Integrated translational and rotational COG motion to enhance the stability for humanoid robots

This paper presents a translational and rotational Center Of Gravity(COG) motion generation method to enhance the stability of the humanoid robot. When urgent cases occur, the humanoid robot requires severe Zero Moment Point(ZMP) adjustment to keep balance. The conventional methods that usually only generate translational COG motion at a constant height lead to large COG acceleration easily. The large acceleration can not be realized due to limited actuator capability or strong tendency to slip even the required large acceleration can be produced. To solve this problem, we propose a method to generate desired translational and rotational COG motion on the condition of minimum slippery tendency to adjust the ZMP. This COG motion can be achieved through coordinated motion in the joint space. This method not only adjusts the ZMP into the stability region but also prevents the occurrence of slippery, especially in the low-friction environments. The effectiveness of the method is demonstrated through simulations.