A Brief History of Electrohydraulic Servomechanisms

Maskrey, R. H.; Thayer, W. J.

doi:10.1115/1.3426352

Cited by 54 publications

(46 citation statements)

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“…The experimental procedure is given as follows: (1) set and fix the torque motor model, (2) position the displacement sensor, (3) calibrate the sensor, and (4) put weights on the pan and record the displacement.…”

Section: Methodsmentioning

confidence: 99%

Stiffness of the elastic system in a servo-valve torque motor

Urata

Suzuki

2011

Proceedings of the Institution of Mechanical Engineers, Part C:

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This article investigates the stiffness of the elastic system in a servo-valve torque motor. A suitable stiffness of the elastic system is necessary because a too low stiffness results in unstable equilibrium while a high stiffness requires a high electric input current. Therefore, designers require an exact estimate of the stiffness of the elastic structure. This article shows that classic beam theory can be used as a design tool for torque motors that have a flexure tube of aspect ratio of about 3 or larger. The beam theory and a finite element method (FEM) analysis are compared with experiments; if the aspect ratio is less than 3, the beam theory induces considerable error and FEM analysis becomes a necessary tool for estimating the elastic characteristics. The benefit of the beam theory is that it can give compact expressions for deflection of the flapper and rotation angle of the armature.

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Section: Methodsmentioning

confidence: 99%

Stiffness of the elastic system in a servo-valve torque motor

Urata

Suzuki

2011

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…The developments of the servovalve are very fast, with various designs to meet the customer's requirements. The applications of these valves are very wide both in industry and in aerospace [1]. The performance of the servovalve depends on many parameters like torque motor characteristics, pressure recovery, flow gain, leakage, flow forces, etc.…”

Section: Introductionmentioning

confidence: 99%

Steady-state analysis of a precision hydraulic flow control servovalve using the finite element method

Singaperumal¹,

Hiremath²,

Kumar³

2006

Journal of Micromechatronics

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In the present paper, an attempt has been made to simulate the steady-state operation of the jet pipe Electro-Hydraulic ServoValve (EHSV) using the Finite Element Method (FEM). The jet pipe servovalve has two stages and consists of two main assemblies: first-stage torque motor assembly and second-stage valve assembly. Between the first and second stage there is a mechanical feedback to stabilize the valve operation. Each assembly has various delicate and precise components. The finite element analysis has been carried out on jet pipe and feedback spring assembly. The analysis shows that the stiffness of flexure tube and feedback spring assembly plays the major role in achieving steady-state valve operation. The stiffness of these components is obtained through the FEM and these results are validated with experiment. The commercial ABAQUS finite element code has been used for the simulation. The mathematical model of the jet pipe EHSV has been developed and simulated using MATLAB to study the spool dynamics with the main emphasis on the steady-state valve operation. The required simulation parameters, like moment of inertia, stiffness of the components and lever arm length. are obtained from the FEM.

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“…Maskrey and Thayer [1] elaborated the historical development, market growth and wide application areas of EHSV. The selection and performance criteria for electrohydraulic servodrives are given [2] and the performance estimation for electrohydraulic control systems are explained [3].…”

Section: Introductionmentioning

confidence: 99%

Fluid structure interaction in electrohydraulic servovalve: a finite element approach

Hiremath

Singaperumal

2009

SPIE Proceedings

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Electrohydraulic servovalves (EHSV) promise unique application opportunities and high performance, unmatched by other drive technologies. Typical applications include aerospace, robotic manipulators, motion simulators, injection molding, CNC machines and material testing machines. EHSV available are either a flapper/nozzle type or a jet pipe type. In the present paper an attempt has been made to study the dynamics of jet pipe EHSV with built-in mechanical feedback using Finite Element Method (FEM). In jet pipe EHSV, the dynamics of spool greatly depends on pressure recovery and hence the fluid flow at spool ends. The effect of pressure recovery on spool dynamics is studied using FEM by creating the fluid-structure-interaction. The mechanical parts were created using general purpose finite elements like shell, beam, and solid elements while fluid cavities were created using hydrostatic fluid elements. The analysis was carried out using the commercially available FE code ABAQUS. The jet pipe and spool dynamics are presented in the paper.Keywords: Fluid-structure-interaction, drain line orifice, mechatronic component, finite element method, feedback. INTRODUCTIONFluid power control is the transmission and control of energy by means of a pressurized fluid, is an old and well recognized discipline. The growth of fluid power has accelerated with our desires to control ever increasing quantities of power and mass with higher speeds and greater precision. More specifically, where precise motion control is desired and space and weight are limited, the convenience of high power-to-weight ratio makes hydraulic servomechanisms the ideal control elements. The demand to achieve more accurate and faster control at high power levels, especially in the areas of machine tools, primary flight controls, and automatic fire control produced an ideal marriage of hydraulic servomechanisms with electronic signal processing. Information could be transduced, generated, and processed more easily in the electronic medium than as pure mechanical or fluid signals, while the delivery of power at high speeds could be accomplished best by the hydraulic servo. This marriage of electronics and hydraulics into electrohydraulic servomechanisms created both a solution to an existing class of control problems and a demand for a whole new strain of components. The evolution of these components is really a story of increasingly demanding applications each of which caused the creation of better, or more efficient, or more reliable, or faster devices. To satisfy this demand, new manufacturing methods had to be conceived and original testing techniques developed.Electrohydraulic Servovalve (EHSV) are faster responding directional, pressure and flow control valves which are frequently used in a closed loop arrangements to produce the highly sophisticated performance, in terms of high

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A Brief History of Electrohydraulic Servomechanisms

Cited by 54 publications

References 0 publications

Stiffness of the elastic system in a servo-valve torque motor

Stiffness of the elastic system in a servo-valve torque motor

Steady-state analysis of a precision hydraulic flow control servovalve using the finite element method

Fluid structure interaction in electrohydraulic servovalve: a finite element approach

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