A design method for an opening and closing light guide arm joint

Abstract

The present invention discloses a design method for an open-and-close light guide arm joint, which first constructs a basic structure of the light guide arm joint, then establishes an equivalent two-dimensional plane theoretical analysis model, gives initial structural parameters, performs parameter design of a special structure, and finally uses a three-dimensional model of the light guide arm joint to analyze the laser transmission pointing error of the open-and-close light guide arm joint. The present invention is directed to a design method for an open-and-close light guide arm joint, and after completing the design of structural parameters, analyzes the pointing error of the open-and-close light guide arm joint in combination with specific structural parameters and the system internal error of the joint, thereby realizing a systematic design of the open-and-close light guide arm joint including structural design and error analysis.

Description

Technical Field

[0001] The invention belongs to the field of laser transmission, and in particular relates to a design method for an open-and-close light guide arm joint. Background Art

[0002] As an important light reflection and transmission device, the light guide device is widely used in ultra-high power laser devices. The use of a reflective light guide device can prevent the laser from producing nonlinear optical effects when passing through transmissive optical elements, thereby preventing the high-power laser from producing frequency migration and causing damage to the optical elements. The robotic arm-like light guide structure can achieve the requirement of freely changing the working posture within a specific spatial range without changing the length of each section of the optical channel. The laser only needs to be transmitted along the optical channel to achieve changes in the emission position and angle within a specific space.

[0003] The opening and closing light guide arm joint is one of the mechanical light guide structures. The opening and closing light guide arm joint can realize the change of laser transmission direction within a specific spatial range during the transmission of the laser along the optical channel. It can effectively utilize the length of the optical pipeline through the industrial robotic arm type, and can realize the lightweight design of the device. The layout and control technology are relatively mature, which is convenient for designing adjustable functions for different specific spaces.

[0004] The pointing accuracy of the open-and-close light guide arm joint has an important impact on the laser transmission system. If the pointing error of the open-and-close light guide arm joint cannot be effectively controlled, the pointing error will gradually accumulate after transmission through multiple joints, causing the laser beam transmission direction to deviate from the direction of the light guide arm, causing part or even all of the laser beam to irradiate the side wall of the light guide arm, causing the beam energy to be lost and stray light to be generated, reducing the beam quality, and even causing the beam to be unable to be emitted, the side wall of the light guide arm to be damaged, and the laser leakage to cause safety accidents. Therefore, in the design process of the open-and-close light guide arm joint, the pointing error analysis is very important. However, there is currently a lack of systematic design methods for the open-and-close light guide arm joint, especially design methods that include joint pointing error analysis. Summary of the invention

[0005] In view of this, in order to overcome the defect of the existing laser transmission device that lacks a systematic design method, the present invention proposes a systematic design method including joint pointing error analysis.

[0006] To achieve this purpose, the present invention adopts the following technical solution: a method for designing an openable and closable light guide arm joint, the method comprising:

[0007] S1: Given the basic structure of the opening and closing light guide arm joint, establish its equivalent two-dimensional plane theoretical analysis model;

[0008] S2: Determine the opening and closing angle α between the light guide arms and the structural parameters of the light guide arms according to the actual laser system to be embedded in the opening and closing light guide arm joints;

[0009] S3: According to the given α and the structural parameters of the light guide arm, the design parameters of each component of the light guide arm joint are determined in turn, and a three-dimensional model of the open-and-close light guide arm joint is established according to each parameter;

[0010] S4: Calculate the laser transmission pointing error of the open-and-close light guide arm joint according to the three-dimensional model of the open-and-close light guide arm joint;

[0011] S5: Complete the design of the opening and closing light guide arm joint.

[0012] Preferably, the basic structure of the opening and closing light guide arm joint in S1 includes: an incident light guide arm, an exit light guide arm and a reflector platform; the incident light guide arm and the exit light guide arm are connected by a hinge axis; the reflector platform includes a reflector fixing platform and a guide rod distributed in a "T" shape, a slide groove is provided on the guide rod, the reflector platform is movably connected to the hinge axis through the slide groove, and the intersection of the optical axes of the incident light guide arm and the exit light guide arm is located at the center of the radiation mirror, and the reflector is installed on the reflector fixing platform.

[0013] Preferably, the structural parameters of the light guide arm in S2 include: the aperture of the light guide arm and the length of the light guide arm.

[0014] Preferably, the parameters of each component in S3 include but are not limited to the cutout structure parameters of the incident light guide arm and the output light guide arm designed to avoid interference between components, the positioning parameters of the reflector platform and the guide rod slot parameters.

