Research On Rollover Control System Of Semi Trailer Train Based On Double MPC

With the rapid growth of China's economy,the transportation industry has developed rapidly.Semi-trailer trains have a broad space for development because of their advantages of comprehensive economic benefits in highway transportation.However,due to the complex structure,high center of gravity,relatively narrow wheel spacing,large aspect ratio,semi-trailer trains are prone to serious traffic accidents such as rollovers,resulting in huge losses of personnel and property.Therefore,the rollover control system of semi-trailer train is studied in this paper.Firstly,based on the principle of vehicle dynamics and using MATLAB/Simulink software,the simplified model of 5-DOF yaw and roll of semi-trailer train and 3-DOF yaw are built.Secondly,by improving the fitness value and adaptive crossover and mutation probability of genetic algorithm,an improved genetic algorithm is proposed.Based on the improved genetic algorithm,the eight key parameters of the vehicle mathematical model are identified under the angular step condition,and the identification results are verified by the design of double line-shifting condition,line-shifting condition and sinusoidal steering condition.The simulation results show that the mean-square error(MSE)between the output curve of the mathematical model and that of the TruckSim vehicle model is 0.0420 under the angular step identification condition and 0.1138 under the three simulation verification conditions,which meets the identification accuracy requirements.It shows that the parameters identified by improved genetic algorithm are accurate and effective,which makes the vehicle mathematical model can well represent the actual vehicle state,and provides a reliable vehicle mathematical model for the subsequent rollover control system research.Then,aiming at the research of rollover control strategy,based on the principle of model predictive control(MPC),a double MPC semi-trailer rollover control system with additional yaw moment controller and expected yaw angular velocity controller is designed.The additional yaw moment needed to restore the vehicle to its ideal running state is obtained,and the differential braking technology is used to realize each control system.The ABS control model was built to avoid wheel lock in the braking process.The control strategy was validated on high and low adhesion pavement under double line shifting conditions.The simulation results show that rollover occurs in 7.2s when rollover control is not applied on high-attached road surface,but after rollover control is applied,rollover does not occur in the whole simulation process,and the output state values of the vehicle converge.When the control is not applied on the low-attached road surface,the actual lateral offset of the vehicle increases and oscillates during the simulation process,but after the control is applied,the oscillation of the vehicle state becomes gentle.It shows that the rollover control system of Semi-trailer Train Based on double MPC can effectively avoid the instability of rollover,shimmy and folding,and improve the running stability of semi-trailer train.Finally,based on NI VeriStand Rapid Prototyping Development platform,a model-in-loop and hardware-in-loop real-time test system is established,and the test system is validated on high-and low-attachment pavement under double line-shifting conditions.The test results show that the model-in-the-loop and hardware-in-the-loop test system designed can run successfully,realize the comprehensive and systematic functional test of ECU,and have a certain practical significance for shortening the development cycle of semi-trailer train rollover control system and reducing the development cost.