Walking of a biped robot with compliant ankle joints: implementation with KUBCA

Presents a compliant ankle mechanism and its implementation for a biped robot without actuators for the ankle joints. Ankle joints have been built using springs and mechanical constraints, which give a flexibility of joint within a predefined range and stiffness beyond the range. The biped with compliant ankles proposed makes foot landing easy, and weight and cost of legs are also reduced. The cost of the advantages is that the control problem becomes more difficult because the control torque of the ankle joint to put the biped in a desired walking gait can not be provided from the compliant ankle joint. To overcome this problem, we propose a pseudo static walking gait with dynamic gait modification method by adjusting the position of a hip joint. Experimental results with the biped KUBCA are given to show the validity of the proposed controller.