This paper presents a new pneumatic actuator for applications requiring moderate, but accurate, force control, such as teleoperation masters and robot wrists. The actuator uses voice-coil flapper valves and low-friction cylinders. Its force is controlled by servoing differential pressure. Aspects of valve design, system modeling, controller design, and experimental results are presented.

This paper presents a new six-degree-of-freedom pneumatic fine-motion device that can be used as a robot wrist, a teleoperation master, or in other fine-motion applications requiring high position resolution and force control. The device uses six pairs of externally pressurized mechanical bellows as a pneumatic suspension without actuator friction. Forces and torques are controlled by servoing differential pressure across each pair of bellows using novel high-flow flapper valves. Aspects of design and control are presented. Experimental results show that the valves employed have no hysteresis and have flow exceeding that of any single stage pneumatic valve currently available on the market, while the pneumatic-suspension device shows promise as a force-reflecting teleoperation master. >

This paper describes the design of a one-person hydraulic motion simulator with six degrees of freedom. An inverted, ceiling-mounted Stewart platform design enables the use of narrower hydraulic cylinders than required with floor-mounted designs, and significantly reduces hydraulic flow requirements and hence the cost. The paper details the platform geometry, shows the effectiveness of Newton's method in solving the direct kinematics, and describes a tested hydraulic system design. Issues of control and safety are also addressed. It is expected that this motion simulator will provide 9.8 m/s/sup 2/, 400/spl deg//s/sup 2/ accelerations and 1 m/s, 30/spl deg//s speeds to a 250 kg payload with 1 m, 45/spl deg/ displacements from a nominal center. Preliminary experiments at low-pressure have been encouraging.>