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Performance evaluation and frequency response analysis of a two stage two spool electrohydraulic servovalve with a linearized model

Mondal Nitesh, Datta Biswanath

Engineering Transactions

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2019

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Vol. 67, iss. 3

411--427

EN

This article focuses on the performance study and frequency response analysis with the state space model of a linearized two stage two spool non-conventional electrohydraulic servovalve from a set of nonlinear state equations. The performance of this valve depends on many valve geometries and fluid parameters. This non-conventional electrohydraulic servovalve is controlled by a pressure controlled pilot, which generates a differential pressure between the upper and lower chambers of two spools. This differential pressure acts as the feedback element, thereby reducing the requirement for a feedback wire. In this paper, the dynamic behaviour and state-space model of the valve is established with the aid of linearized mathematical equations and the coefficients of the equations directly depend on the valves parameters, fluid properties and flow properties. The dynamic performance of this valve and the frequency response are analysed with the help of MATLAB/Simulink.

2

PLC implementation of fractional PI controller in positioning of electrohydraulic servodrive

Rybarczyk D.

Control and Cybernetics

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2016

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Vol. 45, no. 3

301--316

EN

The article describes the implementation of fractional order PI controller with the Programmable Logic Controller (PLC). The control system proposed is used for positioning of an electrohydraulic drive with Bosch Rexroth servo valve. The controller is based on PLC, working under real time operating system Automation Runtime. User interface is equipped with the touch panel of Power Panel 500 type. In the ﬁrst part of the paper the fractional order calculus theory is introduced. In addition, some examples of fractional controller implementations in diﬀerent kinds of objects are presented. The subsequent section focuses on author’s own research. The Oustaloup’s method description is recalled along with its computer implementation. Further, the impact of ﬁnite order of the approximation function is veriﬁed. The article includes the description of test stand structure, code generation and implementation of PI controller on the dedicated PLC.

3

Influence of the feedback spring parameters on the servovalve flow characteristics

Ławniczak A., Rybarczyk D., Sędziak D.

Archives of Mechanical Technology and Automation

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2014

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Vol. 34, no. 4

37--44

EN

One of the most frequently used electrohydraulic transducers is servovalve with mechanical feedback linkage realized by means of a feedback spring. In case of pressure-flow control applications of such servovalve one of the crucial problems is to match its feedback spring rigidity to flow output characteristics. This paper contains a linear mathematical model which enables to obtain suitable relation between the input of current of torque motor and flow output of the valve in steady states.

PL

W artykule opisano liniowy model matematyczny, który umożliwia uzyskiwanie odpowiednich zależności pomiędzy prądem zasilania cewek silnika momentowego a przepustowością serwozaworu.