On the dynamic stability of off-road vehicles

Dynamic stability reflects the vehicle’s ability to traverse uneven terrain at high speeds. It is determined from the set of admissible speeds and tangential accelerations of the center of mass along the path, subject to the ground force constraints and the geometric path constraints. This paper presents an analytical method for computing the stability margins of a planar all-wheel drive vehicle. It consists of mapping the ground force constraints to constraints on the vehicle’s speeds and accelerations along the path. The boundaries of the set of admissible speeds and accelerations determines the static and dynamic stability margins, used to gauge the traversability of the vehicle along the path. The first is the maximum feasible acceleration at zero speed, whereas the second is the maximum feasible speed. Both stability margins are demonstrated for a planar vehicle moving on a sinusoidal path.