Research On Linear Motor Motion Control Based On Friction Compensation And State Observation

With the increasingly fierce competition in the advanced manufacturing industry and the rapid development of emerging industries such as integrated circuit semiconductors,the demand for precision machining and manufacturing is strong,and higher requirements are placed on the accuracy of the motion control system.The direct drive system represented by the linear motor eliminates the intermediate transmission mechanism and can achieve high-precision tracking control.It has been widely studied and applied in precision motion control systems.This dissertation focuses on the friction compensation and output feedback in the linear motor motion control system.The controllers is designed for the uncertainty of the system’s parameter changes,modeling errors and external disturbances,and the control effect is verified by simulation and experiment.First of all,the microscopic mechanism of friction is introduced,and the nonlinear dynamic process and related characteristics of friction are explained and analyzed.For the friction model-based compensation method,the commonly used static and dynamic friction models are compared,and the LuGre dynamic friction model is selected for subsequent compensation control.Then the dynamic model of the linear motor system is established,and the specific method of system identification is given based on the LuGre model.Secondly,in view of the uncertainties such as parameter changes,modeling errors and external disturbances in the system,adaptive and robust controllers are designed separately through the design idea of backstepping,and then an adaptive robust control strategy that effectively combines the two is derived.And built an adaptive robust controller based on the LuGre dynamic friction model,and verified its control effect through simulation experiments.Thirdly,to solve the problem of unmeasurable part of the states of the system,an extended state observer is introduced to realize speed estimation and disturbance compensation.By combining the disturbance compensation of the extended state observer into the adaptive robust control,the original performance is guaranteed and the robustness of the system is further improved.When the speed is unmeasurable,the expanded state observer is used to estimate the speed and disturbance at the same time,and the controller is designed in combination with parameter adaptation,which achieves a good control effect.Then the LuGre friction model is added to the system to further improve the accuracy of the system,and the performance of the system and the effectiveness of the method are verified through simulation experiments.Finally,a linear motor experimental platform is built and experimental analysis is performed to verify the tracking performance and effectiveness of the control method.The experimental results show that the use of LuGre friction model for compensation effectively improves the tracking accuracy of the system,and the designed adaptive robust controller has excellent control performance.The extended state observer achieves reliable estimation of the speed state and effective compensation of disturbances.