Research On Accurate Stopping And Fault-tolerant Control Of Electric Multiple Unit System Based On Multi-mass Model

As one of the mainstream ways of passenger and freight transportation,railway transportation system has developed rapidly in China for its fast speed,strong transportation capacity,low cost,safety,reliability and other advantages.With the support of advanced technology,the train operation control system not only ensures the safe operation of the train during high-speed running,but also realized automatic driving of trains in some operating lines.The rapid development of train operation control technology is inseparable from the advanced control strategy.The control strategy with good performance can not only control the Electric Multiple Unit(EMU)system to run in different operating environments with high control accuracy,but also ensure the EMU system to run safely when faults occur.In this thesis,a multi-mass dynamics model of EMU is established for it’s operation control in different states.The parameter adaptive control strategy is applied to improve the control precision of EMU accurate stopping and tracking operation,and the controller is designed by using the Controlled Lagrange function method to ensure the safety and reliability of EMU operation control under the actuator fault.The internal structure of EMU is complex,and the dynamic characteristics of its model are nonlinear.The precise dynamic model is helpful for the controller to realize more safe and accurate control of EMU.In order to further improve the control accuracy of EMU,this thesis analyzes the dynamic characteristics of EMU in different operating conditions according to the existing theoretical basis and the control mode of EMU traction/braking.At the same time,the influence of environmental factors and the interaction between each compartment during the operation of EMU is considered.Taking each power unit of EMU as a mass point,a multi-mass dynamic model is established which can better describe Electric Multiple Unit’s actual operation conditions and more suitable for the multi-mass dynamic model of power distributed EMU.At the same time,the model makes up for the limitations and deficiency of single mass model of EMU.Based on the model,a dynamic model with unknown model parameters and an underdrive mechanical model for EMU under the condition of single power unit failure are established.On the premise of Electric Multiple Unit’s equipment normal operation,this thesis studies and analyzes the control problems of accurate parking and tracking operation of EMU.Considering that EMU is affected by its own internal factors and environmental factors during operation,its model parameters are uncertain and stochastic.Based on the multi-mass model of EMU,a dynamic model with unknown model parameters is established.The parameter adaptive control law is designed by using the speed deviation and position deviation of EMU in the process of running to deal with the different braking force due to stochastic and uncertain distribution of passengers along carriages.At the same time,a parameter estimation law with parameter error was designed to estimate model parameters in real time,so that the control law can realize the EMU asymptotically tracking the desired trajectory,and effectively cope with the randomness of EMU dynamic model parameters.To prove the asymptotic stability of the proposed control algorithm,a Lyapunov function with parameter estimation law was constructed,and the input-output stability theory was applied to prove it.Different from the traditional EMU single mass model,the algorithm proposed in this thesis has the advantage of ensuring the stopping accuracy of all power units.Aiming at the safety operation control problem of EMU when traction or braking actuator fault,a control strategy based on Controlled Lagrangians(CL)is applied to realize fault tolerant control of EMU in the state of signal power unit failure.Firstly,the nonlinear and coupled multi-mass underactuated mechanical model of EMU under the failure state of single power actuator unit is built.Secondly,the CL function is constructed by using the expected controlled energy and generalized force,and the matching conditions of kinetic energy and potential energy between the controlled equation and the original equation are obtained.By simplifying and solving the partial differential equations in the matching conditions,a nonlinear smooth feedback control law is obtained which enables the system to achieve global asymptotic stabilization of position and velocity simultaneously.Finally,the controlled energy is selected as Lyapunov function,and La Salle invariant theorem is used to prove its asymptotic stability.The proposed algorithm not only fully reflects the nonlinear characteristics of EMU model,but also enables the closed-loop system to converge rapidly with a large convergence range.