[0015] Preferably, the error analysis in S4 includes:

[0016] S41: establishing a global coordinate system of the light guide arm joint and a local coordinate system of each component;

[0017] S42: determining the structural error and assembly error that affect the laser transmission pointing;

[0018] S43: Calculating the transformation matrix between the global coordinate system and each local coordinate system under the premise that each structural error and assembly error exists;

[0019] S44: using the transformation matrix, solving the plane equation of the reflector surface, the straight line equation of the central axis of the incident light guide arm and the central axis of the exit light guide arm in the global coordinate system;

[0020] S45: by using the law of reflection, calculate the linear equation of the optical axis of the outgoing light beam in the global coordinate system after the incident light beam whose optical axis coincides with the central axis of the incident light guide arm is reflected by the reflective mirror;

[0021] S46: The pointing error of the laser transmission of the light guide arm joint is obtained by using the straight line equation of the central axis of the output light guide arm solved in S44 and the straight line equation of the optical axis of the output light beam in the global coordinate system solved in S45.

[0022] Preferably, the global coordinate system in S41 is: a hinge axis coordinate system W, wherein the coordinate system W takes the center position of the hinge axis as the origin O, the central axis of the incident light guide arm as the X axis, and the axis direction of the hinge axis as the Y axis;

[0023] The local coordinate system includes:

[0024] ① Incident light guide arm coordinate system A, coordinate system A origin O A Located on the central axis of the incident light guide arm, and the origin is set to O A The distance from the origin O is projected onto the central axis of the incident light guide arm as x. The X A The axis is set along the central axis of the incident light guide arm, and its positive direction points away from the hinge axis. A The axis is along the axis of the hinge shaft sleeve of the incident light guide arm and is in the same direction as the Y axis;

[0025] ②Outgoing light guide arm coordinate system B, origin of coordinate system B O B Located on the central axis of the output light guide arm, and the origin is set to O B The distance from the origin O is projected onto the central axis of the light guide arm as x. The X B The axis is along the central axis of the output light guide arm, and its positive direction points away from the hinge axis. B The axis is along the axis of the hinge shaft sleeve of the output light guide arm and is in the same direction as the Y axis;

[0026] ③Mirror platform coordinate system C, origin of coordinate system C O C Located on the reflector mounting platform, and set the origin O C The distance from the origin O is y, and the Z of the coordinate system C is C The axis is along the guide rod direction, and its positive direction points away from the hinge axis. C The axis is parallel to the guide rail plane and Z C The axis is vertical and in the same direction as the Y axis;

[0027] ④Reflector coordinate system D, origin of coordinate system D O D Located on the mirror surface, and the origin O D With the origin O C The distance between them is the thickness d of the reflector, and the Z D The axis is the normal direction of the mirror, Y D The axis is on the mirror plane and is in the same plane as the Yc axis of the coordinate system C. Its direction is the same as the Y axis, and Y D Axis perpendicular to ZD axis.

[0028] Preferably, the structural errors in step S42 include: the cylindricity of the hinge shaft, the manufacturing error of the reflector platform and the manufacturing error of the reflector; the assembly errors include: the rotational clearance between the light guide arm and the hinge shaft, the rotational clearance between the guide rod of the reflector platform and the hinge shaft, the free clearance between the two light guide arms and the guide rod on the reflective platform along the axis of the hinge shaft, and the assembly error of the reflector and the reflector platform.

[0029] Preferably, the calculation process of the transformation matrix in step S43 is as follows:

[0030] S431: Determine the rotation and translation between each local coordinate system and the global coordinate system

[0031] Assume that the Euler angles between the local coordinate systems A, B, C and the global coordinate system W are The position offset is (x PW ,y PW ,z PW ), where P in the subscript PW can be replaced by A, B, or C accordingly; let the Euler angle between the local coordinate system D and the local coordinate system C be The position offset is (x DC ,y DC ,z DC ),in:

[0032]

[0033] ψ AW =Δψ AW

[0034] θ AW =Δθ AW

[0035] x AW =x+Δx AW

[0036] y AW =Δy AW

[0037] z AW =l+Δz AW

[0038]

[0039] ψ BW =Δψ BW

[0040] θ BW =α+Δθ BW

[0041] x BW =lsinα+xcosα+Δx BW

[0042] y BW =Δy BW

[0043] z BW =lcosα+xsinα+Δz BW

[0044]

