Simulation of muscle characteristics using an electromagnetic actuator

Abstract To accurately predict human body motion during a vehicle crash, active and passive characteristics of a muscle must be expressed. The crash test dummy presently used only expresses the passive characteristics of a muscle by using springs, so it has limited accuracy in predicting human body motion of current crash test dummies. In this paper, a muscle activation system composed of an electromagnetic actuator and a tensile spring is proposed to resolve such limitation of the current crash test dummy. The proposed actuator reproduces the active characteristics of a muscle. Because the flux path of the actuator is designed by reluctance path modulation using an electromagnet and two permanent magnets, the actuator improves upon non-linearity and power consumption of a conventional electromagnetic actuator. The tensile spring is adopted to resolve the short moving range of the actuator, to increase the bandwidth limit of the muscle activation system, and to reproduce the passive characteristics of a muscle. Tests reproducing the force-length and force-velocity characteristics of a muscle were carried out to verify the performance of the developed muscle activation system. The experimental results showed that the muscle activation system successfully reproduced the force-length and force-velocity characteristics of a muscle.