The Synthesis of Basic Motion Regulator System for Quadrupedal Walking Vehicle and Its Experiments

Abstract

Legged locomotion is considered to be superior to conventional wheeled vehicles with respect to the adaptability in the rough ground conditions. In the past score of years research experiments have been performed, but no practical walking vehicle has ever been realized. The authors have examined this problem and have come to the conclusion that one of the main reasons of the retarded advent of a practical walking vehicle lies in its mechanical aspects, and proposed a “3 dimensional cartesian coodinates pantographic mechanism” for the legs to minimize the mechanical limitation.
This paper discusses the total controlling system for the walking vehicle having this special leg mechanism and elaborates especially on the control subsystem of the basic motion regulation. As a result it is deduced that the total controlling system should have a hierarchy structure. And six basic motion regulations such as the height and the horizontal posture control of the body, the leg adherence control to the ground in 4 leg standing posture or the shirk motion control of the swing leg from the obstacles are shown to be necessary and sufficient for a usual walking movement.
The walking vehicle model is constructed and controlled by microcomputer. It has 8 tactile sensors and a posture detector, measures 870mm in its leg length, and wighs 10kg in total. This walking vehicle model successfully illustrates miscellaneous functions such as the walking on an uneven ground, the walking on a side way or the turning motion while walking with stability and smoothness, and thus proved the validity of the present considerations on the control princiles for walking vehicle.