Investigation of the subjective force perception based on the estimation of the muscle activities during a steering operation

The models of motion and perception characteristics of humans are helpful to evaluate subjective efforts associated with intuitive, safe, and easy-to-use products. Traditionally, the muscle activity and/or the joint torque estimated by using a musculoskeletal model have been evaluated, whereas there are few studies that consider human´s perception characteristics. In this paper, the perception characteristics of force are investigated based on the estimation of the muscle activities. Experimental analysis of human force perception characteristics in a steering wheel operation has revealed that the perceived force depends on the angle of the steering wheel and the direction of the load. This paper proposes the estimation model of the force perceived by a subject that considers human´s posture- and direction-dependent perception characteristics in the steering operation. We estimate the muscle activity during the steering wheel operation by using a three-dimensional musculoskeletal model, develops a perception conversion model that follows the Weber-Fechner law, and describes the experimental results that confirm the feasibility of the proposed force perception estimation.