Hierarchial Control of Hydraulic Active Suspensions of a Fast All-Terrain Military Vehicle

Abstract

This paper describes a procedure to improve the behavior of a light all-terrain military vehicle moving, over rough ground and large obstacles, at high speed. This improvement has governed the choice of a new concept of hydraulic active–passive linking between the body and the ground. A hierarchical control strategy is then proposed which divides the management of vehicle dynamics into two levels: a central control which takes into account the pitch and the gap between the body and the ground and delivers orders to local independent controls devoted to each active suspension and bogie assembly. In this case, the feasibility of this control can be validated on a quarter vehicle moving only in the vertical direction. The local controller uses a classical P.I.D. and the central control implemented uses a Linear Quadratic Gaussian which is suited to the specific purposes of the control. A scale model of a quarter vehicle is used to validate this process. Simulation and experimental results are in good agreement and show the improvement of capacities for crossing large obstacles at speed.