position-sensitive elements to form a light spot. The change in the light spot's position on the sensitive elements is collected to analyze the rotation angle between the optical wedge and the component under test. Due to this unique arrangement of the light source and position-sensitive elements, combined with the optical wedge to detect the component's rotation angle, this system eliminates the need for optical elements such as beam splitters or plane mirrors to change the beam's propagation direction. Therefore, compared to currently known triaxial angle measuring devices, this device has the advantages of compact structure and high integration. Furthermore, because the two light spots are symmetrically distributed around the light source and are relatively close together, satisfying the conditions for using position-sensitive elements as detectors, this device can achieve spatial triaxial angle measurement under confined measurement conditions. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the measurement principle of an embodiment of this application;

[0035] Figure 2 This is a schematic diagram illustrating the changes in light according to an embodiment of this application;

[0036] Figure 3 This is a schematic diagram showing the position of the light spot on the two position-sensitive elements of the optical wedge in its initial state.

[0037] Figure 4 This is a schematic diagram showing the positional change of the corresponding spot of the L2 beam on the position-sensitive element after the optical wedge rotates;

[0038] Figure 5 This is a schematic diagram showing the positional change of the corresponding spot of the L6 beam on the position-sensitive element after the optical wedge rotates.

[0039] Reference numerals: 1. First position sensitive detector; 2. Second position sensitive detector; 3. Light source; 4. Autocollimating lens; 5. Optical wedge. Detailed Implementation

[0040] The technical solutions in this application will be further described in detail below with reference to the accompanying drawings.

[0041] This application discloses a spatial rotation angle detection device. The device includes a self-collimation measurement unit and an optical wedge 5. The self-collimation measurement unit includes a light source 3, a position-sensitive element, and a self-collimation lens 4.

[0042] The light source 3 is a laser light source 3, used to emit a light beam toward the optical wedge 5; the optical wedge 5 is fixedly mounted on the rotating component under test, used to reflect and refract the light beam; the position-sensitive element is used to receive the position information of the light spot formed by the collimated light beam; the autocollimating lens 4 is disposed between the position-sensitive element and the optical wedge 5, used to collimate the light beam emitted by the light source 3 into a parallel collimated beam, and to converge the light beam reflected and refracted by the optical wedge onto the position-sensitive element. Both the position-sensitive element and the light source 3 are located on the focal plane of the autocollimating lens 4.

[0043] Specifically, the position-sensitive element is a PSD position sensor, which is an optical detector capable of measuring the continuous position of a light spot on the detector surface. The PSD position sensor, also known as a coordinate photocell, is a non-segmented device that converts the position of a light spot on the photosensitive surface into an electrical signal. Two position-sensitive elements are provided: a first position-sensitive detector 1 and a second position-sensitive detector 2. The first and second position-sensitive detectors 1 and 2 are arranged symmetrically around the light source 3, meaning they are respectively located on opposite sides of the light source 3, and are used to detect the position of the light spot formed by the light beam reflected and refracted from the light wedge 5.

[0044] The optical wedge 5 is a double-sided reflective optical wedge 5. The front surface of the optical wedge 5 is coated with a partial reflective film, and the rear surface is coated with a total reflective film. The front surface of the optical wedge 5 is the end face of the optical wedge 5 facing the light source 3. More specifically, the partial reflective film has a light reflection rate of 35%–41% and a light transmission rate of 59%–65%, which makes the light spot energy on the first position-sensitive detector 1 and the second position-sensitive detector 2 tend to be consistent. When the partial reflective film has a light reflection rate of 38% and a light transmission rate of 62%, the light spot energy on the first position-sensitive detector 1 and the second position-sensitive detector 2 is closest, thus achieving high accuracy in acquiring the light spot position using the position-sensitive element.

[0045] The position-sensitive element is circular or rectangular, used to capture the light beam reflected and refracted by the light wedge 5 as much as possible, and to reduce the phenomenon of the light beam leaving the position-sensitive element. The area of ​​the light spot formed by the collimated light beam is less than one-twentieth of the photosensitive area of ​​the position-sensitive element, so that when the light wedge 5 rotates within a certain range, the first position-sensitive detector 1 and the second position-sensitive detector 2 can capture the position of the light spot of the reflected and refracted light beams.

[0046] In its initial state, the line connecting the center point of the first position-sensitive detector 1 and the center point of the second position-sensitive detector 2 is parallel to the plane defined by the normal to the front face and the normal to the rear face of the optical wedge. This ensures that the light spot formed by the light beam reflected and refracted from the optical wedge 5 accurately falls on the first position-sensitive detector 1 and the second position-sensitive detector 2.