[0045] ψ CW =Dψ CW +D'ψ CW

[0046] i CW =α / 2+Δθ CW +D'θ CW

[0047] x CW =ycos(α / 2)+Δx CW +D'x CW

[0048] y CW =Δy CW +D'y CW

[0049] z CW =ysin(α / 2)+Δz CW +Δ'z CW

[0050]

[0051]

[0052] i DC =Δθ DC +D'θ DC

[0053] x DC =Δx DC +D'x DC

[0054] y DC =Δy DC +D'y DC

[0055] z DC =d+Δz DC +Δ'z DC

[0056] in: Δψ AW ,Δθ AW They represent the rotation angle, precession angle and tension angle between the local coordinate system A and the global coordinate system W caused by the assembly error. ψ AW ,θ AW angular error; l is the inner radius of the light guide arm, Δx AW ,Δy AW ,Δz AW are the position offset x between the local coordinate system A and the global coordinate system W caused by the assembly error. PW ,y PW ,z PW Position error; Δψ BW ,Δθ BW They represent the rotation angle, precession angle and tension angle between the local coordinate system B and the global coordinate system W caused by the assembly error. ψ BW ,θ BW Angle error; Δx BW ,Δy BW ,Δz BW are the position offset x between the local coordinate system B and the global coordinate system W caused by the assembly error PW ,y PW ,z PW α is the opening and closing angle between the incident light guide arm and the exit light guide arm; Δψ CW ,Δθ CW They represent the rotation angle, precession angle, and stretch angle between the local coordinate system C and the global coordinate system W caused by the assembly error. ψ CW ,θ CW Angle error; Δx CW ,Δy CW ,Δz CW are the position offset x between the local coordinate system C and the global coordinate system W caused by the assembly error. CW ,y CW ,z CW Position error; Δ'ψ CW ,Δ'θ CW are the rotation angle, precession angle and tension angle between the local coordinate system C and the global coordinate system W caused by the structural error. ψ CW ,θ CW Angle error; Δ'x CW ,Δ'y CW ,Δ'z CWare the position offset x between the local coordinate system C and the global coordinate system W caused by the structural error. CW ,y CW ,z CW Position error; Δψ DC ,Δθ DC is the rotation angle, precession angle and tension angle between the local coordinate system D and the local coordinate system C caused by the assembly error ψ DC ,θ DC Angle error; Δx DC ,Δy DC ,Δz DC are the position offset x between the local coordinate system D and the local coordinate system C caused by the assembly error DC ,y DC ,z DC Position error; Δ'ψ DC ,Δ'θ DC are the rotation angle, precession angle and tension angle between the local coordinate system D and the local coordinate system C caused by the structural error ψ DC ,θ DC Angle error; Δ'x DC ,Δ'y DC ,Δ'z DC are the position offset x between the local coordinate system D and the local coordinate system C caused by the structural error. DC ,y DC ,z DC Position error;

[0057] S432: Calculate the transformation matrix between local coordinate systems:

[0058]

[0059]

[0060] Among them, R IJ represents the rotation transformation matrix between the local coordinate system A, B, C and the global coordinate system W, and the rotation transformation matrix between the local coordinate system D and the local coordinate system C, T IJ Represents the translation transformation matrix between the local coordinate systems A, B, C and the global coordinate system W, and the translation transformation matrix between the local coordinate system D and the local coordinate system C; the subscripts IJ in the above transformation matrix formulas are replaced by AW, BW, CW and DC, respectively, that is, after replacement, they represent the rotation angle, precession angle, tension angle and displacement offset between the local coordinate systems A, B, C and the global coordinate system W, and between the local coordinate system D and the local coordinate system C, respectively.

[0061] Preferably, in S44, the process of solving the plane equation of the reflector mirror surface in the global coordinate system, the linear equation of the central axis of the incident light guide arm and the central axis of the outgoing light guide arm is as follows: arbitrarily select two points on the central axis of the incident light guide arm Select any two points on the central axis of the output light guide arm Select three non-collinear points at random on the mirror surface Solve in the global coordinate system W and Point corresponding coordinates and

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069] in and for and Coordinates in the local coordinate system C; then use the global coordinate system W and The straight line equation of the central axis of the incident light guide arm, the straight line equation of the central axis of the exit light guide arm and the plane equation of the reflector surface are calculated respectively.

