Study On Optimal Preview Tracking Control For ATO System

In order to meet the high efficiency and high density demand of urban railway traffic system,automatic train operation(ATO)can use ground information to control train traction and brake system which can at last realize the train's automatic operation on the premise of safety,punctuality,energy-saving and comfort.Speed tracking and precise train stop are the key technologies for ATO system.Speed tracking can follow the operation type profile with the constraints of safety and comfort which will influence the precision of train stop.Stop precision is required within ±30 cm.If the train doesn't stop in this range,it will influence the passenger's getting on and off and be also possible to affect the communication between ground and train with the consequences of delays,etc.So,it is of great significance to conduct study on speed tracking of operation type profile and precise train stop.This thesis takes automatic train operation system as control object and aims at realizing high-precision speed tracking performance on the premise of safety,comfort and precise train stop.After analyzing the automatic train operation process and with the combination of train traction calculation system,the Pade approximation method is used to handle the traction system and brake system with delay and the train model is built.Due to the critical stability of train model,the stable train model is proposed with the state feedback's pole-placement method.Based on the stable train model,the optimal preview tracking control is introduced on taking operation type profile as target and additional resistance and basic resistance as disturbance.After analyzing and setting constraints and control parameters,MATLAB simulation platform is built for verifying the correctness of the optimal preview tracking control method under different line disturbances.In order to restrain the disturbance caused by modelling error and resistance,disturbance observer is added to optimal preview tracking control.On taking the observation value of disturbance as equivalent disturbance input,the robustness of the system is enhanced.Simulation results show the optimal preview tracking control method based on disturbance observer has good robustness,and with the existence of disturbance caused by modelling error and resistance,the value of disturbance can be observed precisely and the performance on speed tracking and train stop precision is better by using this method.