Research On Position Tracking And Cooperative Control Of H-type Motion Stages Driven By Linear Motor

With the progress of technology and the increasing demand for higher processing quality and efficiency,linear motor driven H-type stages motion systems have become a crucial component of modern high-end manufacturing equipment.To meet the requirements of high-performance for direct drive H-type stages in high-end manufacturing equipment,such as high speed and precision,the direct drive H-type stages servo system must possess high-quality single-axis position tracking ability and efficient cooperative motion ability between axes.Position tracking performance of servo system with high dynamic response and steady-state accuracy is a prerequisite for improving the cooperative control ability of the direct drive H-type stages.Meanwhile,the efficient cooperative motion ability between axes is the key to achieving high-performance processing of the direct drive H-type stages.However,the disturbance sensitive structural characteristics of linear motor and the mismatch of servo dynamic characteristics between axes bring great challenges to the design of high-performance controller for direct drive H-type stages servo systems.This thesis focuses on the direct drive H-type stages as the research object and investigates key issues,such as position tracking,parallel-axis synchronous motion,and multi-axis contour control of the direct drive servo system.The main research content comprises the following parts:The key to achieving high-speed and high-precision operation of the direct-drive H-type stages is high-performance position tracking control of the single-axis servo system.To address the matching and mismatching disturbances as well as uncertainties in the friction parameters of a real single-axis direct drive servo system,this thesis proposes a nonlinear integral robust control method based on adaptive friction compensation.This method introduces two auxiliary error variables into the backstepping design framework and integrates the nonlinear integral robust feedback term to eliminate the influence of disturbances.Additionally,an adaptive law based on the given position input is designed to compensate for parameter perturbations and reduce the conservatism of the nonlinear integral robust controller.In this thesis,the stability of the closed-loop system is analyzed and proved by means of Lyapunov stability theory,and the range of control parameters required to keep the system stable is obtained.Simulation results verify the effectiveness of the proposed control strategy.To achieve precise cooperative control of the direct drive H-type stages and overcome the influence of mechanical coupling,parameter mismatch,and other factors on its synchronous motion performance,a synchronous control strategy is proposed.The strategy is based on a coupling parameter identification algorithm and a feedback linear decoupling controller.The response of the linear motor with zero position input in the stages system is considered as disturbance.The coupling parameter identification algorithm based on disturbance observer is designed,and the convergence analysis is carried out.To improve identification accuracy,the orthogonal characteristics of trigonometric functions are used to separate the parameters of coupling stiffness and coupling damping.Based on the identified coupling parameters,it is demonstrated that the coupling model meets the necessary and sufficient conditions of feedback linearization control.Decoupling between the two-axis servo systems is achieved through coordinate transformation and state feedback,thereby avoiding high-order dynamics that may be caused by the internal forces of coupling between the axes.Furthermore,a robust synchronization controller is designed to enhance the robustness of the decoupled linear system.Finally,simulation results confirm the effectiveness of the proposed control strategy.Based on the final requirements for contour tracking of direct drive H-type stages in practical applications,a robust contour control strategy for H-type stages driven by centroid is proposed.This strategy solves the problem that the synchronization error and system load change affect the contour tracking accuracy when the system tracks the nonlinear trajectory,and ensures the smooth and high-performance cooperative operation of the stages.The multi-axis contour motion changes the mechanical characteristics of the system,which leads to the coupling of motion state and redundant driving force.Therefore,a mathematical model of the direct drive H-type stages is established.This model fully characterizes the coupled nonlinear dynamic behavior of the system under the action of load change,driving force and unknown disturbance,and embodied the dynamic and kinematic coupling.In order to improve the cooperative motion ability between axes,a chain error model is constructed by unifying the error types to ensure the high precision control of the system.A robust contour controller is designed with chain error as the state variable to cope with the influence of load changes on the control accuracy of the system.The effectiveness of the proposed control strategy is verified by simulation.Experimental verification and comparative analysis are performed to evaluate the motion control strategies proposed in this thesis.The direct drive H-type stages control system is constructed using hardware components such as the Power PMAC motion control card,linear motor,driver,and grating ruler.The motion system control program is developed using Matlab/Simulink software and Power PMAC controller debugging software.The nonlinear integral robust control based on friction compensation,the decoupling synchronization control based on coupling parameter identification and the robust contour control based on centroid-driven H-type stages are carried out carried out.The experimental results demonstrated the feasibility and effectiveness of the proposed control method.