Physical Limitations for the Bandwidth Frequency of a Pressure Controlled, Axial-Piston Pump

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Noah D. Manring ◽  
Viral S. Mehta
Keyword(s):  
Dynamical Behavior ◽  
Control Valve ◽  
Dynamical Property ◽  
Piston Pump ◽  
Closed Form Expression ◽  
Design Parameters ◽  
Axial Piston Pump ◽  
Axial Piston ◽  
Pressure Controlled ◽  
Valve Model

The objectives of this paper are to identify the design parameters that have the greatest impact on the bandwidth frequency of a pressure controlled, axial-piston pump. This study is motivated by the fact that a physical limitation for these machines has been observed in practice, as it has been difficult to increase the bandwidth frequency much beyond 25 Hz. Though much research has been done over the past thirty years to understand the dynamical behavior of these machines, the essential design-characteristics that determine the bandwidth frequency of the pump remain elusive. In part, this is due to the fact that the machine is complex and when coupled with a hydraulic control valve that is disturbed by steady and transient fluid-momentum effects this dynamical property becomes difficult to assess. In order to achieve the objectives of this research, this paper presents the most comprehensive pump-and-valve model of a pressure controlled, axial-piston machine available in the literature to date. The pump model includes the effects of the discrete pumping-elements acting on the swash plate, while the valve model includes both steady and transient fluid-momentum forces. To identify the dominate features of the model, nondimensional analysis is employed and the complexity of the model is subsequently reduced by eliminating negligible terms. Furthermore, a closed-form expression for the bandwidth frequency is employed and perturbation analysis is used to identify the dominant set of parameters that impact the bandwidth frequency of the pump. In conclusion, it is shown that, by far, the greatest impact on the bandwidth frequency may be achieved by reducing the swept volume of the control actuator and by increasing the flow capacity of the control valve.

Design and Analysis of a Swashplate Control System for an Asymmetric Axial Piston Pump

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Wei He ◽  
Jia-Hai Huang ◽  
Hui-Min Hao ◽  
Long Quan ◽  
Shuai-xu Ji ◽  
...  
Keyword(s):  
Control System ◽  
Open Loop ◽  
System Dynamic ◽  
Piston Pump ◽  
Design Parameters ◽  
Axial Piston Pump ◽  
Swash Plate ◽  
Design Requirements ◽  
Bode Diagram ◽  
Axial Piston

Abstract Based on the previously developed fixed-displacement asymmetric axial piston pump, a variable displacement asymmetric axial piston pump (VDAAPP) with three independent suction/delivery ports is proposed. A basic linear model of VDAAPP is established to get open-loop bode diagram. Based on open-loop Bode diagram features and design requirements, P-controller is determined for VDAAPP. Then VDAAPP's performance is investigated by advanced modeling environment for performing simulations of engineering systems (AMESim) and automatic dynamic analysis of mechanical systems (ADAMS) joint simulation, and some key design parameters are obtained. Next, a VDAAPP prototype with a maximum displacement of 40 cc/rev is designed and manufactured, ratio of flow rates at ports A, B and T is 1:0.6:0.4. Due to hard limitations of the test bench, the performance only under the conditions of the opposite passive loads is tested. Preliminary test results indicate that VDAAPP prototype works normally and meets the design requirements for flow ratio, and the maximum rise time of the test pressure is about 0.32 s. However, due to special design of VDAAPP valve plate, the swash plate torque severely limits system dynamic response. Therefore, an improved swashplate control system based on asymmetric-valve-controlled asymmetric-piston scheme is presented as well, it is found to be an effective way to suppress the negative impact of swash plate torque on system dynamic performance. This provides a direction for the optimization of the swashplate control system for asymmetric axial piston pumps in the future.

