Research On Yaw Stability Control Of Mid-axle Vehicle Train Under Steering And Braking Condition

In recent years,with the vigorous development of the domestic automobile industry,the transportation mode and structure of the transportation industry have changed.Among them,the full-trailer in the road transportation industry has been ordered to prohibit high speed and gradually withdraw from the stage of history,and the development of the central axle trailer in China has ushered in a new opportunity.Due to its multi-degree-of-freedom structure,this kind of combined car train makes the motion state of the vehicle more complex to a certain extent.Especially,this kind of combined car train is more prone to folding and throwing than a single car during the driving process of steering and braking.Therefore,it is very meaningful to study the yaw stability control of center-axle trains under steering braking conditions.Aiming at the yaw instability problem of the center-axle car train under the steering braking condition,this paper proposes an active control system scheme for the center-axle trailer.A method of driving the braking system to achieve a rapid response to pressure build-up.In this paper,based on the active control system of the central axle trailer,a layered control strategy is used to control the yaw stability of the car train under the steering braking condition.Firstly,the vehicle train dynamics model,the motor direct drive braking system model,the tire model,etc.under the steering braking condition are established for the research object,and the vehicle train model under the steering braking condition is established with the help of Matlab/Simulink software.The Truck Sim development software is used to simulate and verify the accuracy of the model to provide guarantee for the subsequent controller design.On the basis of the establishment of the steering braking model,the instability mechanism is analyzed and the relevant simulation verification is carried out.Secondly,after the vehicle train model of the steering braking is established,a steady-state reference model under the steering braking condition is established.The steady-state reference model calculates the steady-state yaw rate and articulation angle under the current motion state of the vehicle,and uses this as the control target of the upper-layer MPC controller,and then calculates the additional direct lateral motion required by the current motion of the front and rear vehicles to reach a steady state.Then,the lower controller controls the wheels according to the yaw moment calculated by the upper controller according to the distribution strategy designed in this paper,that is,the yaw stability control of the whole vehicle steering process is realized through differential control.Finally,this paper uses MATLAB/Simulink,AMESim and Truck Sim to build a cosimulation platform,and uses two working conditions of angular step input and step steering return to carry out simulation verification,and compares the yaw angular velocity as a single control.The simulation results show that the control strategy proposed in this paper can effectively improve the yaw stability of the vehicle and train in the process of steering and braking.