THE DECOMPOSITION APPROACH AND THE CONDITIONS OF UNIQUENESS IN THE SIMULATION OF HYDRAULIC SYSTEMS

2016 ◽  
Vol 8 (3) ◽  
pp. 74-77
Author(s):  
Сазонова ◽  
Svetlana Sazonova
Keyword(s):  
Boundary Conditions ◽  
Hydraulic System ◽  
Zone Model ◽  
Hydraulic Systems ◽  
Decomposition Approach ◽  
Basic Model ◽  
Functional Reduction ◽  
Secondary Zone ◽  
Fourth Form ◽  
The Relationship

In practice, there are three forms of boundary conditions. The feature of the fourth form of the boundary conditions is that the relationship between the above nodal parameters before solving the problem cannot be defined neither in form nor in content. This situation occurs when the decomposition of the hydraulic system. The basis of this mechanism is to transform the basic model estimated in the secondary zone model based on the method of functional reduction. This method is essentially a synthesis of the known methods of transformation models based on the ideas of reduction, diakoptic and cybernetic modeling.

Dynamic balance analysis of contamination control for hydraulic systems based on dynamic filtration ratio

2016 ◽  
Vol 68 (1) ◽  
pp. 45-51
Author(s):  
Guangying Ma ◽  
Shurong Ning ◽  
Yunlong Hu ◽  
jun Gao
Keyword(s):  
Hydraulic System ◽  
Dynamic Balance ◽  
Contamination Level ◽  
Hydraulic Systems ◽  
Level Control ◽  
Content Type ◽  
Contamination Control ◽  
Precise Control ◽  
Dynamic Filtration ◽  
The Relationship

Purpose – The aim of this study is to establish a dynamic model of the filtration ratio. For the problem that the measured value of the filtration ratio is far less than the theoretical value in the actual hydraulic filtering system, the paper aims to find the relationship between the filtration ratio and the parameters of the hydraulic systems, such as the contamination level and the dirt-holding quantity of the filter. Design/methodology/approach – The paper opted for the method of experimental analysis and simulation to determine the relationship between the filtration ratio and the parameters of the hydraulic system, and established a dynamic filtration ratio model. Findings – The paper provides a preliminary model of dynamic filtration ratio, and the model shows that the filtration ratio is exponentially related to the contamination level and the dirt-holding quantity. Different filters have different influence coefficients. The filtering capacity for a certain particle size and the contamination level control of the filter for different hydraulic systems can be judged according to the dynamic balance equation of hydraulic systems. Originality/value – The paper is useful in the selection of filters and in the precise control of the contamination level of the hydraulic system.

Analysis of hydraulic systems on the basis of the decomposition method

2015 ◽  
Vol 8 (2) ◽  
pp. 34-37 ◽  
Author(s):  
Сазонова ◽  
Svetlana Sazonova
Keyword(s):  
Complex Systems ◽  
Boundary Conditions ◽  
Decomposition Method ◽  
Internal Communication ◽  
Target Product ◽  
Hydraulic Systems ◽  
Decomposition Approach ◽  
The Status ◽  
The Individual ◽  
System Nodes

Hydraulic systems belong to the category of complex systems, between the individual elements of the histories and subsystems exist internal communication, precluding the possibility of an Autonomous fashion from cancellation. The scale of such systems and their development trends lead to the inevitable decomposition approach. Research is not always to be the whole system, and some of its fragments, which border taking into account the accepted scheme of allocation of the target product to consumers submit a set of system nodes. In this case, the nodes acquire the status of power units, because through them there is an exchange of energy between IP investigated fragment of the system and the metasystem. Examines the emerging conflict between the need for a complementary decomposition and inner interconnection of all elements. He is overcome by the imposition of conditions one of znanosti, including boundary conditions.

