Experimental Modelling and Identification of Compressible Flow through Proportional Directional Control Valves

Abstract

This paper derives an empirical model of the air flow through a variable area orifice of a 5-port proportional valve, in function of pressures at the supply port and at the pneumatic cylinder, i.e. including the flow resistance of the connecting tubes and fittings, and the (quasi-static) valve’s driving voltage.Effects of nonlinear flow through the valve, air compressibility in cylinder chambers, system identification, numerical simulation and model validation experiments were conducted and compared with theoretical models showing very good agreement. This Experimental model can be used in simulation and control of high performance pneumatic servo positioning systems, with applications in robotics and modern pneumatic tube transportation systems.