Research On Optimal Control Strategy Of Pantograph-catenary System Of High-speed Railway Based On LQR

Along with the increase of the speed of the train,the vibration of the contact force between the pantograph and the catenary becomes more severe,and the current reception quality of the pantograph and the catenary system will be decreased.On the premise that the improvement conditions of pantograph-catenary system structure are limited,this paper uses LQR optimal control algorithm to optimize the pantograph-catenary coupling control system,and then uses genetic algorithm to optimize LQR control algorithm to improve the current collection quality of pantograph-catenary system.The main research work of this paper includes:First of all,DSA350 S and SS4 collectors are chosen as the research object,and the pantograph-catenary dynamic simulation model is established.At the speed of 250km/h,the contact force and the longitudinal displacement evaluation index of pantograph-catenary system under passive control are analyzed,and the current receiving situation of pantographcatenary system without LQR optimal control is determined,so that the simulation results can be compared with LQR control method.Secondly,according to the time-varying characteristics of pantograph-catenary system,the LQR optimal control strategy is adopted to optimize it,Furthermore,LQR optimal active control is used to control the collecting and catenary system.The time-varying feedback gain matrix is obtained by combining the control performance index with Riccati equation through the state feedback law,and the active control force is output through it.Then,based on this,the Hrovat control algorithm is introduced to change the active control into the active variable damping control,that is,the LQR optimal semi-active control.At the speed of 250km/h,the pantograph is subjected to active variable damping force through model simulation,Finally,the optimum results of the contact force and the longitudinal displacement of the DSA350 S and SS4 pantographic catenary system are obtained by using the two LQR control strategies.The results indicate that these two methods are effective in improving the dynamic performance of the catenary system.Finally,in view of the difficulty of the LQR optimal control matrix,the weight matrix is optimized with the global search capability of the genetic algorithm.Firstly,the standard deviation of contact force and bow head displacement is selected as the optimization objective,and the fitness function is designed by real number coding.All initial solutions are assigned to the weight matrix in turn according to heredity,and the weight matrix is optimized under the constraints of high-speed railway technical standards,so as to obtain the optimal values of the weight matrices Q_dsa and Q_ss4,which are substituted into the LQR optimal controller to obtain the state feedback control gain matrix,which can reduce the vibration amplitude of contact force and bow head displacement and make the pantograph-catenary system receive current stably.