Development of 2-D Jaw Movement Simulator (JSN/S1)

Human mastication is performed by coordinated activities of several jaw muscles. To clarify functions of these muscles, we developed a jaw movement simulator (JSN/Sl) consisting of a 2 degrees of freedom (2DOF) mechanism and five muscle actuators able to reproduce jaw movements on a sagittal plane. The actuator is a cable-tendon driven by a DC servomotor controlled by a compliance control scheme to obtain viscoelastic muscle characteristics. To simulate life-like clenching, we controlled occlusal position and force by incorporating position and force sensors, using neural network learning control. Occlusal force successfully converged to a desired value through learning. Tension patterns of muscle actuators during clenching well coincided with human jaw activities.