Disturbance rejection based on momentum compensation for humannoid robots

Robust motion is of great significance when humanoids are placed in complex and uncertain environments. In this paper, multitasks are merged in the way of null space projection according to their priorities. Momentum compensation is considered as one task and utilized to reject unknown disturbances. Two strategies are put forward to restrain the sudden change of momentum. One is to calculate the correction in the joint space with Resolved Momentum Control (RMC) method, the other is to add an end-effector tracking motion in the task space. Experiments are designed to test the proposed algorithm with Nao robot in simulation and the results show that the robot is able to rectify itself to the pre-planned steady stance while encountering undefined external forces.