Piezoelectrically actuated hydraulic valve design for high bandwidth and flow performance

Abstract

The performance of hydraulically actuated machine systems could be improved with the use of valves that have high bandwidth and high flowrates under low pressure drops. Although high flowrates can be achieved using very large spool strokes and/or diameters, the overall bandwidth of the valve will be reduced. Research has therefore been undertaken on a prototype valve design incorporating the Horbiger plate principle, which utilizes multiple metering edges to allow high flowrates to be obtained at low pressure drops and small poppet displacements. The valve is directly activated using a piezoelectric actuator to achieve a fast dynamic response. Valve performance is assessed using a mathematical model that includes the piezoelectric actuator and power amplifier, the supply flow, fluid squeeze forces, end stop response, and valve mechanical components. The steady state relationship between valve flow, force and pressure drop, and the fluid inertance, were determined using computational fluid dynamics software. The simulation model has been validated using test data obtained from experimental tests undertaken on a prototype valve. Good agreement is obtained between the predicted and measured results and it is shown that the valve is capable of opening or closing fully in less than 1.5 ms, and can pass a flow of 65l/min at a pressure drop of 20 bar.

Active control of fluid-bome noise in hydraulic systems using in-series and by-pass structures

“…The experimental tests were conducted on two different rig structures with the FBN cancellation valve in series and bypass configurations. A novel piezoelectric valve was used as the actuator to produce the anti-noise in the system because it had a fast response and high bandwidth [16]. A PI E-481 highpower piezo-amplifier was used to drive the piezoelectric actuator.…”

Coupled Physics Modelling for Bi-Directional Check Valve System

“…Uusitalo et al (2010) developed a static 2-D axisymmetric finite element model for an electromagnetic domain of a novel bistable hammer type digital valve to evaluate electromagnetic force. It was found that the simulated model accurately predicted power consumption values but failed to capture the accurate response time; Wilfong (2011) and Branson et al (2011) both developed the static computational fluid dynamics (CFD) models for the flow domains of their high speed valve systems to acquire flow force profiles at different valve positions. However, this approach does not include the dynamic of the valve poppet/spool, which causes modelling discrepancies with the actual valve performances.…”

“…The response time of this valve ranged from 2 to 8ms. Branson et al (2011) developed a piezo-electrically actuated valve utilizing the Horbiger plate principle and achieved less than a 1.5 ms on/off switching time but only 20L/min nominal flow @ 5bar pressure drop.…”

A Novel Servovalve Pilot Stage Actuated by a Piezo-electric Ring Bender: A Numerical and Experimental Analysis

“…In particular, a promising research field aims to replace the electromagnetic torque motor assembly with piezoelectric actuators, thus reducing complexity and manufacturing costs [2]. Different types of piezoelectric actuators have been used to directly drive the main stage spool or to drive the flapper, jet pipe or deflector jet in the pilot stage [11][12][13][14][15][16][17][18][19][20][21], showing that the idea of using a piezo-electric actuator to drive a servovalve is feasible and promising. One of the commercially available piezoelectric actuators that has been used for this purpose is the stack-type, in which several piezo elements are joined together to form a multi-layer actuator [11][12][13]; in parallel to piezo-stacks actuators, also amplified piezo-stack actuators, which can provide higher displacement but lower forces, have been proposed to replace the torque motors in servovalves [14][15][16].…”