High-speed Train Braking Control Based On Characteristic Model

As the running speed of trains continues to increase,the operating environment of trains deteriorates sharply,high-speed trains are also more sensitive to unknown external disturbances,the dynamic behavior of trains is more non-linear,and the time-varying model parameters and even uncertain model parameters lead to It is difficult to establish an accurate dynamic model of high-speed trains in practice.The design of brake controllers for high-speed trains is highly dependent on their models.The time-varying,uncertain and random interference of model parameters makes it difficult to determine their precise dynamic models.This paper establishes the characteristic model of high-speed train,and design the optimal PID controller for the feature model of high-speed train under the constraint of the quadratic optimal control performance index.The models and the design process of controller mainly includes:(1)For the high-speed train dynamics model's nonlinear,parameter time-varying,etc.,analyzing the high-speed train braking system first.Including the composition of its braking system,braking method,braking deceleration curve and the source of braking force.Establish simple point dynamics model for high-speed trains,and analyze it's high-order information which based on the simple point model.(2)Analyzing the high-order model of the high-speed train,establish its characteristic model on the entire braking interval,and convert the high-order model into a second-order slow time-varying equation to facilitate the design of the controller.The second-order slow time-varying difference of the high-speed train,according to the time-varying characteristics of its parameters,it is determined by the method of system identification,that is,the data collected on the spot is used to identify the time-varying parameters using the least squares identification algorithm with forgetting factors.In addition,when the train brakes,the difference in the response of the brake systems of each car makes the nonlinear characteristics of the braking force in the initial stage of the train braking very obvious.In order to make the model more accurately describe the braking process,the train braking process is divided into the initial system.During the dynamic phase and the continuous braking phase,the characteristic models of the initial braking phase and the continuous braking phase of the high-speed train are established respectively.(3)For the high-speed train braking dynamics model,the input of the model is the braking force and the output is the running speed of the train.This single input and single output system is suitable for PID control structure.In addition,the PID control method has many advantages,such as simple structure and convenient debugging.In this paper,the design of the high-speed train brake controller is to design the optimal PID controller based on the characteristic model of the high-speed train under the constraint of the quadratic optimal control performance index.The control effect of the controller is simulated and verified.The simulation process mainly includes the tracking of the reference braking curveand the tracking of the actual speed curve.