Directional rotary motion of discrete displacement is achieved by sequentially pressurizing the three ports of the motor. Pulsed pressure waves are generated by a remote pneumatic distributor.

The motor assembly includes a motor, gearhead, and incremental position encoder in a compact, central bore construction. A special electronic driver is used to control the new motor with electric stepper indexers and standard motion control cards. The motor accepts open-loop step operation as well as closed-loop control with position feedback from the enclosed sensor. A special control feature is implemented to adapt classic control algorithms to the new motor.

PneuStep was designed to be compatible with magnetic resonance medical imaging equipment, for actuating an image-guided intervention robot (MrBot), for medical applications. The motors were entirely made of nonmagnetic and dielectric materials, such as plastics, ceramics, and rubbers. Encoding was performed with fiber optics so that the motors are electricity free, exclusively using pressure and light.

No other motor satisfies the combined MRI compatibility, medical safety, and reliability required for precision MRI instrumentation. The PneuStep is specifically designed for this application.

The stepper achieves easily controllable precise motion unlike other pneumatic motors. PneuStep is readily applicable to other pneumatic or hydraulic precision motion applications.