Coaxiality error correction system and method based on laser reference and real-time feedback

Abstract

The invention discloses a coaxiality error correction system and method based on a laser reference and real-time feedback, relates to the field of dense shaft system part processing and optical reference calibration, and solves the problems that the existing coaxiality correction depends on secondary clamping correction after offline detection of a three-coordinate measuring instrument; the correction precision is influenced by subjective judgment depending on artificial experience, and the like. According to the method, a closed-loop technical path of signal acquisition, algorithm resolving, instruction generation and feedback execution is constructed, so that the limitation of traditional off-line detection is broken through, an integrated process of'measurement, resolving and compensation 'is realized, and secondary clamping errors are reduced. The method is also suitable for the fields of micron-sized precise shafting machining, optical instrument calibration and online dynamic correction of aerospace high-precision assembly parts.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of precision shafting part machining and optical reference calibration, and particularly relates to a coaxiality error correction system and method based on laser reference and real-time feedback. BACKGROUND

[0002] Currently, many coaxiality correction techniques rely on devices such as three-coordinate measuring machines for offline detection. First, after detection is completed, the workpiece needs to be re-clamped on the machining device for correction. This separate operation mode lacks direct continuity between the detection and machining processes. This results in changes in the position and attitude of the workpiece during offline detection and re-clamping, leading to deviations between the detection data and the actual machining state. These deviations will continue to accumulate, ultimately affecting the accuracy of the coaxiality correction. Offline detection and re-clamping increase the complexity and time cost of the process, reducing production efficiency.

[0003] Secondly, in the existing technology, the accuracy of coaxiality correction often depends on the experience and subjective judgment of the operator. The operator needs to determine the direction and value of correction based on the detection results and their own experience. Due to differences in the experience level and judgment ability of different operators, this will lead to fluctuations in correction accuracy. Even the same operator may make different judgments at different times or states, introducing uncontrollable systematic errors. Due to reliance on human experience, it is difficult to standardize the correction process and it is not easy to replicate and promote between different devices or different operators.

[0004] Finally, traditional coaxiality correction methods lack real-time feedback capabilities and cannot monitor and adjust errors in real time during the machining process. Once machining begins, it is impossible to dynamically compensate for errors that have already occurred. Due to the inability to eliminate dynamic errors during the machining process: dynamic errors occur during the machining process due to factors such as thermal deformation of the machine tool, tool wear, and workpiece deformation. Traditional methods cannot sense and eliminate these errors in real time, leading to a decrease in machining accuracy. For complex workpieces or machining tasks with high precision requirements, traditional methods are difficult to meet the dynamic changing needs and cannot guarantee the stability and consistency of the machining process. SUMMARY

[0005] The present application aims to solve the problems in the prior art that coaxiality correction relies on offline detection by three-coordinate measuring machines and re-clamping for correction, leading to process connection error accumulation, correction accuracy being affected by subjective judgment of human experience dependency, and traditional methods lacking real-time feedback capabilities, which cannot eliminate dynamic errors during the machining process.

[0006] To solve the above technical problems, the present application is implemented by the following technical solutions: The present application proposes the following technical solutions: Scheme one, coaxiality error correction system based on laser reference and real-time feedback, the system comprises a laser reference construction module, dynamic compensation execution module, collaborative control module; The laser reference construction module comprises a reference block, a photosensitive position sensor, a laser, and an optical measurement unit; The dynamic compensation execution module comprises an air float chuck, a tool assembly, and a two-dimensional nanometer displacement platform, which comprises a first two-dimensional nanometer displacement platform, a second two-dimensional nanometer displacement platform, and a third two-dimensional nanometer displacement platform; The collaborative control module comprises a central control module based on FPGA, an integrated least squares fitting algorithm, a PID closed-loop control and error settlement unit, and a spindle motor; A laser is arranged on the first two-dimensional nanometer displacement platform, and a reference block is fixed at the focal plane of the laser. The reference block and the original part to be finished are clamped in the reference block clamp and the air float chuck, respectively. The tool assembly is arranged on one side of the original part to be finished, and the optical measurement unit is arranged on the third two-dimensional nanometer displacement platform; A reference block is arranged on the second two-dimensional nanometer displacement platform, and the reference block is fixed through the reference block clamp. A photosensitive position sensor is arranged on the spindle box, which collects the laser beam emitted by the laser. The optical measurement unit is started synchronously to collect the outer contour boundary data of the original part to be finished. The original part to be finished is rotated by the spindle motor in the spindle box. The minimum boundary position and the minimum deviation amount of the reference block are made to coincide by the error settlement unit and the central control module. The boundary and the deviation amount are compared concentrically to complete the coaxiality error correction.