[0047] In this embodiment, the double-sided reflective wedge 5 has a diameter of 13mm, a thickness of 7mm, a wedge angle of 11.86 degrees, and is made of BK7 (borosilicate crown glass). The refractive index of BK7 is 1.5168. The front surface is coated with a 38% reflective and 62% transmissive film, and the rear surface is coated with a total reflective film.

[0048] The first position sensitive detector 1 and the second position sensitive detector 2 are both S5991 type two-dimensional detectors with a maximum image plane of 9mm×9mm. They are set at the focal plane of the autocollimating lens. A 4mm gap is reserved between the first position sensitive detector 1 and the second position sensitive detector 2 for placing the light source 3.

[0049] Light source 3 is a 940nm wavelength laser light source 3, located between two position-sensitive detectors; the diameter of the collimated beam emitted by light source 3 after being collimated by the self-collimating lens is less than 4mm.

[0050] The autocollimating lens 4 consists of three elements, which are combined to form a collimating lens. Each autocollimating lens 4 has a diameter of 26mm, a focal length of 30mm, an effective receiving field of view of 40°, and an outgoing light parallelism better than 0.1°.

[0051] The light source 3, two position-sensitive elements and a collimating lens are installed in a housing, the dimensions of which (length*width*height) are 50*50*53mm.

[0052] The implementation principle of this application embodiment is as follows:

[0053] Before measurement, the autocollimating measurement unit is first fixed inside a housing or on a base, and the optical wedge 5 is fixed on the rotating component to be measured. In this embodiment, the distance between the base and the rotating component to be measured is 67mm. Then, the autocollimating measurement unit is aligned with the center of the optical wedge 5. After the position is adjusted, the autocollimating measurement unit is powered on, causing the light source 3 to emit a light beam. After passing through the autocollimating lens 4, the collimated light beam is emitted. When the light beam illuminates the front surface of the optical wedge 5, a portion of the beam is directly reflected. Figure 1 The optical path L1-L2-L3 shown in the diagram is focused onto the second position-sensitive detector 2; the remaining portion is refracted into the interior of the optical wedge 5, reflected off the rear surface of the optical wedge 5, and refracted out from the front surface of the optical wedge 5, following the sequence... Figure 1 The optical path L1-L4-L5-L6-L7 shown is focused onto the first position-sensitive detector 1. By calculating the position information of the two light spots, the angle information of the rotating component under test can be calculated even in a confined measurement environment.

[0054] This application is compared with existing testing equipment:

[0055] Existing device 1: Existing technology 1 provides a triaxial angle measurement method that uses the basic internal structure of a conventional autocollimator and replaces the plane mirror with a non-standard corner cube prism. A comparison of the dimensions of this structure with the structure in this application is shown in Table 1.

[0056] Table 1 compares the parameters with those of existing equipment 1.

[0057]

[0058] The existing device 1 is too large in size, and the large-area CMOS camera used in the spot detector in the existing device 1 is no longer suitable for some usage environments that require high data update frequency (such as providing feedback signals for line-of-sight stabilization servo control).

[0059] Existing device 2: Existing device 2 provides a triaxial angle measuring device based on a combined target reflector. The structural dimensions of this device are compared with those in this application in Table 2.

[0060] Table 2 compares the parameters with those of existing equipment 2.

[0061]

[0062]

[0063] The existing device 2 also includes a light source, seven reflective elements, five collimating elements, two beam splitting elements, and two position detection elements. The measurement range of this device is ±0.055°.

[0064] Existing device 3: Existing device 3 proposes a laser autocollimation triaxial angle measurement method based on a transmission grating and a combined reflector. The device used in this method is at least 200mm long and includes 3 PSDs, 1 beam splitter prism, 3 collimating lenses and 1 combined reflector. The size and structure are relatively large. During measurement, two biaxial photoelectric autocollimators need to be used for intersection measurement, which requires a large space and requires the calculation of three optical paths, making the calculation principle complex.

[0065] Existing Equipment 4: Existing Equipment 4 proposes a triaxial angle measurement method that combines moiré fringe technology with autocollimation measurement technology. This method requires three beam splitters in the axial direction to change the propagation direction of light, resulting in a larger axial dimension, approximately 200 mm. The measurement range of this method is ±0.27°, with a measurement error of 5″. Moreover, this method requires the use of filters, apertures, and light sources of different colors, which also results in a complex optical path during the calculation.

