Abstract
This paper describes a control method for the mastication robot in order to reduce the temporomandibular joint force (TMJF). We have developed the WJ (Waseda Jaw) mastication robot series from 1986 using seven Direct-Current (DC) motors, wires, a dental study model and a duralumin madibular, and carried out research theoretically and experimentally by using actual foods. From engineering point of view, we can regard the mandibular and masticatory muscle as a redundant system because the human mandibular has four degrees of freedom and the number of masticatory muscle is more than four. Generally speaking we can not decide the position and orientation of the redundant object. Therefore we must find some kind of control criterion for the mastication robot. So we are convinced that to formulate mandibular's equation of motion and to calculate the set of wire tensions by using linear programming whose objective function is minimizing the TMJF give one quantitative solution for the temporomandibular joint (TMJ) arthrosis. As results of computer simulation we clarified the tension set of wires and experimentally confirmed the reduction of TMJF with our mastication robot.
