Finite Element Modeling of Impact Loads on the Human Head

ABSTRACT When developing a robot control manager for safe human–robot collaboration, it is essential to understand the biomechanics of indentation loading on human body parts. A human subjects study with collision loads is an appropriate methodology to determine biomechanical information for safe human–robot collaboration. However, the ethical requirements for such a study are very strict. Therefore, an available finite element (FE) model must be developed to simulate collisions of robots with the human body, especially for collisions with the human head. In the article, a head FE model specifically designed to replicate the response to impact load with lower energy at various locations in the human head (forehead, temple, and masticatory muscles) is presented. The model is based on the structures of the THUMS (Total Human Model for Safety of TOYOTA) model and the anatomy of the encephalon (MRI axial slices). To enhance model development, optimization, and, most importantly, validation, the experimental from the Fraunhofer IFF human subjects study are utilized, which focuses on power and force limiting as outlined in the ISO/TS 15066. The primary objective was to precisely replicate the biomechanical response of the body locations under consideration to ensure the reliability of the simulation and provide meaningful results that can be used as threshold values for the onset of pain for different collision scenarios. Under specific conditions, this model can be used to validate the pain onset thresholds determined in the human subjects study. Afterward, the simulation results were compared with the ISO/TS 15066 thresholds and the human subjects study.