Study On Coupling Disturbance Suppression And Cooperative Control Of EMS Maglev Multi-point Suspension System

The suspension system is the key system of EMS maglev train.It depends on the suction between electromagnet and steel track to keep the vehicle in contactless suspension state.It is a typical open-loop unstable system,which must be stabilized by feedback control.In addition,in the process of vehicle suspension,the system has nonlinear dynamic characteristics,which is easy to be affected by external interference such as track irregularity,traction motor normal force,vehicle aerodynamic load,mechanical braking,disturbance force caused by signal,and internal coupling disturbance caused by the above comprehensive factors.The maglev suspension frame realizes the levitation function under the common support of multi-point suspension system.How to overcome the external disturbance and internal coupling disturbance and realize the coordinated output of each levitation point brings a great challenge to the design of suspension controller.In recent years,many achievements have been made in the research of EMS type suspension control systems of medium and low speed maglev trans,but the problems and shortcomings still exist as follows: 1)The controller design of single point suspension system is mostly based on current feedback,and the stable region of control parameters is small,which lacks the exploration of the control method based on flux density feedback;2)In the model of single-point suspension system,the coupling disturbance between multi coils is often ignored,and the research on restraining the coupling disturbance in multi-point suspension system is lacking;3)For the electromagnet with two or more independent control loops,the cooperative control research between the multi-point suspension system of electromagnet is lacking;4)For the two electromagnets on both sides of the suspension chassis,there is few research on the cooperative control between the multi-point suspension system of the suspension chassis.In this paper,EMS type medium and low speed maglev train suspension system is selected as the specific research object.Aiming at the above problems and challenges,the adaptive sliding mode control with flux density feedback,feature modeling and coupling disturbance suppression,H? controller design,multi-point suspension system cooperative control and other solutions are studied in depth.The specific work and contributions are as follows:1.A dynamic model of single point suspension system based on flux density is established.A hybrid flux density observer is designed,which combines current mode and voltage mode.An adaptive sliding mode controller based on flux density feedback is proposed.A hardware in the loop simulation platform based on d SPACE system is established.The response effects of the proposed controller and PID controller are compared by simulations and experiments,and the anti-disturbance performance of the adaptive sliding mode controller is verified.(Chapter 3)2.The characteristic model and disturbance suppression method of a single point suspension system considering the coupling interference of the multi-point suspension system are proposed.The general dynamic model of the suspension system is transformed into the characteristic model,the latter,taking the suspension gap as the control target.The least square method with forgetting factor is used to identify the characteristic model coefficients and calculate the estimated range of each coefficient.The improved generalized predictive control method(JGPC)is obtained based on the generalized predictive control method(GPC).The effectiveness of the method to suppress the internal coupling disturbance is verified by simulations and experiments.(Chapter 4)3.In order to optimize the suspension performance of multi coil(multi-point suspension system),the cooperative control method of single side electromagnet multi-point suspension system is studied.H? control algorithm is used to improve the anti-disturbance and robustness of each single point suspension system.The anti-disturbance performance of adaptive sliding mode controller based on flux density feedback,JGPC controller based on characteristic model,H? controller and traditional PID controller are compared by simulations,and the control strategy with the best anti-disturbance performance is selected as the basic control scheme of single point suspension system;According to the dynamic equation of multi-point suspension system,the open-loop state space equation is obtained.By cross coupling the suspension airgap and the change speed of the airgap,and cooperating with the output of the suspension airgap,the coupling disturbance inside the multi-point suspension system is reduced and avoided,and the control accuracy and anti-disturbance ability are improved.The synchronous error analysis of the output of the cross coupling controller is carried out to determine the stability of the system.The numerical simulation results show that the cooperative control algorithm has obvious effect on improving the anti-disturbance ability of the multi-point suspension system.(Chapter 5)4.Based on the cooperative control strategy of the electromagnet multi-point suspension system,the output synchronization of the suspension chassis is coordinated by the adjacent cross coupling synchronous control algorithm,so as to further improve the stability and anti-disturbance ability of the suspension system.Based on the four-points suspension system,a single suspension chassis experiment platform is established.It is verified that when a suspension point of the suspension chassis is disturbed by the impact force and the airgap deviates,the cooperative control system can adjust the relative error in time,so as to improve the overall suspension performance of the suspension frame and enhance the comprehensive anti-disturbance ability of the suspension chassis.(Chapter 6)...