Non-linear Control of a Piezoelectric Two Stage Servovalve

Persson, Johanna; Plummer, Andrew; Bowen, Chris; Elliott, Phil

doi:10.3384/ecp17144310

Cited by 6 publications

(3 citation statements)

References 5 publications

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“…In a limit cycle oscillation study of a low-frequency phenomenon, a higher-order valve model does not show significant difference compared to a lower-order model [13]. Hisa [14] stated that a reduced-order transfer function can be used to approximate a higher-order transfer function, and a first-order model is used as a reference model by Persson et al [15]. As all of the valve operational frequencies in the industrial sector are much lower than 50 Hz, the first-order transfer function Equation (1) is chosen for the valve model.…”

Section: Valve Modelmentioning

confidence: 99%

Analysis of Underlapped Symmetrically Ported Valve-Controlled Asymmetric Cylinder Drive

Wang,

Xu,

Cao

2024

Applied Sciences

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The valve-controlled cylinder drive system is the most common type among hydraulic applications. Nonlinear behaviour in such systems is inevitable when the valve spool is around its null position. We utilised the component linking method to investigate the nonlinearities in a Moog valve-controlled asymmetric cylinder drive system by simulation in Fortran, in which a generalised concept is introduced and validated by comparing to the experimental results. An X factor is proposed in the generalised concept to describe the asymmetric cylinder state, which is a constant when the cylinder is extending or retracting, but numerically calculated when the valve spool is in the underlap region. This analytical solution is approximately 200 times more computationally efficient than the numerical solution method. This paper utilises the component linking method to simulate the Moog valve-controlled asymmetric cylinder drive system in Matlab Simulink, and proposes an analytical solution for the X factor when the valve spool is in the underlap region. This analytical solution is approximately 200 times more computationally efficient than the numerical solution method.

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Section: Valve Modelmentioning

confidence: 99%

Analysis of Underlapped Symmetrically Ported Valve-Controlled Asymmetric Cylinder Drive

Wang,

Xu,

Cao

2024

Applied Sciences

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show abstract

“…In a limit cycle oscillation study of a low-frequency phenomenon, a higher order valve model does not have significant difference compared to a lower order model [14]. Hisa [15] stated that a reduced order transfer function can be used to approximate a higher order transfer function, and a first order model is used as a reference model by Persson et al [16]. As all of the valve operational frequencies in this research are much lower than 50 Hz, the first order transfer function equation 1 is chosen for the valve model.…”

Section: Valve Modelmentioning

confidence: 99%

Analysis of Underlapped Symmetrically Ported Valve Controlled Asymmetric Cylinder Drive

Wang,

Xu,

Cao

2023

Preprint

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The valve controlled cylinder drive system is the most common type among hydraulic applications. The nonlinear behaviour in such system is inevitable when the valve spool around its null position [1] , Leaney [2] utilised component linking method to investigate the nonlinearities in a Moog valve controlled asymmetric cylinder drive system by simulation in Fortran, in which a generalised concept is introduced and validated by comparing to the experimental results. An factor is proposed in the generalised concepts to describe the asymmetric cylinder state, which is a constant when the cylinder in extending or retracting, but numerically calculated when the valve spool in the underlap region [2]. This paper utilises the component linking method to simulate the Moog valve controlled asymmetric cylinder drive system in Matlab Simulink, and proposed an analytical solution for factor when the valve spool in the underlap region.

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“…In a recent valve prototype, a ring bender was used as the pilot stage actuator [15][16][17]. This time the pilot stage was a miniature spool with some overlap used to minimize pilot stage leakage flow.…”

Section: Piezoelectric Actuation Of Valve Pilot Stagementioning

confidence: 99%

A dual lane piezoelectric ring bender actuated nozzle-flapper servo valve for aero engine fuel metering

Bertin

Plummer

Bowen

et al. 2019

Smart Mater. Struct.

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Amongst many other high performance flow control applications, servo valves are used to control aero engines by metering the fuel delivered from the fuel pump. Conventionally, a fuel metering servo valve has a pilot stage with an electromagnetic torque motor moving a flapper which differentially restricts a pair of nozzles to create a hydraulic signal (i.e. a pressure difference). These valve pilot stages use mature, optimised technology such that to achieve improvements requires a novel approach. Torque motors in particular present reliability and manufacturing difficulties, and news solutions should ultimately allow a reduction in manual assembly and set-up, improve repeatability, and eliminate failures associated with fine wire devices. In this paper, a pilot stage actuated by piezoelectric ring benders is proposed, designed, built and tested, and test results are compared with a model used to predict pressure-flow characteristics. A particular challenge is the need to include redundancy, and thus a pair of ring benders is used, allowing isolation between duplicated electrical control channels. Another challenge is the mounting of the ring bender, which has to flex to allow the outer edge of the ring bender to deform, yet be stiff enough to adequately react against generated forces. O-ring mounts made from three different elastomer materials are compared in this study. In aerospace, an added complication is the large range of fuel temperature; F70 fluorosilicone O-rings have been chosen with this in mind, and successfully demonstrated in the range -50C to +180C. With one active and one inactive ring bender to simulate a failure condition, the new dual lane pilot stage achieves +/-50µm displacement under test, giving control port flows up to +/-0.6L/min, and a control port pressure variation of 40bar using a 100bar supply pressure difference (supply minus return pressure). This research establishes that a piezoelectric aero engine fuel valve is feasible, and in particular, that piezoelectric ring bender actuators with elastomeric mountings are highly suited to this application.

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Non-linear Control of a Piezoelectric Two Stage Servovalve

Cited by 6 publications

References 5 publications

Analysis of Underlapped Symmetrically Ported Valve-Controlled Asymmetric Cylinder Drive

Analysis of Underlapped Symmetrically Ported Valve-Controlled Asymmetric Cylinder Drive

Analysis of Underlapped Symmetrically Ported Valve Controlled Asymmetric Cylinder Drive

A dual lane piezoelectric ring bender actuated nozzle-flapper servo valve for aero engine fuel metering

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