Permanent-Pressure Control Tactic of Rudder Based on Fuzzy-Control Theorem

2012 ◽  
Vol 192 ◽  
pp. 360-364
Author(s):  
Xi Guang He ◽  
Ji Feng Xing ◽  
Jia Chen
Keyword(s):  
Fuzzy Control ◽  
Life Span ◽  
Hydraulic System ◽  
Constant Pressure ◽  
Pressure Control ◽  
Hydraulic Systems ◽  
Oil Pump ◽  
Controlling System ◽  
Save Energy ◽  
The Relationship

In order to guarantee that the rudder hydraulic systems work normally, the rudder hydraulic system must supply constant-pressure fluid to it. In this article, the author had analyzed the relationship between the power of the hydraulic oil pump and its motor revs, and done researches on its controlling tactics. Next, the author deigned its controller and controlling system based on fuzzy-control theorem. This system could extend the life-span of the pump motor and save energy, and it can also be utilized in other engineering fields.

scholarly journals РОЗРАХУНКОВА МОДЕЛЬ ГІДРООБПРИСКУВАЛЬНОЇ УСТАНОВКИ ТУНЕЛЬНОГО ТИПУ

2014 ◽  
pp. 96-101
Author(s):  
О. М. Іванов ◽  
В. М. Арендаренко
Keyword(s):  
High Pressure ◽  
Hydraulic System ◽  
Theoretical Studies ◽  
Hydraulic Parameters ◽  
Computational Studies ◽  
Hydraulic Systems ◽  
Chamber Studies ◽  
Main Components ◽  
The Relationship ◽  
Selection Of

Наведено результати теоретичних досліджень зіскладання розрахункової моделі гідрообприскувальноїустановки тунельного типу, призначеної для обприс-кування під високим тиском рослин у тунельній каме-рі. Дослідження проводились із залученням теоріїгідродинаміки та гідростатики для розрахунку скла-дних трубопроводів і багатокомпонентних гідравліч-них систем. За результатами розрахункових дослі-джень було складено аналітичні рівняння, що визна-чають величини гідравлічних параметрів у вузловихточках і встановлюють взаємозв’язок між основни-ми компонентами гідравлічної установки. The results of theoretical studies on the preparation of the computational model hydro spray tunnel designed for spraying high-pressure plants in the tunnel chamber. Studies were carried out using the theory of hydrodynamic and hydrostatic calculations for complex pipelines and multi-hydraulic systems. To achieve the objectives of the study were divided into components of hydraulic systems, each of which is a more simplified version of a complex pipeline. According to the results of computational studies were compiled analytical equations that determine the magnitude of hydraulic parameters at nodes and establish the relationship between the main components of the hydraulic system, and outlines the framework for the selection of a pressure pump for the amount of required pressure and flow.

Soft Switching Approach to Reducing Transition Losses in an On/Off Hydraulic Valve

2009 ◽  
Author(s):  
Michael B. Rannow ◽  
Perry Y. Li
Keyword(s):  
Hydraulic System ◽  
Check Valve ◽  
Fluid Flows ◽  
Soft Switching ◽  
Total System ◽  
System Efficiency ◽  
Hydraulic Systems ◽  
Controlled Systems ◽  
Flow Through ◽  
Hydraulic Valve

A method for significantly reducing the losses associated with an on/off controlled hydraulic system is proposed. There has been a growing interest in the use of on/off valves to control hydraulic systems as a means of improving system efficiency. While on/off valves are efficient when they are fully open or fully closed, a significant amount of energy can be lost in throttling as the valve transitions between the two states. A soft switching approach is proposed as a method of eliminating the majority of these transition losses. The operating principle of soft switching is that fluid can temporarily flow through a check valve or into a small chamber while valve orifices are partially closed. The fluid can then flow out of the chamber once the valve has fully transitioned. Thus, fluid flows through the valve only when it is in its most efficient fully open state. A model of the system is derived and simulated, with results indicating that the soft switching approach can reduce transition and compressibility losses by 79%, and total system losses by 66%. Design equations are also derived. The soft switching approach has the potential to improve the efficiency of on/off controlled systems and is particularly important as switching frequencies are increased. The soft switching approach will also facilitate the use of slower on/off valves for effective on/off control; in simulation, a valve with soft switching matched the efficiency an on/off valve that was 5 times faster.

