A new type of stepping motor, named electric nutation motor was developed. The aim of this research is to develop a new stepping motor with high torque. Based on the magnetic field analysis using finite element method, theoretical value of the electromagnetic force was obtained. Magnetic path was designed and optimized. The force of the electromagnet was 60 N with the current of 0.3 A. The motor was found to have the maximum torque of 0.64 N/spl middot/m, the maximum speed of 4.3 rpm, and positioning accuracy of 1,248 step/rev.

A new type of pneumatic stepping motor, named pneumatic nutation motor, was developed. This motor achieves stepping positioning of 720 steps/rotation without any electrical devices or sensors mounted on the servo mechanisms. This makes the motor possible to be used under hazardous conditions such as in water and in strong magnetic fields where conventional electromagnetic motors cannot be used. The motor torque is so big that the motor can be used as a direct motor. In this report, the driving principle and design of this motor are presented. Its characteristics are analyzed experimentally and theoretically. The motors were applied to a parallel linkage mechanism with six degrees of freedom. The mechanism shows that the pneumatic nutation motors can be used as a direct servo motor for robot mechanisms.