Dynamic Analysis of a Variable Displacement Pump

1990 ◽  
Vol 112 (1) ◽  
pp. 122-132 ◽  
Author(s):  
G. J. Schoenau ◽  
R. T. Burton ◽  
G. P. Kavanagh
Keyword(s):  
Dynamic Performance ◽  
Critical Factor ◽  
Pressure Control ◽  
Control Signal ◽  
Hydraulic Control ◽  
New Techniques ◽  
Swash Plate ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Time Trace

The ability of a variable displacement pump to respond to a control signal is a critical factor in assessing the dynamic performance of the circuit in which the pump is located. The need for a comprehensive dynamic response model of the pump is necessary if new techniques for control are to be realized. This paper presents a mathematical model, based on fluid mechanics considerations, of a variable displacement pump modulated by a hydraulic control signal. Many of the coefficients in the model depend on the pump model. In this study, a Vickers No. PVB5 pump is used. The describing equations are complex, nonlinear, and comprehensive in the initial model. Some nonlinear terms are simplified using linear approximations without significantly affecting accuracy. The model is subjected to a simulated pressure control signal and the output of the swash plate rotary displacement compared to an experimentally generated displacement time trace. The model and the experimental results show a good correlation.

Robust Nonlinear Control of a Novel Indexing Valve Plate Pump: Simulation Studies

2002 ◽  
Vol 124 (4) ◽  
pp. 613-616 ◽  
Author(s):  
X. Zhang ◽  
S. S. Nair ◽  
N. D. Manring
Keyword(s):  
Pressure Control ◽  
Plate Motion ◽  
Nonlinear Simulation ◽  
Response Characteristics ◽  
Model Free ◽  
Swash Plate ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Robust Adaptive ◽  
Improved Performance

A robust adaptive pressure control strategy is proposed for a novel indexing variable-displacement pump. In the proposed approach, parametric uncertainties and unmodeled dynamics are identified to the extent possible using a model free learning network and used to decouple the dynamics using physical insights derived from careful reduced order modeling. The swash plate motion control is then carefully designed to provide the desired pressure response characteristics showing improved performance with learning. The proposed control framework and designs are validated using a detailed nonlinear simulation model.

Robust Nonlinear Control of a Novel Indexing Valve Plate Pump

2001 ◽  
Author(s):  
X. Zhang ◽  
S. S. Nair ◽  
N. D. Manring
Keyword(s):  
Pressure Control ◽  
Plate Motion ◽  
Nonlinear Simulation ◽  
Response Characteristics ◽  
Model Free ◽  
Swash Plate ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Robust Adaptive ◽  
Improved Performance

Abstract A robust adaptive pressure control strategy is proposed for a novel indexing variable-displacement pump. In the proposed approach, parametric uncertainties and unmodeled dynamics are identified to the extent possible using a model free learning network and used to de-couple the dynamics using physical insights derived from careful reduced order modeling. The swash plate motion control is then carefully designed to provide the desired pressure response characteristics showing improved performance with learning. The proposed control framework and designs are validated using a detailed nonlinear simulation model.

An Improved Alternative to the Three-Dimensional, Swash Plate Mechanism

1983 ◽  
Vol 105 (3) ◽  
pp. 468-470 ◽  
Author(s):  
T. E. Shoup ◽  
D. Chi
Keyword(s):  
Theoretical Analysis ◽  
Mechanism Design ◽  
Research Effort ◽  
Three Dimensional ◽  
Design Technique ◽  
Force Transmission ◽  
Swash Plate ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Crank Mechanism

This paper presents a theoretical analysis and a design technique for the use of a special type of adjustable spatial slider crank mechanism to replace the swash plate device commonly used as a variable displacement pump or compressor. This paper is an extension of a previous research effort utilizing the RSSP mechanism [7] and considers the influence of geometric proportions of a device on stroke size, velocity fluctuation, and force transmission effectiveness. The device is shown to have significant kinematic advantages over the traditional form of the swash plate mechanism. Design curves are presented and an example application is provided.