Innovation in SMEs: the role of employee training in German SMEs

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Irem Demirkan ◽  
Ravi Srinivasan ◽  
Alka Nand
Keyword(s):  
Research And Development ◽  
Boundary Conditions ◽  
Product Innovation ◽  
Employee Training ◽  
Lower Proportion ◽  
Economic Research ◽  
Content Type ◽  
The Relationship ◽  
Practical Implications

PurposeThis paper explores the role of effective resource and knowledge management capabilities on product innovation capabilities of the small and medium-sized enterprises (SMEs). Specifically, the authors research the role of the human resource investments in the form of employee training in developing firm's innovation capabilities and how SMEs manage these investments when we account for the boundary conditions such as the level of employee education, SME size and the frequency of investments in research and development (R&D).Design/methodology/approachThe authors use survey data conducted by The Centre for European Economic Research (Zentrum für Europäische Wirtschaftsforschung – ZEW). The final sample for analysis includes 983 SMEs from Germany that belong to 13 different industries. The authors use hierarchical OLS regression to test the hypotheses presented in this paper.FindingsThe authors find a positive association between increased investments in employee training and product innovation capabilities in the context of SMEs. More specifically, the authors’ findings support that (1) the relationship between employee training and innovation capabilities is weaker in industries with greater proportion of employees with university degrees, (2) the effectiveness of investments in employee training is lower among larger SMEs than smaller SMEs, and (3) continuous R&D weakens the relationship between training expenditure and innovation capabilities. While on the one hand the authors’ findings contribute to the debate of whether employee training is necessary for SMEs by affirming this notion, on the other hand the authors show that investments in employee training have differing implications for small and large SMEs within boundary conditions. Moreover, these findings have practical implications for the managers of all SMEs in terms of management of their knowledge resources.Research limitations/implicationsThe authors’ research makes important contributions to the study of innovation in SMEs. First, the authors contribute evidence to the debate whether employee training is necessary for SMEs by showing that employee training is particularly important for SMEs that are smaller in size, have lower proportion of employees with university degrees and when they invest in research and development in a targeted manner. The authors also demonstrate that investments in employee training is not a waste, rather such investments can increase the likelihood of survival for many of these firms through its positive impact on product innovation.Practical implicationsFor managers of SMEs, the authors’ findings suggest that while investments in employee training are important, the managers of particular SMEs with above-mentioned qualities should be persistent in such investments and must make deliberate efforts to reap the benefits in terms of innovative capabilities. Unlike large firms, who have the financial means to carry out investments in an abundant manner, SMEs appear to be more enterprising with their scarce resources when we also consider the role of investments in human resources.Originality/valueThe authors’ research makes important contributions to the study of innovation in SMEs. First, the authors contribute evidence to the debate whether employee training is necessary for SMEs by finding that employee training is particularly important for SMEs that are smaller in size, have lower proportion of employees with university degrees and when they do not invest in R&D continuously. The authors also demonstrate that investments in employee training is not a waste, but such investments can increase the likelihood of survival for many of these firms.

Calculation of a closed hydraulic volumetric system

2021 ◽  
pp. 27-30
Author(s):  
Keyword(s):  
Power Plant ◽  
Wind Power ◽  
Hydraulic System ◽  
Working Fluid ◽  
Wind Power Plant ◽  
Hydraulic Systems ◽  
Hydraulic Motor ◽  
Hydraulic Pump ◽  
Oil Pump ◽  
Selection Of

An algorithm is proposed for calculating a closed volumetric hydraulic pump-hydraulic motor system using the example of the hydraulic system of a wind power plant, based on the calculation of the hydraulic systems of mobile machines. The main characteristics of the system components, the selection of initial data for the calculation, working fluid and diameters of hydraulic lines are analyzed. Keywords: hydraulic system, energy, fluid, oil, pump, motor, renewable energy source, wind power plant, machine. [email protected]

Synchronous Control Characteristics Analysis of Shield Propulsion Hydraulic System Based on Tracking Differentiator and Self-Adaptive Nonlinear PID