[0070] The beneficial effect of the present invention is: the present invention proposes a design method for an open-and-close light guide arm joint. After completing the design of the structural parameters, the method analyzes the pointing error of the open-and-close light guide arm joint in combination with the specific structural parameters and the system internal error of the joint, thereby realizing a systematic design of the open-and-close light guide arm joint that includes structural design and error analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 A schematic diagram of the process of designing a retractable light guide arm joint according to an embodiment of the present application;

[0072] Figure 2 This is a schematic structural diagram of an openable light guide arm joint according to an embodiment of the present application;

[0073] Figure 3 An equivalent two-dimensional plane theoretical analysis model of the retractable light guide arm joint of the embodiment of the present application;

[0074] In the figure: 1. Incident light guide arm 2. Exit light guide arm 3. Articulated shaft 41. Reflector fixing platform 42. Guide rod 421. Slide groove 5. Reflector. DETAILED DESCRIPTION

[0075] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

[0076] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0077] This application discloses Figure 1 A method for designing an openable and closable light guide arm joint is shown, the method comprising:

[0078] The first step is to determine the basic structure of the open-close light guide arm joint and establish an equivalent two-dimensional plane theoretical analysis model of the open-close light guide arm joint; as an example, the structure of the open-close light guide arm joint is as follows: Figure 2 As shown, it mainly consists of an incident light guide arm 1, an outgoing light guide arm 2 and a reflector platform; the incident light guide arm 1 and the outgoing light guide arm 2 are connected by a hinge shaft 3; the reflector platform includes a reflector fixing platform 41 and a guide rod 42 in a "T" shape, and a slide groove 421 is provided on the guide rod 42. The reflector platform is movably connected to the hinge shaft 3 through the slide groove, and the intersection of the optical axes of the incident light guide arm and the outgoing light guide arm is located at the center of the radiation mirror, and the reflector 5 is installed on the reflector fixing platform 41. The above structure is simplified as follows Figure 3 The two-dimensional model shown, Figure 3 In the figure, straight lines a and b represent the central axis of the light guide arm, f represents the reflector, o is the hinge axis, and s is the intersection of the central axis of the light guide arm and the reflector surface.

[0079] Step 2: According to the actual laser system in which the opening and closing light guide arm joint is to be embedded, determine the opening and closing angle α between the light guide arms and the structural parameters of the light guide arms. The structural parameters of the light guide arms include: the light aperture of the light guide arm and the length of the light guide arm. These parameters are the basis for the subsequent structural parameter design; in order to make the designed opening and closing light guide arm joint suitable for most laser systems, the opening and closing angle is generally set to an angle range.

[0080] Step 3: According to the given α and light guide arm structural parameters, determine the design parameters of each component of the light guide arm joint in turn, and establish a three-dimensional model of the open and close light guide arm joint based on each parameter. Figure 3 As shown, in order to ensure that the intersection of the optical axes of the incident light guide arm and the output light guide arm is located at the center of the radiation mirror, the distance L between so so Need to meet: L so =r×sec(α / 2), where r is the distance from the hinge axis to the center of the mirror in the vertical direction. As long as the distance L between the mirror surface and the hinge axis is always maintained so , it can be ensured that the intersection of the optical axes of the incident light guide arm and the output light guide arm is always located at the center of the radiation mirror, thereby achieving accurate deflection of the laser light path.

[0081] Based on the above distance, the remaining structural parameters are designed. The design needs to ensure that the rotation and translation between the joint components do not interfere with each other. If necessary, special structural design is required to avoid interference. The positioning structure of the reflector platform needs to ensure that the distance between the reflector surface and the hinge axis is always L. so =l×sec(α / 2), the size design of the guide rod slot must meet the travel requirements of the reflector translation, etc. For example, in order to avoid structural interference between the reflector platform and the light guide arm, a cut is designed on the side wall of the light guide arm;

[0082] Step 4: Calculate the laser transmission pointing error of the designed opening and closing light guide arm joint. The process is as follows:

[0083] (1) Establish the global coordinate system of the light guide arm joint and the local coordinate system of each component; where:

[0084] The global coordinate system is: the hinge axis coordinate system W, the coordinate system W takes the center position of the hinge axis as the origin O, the central axis of the incident light guide arm as the X axis, and the axis direction of the hinge axis as the Y axis;

