Model predictive control for autonomous vehicle path tracking through optimized kinematics
Jinrui Nan, Z. Ge, Xucheng Ye, Andrew Burke, Jingyuan Zhao
Abstract
Tracking performance and stability of path tracking is crucial for unmanned vehicles' navigational tasks. Researches on vehicle path tracking controllers primarily rely on dynamic models. In contrast, there are less designs and researches that focus on path tracking controller based on kinematic model. This scarcity may stem from the perceived inadequacy in the accuracy of vehicle kinematic models. This research introduces a novel method for modifying the traditional vehicle kinematic model by incorporating a front wheel steering angle modification function to enhance tracking performance of path tracking controllers based on kinematic models. In terms of control strategy selection, the study opted for nonlinear model predictive control with terminal cost. A controller which is founded on the modified model was used on a simulated vehicle on CarSim-Simulink platform to assess the tracking performance. The simulation was designed with a double-shift line reference trajectory and the initial speeds of the simulated vehicle are 5 m/s and 10 m/s, respectively. The results of the simulations indicate that employing a controller based on the modified model could reduce the peak tracking error by 76.45 % and 43.06 %, and the root mean square of the tracking error was reduced by 73.29 % and 36.06 %, respectively. • Analyze the open-loop motion deviation between conventional vehicle kinematic model and CarSim model. • A modification method for the vehicle kinematic model using a front wheel steering angle modification function. • Design an NMPC trajectory tracking controller based on the modified vehicle kinematic model. • Controller based on the modified model exhibits better performance in trajectroy tracking.