3D odometry based on body configuration information of passive linkages

In our current research, we are developing a holonomic mobile system which is capable of running over the step. This system realizes omni-directional motion on flat floor using special wheels and passes over non-flat ground in forward or backward direction using the passive suspension mechanism. Odometry is popular position tracking scheme for a wheeled mobile robot, however, in the case of non-flat ground, it is difficult to estimate its position using odometry because an angular relationship between wheels and ground is unknown. Therefore, in this paper, we propose a new odometry method which extends 2D odometry to the 3D space. Our key idea is using the body configuration information which changes according to the shape of the terrain. Using our idea, our mobile platform can measure the shape of terrain without external sensors. We verify the performance of our proposed control scheme by the experiments using our prototype.