[0085] The local coordinate system includes: ① the incident light guide arm coordinate system A, the origin of the coordinate system A O A Located on the central axis of the incident light guide arm, and the origin is set to O A The distance from the origin O is projected onto the central axis of the incident light guide arm as x. The X A The axis is set along the central axis of the incident light guide arm, and its positive direction points away from the hinge axis. A The axis is along the axis of the incident light guide arm hinge shaft sleeve, and it is in the same direction as the Y axis; ② The output light guide arm coordinate system B, the origin of the coordinate system B is O B Located on the central axis of the output light guide arm, and the origin is set to O B The distance from the origin O is projected onto the central axis of the light guide arm as x. The X BThe axis is along the central axis of the output light guide arm, and its positive direction points away from the hinge axis. B The axis is along the axis of the hinge shaft sleeve of the output light guide arm, and is in the same direction as the Y axis; ③ The reflector platform coordinate system C, the origin of the coordinate system C is O C Located on the reflector mounting platform, and set the origin O C The distance from the origin O is y, and the Z of the coordinate system C is C The axis is along the guide rod direction, and its positive direction points away from the hinge axis. C The axis is parallel to the guide rail plane and Z C The axis is perpendicular and its direction is the same as the Y axis; ④ The reflector coordinate system D, the origin of the coordinate system D is O D Located on the mirror surface, and the origin O D With the origin O C The distance between them is the thickness d of the reflector, and the Z D The axis is the normal direction of the mirror, Y D The axis is on the mirror plane and is in the same plane as the Yc axis of the coordinate system C. Its direction is the same as the Y axis, and Y D Axis perpendicular to Z D axis;

[0086] (2) Determine the structural errors and assembly errors that affect the laser transmission pointing direction; wherein the structural errors include: the cylindricality of the hinge shaft, the manufacturing error of the reflector platform and the manufacturing error of the reflector; the assembly errors include: the rotational clearance between the light guide arm and the hinge shaft, the rotational clearance between the guide rod of the reflector platform and the hinge shaft, the free clearance between the two light guide arms and the guide rod on the reflector platform along the axis of the hinge shaft, and the assembly errors of the reflector and the reflector platform.

[0087] (3) Calculating the transformation matrix between the global coordinate system and each local coordinate system when various structural errors and assembly errors exist;

[0088] ① Determine the rotation and translation between each local coordinate system and the global coordinate system

[0089] Assume that the Euler angles between the local coordinate systems A, B, C and the global coordinate system W are The position offset is (x PW ,y PW ,z PW ), where P in the subscript PW can be replaced by A, B, or C accordingly; let the Euler angle between the local coordinate system D and the local coordinate system C be The position offset is (x DC ,y DC ,z DC ),in:

[0090]

[0091] ψ AW =Dψ AW

[0092] i AW =Δθ AW

[0093] x AW =x+Δx AW

[0094] y AW =Δy AW

[0095] z AW =l+Δz AW

[0096]

[0097] ψ BW =Dψ BW

[0098] i BW =α+Δθ BW

[0099] x BW =lsinα+xcosα+Δx BW

[0100] y BW =Δy BW

[0101] z BW =lcosα+xsinα+Δz BW

[0102]

[0103] ψ CW =Dψ CW +D'ψ CW

[0104] i CW =α / 2+Δθ CW +D'θ CW

[0105] x CW =ycos(α / 2)+Δx CW +D'x CW

[0106] y CW =Δy CW +D'y CW

[0107] z CW=ysin(α / 2)+Δz CW +Δ'z CW

[0108]

