Research On Active Disturbance Rejection Control Strategy Of Maglev System

There is no contact between the suspension and the supporting body of the magnetic levitation system.Therefore the magnetic levitation system overcomes the energy consumption,the speed limit and other issues caused by friction.The magnetic levitation system has no pollution,no noise and be able to work under special circumstances such as dust-free.Because of the advantages of the magnetic suspension technique,it has been widely used in the field of traffic transportation industry,aerospace and industry etc..However,the maglev system has the characteristics of nonlinearity,uncertainty and high real-time requirements,which makes it difficult to design the controller for it.Taking magnetic levitation ball system with single degree freedom as the research object,the active disturbances rejection control is choose to achieve control system design of magnetic levitation system,which based on the comparison and analysis of several control algorithms of the magnetic levitation ball system.Aiming at the problem that the nonlinear function of the control law in active disturbance rejection control can cause excessive control action,and then lead to large overshoot under the disturbance,the linear/nonlinear active disturbance rejection compound controller is designed.Its control action is a kind of compound control law which is combined with linear and nonlinear state error feedback control law via weight factor or weight function.The introduction of linear state error feedback control law reduce the weight of nonlinear state error feedback control law in control action,which can avoid the problem of excessive control action caused by nonlinear function in nonlinear state error feedback control law.According to the different combination rule of linear and nonlinear state error feedback control law in compound control law,linear/nonlinear active disturbance rejection compound control is divided into two kinds: with weight factor and with weight function.Mainly from the perspective of fast performance,the linear/nonlinear active disturbance rejection compound control avoid the problem of large overshoot under disturbance caused by excessive control action which is caused by nonlinear function in control action.Considering of the weight of linear and nonlinear state error feedback control law in compound control law with weight factor will not change when the external system is changed,the weight factor isreplaced by the weight function which changes with system error.The compound control law with weight function can change the weight of linear and nonlinear state error feedback control law in compound control law with the change of system error.Thus,the linear/nonlinear active disturbance rejection compound controller with weight function can possess stronger anti-disturbance for the system with complex and volatile.The simulation results show that the designed linear/nonlinear active disturbance rejection compounded control with weight factor and weight function possesses better rapidity and stronger anti-disturbance ability than traditional active disturbance rejection control,and stronger anti-disturbance than PID.And the experimental results show that the linear/nonlinear active disturbance rejection compounded control with weight factor possesses stronger anti-disturbance ability and higher steady precision than traditional PID.