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CN-121541579-B - Low-drift laser scanning control method and system based on dynamic error compensation

CN121541579BCN 121541579 BCN121541579 BCN 121541579BCN-121541579-B

Abstract

The invention discloses a low-drift laser scanning control method and system based on dynamic error compensation, relates to the technical field of laser scanning control, and aims to solve the drift problem in the laser scanning process and improve the scanning precision. The system comprises five modules, namely system initialization and calibration, data acquisition and storage, error modeling, route planning and correction, real-time compensation and closed-loop optimization, wherein the error modeling and the route planning and correction are key modules. The error modeling module comprises four units of key route screening, data preprocessing and the like and is responsible for constructing a space-time combined error correction model, and the route planning and correction module comprises four units of initial route generation, error prediction and the like and realizes the dynamic correction of a pre-planned route. The system realizes real-time compensation and closed-loop optimization by combining the dynamic error compensation algorithm through cooperation of the modules, effectively reduces scanning drift, ensures low-drift and high-precision laser scanning, and optimizes the subsequent scanning precision.

Inventors

  • ZHENG MINGCHUN
  • ZHOU WENCE

Assignees

  • 北京正时精控科技有限公司

Dates

Publication Date
20260505
Application Date
20260120

Claims (9)

  1. 1. The low-drift laser scanning control method based on dynamic error compensation is characterized by comprising the following steps of: S1, constructing a laser scanning control system, completing initialization and static calibration, and establishing a system basic control model and an error reference; s2, collecting multi-source data of a plurality of groups of scanned routes and carrying out structural storage to form a scanned route database; s3, acquiring space boundaries, precision requirements and environmental parameters of an area to be scanned, and screening key scanned routes from a scanned route database; s4, preprocessing the key scanned route data and extracting error characteristics to construct a space-time combined error correction model; S5, generating an initial pre-planned route of the area to be scanned, and carrying out multi-dimensional dynamic correction on the initial pre-planned route based on the space-time combined error correction model; S6, executing the corrected route to be scanned, synchronously collecting real-time state data and environment data in the scanning process, and realizing real-time compensation and closed-loop optimization by combining a dynamic error compensation algorithm to complete low-drift laser scanning; the step S3 specifically includes: S301, acquiring a design drawing of a region to be scanned, determining space boundary coordinates of the region to be scanned, and further acquiring center coordinates and side lengths of a minimum circumscribed rectangle of the space boundary coordinates of the region to be scanned; s302, inquiring scanned routes of which the distance between an actual execution path and the boundary of a region to be scanned is smaller than or equal to a minimum boundary threshold value based on the spatial index of a scanned route database to form a candidate adjacent route set; S303, acquiring effective adjacent routes of which the deviation of an actual execution path and a pre-planned path is less than or equal to 2 times of a minimum boundary threshold value from a candidate adjacent route set; S304, determining a key area label from a design drawing of an area to be scanned, inquiring a scanned route containing the label in a scanned route database, further determining a fitting error in the key area, and screening a key area route with the fitting error being greater than or equal to a minimum boundary threshold value; The calculation formula of the fitting error in the key area is as follows: In the formula, As the total number of path points within the critical area, 、 Is the first The actual scan coordinates of the individual path points, 、 Is the first Fitting coordinates of the path points; S305, acquiring the current environmental temperature and vibration acceleration of an area to be scanned, inquiring scanned routes with environmental parameters meeting preset constraint boundaries in a scanned route database, further dividing the scanned routes into at least 3 environmental categories, and selecting 1 route with the most representative error from each category to form an environmental difference route set; S306, dividing routes in a database into three groups of morning, afternoon and evening according to scanning time intervals based on time stamps of the scanned routes, and selecting at least 2 effective routes from each group to form a time difference route set; S307, integrating the effective adjacent route, the key area route, the environment difference route and the time difference route, and further removing the repeated route and reserving at least 3 routes as key scanned route to be selected; S308, performing defect detection on a scanning image corresponding to a key scanned route to be selected based on image data in multi-source data of a plurality of groups of scanned routes, removing invalid routes with missing scan, re-scan or light spot distortion, and finally determining the key scanned routes.
