Integrated robust dynamics control of all-wheel-independently-actuated unmanned ground vehicle in diagonal steering

In the future civilian Intelligent Transportation System (ITS) and military area, the Unmanned Ground Vehicles (UGVs) are supposed to replace humans to conduct various tasks in wide civilian or military applications. This paper aims at improving the overall performance of the All-wheel-independently-actuated (AWIA) UGV. Each wheel of the AWIA UGV is independently driven and steered by the motors with independent active suspension equipped to achieve the great potential of mobility, maneuverability, and controllability. Aiming to improve the performance of AWIA UGV in diagonal steering mode under critical circumstances, a novel integrated control approach is extended in this paper based on robust H₂/H_∞ theory. The major control objective is to generate additional vehicle active moment by full X-by-wire technique to collaboratively control lateral and roll motion of the vehicle to maintain a target diagonal steering performance. A wheel force distribution controller in the control executive layer interfaced to actuators is applied to achieve the resultant active control moment at each wheel corner, by controlling each independent drive motor, independent steer motor, and active suspension actuator. The effectiveness of the proposed control approach is validated by an AWIA UGV testbed by performing the step-steer experiments.