Development of a mastication robot using nonlinear viscoelastic mechanism

This paper describes the mathematical and mechanical models that simulate the nonlinearity of human´s masticatory muscle. In addition, the experimental results of a real food chewing experiment by a mastication robot is described. When the lower jaw rapidly closes during the chewing motion, it may come in hard contact with the upper jaw if the food is a crushable one. To clarify the mechanism of this reflective jaw motion, the authors focused on the nonlinearity of human´s masticatory muscle. The authors propose a feasible mathematical model of the muscle and its nonlinearity. A nonlinear viscoelastic mechanism is designed based on the mathematical model. From the result of chewing experiment, the authors confirmed the effectiveness of the proposed mechanism for the control of the robot jaw