  2. 2. The method for controlling low drift laser scanning based on dynamic error compensation according to claim 1, the method is characterized in that the step S1 specifically comprises the following steps: s101, acquiring the precision requirement and scanning range of a laser scanning task, and determining hardware parameters of a laser emitting module, a biaxial scanning galvanometer, a grating ruler position sensor, a temperature-vibration composite sensor and a main control unit; S102, building a laser scanning control system comprising a laser emission link, a scanning execution link, a feedback detection link and a main control link based on the hardware parameters; s103, determining a communication protocol standard preset by the system, further acquiring communication interface parameters of each module, and completing communication initialization of the main control unit and each hardware module; S104, acquiring basic parameters of a target scanning range, scanning frequency and spot diameter based on the requirement of a scanning task, and transmitting the basic parameters to a main control unit to finish initialization of the scanning parameters; s105, controlling a scanning galvanometer to drive a laser beam to complete static scanning of N calibration points on a target through a standard cross target, obtaining driving voltage U_i of each calibration point and actual displacement S_driver detected by a grating ruler, and further determining a mapping relation S_driver=k_ Sensi.U_i+b of the driving voltage and displacement of the galvanometer, wherein k_ Sensi is a sensitivity coefficient, and b is zero bias voltage; S106, establishing a basic control model according to the mapping relation between the driving voltage and displacement of the vibrating mirror, acquiring theoretical displacement S_Theory of each calibration point location through the basic control model, determining inherent error delta S= |S_Thery-S_driver| of each point location, removing the abnormal error value through a3 sigma criterion, acquiring an inherent error mean mu and a variance sigma, and establishing a system inherent error reference table; S107, utilizing an initial environmental Temperature T acquired by a Temperature sensor, controlling a scanning system to complete multi-group static scanning within a range of T+/-5 ℃, acquiring displacement deviation data at different temperatures, and further acquiring a Temperature drift coefficient k_temperature=delta S/delta T, wherein delta T is the Temperature variation of the scanning environment, and establishing a Temperature drift basic model; S108, acquiring a vibration interference Threshold value a_threshold=0.1× (2pi f) 2×D by utilizing the environmental background vibration acceleration a acquired by the vibration sensor and combining the mechanical resonance frequency f of the scanning vibrating mirror, wherein D is the spot diameter of laser scanning, and completing static calibration and error reference establishment.
  3. 3. The method for controlling low drift laser scanning based on dynamic error compensation according to claim 1, the method is characterized in that the step S2 specifically comprises the following steps: S201, based on a basic control model, acquiring a coordinate sequence of a pre-planned path point and a scanning speed curve of each scanned route, and storing the coordinate sequence and the scanning speed curve as control layer data into a temporary cache; S202, based on real-time feedback in the scanning execution process, acquiring real-time angle of a scanning galvanometer, real-time position data of a motor encoder and adjustment quantity of piezoelectric ceramics, and performing time stamp synchronization on the real-time angle, the real-time position data and the adjustment quantity of the piezoelectric ceramics serving as execution layer data and control layer data to obtain an initial synchronization data set; s203, acquiring real-time position measurement data of the grating ruler, scanning area image data acquired by a camera and laser power monitoring data, and binding the data as detection layer data and an initial synchronous data set; s204, acquiring real-time temperature, vibration acceleration and humidity in the scanning process, and supplementing the real-time temperature, vibration acceleration and humidity as environment data to an initial synchronous data set; s205, integrating control layer data, execution layer data, detection layer data and environment data of a single scanned route into a structured data unit based on an initial synchronous data set through a unique path ID generated by a system, wherein the data unit format comprises a path ID, a scanning time stamp, a pre-planned path, an actual execution path, scanning parameters, environment parameters and an image data path; S206, establishing a scanned route database, storing all the structured data units into the database according to the scanning time sequence, and simultaneously establishing a space index and an environment parameter index to support quick inquiry according to path ID, scanning area and environment parameters.
  4. 4. The method for controlling low drift laser scanning based on dynamic error compensation according to claim 1, the method is characterized in that the step S4 specifically comprises the following steps: S401, acquiring a pre-planned path and an actual execution path of each route based on the key scanned routes, and determining an error vector of each path point; s402, carrying out outlier rejection on the error vector of each path point by using a3 sigma criterion to obtain a purified error data set; S403, performing smoothing treatment on the purified error data set to obtain trend error data; s404, acquiring a Time stamp and a scanning Length of a key scanned route, extracting a Time-space Drift trend feature, and obtaining a Drift trend model delta P_drift=k_time.t+k_length.L+b, wherein delta P_drift is a Drift trend error compensation quantity, k_time is a Time Drift coefficient, k_length is a Length Drift coefficient, t is a Time stamp of the key scanned route, L is a scanning Length of