[0007] Further, a preferred embodiment is provided, wherein a rotating motor is further arranged on the tool assembly to drive the tool assembly to cut and realize the convergence of the coaxiality error.

[0008] Further, a preferred embodiment is provided, wherein the first two-dimensional nanometer displacement platform, the second two-dimensional nanometer displacement platform, and the third two-dimensional nanometer displacement platform are arranged in sequence in the transverse direction.

[0009] Scheme two, coaxiality error correction method based on laser reference and real-time feedback, the method is realized based on the system of scheme one, and the method comprises the following steps: S1, the photosensitive position sensor collects the displacement signal of the laser beam emitted by the laser in the two-dimensional nanometer displacement platform in real time, calculates the discrete sampling point coordinates and the dynamic rotation center coordinates, fits the center trajectory based on the synchronous starting of the optical measurement unit to collect the outer contour boundary data of the original part to be finished, generates an initial eccentricity matrix, and generates a tool compensation vector based on the real-time eccentricity ΔEt by the central control module based on FPGA ; S2, rotating the original part to be finished by the spindle motor in the spindle box, and making the minimum boundary position coincide with the minimum deviation amount of the reference block through the error settlement unit and the central control module; comparing the boundary and the deviation amount concentrically, calculating the difference between the boundary and the deviation amount, and calculating the difference between the boundary and the center deviation amount; S3, determining the tool assembly trajectory based on the initial boundary data and the deviation amount value, and generating a tool compensation vector according to the real-time feedback boundary data , rotating the motor to drive the tool assembly to cut, and realizing the coaxiality error convergence through multi-iteration closed-loop control.

[0010] Further, a preferred embodiment is provided, and the method for calculating the discrete sampling point coordinates in S1 is:

[0011] In the formula, is the discrete sampling point coordinate, n is the number of sampling points.

[0012] Further, a preferred embodiment is provided, and the method for generating the tool compensation vector in S2 is:

[0013] In the formula, , is a dynamic gain coefficient.

[0014] Further, a preferred embodiment is provided, and the rotating motor 15 drives the tool assembly 7 to cut in S3, which needs to meet:

[0015] In the formula, is a material removal coefficient, is an eccentric direction angle.

[0016] Further, a preferred embodiment is provided, and the convergence condition of the iteration closed-loop control in S3 is: .

[0017] Scheme four, a computer device, comprising a memory and a processor, the memory stores a computer program, when the processor runs the computer program stored in the memory, the processor executes the method according to scheme two. Scheme four, a computer readable storage medium, the computer readable storage medium is used to store a computer program, the computer program executes the method of scheme two.

[0018] The present application has the advantages of: The coaxiality error correction system and method based on laser datum and real-time feedback, described in this invention, utilizes a coaxiality correction method to achieve precise correction by establishing a collaborative working mechanism between a laser datum coordinate system and a dynamic compensation system. This closed-loop technology path of "signal acquisition - algorithm solution - instruction generation - execution feedback" overcomes the limitations of traditional offline detection, achieving an integrated "measurement - solution - compensation" process and reducing secondary clamping errors.

[0019] The present invention is also applicable to the fields of micron-level precision shaft processing, optical instrument calibration, and online dynamic correction of high-precision aerospace assemblies. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the coaxiality error correction system based on laser reference and real-time feedback according to the present invention.

[0021] Figure 2 This is an enlarged view of the end portion of the rotary motor driven tool assembly described in the present invention.

