Design and Robust Control of Track-based Active Suspension

Abstract

This study presents a new track-based active suspension (TAS) for a tracked robot to mitigate a large variation in acceleration and displacement of the center of mass (COM) of the robot body while traversing rough terrains. In this study, in order to ensure the rapid response and compactness of the track-based active suspension, an electrical motor is adopted instead of hydraulic actuators. In addition, the physical model for the proposed track-based active suspension is derived and verified with experiments to predict its dynamic behavior fairly well while overcoming a square wood. Then, a H infinity controller is designed for the proposed track-based active suspension to ensure its robust performance, that is, reduction in acceleration and displacement of its center of mass (COM) against the uncertainty of rubber tracks and the error between real and physical models. The reductions in the acceleration and displacement of the center of mass (COM) of the proposed TAS are experimentally verified in the time and frequency domains. As a result, in comparison with the PID controller, the proposed H infinity controller exhibits considerable reductions of 33.25% in acceleration and 49.27% in displacement of COM of TAS during overcoming a square wood of 2 cm in height, which implies that the proposed TAS equipped with the H infinity controller has the ability to guarantee the mobile stability and the ride comfort even while traversing rough terrains with obstacles.