Gait pattern generation with knee stretch motion for biped robot using toe and heel joints

This paper presents a new alternative methodology to generate gait pattern with a knee stretched motion for biped robot utilizing toe and heel joints. During walking sequence, human heels act as passive joints that create some support area which enhances the stability of human walking. This research tries to replace human-heel like mechanism with a heel joint in the biped robot foot. The existence of heel joints in the biped robot feet has two main advantages. The first one is that the support area during double support phase will be increased. Secondly, singularity during knee stretch motion can be avoided. The loss of degree of freedom in the knee joint will not produce singularity in the inverse kinematics solution since there is still another degree of freedom in the heel joint. The effectiveness of the algorithm is being studied through a dynamic simulation tool. A stable knee stretch walking pattern utilizing toe and heel joints was generated, which has some similarity to the human walking pattern. Effectiveness of the proposed algorithm in terms of joint torque requirements as well as energy consumptions have also been shown.