the key scanned route, and b is a Drift constant item; S405, acquiring a space boundary of a region to be scanned, mapping error data of a key scanned route to a unified global coordinate system, generating an error distribution thermodynamic diagram of the scanned region, extracting a space error distribution characteristic, and obtaining a space error function delta P (x, y); s406, acquiring environment data and error data corresponding to the key scanned route, and further extracting environment-error correlation characteristics to obtain an environment error model; the environment error model is as follows: ΔP_Environment=k_Temperature·(T_t-T_0)+k_Vibration·(a_t-a_0); Wherein Δp_environment is an environmental error compensation amount, k_temperature is a Temperature drift coefficient, k_vibration is a Vibration error coefficient, t_0 and a_0 are initial environmental Temperature and initial Vibration acceleration, t_t is a real-time environmental Temperature at time T, and a_t is a real-time Vibration acceleration at time T; S407, extracting parameter-error correlation characteristics based on the speed and the acceleration in the scanning parameters to obtain a parameter error model; the expression formula of the parameter error model is as follows: ΔP_Parameter=k_Speed·v_Scan_t+k_Acceleration·a_Scan_t; Wherein, delta P_parameter is the Parameter error compensation quantity, k_speed is the Speed error coefficient, k_accel-tion is the Acceleration error coefficient, v_Scan_t is the real-time scanning Speed in the scanning Parameter, and a_Scan_t is the real-time scanning Acceleration in the scanning Parameter; S408, constructing a space-time combined error correction model based on space-time drift trend characteristics, space error distribution characteristics, environment-error correlation characteristics and parameter-error correlation characteristics, inputting the model into a path point coordinate to be scanned, scanning time, scanning length, environment parameters and scanning parameters, and outputting the model into a total error prediction value; the expression formula of the space-time combined error correction model is as follows: ΔP_United=ΔP_Drift+ΔP(x,y)+ΔP_Environment+ΔP_Parameter; where Δp_united is the error prediction value.
  5. 5. The method for controlling low drift laser scanning based on dynamic error compensation according to claim 1, the method is characterized in that the step S5 specifically comprises the following steps: S501, acquiring a scanning path interval based on the space boundary and the precision requirement of a region to be scanned, and generating an initial pre-planning path point sequence by adopting a raster scanning mode; S502, acquiring a maximum allowable scanning speed based on the efficiency requirement of a scanning task, generating an initial scanning speed curve, and ensuring that the acceleration is smaller than or equal to a preset acceleration threshold; S503, inputting initial pre-planned path point coordinates, initial scanning parameters and current environment parameters into a space-time joint error correction model according to the space-time joint error correction model, and obtaining an error prediction value delta P_United of each path point; s504, carrying out reverse correction on the initial pre-planned path point based on the error prediction value delta P_United to obtain corrected path point coordinates; The calculation formula of the corrected path point coordinates is as follows: P_Revised(x,y)=P_Before(x,y)-ΔP_United; Wherein, P_Revied (x, y) is the corrected path point coordinates, and P_Before (x, y) is the initial pre-planned path point coordinates; S505, smoothing the corrected path point sequence to ensure that the first derivative of the path is continuous and avoid mechanical impact; S506, judging whether the prediction error is greater than the precision requirement or not based on the parameter-error association characteristic, and if so, adjusting the scanning speed v_ Adjusted =v __ Before× (epsilon/delta P_United) of the corresponding path segment, wherein epsilon is a precision requirement threshold; S507, acquiring initial compensation parameters under the current environment based on an environment error model, wherein the initial compensation parameters comprise a Temperature drift coefficient k_temperature and a Vibration error coefficient k_vibration, and storing the initial compensation parameters serving as initial values of real-time compensation into a correction parameter set; S508, selecting at least 3 verification points for local test scanning in the edge area of the area to be scanned based on the corrected path point sequence, the scanning speed curve and the initial compensation parameters, and obtaining the actual error of the test scanning; if the actual error of the trial scanning is smaller than or equal to the precision requirement, taking the corrected route as a final pre-planned route; if the actual error of the test scanning is greater than the precision requirement, updating the coefficient of the space-time combined error correction model, and re-executing the correction flow until the precision requirement is met.
