scholarly journals Identification of Linearized Electro-Hydraulic Servo-Valve Dynamics by Analyzing Self-Excited Oscillations. 2nd Report. A case in which flow-rate detector's delay must be considered.

1997 ◽  
Vol 28 (3) ◽  
pp. 340-346 ◽  
Author(s):  
Shizurou KONAMI ◽  
Takao NISHIUMI ◽  
Kazuyuki HATA
Keyword(s):  
Flow Rate ◽  
Servo Valve ◽  
Hydraulic Servo ◽  
Valve Dynamics

Measuring the Oscillating Flow from an Electro-Hydraulic Servo-Valve Using an Indirect Method

1974 ◽  
Vol 188 (1) ◽  
pp. 519-526 ◽  
Author(s):  
C. R. Burrows ◽  
D. J. Martin
Keyword(s):  
Flow Rate ◽  
Dynamic Performance ◽  
Volumetric Flow Rate ◽  
Fluid Inertia ◽  
Dynamic Flow ◽  
Analogue Model ◽  
Servo Valve ◽  
Hydraulic Servo ◽  
Valve Dynamics ◽  
Experimental Rig

Recently published work concerning the dynamic flow-rate through servo-valves is discussed. It is shown that there is some disagreement amongst workers concerning the effects that fluid inertia and valve discharge coefficients have on the dynamic performance of these devices. The problem of measuring pulsating flow is discussed and the various commercially available transducers are shown to have shortcomings when used in conjunction with servo-valves. An alternative indirect dynamic flow measurement technique is described. The technique is evaluated using an analogue model. It is concluded that the method is capable of determining the dynamic volumetric flow-rate. The difficulties involved in identifying the valve dynamics from these measurements are discussed. The method is applied to determine the volumetric flow-rate in an experimental rig consisting of a servo-valve controlling a rectilinear motor used to position an inertial load.

Development of the Small Flow Rate Water Hydraulic Servo Valve

2010 ◽  
Vol 22 (3) ◽  
pp. 333-340 ◽  
Author(s):  
Toshiya Watanabe ◽  
◽  
Tomokazu Inayama ◽  
Takeo Oomichi
Keyword(s):  
Flow Rate ◽  
Servo Valve ◽  
Test And Evaluation ◽  
Small Flow Rate ◽  
Hydraulic Servo ◽  
Small Flow ◽  
Hydraulic Manipulator ◽  
Water Hydraulic ◽  
Leakage Characteristics ◽  
Small Capacity

A small capacity servo valve was developed for a small size water hydraulic manipulator, focusing the saving energy. The new servo valve optimizes the machines small flow rate use, makes the stroke longer for wideband use, reduces leakage and makes control easier. The test and evaluation of the servo valve was conducted by examining flow rate characteristics, leakage characteristics and responsibility. The flow rate and leak rate of the servo valve shows to be the same as the oil hydraulic servo valve, while the step and frequency response show good controllability for the water hydraulic manipulator.

A High Flow Rate and Fast Response Electrohydraulic Servo Valve Based on a New Spiral Groove Hydraulic Pilot Stage

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Shuai Wu ◽  
Zongxia Jiao ◽  
Liang Yan ◽  
Wenhao Dong
Keyword(s):  
Flow Rate ◽  
High Reliability ◽  
Full Range ◽  
Fast Response ◽  
High Flow ◽  
High Flow Rate ◽  
Design Parameters ◽  
Phase Lag ◽  
Servo Valve ◽  
Hydraulic Servo

High flow rate electrohydraulic servo valve is widely applied in hydraulic servo systems. Typical high flow rate servo valve is three-stage nozzle flapper pilot structure which is complicated, unreliable, and highly costly. This study proposed a new two-stage structure high flow rate and quick response electrohydraulic spiral pilot servo valve (ESPV) using a novel hydraulic full bridge spiral pilot stage (FBSPS) as hydraulic amplifier. Its structure is simpler than traditional servo valve which could increase reliability. A design parameters optimization method for servo valve is proposed. It is using an optimization objective function which can balance dynamic performance, static performance, and pilot state efficiency for different design objectives. The particle swarm optimization (PSO) method was applied to get the best key design parameters of ESPV. A research prototype was developed based on the optimized parameters for fast response. The experimental results indicated that the frequency bandwidth (−3 dB amplitude attenuation and −90 deg phase lag) of the ESPV is up to 150 Hz at 20% of full range. This frequency response performance is competitive with existing servo valves, and the simpler structure can improve reliability and reduce cost. Thus, it may have great potential in hydraulic servo system with high reliability requirement, such as aircraft hydraulic servo control system.

