TRAJECTORY OF A MULTI-SEGMENT WHEELED VEHICLE

In this paper, the movement of a vehicle that consists of many moving segments supported on wheels is investigated. The objective of the stu dy is to develop algorithms for path following of the vehicle, where p aths are described analytically by curves in Cartesian space. Simultan eously, a reference point on the end-effector of the vehicle is made t o follow another given path. It is assumed that the wheels maintain pu re rolling contact with the path during motion. The joint variables of the segments of the vehicle are limited in range of motion. Two algor ithms are developed in this paper, based respectively on position kine matics and rate kinematics of the system. An interesting aspect of the se algorithms is the selection of wheel velocities so that the joints of the vehicle do not exceed their respective limits. The algorithms a re implemented in simulation for vehicles consisting of an arbitrary n umber of segments. These algorithms are designed for three-dimensional paths, as well as for paths in horizontal and vertical planes. Based on this theoretical model, a four-segment robotic vehicle is currently being built to verify the motion planning algorithms experimentally.