Jet Pipe Electro-hydraulic Servo Valve Research Articles

Investigation on the critical parameters affecting the working design dynamics of a torque motor employed in an electro-hydraulic servovalve

The torque motor is an intricate assembly in electro-hydraulic technology and plays a crucial role in converting the electrical signal into controlled mechanical output signal. It involves many precise components, such as the feedback spring, armature and its coil, permanent magnet, feed pipe, flexure shaft, jetpipe, and flexure support. The components are embedded together as a single operating component. Each component contributes to the effective dynamics of the system. The present paper proposes a novel approach to investigate the effect of critical parameters on the working design dynamics of the torque motor employed in the jetpipe electro-hydraulic servovalve. Based on the principles of mechatronics, a mathematical model is developed. The model-based design approach is employed to investigate the dynamics of the system. The required simulation parameters of the critical and precision components were obtained from solid and finite element (FE) models. The solid and FE models of the critical and precision components were first analyzed with suitable boundary and loading conditions to establish the stiffness. To validate the obtained FE results, experiments were carried out with a specially designed and fabricated test set-up. Based on the basic principle of electromagnetics, a nonlinear FE model of torque motor is analyzed for magnetic field distribution, the torque developed, and armature and jetpipe deflection for varied input current. From the results obtained, good agreement was observed between FE, simulated, and experimental values. The present novel approach enables one to improve the working design dynamics of the torque motor.

Analysis of the jet pipe electro-hydraulic servo valve with finite element methods

The dynamic characteristics analysis about the jet pipe electro-hydraulic servo valve based on experience and mathematical derivation was difficult and not so precise. So we have analysed the armature feedback components, torque motor and jet pipe receiver in electrohydraulic servo valve by sophisticated finite element analysis tools respectively and have got physical meaning data on these parts. Then the data were fitted by Matlab and the mathematical relationships among them were calculated. We have done the dynamic multi-physical fields’ Simulink co-simulation using above mathematical relationship, and have got the input-output relationship of the overall valve, the frequency response and step response. This work can show the actual working condition accurately. At the same time, we have considered the materials and the impact of the critical design dimensions in the finite element analysis process. It provides some new ideas to the overall design of jet pipe electro-hydraulic servo valve.

Influence of High Temperature on Couples Matching and Characteristics of Jet Pipe Electrohydraulic Servovalve

Influence of High Temperature on Couples Matching and Characteristics of Jet Pipe Electrohydraulic Servovalve

Comparison of jet pipe servo valve with flapper nozzle servo valve


 
 
 Electro-hydraulic servo valves (EHSVs) serve as an interface between electrical devices and hydraulic systems. They are capable of converting low power electrical input into movement of a spool to control precisely high power, low speed hydraulic actuators. Nowadays, jet pipe electro-hydraulic servo valve and flapper nozzle electro-hydraulic servo valve are typical two-stage control flow servo valve and are the most popular in use. This paper recommends and compares characteristics, working principle and structure for two kinds of servo valve. Besides, the simulation was carried out in a commercially software of Ansys, hence some features of jet pipe servo valve such as outstanding advantages of working feature or reliability are analysed. 
 
 

Multidomain Modeling of Jet Pipe Electro-Hydraulic Servo Valve

The jet pipe electro-hydraulic servo valve is a typical two-stage flow control servo valve, its static and dynamic characteristics are analyzed in this paper. The interaction of the mechatronic and hydraulic system is considered by multidomain simulation tool, the all key parameters are tunable and this provides the optimal possibility to develop a high-performance jet pipe electro-hydraulic servo valve.

Mathematical modelling and simulation of a jet pipe electrohydraulic flow control servo valve

In this paper, the mathematical model of a jet pipe electrohydraulic flow control servo valve with a built-in mechanical feedback is developed. The actuator dynamics is also included. The solid and finite element (FE) models of the critical and precision components, feedback spring assembly and flexure tube of jet pipe assembly, were carried out first and simulated with appropriate boundary and loading conditions in a commercially available FE code, IDEAS, version 7.0, to ascertain the stiffnesses. To validate the obtained finite element results, experiments were carried out with a specially designed and fabricated test set-up. Moderately good agreement was observed between finite element and experimental values. The required simulation parameters for a jet pipe servo valve-actuator system, such as the moment of inertia, mass of the spool, mass of the piston, stiffness of the critical and precision components, and lever arm length, were obtained from the solid and finite element models. The developed model was simulated in commercially available software, MATLAB 6.5, Release 13. The step response of the valve was analysed. The simulation clearly showed the dynamics of the jet pipe, spool, and actuator displacement in achieving the equilibrium position when the applied torque and restoring torques balance, known as the steady state.

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

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.

Modelling the steady-state analysis of a jet pipe electrohydraulic servo valve

In this paper, an attempt has been made to simulate the steady-state operation of a jet pipe electrohydraulic servo valve using the finite element (FE) method. The jet pipe electrohydraulic servo valve is a mechatronic component, used for precise flow control applications in gas turbine engines. It has two assemblies: a first-stage torque motor assembly and a second-stage valve assembly. Between the first and the second stage, there is a mechanical feedback spring assembly to stabilize the valve operation. Each assembly has various delicate and precise components interacting with fluid flows. In the present paper, the structural components were modelled with general-purpose finite elements, e.g. shell, beam, and solid elements, while the fluid cavities were modelled with special-purpose hydrostatic fluid elements. The fluid flows from one fluid cavity to another fluid cavity were modelled with fluid links. The simulation was carried out in a commercially available FE code, ABAQUS, interfaced with user subroutines to form a closed-loop system. The FE simulation clearly showed the dynamics of the jet pipe and spool displacement in achieving the equilibrium position when the applied torque and restoring torques balance, known as steady state. The pressure and flow variations during torque balance are presented. The effect of the feedback loop from the second-stage spool movement to the first-stage jet pipe is seen in the FE results obtained. The theoretical aspects of pressure recovery and flow modelling are presented and used in FE simulation.