Research On Robust Control Of Permanent Magnet Synchronous Linear Motor Servo System Based On QFT Strategy

This thesis takes the servo control system of permanent magnet synchronous linear motor as the research object,considering the characteristics of direct drive of permanent magnet linear motor and the requirements of strong robustness and fast tracking of the servo control system,based on quantitative feedback theory,a robust control method for permanent magnet synchronous linear motor servo system is proposed.The main work is as follows:（1）According to the principle structure and electromagnetic theory of permanent magnet synchronous linear motor,the mathematical model of permanent magnet synchronous linear motor is established,and the electromagnetic thrust equation and mechanical motion equation of permanent magnet synchronous linear motor are introduced.At the same time,uncertain factors existing in the operation of the permanent magnet synchronous linear motor servo control system are analyzed.（2）In order to reduce the influence of the uncertainty of permanent magnet synchronous linear motor servo control system on the actual operation performance of the motor,a design method of permanent magnet synchronous linear motor servo control system based on QFT strategy is proposed.The performance indicators of the permanent magnet synchronous linear motor servo control system are quantitatively calculated,and the frequency domain boundary of the servo control system is obtained,and the frequency domain boundary is drawn on the Nichols diagram.By continuously changing the gain and adding and adjusting the zero and pole,the loop is formed on the Nichols diagram,and the transfer function of the QFT controller is obtained.In order to make the control system meet the servo tracking requirements,the design of the pre-filter is completed,and the simulation model of the control system is built.The simulation results show that the QFT controller designed in this thesis meets the control index requirements of the servo system and has strong robustness to system parameter changes,and has a good inhibitory effect on external disturbances.（3）There are many inconveniences such as drawing and trial and error when using QFT for controller design.Therefore,on the basis of QTF control,this thesis proposes two control methods:hybrid QFT/H_∞control and quadratic inequality QFT control,and uses the H_∞controller solution method and quadratic inequality controller solution method to replace the tedious drawing process in the design of the conventional QFT controller,and obtains the transfer function and pre-filter of the two hybrid controllers.In order to verify the actual control effect of the two hybrid controllers,a simulation model of the permanent magnet synchronous linear motor servo control system was built,and the two hybrid control methods were compared with the conventional QFT control.The simulation results show that the hybrid QFT control strategy can effectively improve the robustness and tracking of the permanent magnet synchronous linear motor control system,and the control performance is better than the conventional QFT control.