A Neuro-Muscular Elasto-Dynamic Model of the Human Arm Part 1: Model Development

In this paper we develop an elasto-dynamic model of the human arm for use in neuro-muscular control and dynamic interaction studies. The motivation for this work is to present a case for developing and using non-quasistatic models of human musculo-skeletal biomechanics. The model is based on hybrid parameter multiple body system (HPMBS) variational projection principles. In this paper, we present an overview of the HPMBS variational principle applied to the full elasto-dynamic model of the arm. The generality of the model allows one to incorporate muscle effects as either loads transmitted through the tendon at points of origin and insertion or as an effective torque at a joint. Though the technique is suitable for detailed bone and joint modeling, we present in this initial effort only simple geometry with the bones discretized as Rayleigh beams with elongation, while allowing for large deflections. Simulations demonstrate the viability of the method for use in the companion paper and in future studies.