Walking With Hand Motion/Force Control and CoM/VRP and Trunk Compliance for Disturbance Accommodation

Abstract

Walking control along preplanned footholds is ensured with the well-known DCM/VRP stabilization approach. To accommodate an external disturbance, the proposed walking controller uses CoM/VRP compliance, i.e. modification of the original DCM trajectories in accordance with the measured/estimated disturbance. The disturbance can also be accommodated with the compliance in the trunk. The class of disturbances considered does not require the re-planning of the footholds. While walking, the hand(s) are allowed to contact the environment for postural robustness and/or to perform a desired hand motion/force control task, such as surface polishing or cleaning. The resulting hand reaction wrenches are also accommodated with the CoM/VRP compliance. Angular momentum damping with arm swinging can be employed to increase the robustness at the feet contacts. The proposed controller is quite efficient from the computational point of view since it does not involve a general iterative solver. It is shown via simulations that the robot is able to walk dynamically in a stable way, undisturbed by the external perturbations and the hand reaction wrenches.