An approach to stable motion control of biped robot with unknown load by torque estimator

This paper describes a novel approach of a stable walking control in 3D biped robot with an unknown loaded object. In general, it is difficult for the biped robot to realize a stable walking action without using the information of a loaded object since there is no fixed point for keeping the stable posture of the robot. Then the estimation of the mass and position of a target object is useful for increasing the walking stability. We propose a torque sensorless estimator of the loaded object by external torque observer. The estimated variables make it easy to determine the stable motion and trajectory of the robot by considering the center of gravity of the robot. The effectiveness of the proposed method is confirmed by several simulations and experiments.