Stability and Performance Analysis of a Metering Poppet Valve

Abstract

Poppet type metering vales have many benefits including low leakage and an economical design. These benefits make the poppet valve an appealing alternative to spool valves in a valve stack. The fact that the metering element is not hydrostatically balanced as in a spool valve leads to control design challenges. In this work, a model of an electro hydraulic metering poppet valve is considered. Due to design compromises, the response of production metering poppet valves tends to be too slow to maintain a desired flow rate when there are fast upstream pressure variations. Re-designing to speed up the response of the valve may lead to stability issues which can be traced to plant uncertainty. Frequency response analysis of the valve model shows that the model varies greatly depending on the operating point chosen for the linearization. The analysis presented will help define the problem of designing hardware and control systems for higher performance but still reliable metering poppet valves.