Fault Diagnosis And Tolerant Control For High Speed Maglev Train Suspension System

As a kind of ground transportation vehicle with a design speed of more than 500 kilometers per hour,the high-speed maglev train is mainly used to solve the problem of rapid transportation between big cities.The suspension system is the core system of high-speed maglev trains,and its performance directly affects the safe and reliable operation of high-speed maglev trains.On the basis of the electromagnetic suspension type high-speed maglev train,the National University of Defense Technology proposed a new type of permanent magnet electromagnetic suspension(PEMS)type high-speed maglev train,which has the advantages of low suspension energy consumption,strong carrying capacity and no easy heating of the electromagnet.In this paper,with the PEMS high-speed maglev train taken as the background,and the joint structure suspension control system taken as the research object,the fault diagnosis and fault-tolerant control of the joint structure suspension system are studied.On the basis of the establishment of the system mechanism model and the design of the nominal controller,the effects of the suspension system failure and the fault characteristics of the permanent magnet electromagnetic hybrid suspension system are analyzed.Based on the controller parameterization theory,a unified fault diagnosis and multi-level fault-tolerant control scheme for high-speed maglev train suspension system is proposed.Combined with the mechanism model and input and output data of suspension system,a residual and data driven based fault diagnosis method for suspension system is proposed.For incipient faults,a fault-tolerant control strategy based on online update of control parameters is proposed.Aiming at the serious system failures,fault-tolerant control methods based on signal reconstruction and switching strategy are proposed.The main achievements and innovations of this paper are as follows:(1)For the PEMS high-speed maglev train suspension system,with the joint structure treated as the basic function unit,modeling analysis and design of the controller have been done firstly.By simulating the system responses under typical faults,the suspension performances of PEMS system and EMS system under the same fault conditions are compared and analyzed,and the influence of the residual permanent magnet on the system performance after fault is analyzed.(2)The merits and demerits of fault-tolerant controller design using different realization forms of Youla parameterization principle are analyzed,and the applicability of different fault-tolerant controller design methods in high speed maglev train suspension system are analyzed.Combined with the characteristics of the suspension system and the impact of various types of faults,an overall unified scheme for fault diagnosis and multi-level fault-tolerant control for different fault situations is proposed.On the basis of residual generator,fault diagnosis and tolerant control for suspension system are dealt with in a unified architecture.By independent processing of residual,an integrated implementation of fault diagnosis and fault toleratn control can be accomplished.(3)The mathematical model of the residual generator and the steps of identifying the residual generator based on the system input and output data are given.Fault detection is accomplished by acquiring the statistical distribution law of residuals,and the fault isolation is completed by the method based on amplitude/angle.On the basis of the above steps,the unanticipated fault diagnosis method is used to confirm the fault isolation result again,which improves the reliability of the fault isolation result.The principal component analysis method is used to map the fault vector to the three-dimensional visual space to make the fault diagnosis result more intuitive and make it easier to analyze complex fault conditions.(4)In the case of incipient faults such as partial demagnetization and partial damage of permanent magnets that may occur in permanent magnet electromagnetic hybrid suspension systems,an active fault tolerant control method independent of fault diagnosis result is proposed.For this fault tolerant control method,the control parameters is updated online and irregularities like intermittent and time varying can be overcome.(5)In the case of accelerometer failure,the reconstruction of the gap differential signal is accomplished by using the tracking differentiator.In the case of single gap sensor failure,aiming at solving the problem of suspension system passing through the track joint,a method of reconstructing gap signal by using accelerometer signal and correcting the reconstructed gap signal by using the difference of current signals on both sides of the joint structure is proposed.In the case of single suspension point failure,the faulty system model is analyzed,and the corresponding fault tolerant controller is designed.The fault-tolerant control purpose for single suspension point failure is achieved by switching the control signal input source between the nominal control and the fault tolerant controller.A PEMS type high speed maglev train suspension system is built up,software control programs are designed and corresponding experimental tests are carried on.The fault diagnosis and fault-tolerant control methods for high-speed maglev train suspension system proposed in this paper have been applied to PEMS high-speed maglev train.The algorithm simulations have positive reference value for subsequent researches and can be extended to the development of the new type high-speed maglev train with speed of 600 km/h.