A Study of Design and Control of a Quadruped Walking Vehicle

The paper addresses some of the fundamental problems of energy efficiency, design, and adaptive gait control of quadru ped walking vehicles. The design principle of a leg called a gravitationally decoupled actuator ( GDA) is shown to be indispensable for realizing energetically efficient walking mo tion. A novel mechanism, the three-dimensional Cartesian- coordinate pantograph ( PANTOMEC), which follows the GDA principle and has a lightweight structure, is introduced. A constructed quadruped walking vehicle model is then de scribed : the walking vehicle has the PANTOMEC leg mecha nisms, eight tactile sensors and a posture detector, and is hierarchically controlled by a microcomputer. Comparatively high energy efficiency and a certain degree of terrain adapt ability is demonstrated. It is thus shown that a practical walking vehicle can be designed using the proposed method. The adaptive gait control problem is formalized, and an algorithm for terrain-adaptive gait control is presented. By computer simulation, it is shown that the algorithm produces an efficient gait while avoiding "deadlock" positions in nego tiating terrain. The algorithm is shown to be applicable for the control of future quadruped walking vehicles with visual sensors.