Pneumatic direct-drive stepping motor for robots

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.