Periodic Input Signal Tracking Control Of Permanent Magnet Linear Servo System

The thesis takes the background with National Natural Science Foundation of China,and takes the permanent magnet linear motor (PMLM) direct drive servo system asresearch object. According to the characteristics of the controlled object itself and CNCmachine tool servo system for tracking performance and robustness requirements. Thetraditional control method has been unable meet it. So combine the internal modelprinciple control, sliding mode control, repetitive control based on disturbance observerand so on including others theoretical and method study for the system periodicdisturbance and parameters uncertainties. The main research contents are as follows：Firstly, on the basis of reading a large number of domestic and overseas literatures,the thesis introduce linear motor and Periodic input signal tracking control developmentsituation in domestic and overseas. And the existent questions in linear motor servo systemcontrol.In the second chapter, in the form of combination of theoretical analysis andsimulation, analyzes the basic structure, working principle and mathematical model ofPMLM, and the vector control (i d=0) method is established. Because of CNC machinetools and other machining precision displacement tracking control high demand, so thisthesis targeted design can effectively inhibit the end effect, load disturbance and parameterchanges of displacement control. The high precision tracking of periodic input control, andeliminate the periodic interference effectively.For linear motor adopts direct drive method, vulnerable to the influence of uncertaintyfactors, uncertainties include: system parameter variations and load disturbances, endeffect and the cogging effect and so on, this thesis adopts the sliding mode control strategybased on internal model principle, the internal model principle is applied to sliding modecontrol, sliding mode control for the system parameter change and paroxysmal interferencehas strong robustness, but because of physical limitations that sliding mode control is chattering phenomenon, and periodic interference suppression effect is not as good as theinternal model principle controller. Internal model principle controller can effectivelyeliminate the influence of periodic interference, but its robustness to system parameters isnot strong. Therefore, combining both the advantages of the system in inhibiting periodicinterference effectively at the same time also made the system parameter mutation hasstronger robustness.For permanent magnet linear motor servo system in periodic disturbance eliminationand the periodic reference input tracking problem, interference is proposed in this thesisbased on sliding mode observer of repetitive control and displacement compensationcontroller with pole assignment method in the design, make the system dynamic error canbe controlled, the plug-in repetitive control system to feed forward compensation ofdisturbance error, periodic interference suppression, the sliding mode disturbance observerto compensate the repetitive control problem of poor robustness, and improve the robustperformance of the system. The simulation results show that the scheme can effectivelysuppress the periodic disturbance, and has strong robustness.