The Research of Oil Pressure Fluctuation Influence to Rolling Mill Control Precision

2013 ◽  
Vol 330 ◽  
pp. 624-628
Author(s):  
Chun Ming Chen ◽  
Ya Jun Liu ◽  
Yun Xia Zhang ◽  
Dan Xia Guo
Keyword(s):  
Pressure Fluctuations ◽  
System Control ◽  
Hydraulic Control ◽  
Control Precision ◽  
Pressure Variable ◽  
Displacement Pump ◽  
Practical Engineering ◽  
Variable Displacement ◽  
Oil Source ◽  
And Control

Oil source made up of constant pressure variable displacement pump, accumulator, and pipeline is widely used to provide stable pressure for electro-hydraulic control system in practical engineering. Based on the experiment, the relationship between initial charging pressure & volume of the accumulator at inlet of the servo valve and control precision is analyzed in detail, and coupling rules between the load variation and the pressure fluctuations of oil-source are obtained, the rules can give reference for selecting initial charging pressure & volume of the accumulator according to the requirement of system control precision, which can further improve control precision and product quality by optimizing equipment parameters.

scholarly journals Active Pressure Ripple Reduction of a Self-Supplied Variable Displacement Pump with Notch Least Mean Square Filter

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 932
Author(s):  
Xiaochen Huang ◽  
Bing Xu ◽  
Weidi Huang ◽  
Haogong Xu ◽  
Fei Lyu ◽  
...  
Keyword(s):  
Control System ◽  
Active Control ◽  
Pressure Pulsation ◽  
Control Signal ◽  
Control Technique ◽  
Mean Square ◽  
Least Mean Square ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Pressure Ripple

As the power sources in hydraulic systems, variable displacement axial piston pumps generate flow fluctuation. Unfortunately, it results in pressure pulsation which excites the system vibration and emitted noise. The majority of studies try to eliminate the pulsation via a passive technique and the active control methodology has not been discussed in detail. In this research, the feasibility of reducing the pressure ripple by properly controlling the proportional valve has been investigated, which also supports the miniaturization of the active control system. A mathematical model of the self-supplied variable displacement pump including the control system has been developed. The filtered-X least mean square algorithm with time-delay compensation is utilized to calculate the active control signal. Simulation results show the effectiveness of the active control technique. The effect of the active control signal on the flow rate from different chambers of the pump has been analyzed. It demonstrates that the variation of the pressure pulsation should be ascribed to the comprehensive reaction of different flow rates. The major reason is that the flow of the actuator piston neutralizes the peak value of the flow ripple, generated by the nine pistons.

Pressure Compensator Design for a Swash Plate Axial Piston Pump

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
N. P. Mandal ◽  
R. Saha ◽  
S. Mookherjee ◽  
D. Sanyal
Keyword(s):  
Critical Role ◽  
Design Procedure ◽  
Swash Plate ◽  
Simulation Based Design ◽  
Displacement Pump ◽  
Popular Pressure ◽  
Variable Displacement ◽  
And Control ◽  
Spool Valve ◽  
Axial Piston

An in-line axial-piston swash-plate pump with pressure compensator is widely used for its fast speed of response and power economy. Although several simulation based design approaches exist to minimize issues like fluid-born noises, ample scope exists for more exhaustive design analysis. The most popular pressure compensator for a variable displacement pump with a spool valve actuating the control and bias cylinders has been taken up here. With an existing comprehensive flow dynamics model, an updated model for swiveling dynamics has been coupled. The dynamics also includes the force containment and friction effects on the swash plate. A design optimization has been accomplished for the pressure compensator. The target of the optimal design has been set as minimizing the transient oscillations of the swash plate, the compensator spool, pressures in the bias and control cylinders along with avoidance of both over-pressurization and cavitation in the bias cylinder. It has been found that the orifice diameters in the spring-side and at the metering port of the spool valve and in the backside of the bias cylinder have critical role in arriving at an optimum design. The study has led to a useful design procedure for a pressure compensated variable displacement pump.

Dynamic Modeling of an Indexing Valve Plate Pump

1999 ◽  
Author(s):  
J. Cho ◽  
X. Zhang ◽  
S. S. Nair ◽  
N. D. Manring
Keyword(s):  
Nonlinear Modeling ◽  
Open Loop ◽  
Valve Plate ◽  
Governing Equations ◽  
Pump Design ◽  
Pressure Port ◽  
Swash Plate ◽  
Plate Design ◽  
Displacement Pump ◽  
Variable Displacement

Abstract The swash-plate in a variable displacement pump experiences very large forces and moments that try to dislocate its position and therefore a large device is required for adequate control. In this paper, the dynamics of an alternative pump design using an indexing valve plate to position the swash-plate are reported. The indexing valve plate design is aimed at controlling the pressure transition for a piston, which is moving from a high-pressure port to a low-pressure port and back. In this paper, the governing equations for the pump are derived and the detailed open-loop, which is necessary for understanding the overall dynamic characteristics of the pump, is reported. Also, linear and nonlinear modeling approaches for the system are compared.

