Semi-active Control Strategy And Optimization Of Rail Vehicle Based On PID

With the increasing speed of rail vehicles in China,the smoothness of vehicle operation is becoming worse and the safety margin is gradually shrinking.At present,the vertical stability of rail vehicles in China can meet the basic requirements,but the lateral vibration of the vehicle body still leads to poor lateral stability of the vehicle,thereby affecting the safety of the vehicle.This phenomenon is mainly due to the parameter limitations of commonly used passive control suspension systems,which is difficult to meet the higher requirements for smoothness and safety when vehicles are running at high speeds.Improving and upgrading the control mode of the suspension system of rail vehicles is one of the effective methods to improve the vehicle dynamics performance.This paper takes a certain type of rail vehicle as the research object,and uses the method of MATLAB/Simulink and SIMPACK joint simulation to compare the optimization effects of four different control modes,namely,passive control,particle swarm optimization PID control,fuzzy control and particle swarm optimization fuzzy PID control.The specific work content is as follows:(1)Firstly,the three degrees of freedom rail vehicle model is taken as the research object,and the passive and semi-active Simulink models of the three degree of freedom rail vehicle are built with MATLAB.The semi-active model is controlled by particle swarm optimization PID control,fuzzy control and particle swarm optimization fuzzy PID control respectively,and the optimization effects of the three kinds of control strategies in lateral vibration reduction are compared and analyzed.(2)Secondly,a passive control dynamic model of the rail vehicle was established using SIMPACK software,and the dynamic performance of the vehicle during straight and curved driving was analyzed.The results indicate that as the vehicle speed increases,some dynamic indicators gradually deteriorate.When the vehicle speed reaches 350km/h,the Sperling index of the vehicle is 2.309,and the maximum wheel load reduction rate is 0.749,both approaching the limit value.This indicates that relying solely on the control of passive suspension systems is difficult to meet the requirements for smoothness and safety of vehicles during high-speed driving.(3)Finally,a joint simulation platform was established using simulation software MATLAB/Simulink and SIMPACK,and the feasibility and correctness of the joint simulation platform was verified.In Simulink,PID control algorithm,fuzzy algorithm and particle swarm optimization fuzzy PID algorithm is used to establish a semi-active control system,which is jointly simulated with the vehicle model in SIMPACK to achieve semi-active control of the vehicle’s secondary suspension lateral damper.The simulation results suggest that the particle swarm optimization fuzzy PID control has the best effect,the maximum improvement rate of the vehicle’s lateral acceleration can reach 50.8%,and the improvement rate of Sperling index is 23.5%.At the same time,the derailment coefficient of the vehicle has been optimized by 36.1%,and the other indexes have little difference with the passive control,which meets the vehicle dynamics performance indexes.