Abstract
New quadruped robot, which has variable walking modes, so-called tall mode, short mode, SCARA mode and stair mode, has been developed. A leg of the robot has 3D.O.Fs with three rotational joints connected in series like SCARA and achieves the GDA. Due to the wide motion range of the legs, the robot can make stable going up/down motion on the stairs and walk on horizontal floors high-efficiently. This paper describes the mechanism of the legs and its characteristics of the motion. And also the miniature robot which has the proposed mechanism has been applied to a basic experiment and the result is mentioned.