A Linear Time Varying Model for On-Off Valve Controlled Pneumatic Actuators

A new linear time varing (LTV) model has been developed for open loop, on-off valve controlled pneumatic actuation systems. This formulation is based on a periodic profile description for variable operating points and directional control valve flow variations. The dynamic behavior of the example case, a single acting cylinder controlled by a two way-two port rotary valve, under the cyclic pressure loading is obtained using the proposed LTV model. Experimental evidence and digital simulation predictions based on the nonlinear mathematical equations validate the analytical formulation. The proposed LTV model is found to be better and more applicable than linear time invariant (LTI) models used previously by many investigators.