The Digital Astronaut Simulation

Abstract

The Digital Astronaut Simulation provides a human biomechanics modeling, simulation, and analysis capability that is enabling spaceflight hardware design to incorporate the human dynamic input early in development cycles as well as characterize performance after prototypes are built. Engineering design may often include posable mannequins for volumetric type assessments or other anthropometric data, but historically lacks higher fidelity multibody dynamics modeling. However, the implementation described herein facilitates quantifying kinematics and dynamic loads which impact hardware function and can hence be used within design iteration. The enhanced toolset includes a modified multibody model, updated motion capture marker sets, and refined methods for scaling and inverse kinematics. These provide increased accuracy for applications in exercise and extravehicular tasks in reduced gravity, especially where upper extremity motion is involved. A core capability highlighted is the calculation of ground reaction forces, moments, and center of pressure based on motion capture, which is compared with force platform measurements. This paper describes 1) the updates made to an OpenSim full body model and motion capture marker sets to improve model scaling methods and inverse kinematics results 2) verification and validation efforts for ground reaction force, moment, and center of pressure computation, and 3) discussion of the human spaceflight applications to date.

Keywords: digital human modeling, biomechanics simulation, multibody dynamics, spaceflight

DOI: 10.54941/ahfe1004457