A study on the support pattern of a quadruped walking robot for aperiodic motion

Though the mobility of a walking robot is superior to a wheel type robot in hazardous terrain, it is not easy for a walking robot to walk avoiding arbitrarily arrayed forbidden areas in the terrain. In order not to step on the forbidden areas, the gait of a walking robot should be aperiodic. But it is very complicated to analyze aperiodic gaits. In this paper, the authors focus on aperiodic gaits for straight motion and spinning motion. Based on the study of optimal periodic gaits, the authors show the support condition that enables aperiodic motion with preservation of the leg-lifting sequence of optimal periodic gaits. The authors introduce a schematic design of a leg mechanism that is spatially decoupled by using a 2-dimensional pantograph mechanism and a vertical linear actuator.