Primary Publication
D. Krüger and S. Wartzack, “A contact model to simulate human–artifact interaction based on force optimization: implementation and application to the analysis of a training machine,” Computer Methods in Biomechanics and Biomedical Engineering, pp. 1–10, Oct. 2017. DOI: 10.1080/10255842.2017.1393804 (2017)  View

Musculoskeletal multibody models are increasingly used to analyze and optimize physical in- teractions between humans and technical artifacts. Since interaction is conveyed by contact between the human body and the artifact, a computationally robust modeling approach for frictional contact forces is a crucial aspect. In this contribution, we propose a parametric con- tact model and formulate an associated force optimization problem to simultaneously estimate unknown muscle and contact forces in an inverse dynamic manner from a prescribed motion trajectory. Unlike existing work, we consider both the static and the kinetic regime of Coulomb’s friction law. The approach is applied to the analysis of a leg extension training machine with the objective to reduce the stress on the tibiofemoral joint. The uncertainty of the simulation results due to a tunable parameter of the contact model is of particular interest.