Biped Robot Walking Control with Centrodial Angular Momentum Preview

In traditional biped robot motion planning and control process, linear invert pendulum model is used to generate walking trajectory, with no consideration of the change of angular momentum, which sometimes cannot be ignored. In this paper, we propose a trajectory compensate method that takes into account the precise change of centroidal angular momentum during robot moving, including upper limb movement, foot swing and torso orientation movement, etc. We also provide a QP based formulation to solve the center of mass (CoM) trajectory from the Centroidal Moment Pivot (CMP) trajectory. We can adjust different properties of the CoM trajectory by adding different cost functions. The QP based formulation also have a bigger tolerance of trajectory error, which enhance the robustness of the solved CoM trajectory. Furthermore, we established an angular momentum preview control scheme, extend the method to not only offline trajectory planning, but also real-time trajectory control circumstances. We test our compensate method and control scheme in simulation and get obvious improvement in robot walking control.