[0066] Compared to existing devices, in this application, the two light spots are symmetrically distributed around the light source, and their positions remain at a certain distance as the optical wedge rotates. This satisfies the requirements for using a PSD as an image detector. Compared to large-area CMOS cameras, PSDs offer higher sampling speeds and simpler post-processing. The PSD used in this application has a sampling frequency of up to 1kHz, far exceeding the sampling frequency of large-area CMOS cameras (which typically have sampling frequencies below 100Hz), making it suitable for a wider range of environments. This application uses an optical wedge as a reflector, allowing the light source and the two PSDs to be arranged on the same focal plane. Therefore, it is unnecessary to position the light source perpendicular to the optical axis, and a beam splitter is not required, resulting in a compact structure, smaller size, and higher integration.

[0067] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0068] This application also discloses a spatial rotation angle detection method, which is applied to the spatial rotation angle detection device described above. It mainly analyzes the vector coordinates of each beam path in the initial state of the optical wedge 5 and the vector expressions of each beam after the optical wedge 5 is rotated, and then calculates the rotation angle of the component to be detected.

[0069] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0070] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0071] This invention provides a method for detecting spatial rotation angles, the main process of which is described below.

[0072] For ease of description, the travel path of the light beam in this embodiment is represented by L1 to L7, as follows: Figure 1 As shown:

[0073] Step S1: List the vector coordinates of the emitted light rays after the optical wedge 5 is rotated by angles a, β, and γ in spatial coordinates; the emitted light rays include the light rays reflected from the optical wedge 5 and the light rays refracted from the optical wedge 5.

[0074] Where a, β, and γ represent the angles of rotation of the optical wedge 5 along the OX, OY, and OZ axes in spatial coordinates, respectively. Listing the vector coordinates of the emitted ray segment after rotating the optical wedge 5 by angles a, β, and γ in spatial coordinates includes the following steps:

[0075] Step S11: Based on the incident beam vector coordinates, rotation matrix, and reflection matrix of the front surface of the light wedge 5, list the vector coordinates of the beam reflected from the front surface of the light wedge 5.

[0076] Among them, the incident beam vector coordinates are the vector coordinates of the beam path L1; the vector coordinates of the beam reflected from the front surface of the optical wedge 5 are the vector coordinates of the beam path L2.

[0077] The vector coordinates A2 of the beam path L2 can be expressed as:

[0078] A2 = M r ·M1·M r T ·A1 (1)

[0079] In equation (1), A1 is the coordinate of the incident light vector, specifically A1 = [0 -1 0]. T M r The rotation matrix is ​​as follows:

[0080]

[0081] In equation (2), a, β, and γ are the angles at which the optical wedge 5 rotates along the OX, OY, and OZ axes in the spatial coordinate system, respectively.

[0082] M1 is the reflection matrix of the front surface of the optical wedge 5, specifically:

[0083]

[0084] In equation (3), d is the angle between the front surface of the optical wedge 5 and the XOZ plane in spatial coordinates.

[0085] Substituting the incident light vector coordinates A1 and equations (2) and (3) into equation (1), we can obtain the vector coordinates A2 of the beam L2 reflected from the front surface of the light wedge 5 as follows:

[0086]

[0087] Step S12: Based on the refractive index of the optical wedge 5 and Snell's law, list the vector coordinates of the light beam refracted into the front surface of the optical wedge 5.

[0088] Among them, the vector coordinates of the light beam refracted into the front surface of the optical wedge 5 are the vector coordinates A4 of the beam path L4, which can be expressed as:

[0089]

[0090] In equation (5), n1 and n2 are the refractive indices of air and the optical wedge 5, respectively, and N1′ is the normal vector of the front surface of the optical wedge 5 after rotation, specifically:

[0091]

[0092] Step S13: Based on the vector coordinates of the beam refracted into the front surface of the optical wedge 5, the reflection matrix and rotation matrix of the rear surface of the optical wedge 5, list the vector coordinates of the beam reflected into the rear surface of the optical wedge 5.

[0093] Among them, the vector coordinates of the beam reflected from the rear surface of the optical wedge 5 are the vector coordinates A5 of the beam path L5, which can be expressed as:

[0094] A5 = M r ·M2·M r T ·A4 (7)

[0095] In equation (7), M2 is the reflection matrix of the rear surface of the optical wedge 5, specifically:

[0096]

[0097] Step S14: Based on the vector coordinates of the beam reflected from the rear surface of the optical wedge 5, the refractive index of the optical wedge 5, and Snell's law, list the vector coordinates of the beam refracted from the front surface of the optical wedge 5.

