Development of an asymmetric servovalve with even underlaps or uneven underlaps

An asymmetric servovalve with even underlaps or uneven underlaps is proposed and investigated. The aim is to speed-up the step response of a pneumatic force control system. By using an asymmetric servovalve whose down-stream port width is twice the up-stream one, first, the structures of the asymmetric servovalve with even underlaps or uneven underlaps are mainly considered and introduced in detail. Next, the steady-state characteristics of these types of servovalves for this approach, which are applicable to different underlaps and different port-width ratios of the spool valve, are investigated. The theoretical results agreed fairly well with the experimental ones.