  This paper presents a method for pose estimation of off-road vehicles moving
over uneven terrain. It determines the contact points between the wheels and
the terrain, assuming rigid contacts between an arbitrary number of wheels and
ground. The terrain is represented by a 3D points cloud, interpolated by a
B-patch to provide a continuous terrain representation. The pose estimation
problem is formulated as a rigid body contact problem for a given location of
the vehicle's center of mass over the terrain and a given yaw angle. The
contact points between the wheels and ground are determined by releasing the
vehicle from a given point above the terrain, until the contact forces between
the wheels and ground, and the gravitational force, reach equilibrium. The
contact forces are calculated using singular value decomposition (SVD) of the
deduced contact matrix. The proposed method is computationally efficient,
allowing real time computation during motion, as demonstrated in several
examples. Accurate pose estimations can be used for motion planning, stability
analyses and traversability analyses over uneven terrain.
