Dynamic Characteristics of an Oil Hydraulic Constant Speed Drive

1968 ◽  
Vol 183 (1) ◽  
pp. 683-694 ◽  
Author(s):  
A. J. Healey ◽  
J. D. Stringer
Keyword(s):  
Dynamic Response ◽  
Machine Tool ◽  
Special Reference ◽  
Dynamic Characteristics ◽  
Hydraulic System ◽  
Control Valve ◽  
Analogue Computer ◽  
Flow Control Valve ◽  
Stick Slip ◽  
Speed Regulation

Experimental and analytical studies are made of an oil hydraulic system which uses a pressure compensated flow control valve for speed regulation. The study concerns dynamic response with special reference to the effects on the system of the sudden application of a retarding force to the mass it is moving. Equations of a typical ‘meter-out’ type of system are first developed and solved. The consequent predictions are then compared with experimental results from an apparatus which simulated a machine tool application. The advantages of incorporating a restrictor in the inlet (supply) line are then examined both experimentally and analytically using an analogue computer. The results show that the mathematical models give satisfactory predictions of the maximum changes of velocity and pressure occurring during the transients. The restrictor reduced the magnitudes of these transient changes and also eliminated ‘stick-slip’ oscillations at low speed. It is concluded that the methods of analysis outlined in this paper could be used to advantage in the design of practical systems.

Research Regarding Pressure Compensated Flow Control Valves

2015 ◽  
Vol 809-810 ◽  
pp. 992-997
Author(s):  
Irina Tiţa ◽  
Irina Mardare
Keyword(s):  
Power Systems ◽  
Flow Control ◽  
Hydraulic System ◽  
Block Diagram ◽  
Control Valve ◽  
Operating Conditions ◽  
Flow Control Valve ◽  
Constant Flow ◽  
Working Pressure ◽  
Displacement Pump

In fluid power systems, flow control may be done either with variable displacement pump or using variable orifice. In this paper is considered the second method for flow control. In a hydraulic system, working pressure is frequently variable and therefore the use of the method does not provide constant flow rates in all operating conditions. In order to keep a constant flow, if this is important in a certain case, the flow control must be accomplished using a pressure compensated flow control valve. In this paper are analyzed possible structural diagrams, mathematical model, block diagram and functional diagram for this kind of equipment. The influence of the spring compression is analyzed also. The diagrams proposed in the paper will be used for the study of a hydraulic system designated for applications with strict flow control. It will represent an important research instrument for such cases.

Power-Saving Solutions for Pre-Compensated Load-Sensing Systems on Mobile Machines

2021 ◽  
Vol 64 (5) ◽  
pp. 1435-1448
Author(s):  
Xin Tian ◽  
Patrick Stump ◽  
Andrea Vacca ◽  
Stefano Fiorati ◽  
Francesco Pintore
Keyword(s):  
Energy Efficiency ◽  
Hydraulic System ◽  
Power Saving ◽  
Control Valve ◽  
Cost Effective ◽  
Fluid Power ◽  
Flow Control Valve ◽  
List Type ◽  
Load Sensing ◽  
Agricultural Tractors

HighlightsTwo methods (VPM and HVM) are proposed to improve the hydraulic system efficiency of agricultural tractors.VPM and HVM both target reducing the power loss at the flow control valve of the hydraulic system.The solutions are presented conceptually and then numerically modeled, and VPM is tested on an actual tractor.Results show that the VPM solution achieves 6.7% power saving, while HVM achieves 15.6% power saving.Abstract. Load sensing (LS) is a dominant fluid power actuation technology in mobile machines, particularly in construction and agriculture. It has the advantage of guaranteeing good controllability in systems with multiple actuators while promoting higher energy efficiency. Several variants of LS systems have been proposed over the years, and research on cost-effective methods to further increase their efficiency is still of interest for original equipment manufacturers (OEMs) and the fluid power community. This article presents two solution, referred to as variable pump margin (VPM) and hybrid variable margin (HVM), suitable to improve the energy efficiency in pre-compensated LS systems such as those used in agricultural tractors. Both methods allow either downsizing the control valves or reducing the power consumption over the working range. Compared to a standard LS system, the VPM solution lowers the pump pressure using an electronic proportional pressure-reducing valve (ep-PRV), while the HVM solution uses a second ep-PRV in the compensator’s pilot line to further minimize the pressure differential across the LS valve. Simulation and experimental results show that, among the main working conditions, the VPM solution on average achieved 6.7% power saving over the standard LS system, while the model predicted an average improvement of 15.6% for the HVM solution. Keywords: Efficiency, Experiments, Hydraulic, Load sensing, Modeling, Pump.

Simulation for Dynamic Characteristics of Hydraulic Breaker

2013 ◽  
Vol 663 ◽  
pp. 537-544
Author(s):  
Li Shun Li ◽  
Xiang De Meng ◽  
Hong Xun Li ◽  
Shu Jun Tian
Keyword(s):  
Dynamic Response ◽  
Simulation Model ◽  
Numerical Method ◽  
Dynamic Characteristics ◽  
Time Domain ◽  
Hydraulic System ◽  
Bond Graph ◽  
Power Bond Graph ◽  
Working Parameters

Based on the method of power bond graph, the simulation model of the hydraulic system of the hydraulic breaker is presented. Treanor’s numerical method is applied to calculate the dynamic response of the hydraulic breaker in time domain. The dynamic Characteristics of the piston and the spool is achieved. The influence regularity of the working parameters on the performance of hydraulic breaker is shown.