Servo Valve Nozzle Fuzzy Clustering Analysis Pairing Algorithm

2015 ◽  
Vol 667 ◽  
pp. 476-480
Author(s):  
Xu Dong Pan ◽  
Wen Dong Zhu ◽  
Guang Lin Wang
Keyword(s):  
Flow Rate ◽  
Clustering Analysis ◽  
Characteristic Curve ◽  
Orifice Diameter ◽  
Servo Valve ◽  
Fuzzy Clustering Analysis ◽  
Direct Measurements ◽  
Rate Characteristic ◽  
Hydraulic Servo ◽  
Flow Rate Characteristic

Electro-hydraulic servo valve is the key component of an electro-hydraulic servo control system, and double nozzle flapper valve is the main type of electro-hydraulic servo valve. Nozzles are the important part of a double nozzle flapper valve, the pairing quality is directly related to the performance of the servo valve .Servo valve is of symmetrical structure, and the use of nozzles is also in pairs. The process of nozzles matched in pairs is called pairing process. Because the orifice diameter of the nozzle is only about 0.2 to 0.3 mm, it is difficult to pair with the method of direct measurements. Besides, as a kind of hydraulic components, nozzles are usually paired by flow rate measured under differential pressure. Two nozzles will be matched to a pair if their pressure-flow rate characteristic curve is within the allowed tolerance. To ensure the success rate of pairing, it usually needs a large number of machined nozzles to be sifted. According to the principle of clustering analysis, we propose a new paring algorithm which can match nozzles efficiently and automatically.

Research on the Impact Pressure of the Hydraulic Rolling-Cut Shear

2010 ◽  
Vol 145 ◽  
pp. 410-413 ◽  
Author(s):  
Jing Wang ◽  
He Yong Han ◽  
Qing Xue Huang ◽  
Jun Wang
Keyword(s):  
Hydraulic System ◽  
Impact Pressure ◽  
Direct Impact ◽  
Actual Situation ◽  
Work Situation ◽  
Servo Valve ◽  
Indirect Impact ◽  
Hydraulic Servo ◽  
Hydraulic Servo System ◽  
The Impact

The reasons for impact pressure are obtained by the research the hydraulic system of Hydraulic Rolling-Cut Shear. The impact pressure of hydraulic system is divided into direct impact and indirect impact. Based on analyzing the actual situation the measures should be taken to reduce the impact pressure when design hydraulic system. The suitable length of pipeline can improve the performance of the hydraulic system because the length is important for the impact pressure. The accumulator can absorb impact pressure and improve the work situation of servo valve. Therefore, the suitable accumulators should be set in the hydraulic system. The study provides theory basis for the pipe design of large hydraulic servo system.

Feasibility Study on the Use of a Voice Coil Motor Direct Drive Flow Rate Control Valve

2009 ◽  
Author(s):  
Shuai Wu ◽  
Richard Burton ◽  
Zongxia Jiao ◽  
Juntao Yu ◽  
Rongjie Kang
Keyword(s):  
Neural Network ◽  
Flow Control ◽  
Flow Rate ◽  
Rate Control ◽  
Network Flow ◽  
Voice Coil Motor ◽  
Direct Drive ◽  
Hydraulic Test ◽  
Servo Valve ◽  
Flow Rate Control

This paper considers the feasibility of a new type of voice coil motor direct drive flow control servo valve. The proposed servo valve controls the flow rate using only a direct measurement of the spool position. A neural network is used to estimate the flow rate based on the spool position, velocity and coil current. The estimated flow rate is fed back to a closed loop controller. The feasibility of the concept is established using simulation techniques only at this point. All results are validated by computer co-simulation using AMESim and Simulink. A simulated model of a VCM-DDV (Voice Coil Motor-Direct Drive Valve) and hydraulic test circuit are built in an AMESim environment. A virtual digital controller is developed in a Simulink environment in which the feedback signals are received from the AMESim model; the controller outputs are sent to the VCM-DDV model in AMESim (by interfacing between these two simulation packages). A LQR (Linear Quadratic Regulator) state feedback and nonlinear compensator controller for spool position tracking is considered as this is the first step for flow control. A flow rate control loop is subsequently included via a neural network flow rate estimator. Simulation results show that this method could control the flow rate to an acceptable degree of precision, but only at low frequencies. This kind of valve can find usage in open loop hydraulic velocity control in many industrial applications.

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