[0098] Among them, the vector coordinates of the beam refracted from the front surface of the optical wedge 5 are the vector coordinates A6 of the beam path L6, which can be expressed as:

[0099]

[0100] In equation (9), N2' is the normal vector of the front surface of the optical wedge 5 after rotation, specifically:

[0101]

[0102] The vector coordinates of the light beam reflected from the front surface of the light wedge 5 and the vector coordinates of the light beam refracted from the front surface of the light wedge 5 in steps S11 and S14 are the vector coordinates of the emitted light beam segment after the light wedge 5 is rotated by angles a, β, and γ in spatial coordinates as described in step S1.

[0103] Step S2: List the vector coordinates of the emitted light rays in the initial state of the light wedge 5 in spatial coordinates.

[0104] The light reflected from the optical wedge 5 is... Figure 1 In the L2 beam segment, the light refracted from the optical wedge 5 is... Figure 1 The L6 beam segment. The vector coordinates A2' of beam L2 are:

[0105]

[0106] In the formula, A2' is the vector coordinate of beam L2; M1 is the reflection matrix of the front surface of the light wedge 5, which is Equation (3); A1 is the incident light vector coordinate, specifically A1 = [0 -1 0]. T d is the angle between the front surface of the optical wedge 5 and the XOZ plane in spatial coordinates.

[0107] The vector coordinates of beam L6 can be derived by referring to steps S11 to S14. The vector coordinates A6' of beam L6 are specifically represented by the following formula:

[0108]

[0109] In the formula, A6' is the vector coordinate of beam L6; n1 is the refractive index of air; n2 is the refractive index of the material of optical wedge 5; A5' is the vector coordinate of beam L5; N2 is the front surface normal vector of optical wedge 5 in the initial state, specifically:

[0110]

[0111] During the actual detection process, the initial positions of the light spots corresponding to beams L2 and L6 on the first position-sensitive detector 1 and the first position-sensitive detector 2, respectively, are as follows: Figure 3 As shown.

[0112] Step S3: Based on the vector coordinates of the emitted light segment of the optical wedge 5 in the initial state, the vector coordinates of the emitted light segment after the optical wedge 5 is rotated, and the properties of the autocollimating lens 4, list the expression for the change value of the light spot on the position-sensitive element of the emitted light.

[0113] Among them, the properties of the autocollimating lens 4 include its focal length. Please refer to... Figure 2 Taking beam L2 as an example, the vectors of beam L2 in the initial state are x2', y2', and z2'. After L2 rotates, its vector coordinates change to x2, y2, and z2. Beam L2 is imaged on the image plane of the first position sensitive detector 1. Figure 2 In the ZOY plane of spatial coordinates, the angle between the beam L2 and the y-axis changes, and the distance between the beam L2's spot and the origin in the OZ direction also changes. Therefore, we can conclude that:

[0114] tana=z / f (14)

[0115] In the formula, f is the focal length of the autocollimating lens 4.

[0116] From equation (14), we can see that:

[0117] In the initial state, the position of the light spot on the position-sensitive element of beam L2 is:

[0118] After beam L2 rotates and moves, the position of the light spot on the position-sensitive element is:

[0119] Therefore, the change in the z-direction of the light spot corresponding to beam L2 on the first position sensitive detector 1 is:

[0120]

[0121] Similarly, the change in the x-direction of the light spot corresponding to beam L2 on the first position sensitive detector 1 is:

[0122]

[0123] In the actual detection process, the changes in the light spot corresponding to beam L2 on the first position sensitive detector 1 are as follows: Figure 4 As shown.

[0124] From equation (14), we can see that:

[0125] The changes in the z and x directions of the light spot corresponding to beam L6 on the second position sensitive detector 2 are as follows:

[0126]

[0127]

[0128] During the actual detection process, the changes in the light spot corresponding to beam L6 on the second position sensitive detector 2 are as follows: ΔZ6 and ΔX6 Figure 5 As shown.

[0129] Step S4: Solve the equations simultaneously based on the expression for the change in light spot value to obtain the rotation angles of the light wedge 5 in three directions in space.

[0130] Among them, the expression for the change value of the light spot is Equation (15) to Equation (18). Substitute the original state vector coordinates of the emitted light obtained in step S1 and step S2 and the vector coordinates after rotation and movement into Equation (15) to Equation (18), solve the equations simultaneously, and obtain the values ​​of a, β, and γ, that is, obtain the rotation angle of the component under test in space.

