Robust Performance Improvement of Active Suspension via H infinity Control for Track Uncertainty

Abstract

Robust Performance Improvement of Active Suspension via H infinity Control for Track Uncertainty In this paper, the authors introduce the design of an active suspension system for a tracked vehicle to enhance robust performance on uneven ter- rain. The focus is on ensuring robustness against uncertainty related to rubber tracks and modeling errors through the design of an H∞ controller. The flexi- ble rubber track induces dynamic uncertainty, and challenging situations arise in ensuring robustness in uneven terrain. Furthermore, the paper discusses two trade-offs present in the system. It addresses the trade-off between ride comfort and vehicle stability, aiming to alleviate this conflict. Additionally, it analyzes the trade-off between robustness and performance. Moreover, to en- hance the responsiveness of the suspension actuator, a novel actuator using a motor was introduced, and the responsiveness and trade-off relationship were improved through H∞ control. This paper demonstrates model matching with a new structure of suspension under road disturbances such as square wood and gravel. The reduction in the acceleration of the robot’s center of gravity and the displacement of the center of gravity are proven in both the time and frequency domains. Through experiments, the utilized H∞ controller showed improved performance with acceleration and suspension displacement, which are commonly used indicators for good ride comfort. Compared to the PID controller designed using loop-shaping techniques, the H∞ controller exhib- ited a reduction of 8% in acceleration and 49% in suspension displacement, demonstrating enhanced performance.