Research On Trajectory Tracking Control Strategy For The In-wheel Motor Actuated Electric Vehicle

A trajectory tracking control strategy with high precision and strong adaptability is one of the basic conditions for electric vehicles to realize intelligence and practicality.This dissertation combines the advantages of the front-wheel steering and the in-wheel motor-driven differential steering control to study the trajectory tracking control strategy of the in-wheel motor-driven electric vehicle.Establish vehicle dynamics model and tire model,combine PID control and Ackermann-Jeantand steering model to build an electronic differential model.Based on the vehicle kinematics,a model is established to predict the trajectory tracking control driver model.With the help of the Car Sim and Simulink co-simulation model,the above electronic differential model,driver model and vehicle model are combined,and the simulation verifies the trajectory tracking effect.Three different control strategies are designed for MPC steering control based on direct vehicle speed,MPC speed/front-wheel steering control based on curvature determination,and vehicle speed/front-wheel steering coordinated control based on PID-MPC to solve model prediction and control when the vehicle speed is high.Problems such as sideslip and repeated swings.In order to further improve the accuracy of trajectory tracking,a variable parameter MPC vehicle speed/front wheel steering coordinated control trajectory tracking controller is designed.Considering that the differential steering and the front wheel steering can be controlled at the same time,the PID differential steering control is designed,and the differential steering is added on the basis of the front wheel steering trajectory tracking,and the front wheel-differential steering coordinated control trajectory tracking is designed.Controller.In order to verify the feasibility of the designed trajectory tracking control strategy,a signal conversion device and required sensors were installed on the in-wheel motordriven experimental vehicle,the actual vehicle experimental plan was designed,and the parameters were changed under the low-speed double-line shifting condition MPC vehicle speed/front wheel steering coordinated control of the front wheel steering trajectory tracking road experiment.Research shows that:(1)PID-MPC-based vehicle speed/front-wheel steering coordinated control can maintain effective tracking of the reference trajectory;(2)Variable-parameter MPC vehicle speed/front-wheel steering coordinated control is compared with vehicle speed/front-wheel steering coordinated control,The trajectory tracking accuracy is higher under the double-line shifting conditions at vehicle speeds of 30 km/h,45 km/h and 60 km/h;(3)Variable parameter MPC vehicle speed/frontwheel steering coordinated control and front-wheel-differential steering The comprehensive evaluation function of the coordinated control is less than zero under the three speed double-line shifting conditions,and the front wheel-differential steering coordinated control has a better trajectory tracking ability;(4)The vehicle completed the reference trajectory tracking driving in the experiment.It confirms the feasibility and adaptability of the designed front wheel steering trajectory tracking strategy.