[0131] The above-described embodiments are merely one implementation of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. A method for detecting spatial rotation angles, applied to a spatial rotation angle detection device, the spatial rotation angle detection device comprising: A light source, used to emit light beams; An optical wedge, fixedly mounted on the rotating component under test, is used to reflect and refract the collimated beam. A position-sensitive element used to detect the position information of the spot formed by the collimated beam; A self-collimating lens is disposed between the position-sensitive element and the optical wedge to collimate the light beam emitted by the light source into a parallel collimated beam and to converge the light beams reflected and refracted by the optical wedge onto the position-sensitive element; wherein, both the position-sensitive element and the light source are disposed on the focal plane of the self-collimating lens; the optical wedge is a double-sided reflective optical wedge, the front surface of the optical wedge is coated with a partial reflective film, and the rear surface of the optical wedge is coated with a total reflective film; the front surface of the optical wedge is the end face of the optical wedge facing the light source; characterized in that the method includes: List the vector coordinates of the emitted light rays in the initial state of the optical wedge in spatial coordinates; the emitted light rays include the light rays reflected from the optical wedge and the light rays refracted from the optical wedge; List the rotation of the light wedge in spatial coordinates , , The vector coordinates of the emitted ray segment after the angle; the , , These represent the angles by which the optical wedge rotates along the OX, OY, and OZ axes in spatial coordinates; Based on the vector coordinates of the emitted light segment of the optical wedge in its initial state, the vector coordinates of the emitted light segment after the optical wedge is rotated, and the properties of the autocollimating lens, an expression is derived for the change in the light spot value of the emitted light on the position-sensitive element. Solve the simultaneous equations based on the expression for the change in light spot value. , , The rotation angles of the light wedge in three directions in space were obtained.

2. The spatial rotation angle detection method according to claim 1, characterized in that: The listed optical wedges rotate in spatial coordinates. , , The vector coordinates of the emitted ray segment after the angle, specifically including: Based on the incident beam vector coordinates, rotation matrix, and reflection matrix of the front surface of the optical wedge, list the vector coordinates of the beam reflected from the front surface of the optical wedge; Based on the refractive index of the optical wedge and Snell's law, list the vector coordinates of the light beam refracted into the front surface of the optical wedge; Based on the vector coordinates of the light beam refracted into the front surface of the optical wedge, the reflection matrix and rotation matrix of the rear surface of the optical wedge, list the vector coordinates of the light beam reflected into the rear surface of the optical wedge. Based on the vector coordinates of the beam reflected from the rear surface of the optical wedge, the refractive index of the optical wedge, and Snell's law, list the vector coordinates of the beam refracted from the front surface of the optical wedge. The vector coordinates of the light beam reflected from the front surface of the optical wedge and the vector coordinates of the light beam refracted from the front surface of the optical wedge represent the rotation of the optical wedge in spatial coordinates. , , The vector coordinates of the emitted ray segment after the angle.

3. The spatial rotation angle detection method according to claim 1, characterized in that: The properties of the autocollimating lens include its focal length.

4. A spatial rotation angle detection device, used to execute the spatial rotation angle detection method according to any one of claims 1 to 3, characterized in that: The spatial rotation angle detection device includes: A light source, used to emit light beams; An optical wedge, fixedly mounted on the rotating component under test, is used to reflect and refract the collimated beam. Position-sensitive elements are used to detect the position information of the spot formed by the collimated beam; and A self-collimating lens is placed between the position-sensitive element and the optical wedge to collimate the light beam emitted by the light source into a parallel collimated beam and to converge the light beam reflected and refracted by the optical wedge onto the position-sensitive element. The position-sensitive element and the light source are both located on the focal plane of the autocollimating lens.

5. The spatial rotation angle detection device according to claim 4, characterized in that: The light source is a laser light source.

6. The spatial rotation angle detection device according to claim 4, characterized in that: The position-sensitive element includes a first position-sensitive detector and a second position-sensitive detector, which are arranged symmetrically with the light source as the center.

7. The spatial rotation angle detection device according to claim 4, characterized in that: The light wedge is a double-sided reflective light wedge, with a partial reflective film coated on the front surface and a total reflective film coated on the rear surface; the front surface of the light wedge is the end face of the light wedge facing the light source.

8. The spatial rotation angle detection device according to claim 7, characterized in that: The partially reflective film has the properties of 35%~41% light reflection and 59%~65% light transmission.

9. A spatial rotation angle detection device according to claim 6, characterized in that: The position-sensitive element is circular or rectangular, and the area of ​​the light spot formed by the collimated beam is less than one-twentieth of the photosensitive area of ​​the position-sensitive element.

10. A spatial rotation angle detection device according to claim 6, characterized in that: The line connecting the center point of the first position-sensitive detector and the center point of the second position-sensitive detector is parallel to the plane defined by the normal to the front end face and the normal to the rear end face of the optical wedge.

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