A closed-loop directional dynamics control with LQR active trailer steering for articulated heavy vehicle

Abstract

To improve the directional performance of articulated heavy vehicles (AHV), three previewed points driver model and LQR active trailer steering (ATS) strategy are proposed and examined using closed-loop driver/vehicle dynamics simulation. Firstly, a simplified linear three-degree-of-freedom (3-DOF) yaw plane model for AHV is established and validated. Secondly, based on the multi-point preview-predictor following strategy, the weighted-average error of three previewed points of the tractor is defined as the final lateral previewed displacement error. According to the assumption of constant yaw rate and the trajectory prediction of AHV, and three previewed points driver model has been configured, it’s path-following performance is verified. Thirdly, instead of using the idea of minimization, a linear quadratic regulator (LQR) controller is proposed based on the linear 3-DOF yaw plane model of AHV to make the control variables to keep following the desired responses. Through joint simulations using MATLAB/Simulink and TruckSim, the effectiveness of the built-in driver model, three-previewed point driver model and three-previewed point driver model + LQR ATS control methods on improving vehicle orientation performance were compared and analyzed through closed-loop driver/vehicle dynamics simulations. The significant effectiveness of the proposed method in improving maneuverability and stability is verified through low-speed 360° trajectory tracking tests and high-speed double lane change maneuver simulations. Finally, a hardware-in-the-loop (HIL) platform is used to further verify the effectiveness of the designed strategy.