Active LQR Multi-Axle-Steering Method for Improving Maneuverability and Stability of Multi-Trailer Articulated Heavy Vehicles

Directional performance and highway stability are two important aspects that need to be considered in development and design of a heavy articulated vehicles. To improve the maneuverability and stability of a multi-trailer articulated heavy vehicle (MTAHV), an active linear quadratic regulator (LQR) multi-axle-steering method is designed and examined. First, a linear yaw-plane model with four-degree-of freedom (4-DOF) for MTAHV is built and validated. Thus, a reference model supplying the desired state responses is introduced. Then, an active control algorithm of multi-axle-steering for the rear axles of tractor and full-trailer is investigated, and a LQR controller is proposed based on the linear vehicle model to make the control variables track the desired state responses. The control strategy concentrates on keeping the actual yaw rate and side-slip angle follow the steady-state yaw rate and zero side-slip angle. Finally, the effectiveness of the designed approach on enhancing the maneuverability and stability of the MTAHV have been validated through the simulations of the low-speed 360° roundabout and the single lane-change maneuver with high speed, respectively. The method has a certain reference value for improving the active safety of the MTAHV.