Modelling a Loaded Two-Way Pneumatic Actuator

This paper describes experiments on a low-pressure pneumatic actuator and load. An impulse test is described, in which the transient behaviour of a loaded actuator, operating in a particularly simple mode, was observed. The results are used to explain the nature of the expansion and compression processes in the actuator and to aid understanding of the effects of piston leakage and friction. Numerical values are obtained for the poly tropic gas constant and for the friction and piston leakage coefficients. The conclusions are shown to be relevant to an actuator operating in more complex modes and as a component of a pneumatic servomechanism.