Optimized multi-body modelling of automobile drivers for analysing biodynamic responses and ride comfort under whole-body vibration

Drivers experience significant discomfort and vibrations due to prolonged sitting, irregular work shifts, environmental stressors, and limited sleep. These factors can lead to fatigue, discomfort, and performance issues, with long-term sitting causing abnormal changes in the lumbar spine, pelvis, and thighs. Working with real humans to examine biodynamic responses can be risky and requires ethical clearance. Researchers often use multi-body (MB) models to represent the human body to meet these challenges. This paper proposes a 32-degree-of-freedom ( dof ) MB model to investigate driver biodynamic responses. The MB model segments are symmetrically divided and connected by cross-coupled springs and dampers. In addition, the MB model parameters are optimized using the firefly algorithm, focusing on multiple biodynamic response objective functions. These optimized parameters help compare analytical and experimental biodynamic responses, analysing vibrations from the seat to various body segments. The driver biodynamic model is also integrated into an 8- dof full-car passenger model to assess ride comfort according to ISO 2631-1:1997 standards. Sensitivity analysis identifies the impact of biomechanical parameters on peak seat-to-head transmissibility (STHT). This comprehensive approach enhances the understanding of driver biodynamic responses and aids in improving ride comfort.