Nonlinear Model Predictive Control for Time-Optimal Turning Around of an Autonomous Vehicle Under Steering Lag

In this article, a time-optimal turning around method is designed based on model predictive control (MPC) for an autonomous vehicle under steering lag. To address the steering lag issue, a second-order steering model is established for the autonomous vehicle through system identification. A time-optimal turning around trajectory is obtained using a quintic polynomial method and a nonlinear MPC optimization problem. A nonlinear MPC algorithm is then developed to track the time-optimal trajectory with compensation for the steering lag. Asymptotic stability and recursive feasibility are analyzed for the autonomous vehicle based on the nonlinear MPC algorithm. Experimental results demonstrate the feasibility and effectiveness of the time-optimal turning around method in an autonomous electric vehicle with steering lag.