Achieving a Variable Flow Supply by Controlled Unloading of a Fixed-Displacement Pump

1992 ◽  
Vol 114 (1) ◽  
pp. 166-171 ◽  
Author(s):  
S. P. Tomlinson ◽  
C. R. Burrows

This paper addresses the operational performance of a fixed-displacement pump controlled by an unloading valve to provide a fluctuating flow source. This approach should be cheaper and more efficient than the use of a variable-displacement unit. Computer simulation is used to predict the performance of the system and act as a guide in optimizing the control system. An experimental rig has been constructed to examine the practicalities of these ideas. Some experimental results are presented. Future work will be concerned with noise and efficiency studies.

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 932
Author(s):  
Xiaochen Huang ◽  
Bing Xu ◽  
Weidi Huang ◽  
Haogong Xu ◽  
Fei Lyu ◽  
...  

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.


2010 ◽  
Vol 34-35 ◽  
pp. 1028-1033
Author(s):  
Hai Gang Ding ◽  
Ji Yun Zhao ◽  
Liang Zhao

To achieve the highly reliable and highly accurate adjustment for electrohydraulic proportional pump A4VSO, an adjustment system is established, in which a servoproportional valve replaces a servo valve or a proportional valve. Then its mathematic model is obtained and simulated on Matlab/Simulink, and performance tests about pump displacement and output flow of the pump are carried out under different pressures. Both simulation and experimental results indicate that the adjustment system controlled by servoproportional valve is characterized by higher steady accuracy and more reliability, both the pump displacement and output flow of the pump A4VSO maintain proportional to the control signal, respectively.


2013 ◽  
Vol 655-657 ◽  
pp. 1179-1188
Author(s):  
Hai Bo Fan ◽  
Jian Jin ◽  
Ke Li Xing

Electro-hydraulic proportional variable displacement piston pump is widely used in various fields because of energy-saving, low noise and advanced control technology. In this study, a fuzzy logic controller was used in a flow and pressure integrated controlled electro-hydraulic proportional variable displacement piston pump’s control system. The simulation model of variable displacement pump was built based on AMESim, and the model of control system with fuzzy logic controlled was built in Simulink. This study research the characteristics of electro-hydraulic proportional variable displacement piston pump’s control system through co-simulation.


1998 ◽  
Vol 37 (12) ◽  
pp. 285-292 ◽  
Author(s):  
Hiroshi Tsugura ◽  
Tetufumi Watanabe ◽  
Hiroshi Shimazaki ◽  
Shoichi Sameshima

A method for measuring both dissolved ozone (DO3) concentration and UV absorbance was developed adopting ultraviolet (UV) absorption method (JWWA, 1993) using sodium thiosulfate (Na2S2O3) solution for removing residual ozone in ozonated water. A DO3 monitor based on this method was tested. This method was proven to be effective from experimental results. The performance of the monitor was examined with continuous ozonated water. As a result, the monitor performed stably during about 2 months, so that both DO3 concentration and UV absorbance in the ozonated water could be accurately measured. Therefore, the authors have proposed the new aquatic control system with this monitor for ozonation.


2012 ◽  
Vol 182-183 ◽  
pp. 1751-1755
Author(s):  
Xi Feng Zheng ◽  
Feng Chang

For the purposes of correcting the LED display image, a method based on computer simulation is proposed. First, the development of the LED display panel is introduced. Second, analyze the causes of the problem which image in LED display panel has serious high non-uniformity, and introduce the existed correction techniques which are used to reduce the non-uniformity of LED display image. Simultaneously, point out the ground for shortcomings of these techniques. Third, describe the principle of correction method based on computer simulation detail from two steps, which are the luminous collection and luminous copulation. Forth, describe the realization steps of this method in accordance with the third step. Finally, this method is supplied in a LED display panel, whose resolution is 640×480. Experimental results show that this method is able to reduce the non-uniformity of images from 11.06% to 0.98%..


Author(s):  
Samir Kumar Hati ◽  
Nimai Pada Mandal ◽  
Dipankar Sanyal

Losses in control valves drag down the average overall efficiency of electrohydraulic systems to only about 22% from nearly 75% for standard pump-motor sets. For achieving higher energy efficiency in slower systems, direct pump control replacing fast-response valve control is being put in place through variable-speed motors. Despite the promise of a quicker response, displacement control of pumps has seen slower progress for exhibiting undesired oscillation with respect to the demand in some situations. Hence, a mechatronic simulation-based design is taken up here for a variable-displacement pump–controlled system directly feeding a double-acting single-rod cylinder. The most significant innovation centers on designing an axial-piston pump with an electrohydraulic compensator for bi-directional swashing. An accumulator is conceived to handle the flow difference in the two sides across the load piston. A solenoid-driven sequence valve with P control is proposed for charging the accumulator along with setting its initial gas pressure by a feedforward design. Simple proportional–integral–derivative control of the compensator valve is considered in this exploratory study. Appropriate setting of the gains and critical sizing of the compensator has been obtained through a detailed parametric study aiming low integral absolute error. A notable finding of the simulation is the achievement of the concurrent minimum integral absolute error of 3.8 mm s and the maximum energy saving of 516 kJ with respect to a fixed-displacement pump. This is predicted for the combination of the circumferential port width of 2 mm for the compensator valve and the radial clearance of 40 µm between each compensator cylinder and the paired piston.


2014 ◽  
Vol 971-973 ◽  
pp. 714-717 ◽  
Author(s):  
Xiang Shi ◽  
Zhe Xu ◽  
Qing Yi He ◽  
Ka Tian

To control wheeled inverted pendulum is a good way to test all kinds of theories of control. The control law is designed, and it based on the collaborative simulation of MATLAB and ADAMS is used to control wheeled inverted pendulum. Then, with own design of hardware and software of control system, sliding mode control is used to wheeled inverted pendulum, and the experimental results of it indicate short adjusting time, the small overshoot and high performance.


Author(s):  
V Domala ◽  
R Sharma

This paper presents the design and development of an efficient modular ‘Computer Simulation Model (CSM)’ for response analysis of a moored semi-submersible. The computer simulation model is designed in two split models (i.e. computational and experimental models) and each of these models consists of various modules. The modules are developed from basic governing equations related to motion and modules are integrated and we aim for a seamless integration. The moored semi-submersible is represented mathematically as six degrees of freedom dynamic system and the coupling effects between the structure and mooring lines are considered. The basic geometric configuration of semi- submersible is modelled and analyzed for stability computations in MS-Excel*TM and then the basic governing equations related to motion are modelled mathematically in a module and solved numerically with Ansys-AQWA**TM. The computational model is validated and verified with some available experimental results. The CSM is utilized to study the surge and sway responses with respect to the horizontal range of mooring lines and our results show good validation with the existing experimental results. Our presented results show that the fibre wires have minimum steady state response in surge and sway degrees of freedom as compared with the steel wires. However, they have large drift as compared with steel wires. Finally, we show that the computer simulation model can help in detailed analysis of responses and results can be utilized for design and development of new age semi-submersibles for optimum performances for a given set of parameters.


2018 ◽  
Vol 155 ◽  
pp. 01041 ◽  
Author(s):  
Aleksandr Pilipenko ◽  
Sergei Petrov

In the article the authors solve a crucial objective of reducing the cost of heating services through the introduction of a system, controlling boilers and heating devices, based on modelling of the building and predicting heating systems functioning and operation. The authors describe the method of mathematical modelling of heating systems of the building and represent the developed mathematical models, pledged and installed into the developed automated system. The authors have offered an automated system of dispatch control of the boilers with the elements of computer simulation and modelling.


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