Stability polygons reshaping and morphing for smooth multi-contact transitions and force control of humanoid robots

Abstract

In this paper we provide hindsight on how to use the information provided by the explicit computation of the stability polygon and build on task-based QP controllers to achieve both stable multi-contact smooth transitions and force control without jeopardizing stability. This entails computing stability polygons with unilateral and bilateral contacts and devising a method to continuously constrain the CoM position throughout multi-contact motion in order to effectively regulate the forces applied on the environment while avoiding hard constraints on the CoM and discontinuity between stances.