| A binocular vision system based on two solid-state TV cameras was designed and constructed to facilitate rough terrain locomotion of the OSU Hexapod, a six-legged walking vehicle. As an intermediate step toward the realization of a fully autonomous vehicle, the Follow-The-Leader control mode was investigated and implemented. In this operation, an operator specifies footholds for the front feet by aiming a laser beam at desired locations on terrain surface. The vision system perceives the image of the laser beam and provides the image coodinates in both frames. The three-dimensional coordinates of a foothold is computed using triangulation techniques. Based on the information of the footholds of all legs, algorithms were developed to navigate the vehicle, under a proper timing, toward a destination where the stability is enhanced. A heuristic algorithm which seeks to optimize the stability margin of a supporting polygon is also presented. As the vehicle moves forward, the middle and the rear legs follow in the footprints of the front feet, hence only those footholds assigned by the operator are used during locomotion. Consequently, the Hexapod is able to walk over even/rough terrain, step-by-step, under the guidance of the operator. |
