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Статті в журналах з теми "Reversible hydraulic machine"
1
Borovin, Gennady Konstantinovich, and Veniamin Vadimovich Tkachuk. "About the works of modeling and designing a pump-turbine system in pumped-storage power plants (review)." Keldysh Institute Preprints, no. 9 (2022): 1–22. http://dx.doi.org/10.20948/prepr-2022-9.
Повний текст джерелаАнотація:
The paper presents an overview of research in the world on the design and creation of pumped hydroelectric energy storage with hydraulic machines having optimal characteristics according to the principle of operation of reversible pump turbines, optimization of their flow part. Special attention was paid to the work on the study of the operation of the hydraulic machine in pumping and turbine modes. As the study of publications has shown, active research is being conducted abroad on the design and creation of hydroelectric power plants with hydraulic machines having optimal characteristics. When designing hydraulic machines, various mathematical modeling systems are used. As international experience shows, the study of hydraulic machines and, in particular, the pump-turbine, using computational fluid dynamics tools, for example, CFD modeling is becoming increasingly widespread.
2
Tynyanova, Irina, Viktor Drankovskiy, Kseniya Rezvaya, and Оleksandr Kosorukov. "MODELING OF THE HYDRODYNAMIC CHARACTERISTICS OF A REVERSIBLE HYDRAULIC MACHINE." Bulletin of the National Technical University "KhPI". Series: Hydraulic machines and hydraulic units, no. 1 (September 27, 2019): 51–57. http://dx.doi.org/10.20998/2411-3441.2019.1.08.
Повний текст джерела
3
Ionov, Pavel A., Petr V. Senin, Sergey V. Pyanzov, Aleksey V. Stolyarov, and Alexander M. Zemskov. "Developing a Stand for Evaluating Technical Condition of Volumetric Hydraulic Drives with a Hydraulic Loading Device." Engineering Technologies and Systems 29, no. 4 (December 31, 2019): 529–45. http://dx.doi.org/10.15507/2658-4123.029.201904.529-545.
Повний текст джерелаАнотація:
Introduction. The article deals with the development of a device for evaluating technical condition on of volumetric hydraulic drives made in Russia and abroad at repair and service centres. Materials and Methods. The study uses the statements of theoretical mechanics and hydrodynamics, the basic principles of mechanisms and machines production. For technical condition evaluating of volumetric hydraulic drives, the method of hydraulic loading of hydraulic motor was applied. Reliability of results was confirmed during experimental settings of the hydraulic loading device stand. Results. A stand design with the hydraulic loading device was developed and put into practice for new technical condition evaluating of volumetric hydraulic drives, made in Russia and abroad, at repair and service centres. A property of the stand is the use of the hydraulic loading method when the torque (braking) moment on the shaft of the tested hydraulic rotor is created using a hydraulic machine. The stand consists of data processing and measurement units. The data processing unit is based on a multifunctional data acquisition board connected with a personal computer. The structure of the data measurement unit includes a frequency converter connected to an electric motor, a drive shaft for connecting the shaft of the tested hydraulic pump; hydraulic system having a hydraulic tank; suction, control, drain, and discharge lines and reversible flow chokes installed in discharge lines and connected with the hydraulic pump and hydraulic rotor; loading device with the reversible hydraulic pump, drive shaft joined with the shaft of the tested hydraulic motor. Additionally, reversible throttle flow meters are connected via special ports and electric lines to the data acquisition board. The developed stand allows evaluating the technical condition of most widespread models of volumetric hydraulic drives used in modern agricultural and road construction equipment. The stand is characterized by good energy efficiency, simplicity of design, low costs, good technical characteristics that make it competitive. Discussion and Conclusion. The new stand design with the hydraulic loading device allows implementating of the dynamic testing methodology and guarantees high accuracy of evaluating the technical condition of the most widespread Russian and foreign volumetric hydraulic drives at repair and service centres. Further improvement of the evaluating the technical condition of volumetric hydraulic drives is related to the development of specialized software for processing and analysing test results in real-time.
4
Volkov, A. V., A. G. Parygin, A. A. Vikhlyantsev, and A. A. Druzhinin. "On optimization of flow passages of impellers of centrifugal pumps." Safety and Reliability of Power Industry 11, no. 4 (January 21, 2019): 311–18. http://dx.doi.org/10.24223/1999-5555-2018-11-4-311-318.
Повний текст джерелаАнотація:
The conventional solution for HAPPs is the use of reversible hydraulic machines operating both in the pump mode as well as in the turbine mode. At the same time, for example, a blade system of a hydraulic machine designed for the pumping mode has a high efficiency. However, in the turbine mode, the energy characteristics of such machine are far from optimal. Considering different patterns of micro- and mini-HAPPs (up to 100 kW) of modular design, it is most appropriate to use a pump and a turbine separately, since the efficiency of hydraulic machines is very important in the case of such low power. To date, approaches to the design of hydraulic turbines are quite developed and allow to achieve high energy performance [1, 2]. According to different data sources the level of axial turbine efficiency with power less than 100 kW is about 80÷91%. At the same time, for centrifugal pumps, especially those of low specific speed, the problem of increasing energy efficiency is very urgent. E.g., for pumps with a specific speed ns< 80 the efficiency level is usually 40 to 65%. The aim of the presented research is the development of methods of synthesis and optimization of the flow passages of centrifugal pumps using the approaches of the theory of optimal control and increasing energy performance of hydraulic machines. Various ways of local correction of geometry of flow passages are presented in the paper. As an alternative to empirical approaches, methods based on the control of the circulation distribution are considered in detail. Various mathematical dependences of the flow circulation on the coordinate of the point lying on the surface of the blade are analyzed. Possibilities of application of the theory of experiment planning in relation to the problems to be solved are considered.
