Research On Intelligent Vehicle Trajectory Tracking Control Considering Lateral And Longitudinal Coupling

Intelligent vehicles have shown tremendous potential in improving driving safety and enhancing traffic efficiency,and have become a hot research topic.Trajectory tracking control is one of the key technologies for autonomous driving of intelligent vehicles,which aims to enable vehicles to track desired trajectories quickly and steadily.Distributed-driven electric vehicles have great potential for improving vehicle trajectory tracking performance due to their independently controllable wheel torques and coordinated control with active steering.This paper is based on the National Key research and Development Program "Development and Application of Automotive Grade High Precision Integrated Navigation Sensor System"(Project number: 2021YFB3202300).A trajectory tracking control strategy considering longitudinal-lateral coupling based on Distributed-driven vehicle is proposed to overcome the limitations of trajectory tracking and lateral motion control only through front wheel steering angle.The main research contents of this paper are as follows:(1)A distributed drive vehicle dynamic model was constructed.A vehicle dynamic model including the vehicle body dynamics model,the Gim tire model,and the motor model is established,and a vehicle model with the same parameters is built on the Car Sim platform for closed-loop validation with the constructed distributed drive vehicle dynamic model.(2)A model-predictive trajectory tracking controller was established.A vehicle trajectory tracking model that comprehensively considers vehicle dynamics and kinematics is constructed.Based on this model,a trajectory tracking controller is designed,considering the deviation of the vehicle from the target trajectory and the vehicle driving stability as the design objective function.Using the Matlab/Simulink and Car Sim joint simulation platform,the designed controller can complete the double lane change trajectory tracking at a speed of 72 km/h on high and low adhesion road surfaces,but the vehicle becomes unstable when tracking the double lane change trajectory at a speed of 90km/h on a low-adhesion road surface.(3)A trajectory tracking controller considering longitudinal-lateral coupling was designed.The mechanism of tire lateral-longitudinal force coupling is analyzed,and a trajectory tracking controller considering longitudinal-lateral coupling is designed using a hierarchical control structure.The upper-layer controller designs a motion tracking controller to solve the front wheel steering angle and additional yaw moment required by the torque optimization allocation controller.The lower-layer torque optimization allocation controller is designed using quadratic programming to determine the torque of each wheel based on the generalized longitudinal force and additional yaw moment.Through simulation analysis,the trajectory tracking controller considering longitudinal-lateral coupling can track the double lane change trajectory at a speed of 90km/h on a low-adhesion road surface,with a maximum lateral error of only 0.6844 m.(4)The article conducted hardware-in-the-loop testing and on-vehicle testing of trajectory tracking algorithm under low speed scenarios.The designed control algorithm was run using a Speedgoat real-time machine as the controller,and the vehicle model was run on the NI PXIe target real-time machine to verify the effectiveness of the designed algorithm under different working conditions.A model predictive trajectory tracking control algorithm was deployed on the vehicle,and single and double lane path designs were used to verify the algorithm.The results show that the designed algorithm can accurately control the vehicle to track the target trajectory.