An on-line gait synthesis strategy for biped robot with Capture Points combining with RNS

Biped robots can extremely extend the range of robot applications for its fast locomotion ability and good adaptation for complicated environments. It has been a great endeavor for gait planning and locomotion control of biped robot due to its complex mechanical structure with multiple DoFs and strong coupling multi-link mechanism. In this paper, a general scheme that combines Capture Points Theory (CPT) with Reaction Null Space (RNS) was proposed to solve the on-line gait synthesis problem for bipedal walking of a humanoid robot. Firstly, the CPT combining with 3-D inverted pendulum model was employed to calculate the foothold of robot for the next step to obtain the desired ZMPs for stable walking. Then the joint angles were obtained by using the geometry model of lower limbs. To ensure the stable status of supporting leg, RNS was used to constrain the motion of leg joints of biped robot. Real experimental results indicated the correctness and effectiveness of the proposed method.