[0109] ψ DC =Δψ DC +Δ'ψ DC

[0110] θ DC =Δθ DC +Δ'θ DC

[0111] x DC =Δx DC +Δ'x DC

[0112] y DC =Δy DC +Δ'y DC

[0113] z DC =d+Δz DC +Δ'z DC

[0114] in: Δψ AW ,Δθ AW They represent the rotation angle, precession angle and tension angle between the local coordinate system A and the global coordinate system W caused by the assembly error. ψ AW ,θ AW angular error; l is the inner radius of the light guide arm, Δx AW ,Δy AW ,Δz AW are the position offset x between the local coordinate system A and the global coordinate system W caused by the assembly error. PW ,y PW ,z PW Position error; Δψ BW ,Δθ BW They represent the rotation angle, precession angle and tension angle between the local coordinate system B and the global coordinate system W caused by the assembly error. ψ BW ,θ BW Angle error; Δx BW ,Δy BW ,Δz BW are the position offset x between the local coordinate system B and the global coordinate system W caused by the assembly error PW ,y PW ,z PWα is the opening and closing angle between the incident light guide arm and the exit light guide arm; Δψ CW ,Δθ CW They represent the rotation angle, precession angle, and stretch angle between the local coordinate system C and the global coordinate system W caused by the assembly error. ψ CW ,θ CW Angle error; Δx CW ,Δy CW ,Δz CW are the position offset x between the local coordinate system C and the global coordinate system W caused by the assembly error. CW ,y CW ,z CW Position error; Δ'ψ CW ,Δ'θ CW are the rotation angle, precession angle and tension angle between the local coordinate system C and the global coordinate system W caused by the structural error. ψ CW ,θ CW Angle error; Δ'x CW ,Δ'y CW ,Δ'z CW are the position offset x between the local coordinate system C and the global coordinate system W caused by the structural error. CW ,y CW ,z CW Position error; Δψ DC ,Δθ DC is the rotation angle, precession angle and tension angle between the local coordinate system D and the local coordinate system C caused by the assembly error ψ DC ,θ DC Angle error; Δx DC ,Δy DC ,Δz DC are the position offset x between the local coordinate system D and the local coordinate system C caused by the assembly error DC ,y DC ,z DC Position error; Δ'ψ DC ,Δ'θ DC are the rotation angle, precession angle and tension angle between the local coordinate system D and the local coordinate system C caused by the structural error ψ DC ,θ DC Angle error; Δ'x DC ,Δ'y DC ,Δ'z DCare the position offset x between the local coordinate system D and the local coordinate system C caused by the structural error. DC ,y DC ,z DC Position error;

[0115] ② Calculate the transformation matrix between local coordinate systems:

[0116]

[0117]

[0118] In order to save space here, R is set IJ It is a unified expression for the rotation transformation matrix between the local coordinate systems A, B, C and the global coordinate system W, and the rotation transformation matrix between the local coordinate system D and the local coordinate system C, T IJ It is a unified expression of the translation transformation matrix between the local coordinate systems A, B, C and the global coordinate system W, and the translation transformation matrix between the local coordinate system D and the local coordinate system C; the subscripts IJ can be replaced by AW, BW, CW and DC respectively to calculate the transformation matrices between different coordinate systems.

[0119] Step 4: Use the transformation matrix to solve the plane equation of the reflector surface, the linear equation of the central axis of the incident light guide arm and the central axis of the exit light guide arm in the global coordinate system;

[0120] The process of solving the plane equation of the reflector mirror surface in the global coordinate system, the linear equation of the central axis of the incident light guide arm and the central axis of the outgoing light guide arm is as follows: select two points on the central axis of the incident light guide arm at random Select any two points on the central axis of the output light guide arm Select three non-collinear points at random on the mirror surface Solve in the global coordinate system W and Point corresponding coordinates and

[0121]

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128] in and for and Coordinates in the local coordinate system C; then use the global coordinate system W and Points, according to the principle that two points determine a straight line and three points determine a plane, the straight line equation of the central axis of the incident light guide arm, the straight line equation of the central axis of the exiting light guide arm and the plane equation of the reflector surface are calculated respectively.

[0129] Step 5: Through the law of reflection, calculate the linear equation of the optical axis of the light beam incident along the central axis of the incident light guide arm in the global coordinate system after reflection by the reflecting mirror. This is an absolutely ideal state, that is, assuming that the system does not introduce any error, the light beam incident along the central axis of the incident light guide arm will be emitted strictly along the central axis of the exit light guide arm after reflection.

[0130] Step 6: Through the linear equation of the central axis of the outgoing light guide arm solved in the fourth step and the linear equation of the optical axis of the outgoing light beam in the global coordinate system solved in the fifth step, the pointing error of the laser transmission of the light guide arm joint is obtained, thus completing the design of the entire opening and closing light guide arm joint.

Claims

1. A method for designing an opening and closing light guide arm joint, characterized in that: The method comprises: S1: Given the basic structure of the opening and closing light guide arm joint, establish its equivalent two-dimensional plane theoretical analysis model; S2: Determine the opening and closing angle α between the light guide arms and the structural parameters of the light guide arms according to the actual laser system to be embedded in the opening and closing light guide arm joints; S3: According to the given α and the structural parameters of the light guide arm, the design parameters of each component of the light guide arm joint are determined in turn, and a three-dimensional model of the open-and-close light guide arm joint is established according to each parameter; S4: Calculating the laser transmission pointing error of the open-and-close light guide arm joint according to the three-dimensional model of the open-and-close light guide arm joint; the laser transmission pointing error analysis in S4 includes: S41: establishing a global coordinate system of the light guide arm joint and a local coordinate system of each component; S42: determining the structural error and assembly error that affect the laser transmission pointing; S43: Calculating the transformation matrix between the global coordinate system and each local coordinate system under the premise that each structural error and assembly error exists; S44: using the transformation matrix, solving the plane equation of the reflector surface, the straight line equation of the central axis of the incident light guide arm and the central axis of the exit light guide arm in the global coordinate system; S45: Calculate the linear equation of the optical axis of the outgoing light beam in the global coordinate system after the incident light beam whose optical axis coincides with the central axis of the incident light guide arm is reflected by the reflective mirror through the reflection law; S46: The pointing error of the laser transmission of the light guide arm joint is obtained by using the linear equation of the central axis of the output light guide arm solved in S44 and the linear equation of the optical axis of the output light beam in the global coordinate system solved in S45. S5: The design of the opening and closing light guide arm joint is completed.

