1305 Mechanical characteristics of driver-steering system and stability in holding steering wheel

Driver is steering, keeping his/her posture and holding steering wheel during driving cars. Holding steering wheel has good effects on stability of cars, but the mechanism of it isn't understood clearly. We did steering wheel shaking experiment and identified of mechanical characteristics of driver-steering system. Firstly, shoulder support ofseatback decreased inertia of driver system, but it didn't have effect on stiffness and viscosity. But it decreased muscle activity to keep driving posture, and helped to push steering wheel easily. Secondly, holding steering wheel tight didn't have significant effects on mechanical characteristics of driver-steering system. But we need measure steering wheel grip force accurately to discuss effect of holding steering wheel in more detail. Finally, pushing steering wheel increased stiffness and viscosity of driver system. And contributing rate of geometric stiffness to increase of stiffness with pushing steering wheel was estimated at about 20-30%.