2021 ◽  
Author(s):  
Sen Li ◽  
XiaoHua Cao
Keyword(s):  
Pid Control ◽  
Hydraulic System ◽  
Control Method ◽  
Hydraulic Systems ◽  
Fuzzy Pid Control ◽  
Synchronous Control ◽  
Tracking Differentiator ◽  
Characteristics Analysis ◽  
Servo Tracking ◽  
Self Adaptive

Aiming at the low precision problem of multi-cylinder cooperative propulsion control in different regions of shield propulsion hydraulic systems under conditions of large load changes, this paper proposes a tracking differentiator and self-adaptive nonlinear PID (TD-NPID) control method to improve the synchronous control characteristics of shield propulsion hydraulic systems. First, the working principles of shield propulsion hydraulic systems were analyzed, and a mathematical model and TD-NPID controller were developed. Then, a simulation model was developed in AMESim-MATLAB environment, and the synchronous dynamic performances of fuzzy PID control, conventional PID control, and TD-NPID control were compared and analyzed. The results demonstrated that the shield propulsion hydraulic system with TD-NPID control had better servo tracking ability and steady-state performance than the systems with fuzzy or conventional PID control, which verified the feasibility of the application of TD-NPID control for the synchronous control of shield propulsion hydraulic systems.

scholarly journals The Influence of Valve-Pump Weight Ratios on the Dynamic Response of Leaking Valve-Pump Parallel Control Hydraulic Systems

2018 ◽  
Vol 8 (7) ◽  
pp. 1201 ◽  
Author(s):  
Haigang Ding ◽  
Jiyun Zhao ◽  
Gang Cheng ◽  
Steve Wright ◽  
Yufeng Yao
Keyword(s):  
Dynamic Response ◽  
Hydraulic System ◽  
Weight Ratio ◽  
Open Loop ◽  
Hydraulic Systems ◽  
Variable Speed ◽  
Weight Factors ◽  
Wide Range ◽  
Parallel Control ◽  
Valve Control

A new leaking valve-pump parallel control (LVPC) oil hydraulic system is proposed to improve the performance of dynamic response of present variable speed pump control (VSPC) system, which is an oil hydraulic control system with saving energy. In the LVPC, a control valve is operating at leaking status, together with a variable speed pump, to regulate the system flow of hydraulic oil simultaneously. Therefore, the degree of valve control and pump control can be adjusted by regulating the valve-pump weight ratio. The LVPC system design, mathematical model development, system parameter and control performance analysis are carried out systematically followed by an experimental for validation process. Results have shown that after introducing the valve control, the total leakage coefficient increases significantly over a wide range with the operating point and this further increases damping ratios and reduces the velocity stiffness. As the valve-pump weight ratio determines the flow distribution between the valve and the pump and the weight factors of the valve and/or the pump controls determines the response speed of the LVPC system, thus if the weight factors are constrained properly, the LVPC system will eventually have a large synthetic open-loop gain and it will respond faster than the VSPC system. The LVPC will enrich the control schemes of oil hydraulic system and has potential value in application requiring of fast response.

Nonlinear distributed model predictive control for complex systems: application for hydraulic system

2018 ◽  
Vol 41 (10) ◽  
pp. 2751-2763 ◽  
Author(s):  
Nadia Hajji ◽  
Saber Maraoui ◽  
Larbi Chrifi-Alaoui ◽  
Kais Bouzrara
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Hydraulic System ◽  
Water Levels ◽  
Distributed Model ◽  
Dual Decomposition ◽  
Decomposition Approach ◽  
Distributed Model Predictive Control ◽  
Nonlinear Predictive Control ◽  
Tank System

In this paper, a nonlinear distributed model predictive control based on dual decomposition approach is proposed for complex system. The global system can be decomposed into several subsystems and each one will be managed by its own controller. To design the nonlinear predictive control in a distributed fashion, an analytical solution is proposed. The latter is based on the approximation of the error using its expansion of Taylor series. The proposed approach is implemented on the three tank system to control the water levels. Simulation results demonstrate the effectiveness of the proposed approach.

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