Research On Synchronous Coordinated Braking And Stability Control Of Travel Trailer

With the development of domestic economy,the improvement of people's living standards and the improvement of relevant laws and regulations,travel trailer has shown great market potential in China.As one of the factors affecting vehicle driving safety,braking performance has always been the focus of attention.Because of the convenient connection/separation requirement between tractor and travel trailer,the flexible disassembly and connection ball head mechanism is equipped.While ensuring the flexible disassembly and assembly,braking instability is more likely to occur than that of conventional semi-trailer,and even dangerous accidents such as folding and tail rejection may occur under extreme working conditions.Therefore,it is of great significance to study the braking stability of travel trailer for ensuring safety.In this paper,through the theoretical analysis of kinematics and dynamics of travel trailer,with the help of Kalman filter and sliding mode control,the key issues such as braking model establishment,state estimation,synchronous braking control,differential braking control,test platform construction and controller development are discussed.The following research is mainly carried out in this paper:(a)The tire model,suspension model,electromagnetic brake model with electromechanical coupling characteristics and hook model with flexible connection characteristics are established.On this basis,the kinematics and dynamics of the travel trailer are analyzed,and the steering and braking mathematical model of the 19 DOF travel trailer is built.The accuracy of the simulation model is verified by using TruckSim software.(b)In order to improve the straight-line braking stability of travel trailer,based on the synchronous braking model and Kalman filter algorithm,the longitudinal hook force estimator of travel trailer is designed.By introducing terminal sliding mode variable structure control algorithm,the dynamic equation of the error between the estimated value of longitudinal hook force and the target value is established,and the synchronous coordinated braking of tractor and trailer is realized.(c)On the basis of straight-line synchronous braking,in order to ensure the stability of the vehicle's steering braking and good driving path,a differential braking control method for the trailer based on articulation angle and yaw angular velocity is proposed.By establishing the estimation model of articulation angle of travel trailer in steady state,introducing multi-objective PID weighted control algorithm and multiobjective PID coordinated control algorithm,applying the control principle of differential braking to control yaw moment,good yaw stability and driving path are achieved when the travel trailer steer and brake.(d)The co-simulation model of TruckSim and MATLAB/Simulink is built to verify the effectiveness of the control strategy of straight-line synchronous coordinated braking and steering differential braking for travel trailer;The real vehicle of travel trailer is built and road test is carried out.The synchronous brake controller of travel trailer is developed.The step braking test of travel trailer under different steering conditions is carried out to verify the accuracy of braking model of travel trailer and state estimation and the effectiveness of synchronous braking control strategy.