On the equivalence between forward and inverse dynamic analysis of human motion tasks

Abstract

The vast majority of musculoskeletal models of the upper limb follow an inverse dynamic approach due to its efficiency. Yet, a forward dynamic approach is more powerful. The aim of this study is to develop a forward dynamic model of the upper limb and to investigate its ability to track prescribed motions. For that purpose, an inverse dynamic model is applied to estimate the muscle forces responsible for two experimentally acquired motions, which are then given as input to the forward dynamic model. In order to enhance numerical stability, a proportionalderivative controller is implemented in a feedback loop. The results show that the forward dynamic approach is able to successfully simulate the acquired motions without needing relevant control forces or torques.