Speaker
Description
This study is a follow-up to the study "Finite element modeling of concentrated impact loads on the masticatory muscles at the head" in GAMM 2024 Magdeburg. A human-subject study with collision loads is an appropriate methodology to determine thresholds for safe human-robot collaboration. However, the ethical requirements for such a study are very strict. Therefore, an available FE model has to be developed to simulate human-robot collisions, especially for collisions with the human head. A FE model of the head is presented in the article specifically designed to replicate the response to impact loads on various locations on the human head (forehead, temple, and masticatory muscles). The model is based on the structures of the THUMS model and the anatomy of the encephalon (MRI axial slices). To enable the intended use for collision simulations with cobots, the model is tailored to the biomechanical threshold listed in ISO/TS 15066 and focuses on the characteristics of soft tissues. For the model development, optimization and, most importantly, validation, we have used experimental data (force-deformation curves) from the said human-subject study. A novel technique for developing biomechanical corridors was used to calculate the force-deformation curves (data from a human-subject study) used for model development, optimization, and validation. The primary objective was to precisely replicate the biomechanical response of the body locations under consideration (mainly the upper tissue layer) in order to ensure the reliability of the simulation and provide meaningful results that can be used as threshold values for pain onset for different collision scenarios. The results of the optimization and validation show that the degree of overlap between the reference data and the response from the simulation is considerably high. The biomechanical properties of the soft tissues used for the three body locations on the head have been successfully reconstructed in the FE model. Under specific conditions, we can now use the model to validate the pain-onset thresholds determined in the human-subject study. Afterward, we conducted a series of collision simulations with a collaborative robot at the said body locations using the new head model. In the last step, we compared the simulation outcomes with the thresholds from ISO/TS 15066 and the human-subject study.