[0022] Among them, there are laser 1, reference block 2, reference block fixture 3, photosensitive position sensor 4, air floating chuck 5, original part to be trimmed 6, tool assembly 7, optical measurement unit 8, first two-dimensional nano-moving platform 9, spindle box 10, second two-dimensional nano-moving platform 11, third two-dimensional nano-moving platform 12, slide rail 14, and rotating motor 15. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, it is obvious that the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0024] Embodiment 1: This embodiment provides a coaxiality error correction system based on laser reference and real-time feedback, the system including a laser reference construction module, a dynamic compensation execution module, and a collaborative control module; The laser reference building module includes a reference block 2, a photosensitive position sensor 4, a laser 1, and an optical measurement unit 8; The dynamic compensation execution module includes an air-floating chuck 5, a tool assembly 7, and a two-dimensional nano-displacement platform. The two-dimensional nano-displacement platform includes a first two-dimensional nano-moving platform 9, a second two-dimensional nano-moving platform 11, and a third two-dimensional nano-moving platform 12; The collaborative control module includes an FPGA-based central control module, which integrates a least squares fitting algorithm with a PID closed-loop control and error settlement unit, and a spindle motor; The first two-dimensional nano mobile platform 9 is provided with a laser 1, a fiducial block 2 is fixed at the focal plane of the laser 1, the fiducial block 2 and the original part to be trimmed 6 are respectively clamped on the fiducial block clamp 3 and the air floating chuck 5, the cutter assembly 7 is arranged on one side of the original part to be trimmed 6, and the optical measurement unit 8 is arranged on the third two-dimensional nano mobile platform 12; The second two-dimensional nano mobile platform 11 is provided with the fiducial block 2, and the fiducial block 2 is fixed through the fiducial block clamp 3; the main shaft box 10 is provided with a photosensitive position sensor 4, the photosensitive position sensor 4 collects the laser beam emitted by the laser, and the optical measurement unit 8 is started synchronously to collect the outer contour boundary data of the original part to be trimmed 6, the original part to be trimmed 6 is rotated through the main shaft motor in the main shaft box 10, the minimum boundary position is coincided with the minimum deviation amount of the fiducial block 2 through the error settlement unit and the central control module, the boundary and the deviation amount are compared concentrically, and the coaxiality error correction is completed.

[0025] Embodiment two, the embodiment is a further limitation of the coaxiality error correction system based on the laser reference and the real-time feedback according to the embodiment one, the cutter assembly 7 is further provided with a rotating motor 15, which is used for driving the cutter assembly 7 to cut and realize the coaxiality error convergence.

[0026] Embodiment three, the embodiment is a further limitation of the coaxiality error correction system based on the laser reference and the real-time feedback according to the embodiment one, the first two-dimensional nano mobile platform 9, the second two-dimensional nano mobile platform 11 and the third two-dimensional nano mobile platform 12 are arranged transversely in sequence.

[0027] Embodiment four, the embodiment proposes a coaxiality error correction method based on the laser reference and the real-time feedback, the method is realized based on the system according to any one of the embodiments one to three, and the method comprises the following steps: S1, the photosensitive position sensor 4 collects the displacement signal of the laser beam emitted by the laser in the two-dimensional nano displacement platform in real time, calculates the discrete sampling point coordinates and the dynamic rotation center coordinates, starts the optical measurement unit 8 synchronously to collect the outer contour boundary data of the original part to be trimmed 6, fits the center track, generates an initial eccentricity matrix, and generates a cutter compensation vector based on the FPGA central control module according to the real-time eccentricity ΔEt ; S2, the original part to be trimmed 6 is rotated through the main shaft motor in the main shaft box 10, the minimum boundary position is coincided with the minimum deviation amount of the fiducial block 2 through the error settlement unit and the central control module; the boundary and the deviation amount are compared concentrically, the difference between the boundary and the deviation amount is calculated, and the difference between the boundary and the center deviation amount is calculated; S3, based on the initial boundary data and the deviation amount, the cutter assembly 7 track is determined, the cutter compensation vector is generated according to the real-time feedback boundary data The rotating motor 15 drives the tool assembly 7 to cut, and through multi-iteration closed-loop control, the coaxiality error convergence is realized.

[0028] Embodiment five, this embodiment is a further limitation of the coaxiality error correction method based on laser reference and real-time feedback of embodiment four, the method for calculating the discrete sampling point coordinates in S1 is:

[0029] In the formula, is the discrete sampling point coordinates, n is the number of sampling points.

[0030] Embodiment six, this embodiment is a further limitation of the coaxiality error correction method based on laser reference and real-time feedback of embodiment four, the method for generating the tool compensation vector in S2 is:

[0031] In the formula, , is the dynamic gain coefficient.

[0032] Embodiment seven, this embodiment is a further limitation of the coaxiality error correction method based on laser reference and real-time feedback of embodiment four, the rotating motor 15 drives the tool assembly 7 to cut in S3 needs to meet:

[0033] In the formula, is the material removal coefficient, is the eccentric direction angle.

[0034] Embodiment eight, this embodiment is a further limitation of the coaxiality error correction method based on laser reference and real-time feedback of embodiment four, the convergence condition of the iteration closed-loop control in S3 is: .

[0035] Embodiment nine, this embodiment proposes a computer device, including a memory and a processor, the memory has a computer program stored therein, when the processor runs the computer program stored in the memory, the processor executes the method of embodiment four.

[0036] Embodiment ten, this embodiment proposes a computer device, including a memory and a processor, the memory has a computer program stored therein, when the processor runs the computer program stored in the memory, the processor executes the method of embodiment four.

