| Permanent magnet linear synchronous motor（PMLSM）has the advantages of precise positioning,high reliability,large thrust,fast response and so on.It is widely used in various linear motion equipment,such as industrial processing,transportation,military,automation and other fields.However,due to the PMLSM simplifies the mechanical transmission structure,there is no buffer of intermediate mechanical links,so that a series of uncertain factors such as external disturbance,nonlinear friction and end effects of the system directly act on the linear motor,in this way,the tracking performance and robustness of the system in actual work will be affected to a certain extent,which increases the control difficulty of PMLSM.Therefore,this thesis designs a mixed H2/H∞control based on linear matrix inequality（LMI）and a mixed H2/H∞control based on intelligent algorithms to improve the tracking performance and robustness of the system.Firstly,this thesis mainly describes the structure and basic working principle of PMLSM,and analyzes the disturbance factors that affect the PMLSM system.On this basis,using the vector control method of di=0,the mechanical motion equation is obtained through the flux linkage equation,voltage balance equation and electromagnetic thrust equation of PMLSM.Then,the PMLSM mathematical model considering the external disturbance,nonlinear friction force and end effect is established.Secondly,on the premise of understanding the optimization method of linear matrix inequality and robust control,a robust H∞control based on LMI is designed.Through MATLAB software simulation,it can be seen that compared with the traditional PID control,the H∞robust control better guarantees the robust stability and tracking performance of the system.In order to improve the dynamic performance of the system,on this basis,a mixed H2/H∞robust control based on LMI is designed.By comparing the simulation results,it can be found that the mixed H2/H∞robust control can accelerate the convergence speed of the system,effectively reduce the tracking error,and simultaneously take into account the robust stability of the system.Finally,In order to reduce the complexity of the solution of the inequality system,the variable substitution method is adopted by the LMI optimization method when solving the mixed H2/H∞robust control problem,this makes the LMI optimization method conservative in solving the problem to a certain extent,and then affects the accuracy of the controller results.Therefore,the particle swarm optimization algorithm in the intelligent algorithm is used to deal with the mixed H2/H∞robust control problem,and the obtained controller performance is simulated and analyzed.Compared with the LMI optimization method,it can be concluded that the mixed H2/H∞robust control based on particle swarm optimization algorithm can obtain better and more accurate control results,thus improving the tracking performance and robustness,so that the PMLSM system has a better control effect. |
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