Static and Dynamic Experimental Investigation of a Pneumatic Open Loop Proportional Valve

Fluid power regulation elements play a fundamental role in determining the characteristics of a servosystem. Valve is a critical component when deciding the overall performance, as it influences both running and transient conditions. It is hence important to correctly predict the performances of that component by an accurate numerical non linear model. The non linearities of the valve influence steady state accuracy of a system, especially in position servo systems. In the paper a methodology to test a pneumatic open loop proportional valve, with the description of the test bench and of the experimental scheme to measure the interested magnitudes, is presented. Results of the experimental activities, both in static and dynamic conditions, are reported, with particular attention to the flow magnitude, pressures and spool displacement. The analysis of the experimental data points out the non linearities of the system and the strong influence of force disturbances on the displacement of the spool, which works in open loop. The outcome of the experimental investigation allows to relate the input/output magnitudes in a graphical way, using a map of the data and to develop static and dynamic models for computer simulation, mechatronic design and control algorithm.