Force Control with A Muscle-Activated Endoskeleton

Abstract

The advantages and challenges of producing and controlling force with a mechanism like the human skeleton driven by actuators like mammalian muscles are considered. Some counter-intuitive subtleties of musculo-skeletal biomechanics are discovered: despite the energetic cost of isometric muscle activation, exerting forces that do no work may reduce metabolic energy consumption; in some circumstances, anatomical antagonist muscles may become functional synergists; and muscle tension acts to make skeletal posture statically unstable. The latter effect can be counteracted by muscle mechanical impedance, which emerges as an essential adjunct to muscle force production.