2. The method for designing an openable light guide arm joint according to claim 1, characterized in that: The basic structure of the opening and closing light guide arm joint in S1 includes: an incident light guide arm, an exit light guide arm and a reflector platform; the incident light guide arm and the exit light guide arm are connected by a hinge axis; the reflector platform includes a reflector fixing platform and a guide rod distributed in a "T" shape, a slide groove is provided on the guide rod, the reflector platform is movably connected to the hinge axis through the slide groove, and the intersection of the optical axes of the incident light guide arm and the exit light guide arm is located at the center of the radiation mirror, and the reflector is installed on the reflector fixing platform.

3. The method for designing an openable light guide arm joint according to claim 2, characterized in that: The structural parameters of the light guide arm in S2 include: the aperture of the light guide arm and the length of the light guide arm.

4. The method for designing an openable light guide arm joint according to claim 3, characterized in that: The parameters of each component in S3 include but are not limited to the cutout structure parameters of the incident light guide arm and the output light guide arm designed to avoid interference between components, the positioning parameters of the reflector platform and the guide rod slot parameters.

5. The method for designing an openable light guide arm joint according to claim 1, characterized in that: The global coordinate system in S41 is: a hinge axis coordinate system W, wherein the coordinate system W takes the center position of the hinge axis as the origin O, the central axis of the incident light guide arm as the X axis, and the axis direction of the hinge axis as the Y axis; The local coordinate system includes: ① Incident light guide arm coordinate system A, coordinate system A origin O A Located on the central axis of the incident light guide arm, and the origin is set to O A The projection of the distance from the origin O on the central axis of the incident light guide arm is x, and the X A The axis is set along the central axis of the incident light guide arm, and its positive direction points away from the hinge axis. A The axis is along the axis of the hinge shaft sleeve of the incident light guide arm and is in the same direction as the Y axis; ②Outgoing light guide arm coordinate system B, origin of coordinate system B O B Located on the central axis of the output light guide arm, and the origin is set to O B The distance from the origin O is projected onto the central axis of the light guide arm as x. The X B The axis is along the central axis of the output light guide arm, and its positive direction points away from the hinge axis. B The axis is along the axis of the hinge shaft sleeve of the output light guide arm and is in the same direction as the Y axis; ③Mirror platform coordinate system C, origin of coordinate system C O C Located on the reflector mounting platform, and set the origin O C The distance from the origin O is y, and the Z of the coordinate system C is C The axis is along the guide rod direction, and its positive direction points away from the hinge axis. C The axis is parallel to the guide rail plane and Z C The axis is vertical and in the same direction as the Y axis; ④Reflector coordinate system D, origin of coordinate system D O D Located on the mirror surface, and the origin O D With the origin O C The distance between them is the thickness d of the reflector, and the Z D The axis is the normal direction of the mirror, Y D The axis is on the mirror plane and is in the same plane as the Yc axis of the coordinate system C. Its direction is the same as the Y axis, and Y D Axis perpendicular to Z D axis.

6. The method for designing an openable light guide arm joint according to claim 5, characterized in that: The structural errors in step S42 include: the cylindricity of the hinge shaft, the manufacturing error of the reflector platform and the manufacturing error of the reflector; the assembly errors include: the rotational clearance between the light guide arm and the hinge shaft, the rotational clearance between the guide rod of the reflector platform and the hinge shaft, the free clearance between the two light guide arms and the guide rod on the reflective platform along the axis of the hinge shaft, and the assembly error of the reflector and the reflector platform.

