Development of 2-D Jaw Movement Simulator (JSN/S1)
Shin-ichi Nakajima*, Toyohiko Hayashi** and Hiroshi Kobayashi***
*Department of Mechanical and Control Engineering, Niigata Institute of Technology, 1719 Fujihashi, Kashiwazaki, Niigata 945-1195, Japan
**Department of Biocybernetics, Faculty of Engineering, Niigata University, 2-8050 Ikarashi, Niigata 950-2181, Japan
***Department of Removable Prosthodontics, School of Dentistry, Niigata University, 2-5274 Gakko-cho, Niigata 951-8514, Japan
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.