Gain-adaptive Skyhook-LQR: a coordinated controller for improving truck cabin dynamics

Truck manufacturers place more emphasis on drivers' health, safety, and comfort in recent decades. Some progresses have been made in reducing drivers' vibration exposure levels by adding semi-active cabin suspension systems. Considering various driving conditions of a commercial vehicle, an advanced cabin suspension control needs to be capable of solving multi-objective optimization problems in real-time and adapting to different road conditions. To minimize the undesired vibrations in vertical, pitch, and roll directions, a new coordinated control system is introduced in this paper, namely integrated Skyhook-LQR. Specifically, the controller integrates Skyhook and Linear Quadratic Regulator (LQR) in order to attenuate the vibrations transmitted to the cabin, by which the computational cost is affordable for real-time implementation on microcontrollers. Moreover, a gain-adaptive algorithm is designed to intelligently adjust the controller gains based on the higher modes of the cabin vibrations. The performance of the proposed control system is evaluated through the co-simulation between ADAMS/Car and MATLAB/Simulink. The results demonstrate that the gain-adaptive Skyhook-LQR takes the advantage of the Skyhook control when the vertical disturbances are dominate and utilizes the benefits of the LQR algorithm when all modes of vibrations (pitch, roll, and vertical) are present. As a result, the proposed coordinated control system achieves optimum ride comfort under various driving and road conditions with minimum computational costs.