7. The method for designing an openable light guide arm joint according to claim 6, characterized in that: The calculation process of the transformation matrix in step S43 is as follows: S431: Determine the rotation and translation between each local coordinate system and the global coordinate system Assume that the Euler angles between the local coordinate systems A, B, C and the global coordinate system W are The position offset is (x PW ,y PW ,z PW ), where P in the subscript PW is replaced by A, B, and C accordingly; let the Euler angle between the local coordinate system D and the local coordinate system C be The position offset is (x DC ,y DC ,z DC ),in: ψ AW =Dψ AW i AW =Δθ AW x AW =x+Δx AW y AW =Δy AW z AW =l+Δz AW ψ BW =Dψ BW i BW =α+Δθ BW x BW =lsinα+xcosα+Δx BW y BW =Δy BW With BW =lcosα+xsinα+Δz BW ψ CW =Dψ CW +D'ψ CW i CW =α / 2+Δθ CW +D'θ CW x CW =ycos(α / 2)+Δx CW +D'x CW y CW =Δy CW +Δ'y CW With CW =ysin(α / 2)+Δz CW +Δ'z CW ψ DC =Dψ DC +D'ψ DC i DC =Δθ DC +D'θ DC x DC =Δx DC +Δ'x DC y DC =Δy DC +Δ'y DC z DC =d+Δz DC +Δ'z DC in: Δψ AW ,Δθ AW They represent the rotation angle, precession angle and tension angle between the local coordinate system A and the global coordinate system W caused by the assembly error. ψ AW ,θ AW angular error; l is the inner radius of the light guide arm, Δx AW ,Δy AW ,Δz AW are the position offset x between the local coordinate system A and the global coordinate system W caused by the assembly error. PW ,y PW ,z PW Position error; Δψ BW ,Δθ BW They represent the rotation angle, precession angle and tension angle between the local coordinate system B and the global coordinate system W caused by the assembly error. ψ BW ,θ BW Angle error; Δx BW ,Δy BW ,Δz BW are the position offset x between the local coordinate system B and the global coordinate system W caused by the assembly error PW ,y PW ,z PW α is the opening and closing angle between the incident light guide arm and the exit light guide arm; Δψ CW ,Δθ CW They represent the rotation angle, precession angle, and stretch angle between the local coordinate system C and the global coordinate system W caused by the assembly error. ψ CW ,θ CW Angle error; Δx CW ,Δy CW ,Δz CW are the position offset x between the local coordinate system C and the global coordinate system W caused by the assembly error. CW ,y CW ,z CW Position error; Δ'ψ CW ,Δ'θ CW are the rotation angle, precession angle and tension angle between the local coordinate system C and the global coordinate system W caused by the structural error. ψ CW ,θ CW Angle error; Δ'x CW ,Δ'y CW ,Δ'z CW are the position offset x between the local coordinate system C and the global coordinate system W caused by the structural error. CW ,y CW ,z CW Position error; Δψ DC ,Δθ DC is the rotation angle, precession angle and tension angle between the local coordinate system D and the local coordinate system C caused by the assembly error ψ DC ,θ DC Angle error; Δx DC ,Δy DC ,Δz DC are the position offset x between the local coordinate system D and the local coordinate system C caused by the assembly error DC ,y DC ,z DC Position error; Δ'ψ DC ,Δ'θ DC are the rotation angle, precession angle and tension angle between the local coordinate system D and the local coordinate system C caused by the structural error ψ DC ,θ DC Angle error; Δ'x DC ,Δ'y DC ,Δ'z DC are the position offset x between the local coordinate system D and the local coordinate system C caused by the structural error. DC ,y DC ,z DC Position error; S432: Calculate the transformation matrix between local coordinate systems: Among them, R IJ represents the rotation transformation matrix between the local coordinate system A, B, C and the global coordinate system W, and the rotation transformation matrix between the local coordinate system D and the local coordinate system C, T IJ Represents the translation transformation matrix between the local coordinate systems A, B, C and the global coordinate system W, and the translation transformation matrix between the local coordinate system D and the local coordinate system C; the subscripts IJ in the above transformation matrix formulas are replaced by AW, BW, CW and DC respectively.

8. The method for designing an openable light guide arm joint according to claim 7, characterized in that: In S44, the process of solving the plane equation of the reflector mirror surface in the global coordinate system, the linear equation of the central axis of the incident light guide arm and the central axis of the outgoing light guide arm is as follows: arbitrarily select two points on the central axis of the incident light guide arm Select any two points on the central axis of the output light guide arm Select three non-collinear points at random on the mirror surface Solve in the global coordinate system W and Point corresponding coordinates and in and for and Coordinates in the local coordinate system C; then use the global coordinate system W and The straight line equation of the central axis of the incident light guide arm, the straight line equation of the central axis of the exit light guide arm and the plane equation of the reflector surface are calculated respectively.

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