  6. 6. The method for controlling low drift laser scanning based on dynamic error compensation according to claim 1, the method is characterized in that the step S6 specifically comprises the following steps: S601, transmitting the final pre-planned route data to a main control unit, and controlling a scanning galvanometer to start scanning according to the corrected path points and the corrected speed curve; S602, synchronously acquiring real-time position data, real-time temperature and real-time vibration acceleration in the scanning process based on a grating ruler position sensor and a temperature-vibration composite sensor; s603, acquiring real-time environment compensation quantity according to initial compensation parameters and combining environment data acquired in real time; the calculation formula of the real-time environment compensation quantity is as follows: ΔP_Environment_t=k_Temperature_true·(T_t-T_0)+k_Vibration_true·(a_t-a_0); Wherein Δp_environment_t is a real-time Environment compensation amount, k_temperature_true is an updated Temperature drift coefficient, and k_vibration_true is an updated Vibration error coefficient; S604, determining a real-time position error based on the real-time position data and the corrected pre-planned path points; The calculation formula of the real-time position error is as follows: ΔP(t)=P(t)-P_END; wherein, delta P (t) is real-time position error, P (t) is real-time position data, and P_END is corrected pre-planned path point coordinates; s605, filtering the real-time position error, and eliminating sensor noise to obtain a filtered error; S606, determining a total compensation amount based on the filtered error and the real-time environment compensation amount; The calculation formula of the total compensation quantity is as follows: ΔP(t)_Total=K_p·ΔP(t)_F+K_j·∫ΔP(τ)dτ+K_d·dΔP(t)_F/dt+ΔP_Environment_t; Where K_p is a scale factor, K_j is an integral factor, K_d is a differential factor, ΔP (t) _F is a filtered error, ΔP (τ) dτ is an integral term of the filtered error, dΔP (t) _F/dt is a differential term of the filtered error; S607, converting the total compensation amount into a driving voltage correction amount of the scanning galvanometer, and transmitting the driving voltage correction amount to a galvanometer driving module to complete real-time compensation, and obtaining compensated real-time position data; wherein, the formula of calculation of the driving voltage correction is: ΔU=ΔP(t)_Total/k_Sensi; Where k_ Sensi is the sensitivity coefficient; S608. determining a residual error Δp (t) _ Remains =p (t) _u-p_end based on the compensated real-time position data; Wherein P (t) _U is the compensated real-time actual position data; if the residual error is greater than the precision requirement, dynamically adjusting the PID control parameters to enable the residual error to be converged rapidly; s609, after the scanning task is completed, recording full execution data, compensation parameters and error data of the corrected route, and adding the full execution data, the compensation parameters and the error data into a scanned route database; s610, updating coefficients of the space-time combined error correction model through error data of the current scanning in the scanned route database, optimizing correction accuracy of the subsequent scanning, and completing closed loop optimization.
  7. 7. A low drift laser scanning control system based on dynamic error compensation for implementing the control method according to any one of claims 1-6, comprising: The system initialization and calibration module is used for building a laser scanning control system and completing initialization and static calibration, and establishing a system basic control model and an error reference; The data acquisition and storage module is used for acquiring multi-source data of a plurality of groups of scanned routes and carrying out structured storage to form a scanned route database; The error modeling module is used for acquiring the space boundary, the precision requirement and the environmental parameter of the area to be scanned, screening a key scanned route from a scanned route database, preprocessing key scanned route data and extracting error characteristics, and constructing a space-time combined error correction model; wherein the error modeling module comprises: The key route screening unit is used for acquiring the space boundary, the precision requirement and the environmental parameter of the area to be scanned and screening a key scanned route from the scanned route database; the route planning and correcting module is used for generating an initial pre-planned route of the area to be scanned and carrying out multi-dimensional dynamic correction on the initial pre-planned route based on the space-time combined error correction model; The real-time compensation and closed-loop optimization module is used for executing the corrected route to be scanned, synchronously collecting real-time state data and environment data in the scanning process, realizing real-time compensation and closed-loop optimization by combining a dynamic error compensation algorithm, and completing low-drift laser scanning.
  8. 8. The low drift laser scan control system based on dynamic error compensation of claim 7, wherein said error modeling module comprises: The data preprocessing unit is used for preprocessing the key scanned route data; The error feature extraction unit is used for extracting error features of the preprocessed key scanned route data; And the error model construction unit is used for constructing a space-time combined error correction model based on the extracted error characteristics.
  9. 9. The low drift laser scanning control system based on dynamic error compensation of claim 7, wherein said route planning and correction module comprises: An initial route generation unit for generating an initial pre-planned route of the area to be scanned; The error prediction unit is used for carrying out error prediction on each path point of the initial pre-planned route of the area to be scanned based on the space-time combined error correction model; the dynamic correction unit is used for carrying out multidimensional dynamic correction on the initial pre-planned route based on the error prediction result; And the correction verification unit is used for verifying the precision of the dynamically corrected pre-planned route and ensuring that the precision requirement of the scanning task is met.