[0037] Implementation 11: To further explain Implementations 1 through 10 above, this implementation describes a coaxiality error correction system and method based on a laser reference and real-time feedback. This system achieves precise correction by establishing a collaborative working mechanism between a laser reference coordinate system and a dynamic compensation system. This closed-loop technology path of "signal acquisition - algorithm solution - command generation - execution feedback" overcomes the limitations of traditional offline detection, achieving an integrated "measurement - solution - compensation" process and reducing secondary clamping errors.

[0038] It mainly includes the following steps: 1. Establishment of reference coordinate system First, clamp the reference block 2 and the original part to be trimmed 6 to the reference block fixture 3 and the high-precision air-floating chuck 5 respectively. Install the original part to be trimmed 6 and the reference block 2. Adjust the high-precision two-dimensional mobile platform to make the centers of the light tube, optical measurement unit 8, reference block 2, photosensitive position sensor 4, and the original part to be trimmed 6 coincide. In addition, fix the reference part at the focal plane of the laser 1. Clamp the reference block 2 and the original part to be trimmed 6 to the air-floating chuck 5 respectively. A two-dimensional displacement platform is used to achieve spatial alignment between the optical axis and the workpiece axis. Start the reference part to rotate at a constant speed. The photosensitive position sensor 4 array captures the displacement signal of the laser beam in the XY plane in real time. The formula is used. , where are the coordinates of discrete sampling points, n Calculate the dynamic rotation center coordinates: Synchronously collect the outer contour boundary data of the original part 6 to be trimmed, fit the center trajectory based on the algorithm, generate the initial eccentricity matrix, and the central control system generates the compensation vector according to the real-time eccentricity ΔEt ; The central control module generates a compensation vector according to the solid eccentricity ΔEt , , where 、 is the dynamic gain coefficient.

[0039] The servo system drives the tool assembly 7 to perform cutting depth compensation, cutting amount satisfy:

[0040] Where, is the material removal coefficient, is the eccentric direction angle.

[0041] Through iterative closed-loop control, the convergence condition is: , achieving exponential attenuation of coaxiality error.

[0042] The optical positioning reference is established by the reference block of the laser transmission film with the micro-hole structure arranged in the center, the reference block 2 rotates continuously at a uniform speed, the photosensitive position sensor 4 captures the displacement signal of the laser beam in the XY plane, the dynamic rotation center coordinates of the reference member are solved by the least square fitting algorithm, here the central control system and the error settlement unit are required to cooperate, the optical measurement unit 8 is started synchronously, the outer contour boundary data of the original part 6 to be finished are continuously collected, the center coordinates are obtained by the least square fitting algorithm, the central control system and the error settlement unit generate compensation instructions according to the initial boundary data and the real-time deviation, and drive the three-jaw air floating chuck 5 to implement micron-level radial compensation, so that the spatial deviation between the dynamic rotation center of the original part 6 to be finished and the reference axis converges.

[0043] 2, finishing stage: Based on the values of the initial boundary data and the deviation, the tool path is determined, the tool compensation feed vector is generated by the system according to the real-time feedback boundary data, the servo system drives the tool to cut, and the coaxiality error convergence is realized.

[0044] When entering the cutting correction stage, the system forms a tool feed vector model based on the real-time collected eccentricity and the light structure of the reference member: the tool pose compensation amount is solved by the algorithm, and the spatial pose of the cutting tool is adjusted synchronously by driving the cutting assembly. In the continuous rotation process of the workpiece, the cutting depth compensation curve is generated in real time according to the boundary curve produced by the optical detection assembly, and the servo control system is controlled to realize the feed compensation. Through multi-iteration closed-loop control, the coaxiality error is attenuated, and finally the machining precision with small residual eccentricity is achieved. The cutting assembly is matched with a high-precision servo drive system to control the tool assembly feed, which can rotate and translate.

[0045] Those skilled in the art can understand that the above description is only a preferred embodiment of the present application, and the features described in each embodiment and / or technical solution of the present disclosure can be combined or combined, even if such combination or combination is not explicitly described in the present disclosure. It is not used to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, and those skilled in the art can modify the technical solutions described in the foregoing embodiments or make equivalent replacement of part of the technical features, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

[0046] While the preferred embodiments of the application have been described, additional variations and modifications can be made to these embodiments by those skilled in the art once they have the benefit of the present disclosure. Therefore, the appended claims are intended to encompass within their scope all possible variations and modifications of the preferred embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application encompass all such modifications and variations as fall within the scope of the present disclosure and its equivalents.

