A Novel Double-Acting, Air-Floating, Frictionless Pneumatic Actuator

Due to the time-varying characteristics of pneumatic cylinder friction force, it is usually impossible to obtain the friction force situation of ordinary pneumatic cylinders precisely. Therefore, the ordinary pneumatic cylinder is unable to achieve high precision servo control of the output force. In this paper, based on the principle of hydrostatic gas lubrication, a novel double-acting air-floating frictionless pneumatic cylinder is designed, which has an air-floating piston with independent air supply and exhaust channels. In the design of the air-floating frictionless pneumatic cylinder, the load capacity and air consumption of the air-floating piston are the two main points to be concerned. To this end, the effects of key parameters such as pressure relief groove position, orifice position, orifice diameter, pressure-equalizing groove size and average air film thickness on the load capacity and air consumption of the air-floating piston are analyzed by simulation. After comprehensive consideration, the key structural parameters of the air-floating piston are determined, and the prototype of the air-floating pneumatic cylinder is machining. The friction force of the prototype is tested and found to be less than 0.0098 N. In addition, the tracking experiments of continuous step and multi-frequency sinusoidal signals are conducted on the pneumatic output force control system based on the prototype, and the results show that the developed airfloating pneumatic cylinder can achieve very high precision of output force tracking control.