Leakage Based Condition Monitoring and Pressure Control of the Swashplate Axial Piston Pump

2019 ◽  
Author(s):  
Neeraj Kumar ◽  
Bikash Kumar Sarkar ◽  
Subhendu Maity
Keyword(s):  
Hydraulic System ◽  
Pressure Control ◽  
Piston Pump ◽  
Chamber Pressure ◽  
Leakage Flow ◽  
Axial Piston Pump ◽  
Highly Nonlinear ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Axial Piston

Abstract This research mainly focused on the axial piston variable displacement pump, which is the most important part of the fluid power system. The variable displacement axial piston has been found as versatile and flexible for electro-hydraulic applications. Heavy industries such as automobile, aircraft, and mining use an axial piston pump due to its high power to weight ratio, continuous variable power transmission, low inertia, self-lubricating properties, and good controllability. The main challenges with the hydraulic system are highly nonlinear, leakages, unknown external disturbance, etc. The mathematical model of the variable displacement pump along with swashplate control has been developed. The model is used to identify the pump health condition with pressure and flow measurement, i.e., ripple pattern. The pressure and flow ripple will vary from the regular pattern due to wear and tear, i.e., increased leakage flow. The main source of the increase in leakage flow is due to wear in piston and cylinder bore. The piston chamber pressure, kinematical flow, and discharge area model of the pump has been validated with the existing results. The pump pressure control is very much essential for the enhancement of the performance of the electro-hydraulic system. In the present study, a conventional PID controller has been used as a backup to maintain system performance within the permissible faults. The electro-hydraulic system has been employed for swash-plate control of the pump to obtain desire pressure flow at the exit of the pump. MATLAB Simulink has been used for the simulation study of the pump.

Virtually Variable Displacement Hydraulic Pump Including Compressability and Switching Losses

2006 ◽  
Author(s):  
Mark A. Batdorff ◽  
John H. Lumkes
Keyword(s):  
High Speed ◽  
Control Valve ◽  
Switching Control ◽  
Optimum Pressure ◽  
Fast Switching ◽  
Switching Losses ◽  
Swash Plate ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Axial Piston

Hydraulic pumps can be fixed or variable displacement. Fixed displacement pumps are typically smaller, lighter, less expensive, and can be of any design (gear, vane, axial piston, radial piston, ect.)[1]. Variable displacement pumps are often axial piston with an adjustable swash plate. A virtually variable displacement pump (VVDP) is a fixed displacement pump combined with a fast switching control valve that performs the same function as a variable displacement pump. This is done by always pumping full flow, but using the control valve to divert only a certain percentage of flow to the system, and the rest back to tank. A VVDP has several advantages over a traditional variable swash axial piston pump. First, the pump can be of any design, not just axial piston. Second, the flow control bandwidth can be much faster because it is only limited by the bandwidth of the fast switching control valve and system accumulator, not the bandwidth of a swash plate. Third, a VVDP pump can be more efficient because it can operate at its optimum pressure and flow setting. On the downside a VVDP will require a high speed valve. There are also added switching power losses due to constant metering over valves, compressing and decompressing hydraulic oil, and metering during transition between pumping to system and tank. This paper concentrates on modeling these three switching losses.

scholarly journals Experimental Validation of a Hydrostatic Transmission for Community Wind Turbines

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 376
Author(s):  
Biswaranjan Mohanty ◽  
Kim A. Stelson
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Pressure Control ◽  
Speed Ratio ◽  
Hydrostatic Transmission ◽  
Design Flexibility ◽  
Power Capture ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Hydrostatic Transmissions

Hydrostatic transmissions are commonly used in heavy-duty equipment for their design flexibility and superior power density. Compared to a conventional wind turbine transmission, a hydrostatic transmission (HST) is a lighter, more reliable, cheaper, continuously variable alternative for a wind turbine. In this paper, for the first time, a validated dynamical model and controlled experiment have been used to analyze the performance of a hydrostatic transmission with a fixed-displacement pump and a variable-displacement motor for community wind turbines. From the dynamics of the HST, a pressure control strategy is designed to maximize the power capture. A hardware-in-the-loop simulation is developed to experimentally validate the performance and efficiency of the HST drive train control in a 60 kW virtual wind turbine environment. The HST turbine is extensively evaluated under steady and time-varying wind on a state-of-the-art power regenerative hydrostatic dynamometer. The proposed controller tracks the optimal tip-speed ratio to maximize power capture.

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