Claims

1. The coaxiality error correction system based on laser reference and real-time feedback is characterized by: The system includes a laser reference construction module, a dynamic compensation execution module, and a collaborative control module; The laser reference building module comprises a reference block (2), a photosensitive position sensor (4), a laser (1), and an optical measurement unit (8); The dynamic compensation execution module comprises an air-floating chuck (5), a tool assembly (7), and a two-dimensional nano-displacement platform, wherein the two-dimensional nano-displacement platform comprises a first two-dimensional nano-moving platform (9), a second two-dimensional nano-moving platform (11), and a third two-dimensional nano-moving platform (12); The collaborative control module includes an FPGA-based central control module, which integrates a least squares fitting algorithm with a PID closed-loop control and error settlement unit, and a spindle motor; A laser (1) is provided on the first two-dimensional nano-moving platform (9), a reference block (2) is fixed at the focal plane of the laser (1), the reference block (2) and the original part to be trimmed (6) are clamped on the reference block fixture (3) and the air-floating chuck (5) respectively, a tool assembly (7) is provided on one side of the original part to be trimmed (6), and an optical measurement unit (8) is provided on the third two-dimensional nano-moving platform (12); A reference block (2) is provided on the second two-dimensional nano-moving platform (11), and the reference block (2) is fixed by a reference block fixture (3); a photosensitive position sensor (4) is provided on the spindle box (10), and the photosensitive position sensor (4) collects the laser beam emitted by the laser, and synchronously starts the optical measurement unit (8) to collect the outer contour boundary data of the original part (6) to be trimmed, and the original part (6) to be trimmed is rotated by the spindle motor in the spindle box (10), and its minimum boundary position is made to coincide with the minimum deviation of the reference block (2) through the error settlement unit and the central control module, and the boundary and the deviation are concentrically compared to complete the coaxiality error correction.

2. The coaxiality error correction system based on laser reference and real-time feedback according to claim 1 is characterized in that: The tool assembly (7) is also provided with a rotating motor (15) for driving the tool assembly (7) to perform cutting and achieve convergence of coaxiality error.

3. The coaxiality error correction system based on laser reference and real-time feedback according to claim 1 is characterized in that: The first two-dimensional nano-mobile platform (9), the second two-dimensional nano-mobile platform (11), and the third two-dimensional nano-mobile platform (12) are arranged laterally in sequence.

4. The coaxiality error correction method based on laser reference and real-time feedback is characterized in that: The method is implemented based on the system according to any one of claims 1 to 3, and the method comprises the following steps: S1, the photosensitive position sensor (4) collects the displacement signal of the laser beam emitted by the laser on the two-dimensional nano-displacement platform in real time, and calculates the coordinates of the discrete sampling points and the dynamic rotation center coordinates. Based on the synchronous start of the optical measurement unit (8), the outer contour boundary data of the original part to be trimmed (6) is collected to fit the center trajectory and generate the initial eccentricity matrix. The central control module based on FPGA generates the tool compensation vector according to the real-time eccentricity ΔEt ; S2, rotating the original workpiece (6) to be trimmed by the spindle motor in the spindle box (10), and making its minimum boundary position coincide with the minimum deviation of the reference block (2) through the error settlement unit and the central control module; performing concentric comparison between the boundary and the deviation, calculating the difference between the boundary and the deviation, and calculating the difference between the boundary and the center deviation; S3, based on the initial boundary data and the value of the deviation, determine the trajectory of the tool assembly (7), and generate the tool compensation vector according to the boundary data fed back in real time , the rotating motor (15) drives the tool assembly (7) to perform cutting, and the coaxiality error convergence is achieved through multi-iteration closed-loop control.

5. The coaxiality error correction method based on laser reference and real-time feedback according to claim 4 is characterized in that: The method for calculating the coordinates of discrete sampling points in S1 is: Where, are the coordinates of discrete sampling points, n is the number of sampling points.

6. The coaxiality error correction method based on laser reference and real-time feedback according to claim 4 is characterized in that: Generate tool compensation vector in S2 The method is: Where, 、 is the dynamic gain coefficient.

7. The coaxiality error correction method based on laser reference and real-time feedback according to claim 4 is characterized in that: The rotating motor (15) in S3 drives the tool assembly (7) to perform cutting, which needs to meet the following requirements: Where, is the material removal coefficient, is the eccentric direction angle.

8. The coaxiality error correction method based on laser reference and real-time feedback according to claim 4 is characterized in that: The convergence condition of iterative closed-loop control in S3 is: .

9. A computer device comprising a memory and a processor, characterized in that A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes the method according to claim 4.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method according to claim 4 are implemented.

Images