Development of leg-wheel hybrid quadruped “AirHopper” design of powerful light-weight leg with wheel

This paper proposes a new leg-wheel hybrid jumping robot ldquoAirHopperrdquo. AirHopper is expected to overcome uneven terrain, which is difficult to move around for ordinary vehicles which carry supplies for disaster areas or isolated districts. To acquire high mobility and jumping, AirHopper consists of the following mechanisms. 1) 4 legs that are widely spread like a spider for stability, 2) active wheels on its feet which are driven by built-in motors and transmissions, 3) 2 decoupled pneumatic cylinders per leg and a built-in piston that drive 4-bar linkage leg mechanism. In this paper, we proposed the design of a powerful light weight leg-wheel mechanism, and verified its validity. AirHopper jumped 850 mm vertically, and landed on the ground softly by means of controlling in-cylinder pressure. Running jump motion was also achieved.