Description

Low-drift laser scanning control method and system based on dynamic error compensation Technical Field The invention relates to the technical field of laser scanning control, in particular to a low-drift laser scanning control method and system based on dynamic error compensation. Background The laser scanning technology is widely applied to high-end fields such as precision manufacturing, laser measurement, microelectronic processing and the like, and the scanning precision directly determines the product quality and the detection reliability. Along with the continuous improvement of the precision requirements of the industry, the error problems caused by factors such as temperature drift, vibration interference and the like in the scanning process are more remarkable, low drift control and dynamic error compensation become core requirements for improving the laser scanning performance, and the research and development of the high-efficiency stable low drift laser scanning control system has important engineering application value and practical significance. The existing low-drift laser scanning control method and system based on dynamic error compensation do not fully integrate multidimensional error characteristics such as space time, environment and the like, so that the error prediction precision is insufficient, the route correction lacks accurate error prediction supporting and verifying links, the correction effect is unstable, meanwhile, the real-time compensation and closed loop optimization cooperativity is poor, the environment and state change in the scanning process are difficult to dynamically adapt, the whole-flow low-drift high-precision scanning requirements cannot be effectively guaranteed, and the low-drift laser scanning control method and system based on dynamic error compensation are needed to solve the problems. Disclosure of Invention In order to solve the technical problems, the technical scheme provides a low-drift laser scanning control method and system based on dynamic error compensation, which solve the problems that the existing low-drift laser scanning control method and system based on dynamic error compensation provided in the background art is insufficient in error prediction precision due to insufficient fusion of multi-dimensional error characteristics such as space time, environment and the like, and the route correction lacks accurate error prediction supporting and verifying links, the correction effect is unstable, meanwhile, the real-time compensation and closed loop optimization cooperativity is poor, the environment and state change in the scanning process are difficult to dynamically adapt, and the requirements of the whole-flow low-drift and high-precision scanning cannot be effectively guaranteed. In order to achieve the above purpose, the invention adopts the following technical scheme: a low-drift laser scanning control method based on dynamic error compensation comprises the following steps: S1, constructing a laser scanning control system, completing initialization and static calibration, and establishing a system basic control model and an error reference; s2, collecting multi-source data of a plurality of groups of scanned routes and carrying out structural storage to form a scanned route database; s3, acquiring space boundaries, precision requirements and environmental parameters of an area to be scanned, and screening key scanned routes from a scanned route database; s4, preprocessing the key scanned route data and extracting error characteristics to construct a space-time combined error correction model; S5, generating an initial pre-planned route of the area to be scanned, and carrying out multi-dimensional dynamic correction on the initial pre-planned route based on the space-time combined error correction model; S6, executing the corrected route to be scanned, synchronously collecting real-time state data and environment data in the scanning process, and realizing real-time compensation and closed-loop optimization by combining a dynamic error compensation algorithm to complete low-drift laser scanning. In an alternative embodiment, step S1 specifically includes: s101, acquiring the precision requirement and scanning range of a laser scanning task, and determining hardware parameters of a laser emitting module, a biaxial scanning galvanometer, a grating ruler position sensor, a temperature-vibration composite sensor and a main control unit; S102, building a laser scanning control system comprising a laser emission link, a scanning execution link, a feedback detection link and a main control link based on the hardware parameters; s103, determining a communication protocol standard preset by the system, further acquiring communication interface parameters of each module, and completing communication initialization of the main control unit and each hardware module; S104, acquiring basic parameters of a target scanning range, scanning frequency and spo