Research On Active Control Of Anti-rollover For Heavy-duty Semi-trailer Trains

Heavy-duty semi-trailer trains have become the main vehicle of medium and long-distance logistics transportation due to their high transportation efficiency,low operating cost and flexible combination.The heavy-duty semi-trailer has its own center of gravity,large weight and large wheel height relative to the height of the vehicle.The narrower and kinematic and dynamic coupling relationship between the tractor and the trailer makes it more prone to lateral instability,lateral rollover and "folding" during driving.Therefore,based on the theory of vehicle system dynamics,the study of active steering and direct yaw moment control strategies for heavy-duty semi-trailer trains is of great theoretical significance for effectively suppressing vehicle rollover and “folding” trends and improving vehicle rollover stability and practical application value.This paper combines the research content of the National Natural Science Foundation project(approval number: 51278514)and the Chongqing Natural Science Foundation Project(cstc2018jcyjA2536).This paper analyzes the lateral instability mechanism of vehicles based on the comprehensive research fields at home and abroad,identifies the key parameters of the vehicle,which determines the actual driving of the vehicle state.Research on active front wheel steering and direct yaw moment control system,propose anti-rollover active control strategy,reduce the instability of heavy-duty semi-trailer trains under high and low road surface adhesion coefficient.The main research work is as follows:A five-degree-of-freedom vehicle dynamics model that describes the rollover characteristics of heavy-duty semi-trailer trains is established.The analysis of the force of the semi-trailer train and the establishment of the lateral,roll and yaw differential equations of the tractor and trailer.The heavy-duty semi-trailer trains are difficult to determine due to the large load changes.The virtual semi-trailer train provided by Trucksim as a reference model,the prototype used genetic algorithm to identify the key parameters of the vehicle.Through joint simulation,it is verified that the main parameters of the model agree well with the data of Trucksim vehicle model parameters,which lays a foundation for the subsequent active control of vehicle rollover prevention.The active front wheel steering and direct yaw moment control strategy is used to control the rollover stability of heavy-duty semi-trailer trains.Based on the linear quadratic optimal control theory,the active front wheel steering control characteristics are studied and analyzed,the workload of solving the weighting matrix Q is reduced,and the weighting matrix Q is optimized by genetic algorithm.The direct yaw moment control is controlled by the model predictive control theory.The research and analysis are carried out,the vehicle side slip threshold interval is determined by simulation test and the vehicle rollover dynamic factor-transverse load transfer rate is derived.The direct yaw moment control rule is determined by using the vehicle real-time driving state parameter and the lateral instability factor,Trucksim-Simulink is used.The joint simulation proves that it lays a theoretical foundation for the coordinated control of anti-rollover for heavy-duty semi-trailer trains.The anti-rollover coordinated control strategy for heavy-duty semi-trailer trains with active front wheel steering and direct yaw moment control is designed.The model predictive decision is used to suppress the total target yaw moment of the lateral instability of the semi-trailer train.The vehicle state parameters and the lateral instability factor are used as the total target yaw moment distribution conditions,and the active front wheel steering and direct yaw moment control subsystem are coordinated.Completing their respective missions,the simulation verification design of the anti-rollover coordination control can reduce the lateral instability of heavy-duty semi-trailer trains on complex and variable roads,which improve the vehicle’s anti-rollover capability.