Stability Measure of Postural Dynamic Equilibrium Based on Residual Radius

This paper formalizes the robustness of a virtual human dynamic equilibrium through the residual radius of its admissible generalized force set. The admissible generalized force set is defined as the image of the contact force constraints (corresponding to the Coulomb model) in the generalized force space. This set is approximated by a polyhedron and its residual radius is computed using a linear program. The measure relevance is analyzed from experimental data of a sit-to-stand motion on which residual radius is evaluated.