Dynamic analysis of a hydro-motor drive system using priority valve

2018 ◽  
Vol 233 (3) ◽  
pp. 508-525 ◽  
Author(s):  
Sujit Kumar ◽  
K Dasgupta ◽  
SK Ghoshal ◽  
J Das
Keyword(s):  
Hydraulic System ◽  
System Modeling ◽  
Dynamic Performance ◽  
Control Valve ◽  
Drive System ◽  
Motor Drive ◽  
Flow Control Valve ◽  
Mining Equipment ◽  
Design And Optimization ◽  
Motor Drive System

The priority valve is considered to be one of the critical parts of the hydraulic system used in mining equipment. This article analyzes the dynamic performance of a hydro-motor drive system using priority valve through system modeling and simulation. A typical hydraulic system of a mining equipment is considered for the analysis, where a stable source of flow is supplied to two hydro-motors through priority flow divider valve. Bondgraph simulation technique is used for the modeling of the complete system, which is validated experimentally. The influences of some key parameters on the transient response of the system have been studied through simulation. The work presented in this article forms the basis idea for the design and optimization of the priority flow control valve for a given application.

Dynamic Performance of Flow Control Valve Using Different Models of System Identification

2010 ◽  
Vol 437 ◽  
pp. 393-396
Author(s):  
Ho Chang
Keyword(s):  
System Identification ◽  
Flow Control ◽  
Dynamic Characteristics ◽  
Moving Average ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Control Valve ◽  
Flow Control Valve ◽  
Auto Regressive ◽  
Input Model

This study measures the dynamic characteristics of flow control valve by a self-developed square pressure wave generator (SPWG). Comprised of a revolving shaft and a fixed ring, SPWG generates square pressure waves by the differential function of rotation between these two critical components. With the highly sensitive piezoelectric pressure sensor as the reference sensor, tests are conducted concurrently using a flow control valve. Under the same experimental parameters, the dynamic characteristics of flow control valve are evaluated by four kinds of system identification methods, namely ARX (Auto-Regressive with eXogenous input model), ARMAX (Auto-Regressive moving Average with eXogenous input model), OE (Output Error model) and BJ (Box-Jenkins model). The experimental results indicate that the dynamic performance of the tested flow control valve for resonance frequency, resonance peak and damping ratio are 1565.6 Hz, 0.9753 db and 0.4044, respectively.

Nonlinear dynamic modeling and fluid–mechanism interaction analysis of reciprocating pump–pipeline system

2020 ◽  
pp. 095965182096510
Author(s):  
Zhenjie Gu ◽  
Changqing Bai ◽  
Hongyan Zhang
Keyword(s):  
Dynamic Modeling ◽  
Dynamic Characteristics ◽  
Pressure Pulsation ◽  
Control Valve ◽  
Pipeline System ◽  
Flow Control Valve ◽  
Proposed Model ◽  
Reciprocating Pump ◽  
Nonlinear Dynamic Modeling ◽  
Crank Mechanism

The dynamic characteristics of reciprocating pump–pipeline system are directly affected by the fluid–mechanism dynamic interaction related to the slider-crank mechanism, valves and pipes conveying fluid. In this article, the fluid–mechanism interaction and nonlinearities involved in the kinetic of slider-crank mechanism, the motions of pump valves and the dynamic transmission in pipeline are explored for the nonlinear dynamic modeling of reciprocating pump–pipeline interaction systems. The nonlinear fluid–mechanism coupling model and corresponding analysis procedure are presented for investigating the system dynamic characteristics at all operating conditions. An experiment platform consisting of a simplex plunger reciprocating pump and suction and discharge pipes with a flow control valve is established to validate the proposed model. By the comparisons of pressure pulsations under multi-working conditions, the results obtained from the proposed model show good agreement with the test data. The dynamic characteristic of pump, as well as the effects of interaction and nonlinearity on the flow pulsation, are studied with the proposed model. It is found that nonlinear factors such as joint clearance and nonlinear spring stiffness are of great importance to the lag characteristics of pump valves and the pressure pulsation of pump–pipe system. The amplitudes of pressure pulsation increase with the decrease of control valve opening nonlinearly, and the effect of flow control valve becomes significant when the opening is less than 40%.

Study of Dynamic Characteristics about Controllable Vane Damp

2014 ◽  
Vol 487 ◽  
pp. 370-373
Author(s):  
Wen Rui Wang ◽  
Jia Ming Zhang ◽  
Shuai Nie
Keyword(s):  
Control System ◽  
System Design ◽  
Dynamic Characteristics ◽  
Analytical Method ◽  
Flow Model ◽  
Control Valve ◽  
Control System Design ◽  
Flow Control Valve ◽  
The Relationship ◽  
Proportional Flow

The characteristic of controllable vane damp is about the relationship between choke opening and damp parameter of proportional flow control valve, the relationship between the input current of electromagnet and controllable damp parameter is available after knowing the characteristics of electromagnet. This is the basic of control system design and the central dynamic characteristics of vane damp. The structure of vane damp is analyzed and the flow model is established, to provide the theoretical guidance with the design, analysis and improvement of vane damp, a simple calculating and accurate analytical method is proposed.

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