COMPLIANT FOOT SYSTEM DESIGN FOR BIPEDAL ROBOT WALKING OVER UNEVEN TERRAIN

This paper presents a new foot system for biped walking on uneven terrain and its design process. Stabilization of contact states between the foot and the ground and proper landing on unknown terrain are the criteria that ensure stable walking motion on uneven terrain. Generally, the conventional rigid and flat foot could not maintain level when the robot is walking on uneven terrain. In addition, the impulsive force exerted during landing on rough terrain must be suppressed. The authors proposed a point-contact type foot with hydraulic fluid balance mechanism. The size of the proposed foot mechanism is 160 mm x 277 mm and its weight is 1.6 kg. The foot system consists of four contact points each of which is equipped with a force sensing resistor (FSR) to detect the landing state. The foot can generate a support polygon on uneven terrain by using three or four contact points. The main advantages of the proposed foot system are that it enables the stabilization of the contact state and absorption of the impact when the swing foot lands.