Auto Disturbance Rejection Control Of PMSLM Based On Expanded State Observer

Direct thrust is produced and mechanical abrasion is reduced by linear motor without any conversion device.High gain and precise feed-forward are maintained by the system, the given processing path can be accurately tracked with high speed.However the system servo performance and precision machining are seriously affected when the motor internal parameters,end-effects and nonlinear factors are changed.Therefore,adopting a reasonable and effective control strategy to make linear motor "fast and stable" is an important thing in the industrial scene.Auto disturbance rejection control(ADRC) technique is a new type of digital control technique in which system model is not relied on,the algorithm in ADRC is simple,fast without overshoot,and the identification of accuracy is precise;the capabilities of tracking and anti-parameter disturbances are strong.Real-time estimation and compensation of system exterior and interior disturbances can be realized by ADRC with special nonlinear feedback structure to achieve good quality.In this thesis,ADRC is adopted to control permanent magnet synchronous linear motor(PMSLM) in order to harmonize the conflict issues between fast running and stability of PMSLM.Firstly,the mathematical model of permanent magnet synchronous linear motor is cleared.Secondly,theoretical foundation of auto disturbance rejection controller is researched,at the same time,the conception of "nonlinear" and "inverse control" can be introduced to control PMSLM forwardly.Tracking-differentiator, expanded state observer and nonlinear state error feedback are analyzed deeply,the significance of internal nonlinear function and parameters are all understood strongly. Again,ADRC schematic diagram of PMSLM is constructed,auto disturbance rejection controller of excitation current and speed for PMSLM are designed,at the same time, torque current controller is also designed.Then,after simplifying the part of system structure,the various parameters are tuned dynamically based on the practical experience and theoretical analysis.Abrupt change of external disturbances and internal parameters change disturbances of PMSLM are recognized as a total disturbance,and then can be observed and compensated dynamically through expanded state observer.Finally,a specific PMSLM is simulated by MATLAB.The results of simulation test indicate that the anti-disturbance ability and robustness of PMSLM are strong while the speed of start-up is rapid and the stable performance is excellent.Thus,the control effectiveness and feasibility of ADRC are proved.