Optimal Control Theory Applied to Pressure-Controlled Axial Piston Pump Design

1990 ◽  
Vol 112 (3) ◽  
pp. 475-481 ◽  
Author(s):  
S. J. Lin ◽  
A. Akers
Keyword(s):  
Optimal Control ◽  
Control Theory ◽  
Optimal Control Theory ◽  
Control Valve ◽  
Open Loop ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Response Curves ◽  
Pump Design ◽  
Axial Piston

This work presents a study of the applicability of optimal control theory to the design of a pressure regulator by use of an axial piston pump with a two-stage electrohydraulic servovalve. The control valve has been modeled and an optimal control law has been formulated. The time response curves due to a step input in flow rate to the pump have been obtained for the open loop and the for the optimal control system. An examination of the results has shown that the performance, in terms of pressure peaks and frequency during recovery to the flow disturbance, is significantly improved over that obtained when a single-stage valve is used.

Impact of Valve Plate Design on Noise, Volumetric Efficiency and Control Effort in an Axial Piston Pump

2006 ◽  
Author(s):  
Ganesh Kumar Seeniraj ◽  
Monika Ivantysynova
Keyword(s):  
Volumetric Efficiency ◽  
Valve Plate ◽  
Piston Pump ◽  
Design Parameters ◽  
Axial Piston Pump ◽  
Control Effort ◽  
Flow Ripple ◽  
Swash Plate ◽  
Plate Design ◽  
Axial Piston

In designing an axial piston pump, lot of attention is given to the design of the valve plate. A well designed valve plate can reduce both flow pulsations as well as oscillating forces on the swash plate. In the presented study, a computational tool, CASPAR, has been used for investigating the effect of valve plate design on flow ripple (fluid borne noise), oscillating forces (structure borne noise) and volumetric efficiency. The impact of various valve plate design parameters such as precompression grooves, cross port, indexing and additional precompression volume will be presented using simulation results from CASPAR. The study also details how rate of pressurization and decompression inside the displacement chamber directly relate to the flow ripple, forces applied on swash plate and the control effort needed to stroke the swash plate. The effect of noise reduction techniques on volumetric efficiency will also be presented with simulated results.

scholarly journals Novel design of hydrodynamic–magnetic compound support for cylinder block–valve plate in axial piston pump

AIP Advances ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 115221
Author(s):  
Jihai Jiang ◽  
Boran Du ◽  
Jian Zhang ◽  
Geqiang Li
Keyword(s):  
Valve Plate ◽  
Piston Pump ◽  
Cylinder Block ◽  
Axial Piston Pump ◽  
Axial Piston ◽  
Novel Design

The Performance Analysis and Experimental Research of Multiple Oil Ports Axial Piston Pump which Able to Control the Movement of Differential Cylinder Directly in the Closed Circuit

2011 ◽  
Vol 308-310 ◽  
pp. 388-400
Author(s):  
Xiao Gang Zhang ◽  
Long Quan
Keyword(s):  
Digital Simulation ◽  
Flow Distribution ◽  
Closed Circuit ◽  
Piston Pump ◽  
Distribution Area ◽  
Axial Piston Pump ◽  
Hydraulic Pump ◽  
Asymmetric Flow ◽  
New Type ◽  
Axial Piston

In order to realize that an asymmetric flow piston pump can control an asymmetric differential cylinder, a proposal about the application of an asymmetric flow-distributing axial piston pump is put forward. The new type of piston pump can output the flows with two different values to control the movement of the differential cylinder directly in the closed circuit and realize much ideal result of the control of the differential cylinder by a single pump. Also a simulation model of the hydraulic pump is established under the circumstance of SimulationX software, considering the characteristics of the movement of an individual piston, the oil compressibility, and the flow distribution area changed with the rotation angle. The key data of the pump is defined by means of digital simulation. In particular, an analysis is made on the dimension of the unloading groove of the port plate and the characteristics of the flow pulse of the pump. Furthermore, an experimental model pump is manufactured, the basic performances of the pump is tested on the experimental platform at various rotatory speeds such as pressure, flow and noise, in the end the accuracy of the principle is verified.

Sign in / Sign up

Export Citation Format

Share Document