Partial Yaw Moment Compensation using an Optimization-based Multi-Objective Motion Solver

Any arbitrary motion generated by a humanoid robot produces a yaw moment which may exceed the one created by the friction between its feet and the ground, inducing a yaw rotation that deviates the robot from its desired path. This paper describes an on-line compensation scheme for the yaw moment of a humanoid robot about the Zero Moment Point (ZMP), formulated as a task of a Quadratic Program (QP) solving for multiple weighted objectives and constraints. This allows to use the motion of every single link of the robot to contribute to the compensation, according to the relative weight of other primary tasks that it should perform. Within the proposed approach the yaw moment is partially compensated; that is, mostly when exceeding a predefined threshold, allowing to slow down the residual motion of the links triggered by the compensation.