5
Zamyslov, V. "Control of a reversible electric machine included in the vehicle suspension." Journal of Physics: Conference Series 2061, no. 1 (October 1, 2021): 012052. http://dx.doi.org/10.1088/1742-6596/2061/1/012052.
Повний текст джерелаАнотація:
Abstract The relevance of the work is due to the constantly growing requirements for the ride comfort of automobiles. The purpose of the study is a rational choice and combination of principles for constructing an algorithm for controlling an electric machine, replacing a hydraulic damper in the design of a vehicle’s suspension system. The study of the behavior of suspension, depending on the applied control algorithms, was carried out by the method of mathematical modeling. In this work, the control of the suspension of one wheel was considered. The angular and longitudinal oscillations of the body were not the subject of this study. In this regard, the applied design scheme is two-mass. The positive and negative aspects of various principles for calculating the target force generated by an electric machine are considered, and an algorithm for calculating the magnetic flux and armature current of an electric machine necessary for the implementation of the target force under various conditions is developed. It is shown that the calculation of the target force should be based on a combination of several principles, since this allows significant expanding of the suspension operating conditions range.
6
Adamkowski, Adam, Waldemar Janicki, and Mariusz Lewandowski. "Measurements of Discharge through a Pump-Turbine in Both Flow Directions Using Volumetric Gauging and Pressure-Time Methods." Energies 13, no. 18 (September 9, 2020): 4706. http://dx.doi.org/10.3390/en13184706.
Повний текст джерелаАнотація:
This article presents the original procedures for measuring the flow rate using the pressure-time and the volumetric gauging method in the case of performance tests of a reversible hydraulic machine in either turbine or pump modes of operation. Achieving the lowest possible measurement uncertainty was one of the basic conditions during implemented machine tests. It was met using appropriate measuring procedures and high-class measuring equipment. Estimation of the uncertainty for both methods was made on the basis of an analysis consistent with current requirements in this respect. The pressure-time method was supplemented by the computational fluid dynamics (CFD) analysis that allowed reducing the impact of the pipeline complex irregular geometry on the uncertainty of flow measurement. Appropriate modifications of the calculation procedure enabled accurate measurements of flow during the pump mode of operation of the tested machine as well. The volumetric gauging method, thanks to a special procedure used for accurate measurement of the water level in the upper reservoir of the power plant, allowed measuring the discharge through the tested reversible machine with very low uncertainty. The obtained results allowed for a detailed comparison and mutual verification of the methods used to measure the discharge of the tested reversible machine in both modes of its operation. The most possible causes of obtained results are discussed and summarized in the paper. The need for further research was pointed out to explain the differences obtained and their influence on the accuracy of discharge measurement using the pressure-time method in pump operation mode.
7
Seleznev, V. N. "Numerical simulation of cavitation in the flow path of a reversible hydraulic machine for a head up to 250m." Izvestiya MGTU MAMI 15, no. 4 (December 15, 2021): 43–48. http://dx.doi.org/10.31992/2074-0530-2021-50-4-43-48.
Повний текст джерелаАнотація:
In areas where thermal and nuclear power plants are mainly located, the problem of lack of maneuverable capacities, the coverage of peak loads and the passage of periods of reduced energy consumption is solved through the construction of large pumped storage power plants (PSPP). To create highly efficient flow paths for pump-turbines, one of the modern trends is the use of numerical modeling of three-dimensional fluid flow. Nowadays, there are many software products that implement numerical modeling by the finite volume method. The most famous among them are Fluent, CFX, StarCD, Numeca, Flow Vision and CADRUN. Verification of the computational model remains an urgent task. It is important to choose a methodology that will allow you to get an acceptable result with optimal time spent on preparing data and conducting computational studies.
The article examines the flow path of a radial-axial pump-turbine designed for use at a maximum head up to 250m. Numerical modeling of the cavitation process arising in the turbine mode at a significant distance from the optimum of the characteristic was carried out. The calculations were performed using the Ansys CFX software package, version 2021R1. A brief description of the problem statement, the computational grids used and the assumptions made is given. Comparison of calculation results with experimental data is presented. A qualitative comparison of the cavitation origination regions obtained by numerical simulation with the data of monitoring the state of the base metal and welded joints of the hydroelectric unit impeller by the method of non-destructive testing is carried out.
The aim of the work was to present an economical technique for numerical simulation of cavitation to determine the places of possible occurrence of cavitation wear. The technique consists in describing the formulation of the problem, the computational grids used and the assumptions made for the optimal use of computing resources without a significant loss in the accuracy of the results.
8
Hu, Ying, Qing Xue Huang, Xiao Hong Hao, and Shao Zhen Jin. "The Supervisory Control and Data Acquisition System for Plate Leveler Based on Multi-Fieldbus." Advanced Materials Research 156-157 (October 2010): 992–95. http://dx.doi.org/10.4028/www.scientific.net/amr.156-157.992.
Повний текст джерелаАнотація:
To improve the quality of the steel plate, The No.2 Roll Mill of Wuyang Iron and Steel Company has adopted the hydraulic reversible 11 rolls leveler developed by Taiyuan University of Science and Technology and the Taiyuan Heavy Industry Co., Ltd. The machine uses a number of advanced technologies and new equipments. For example, this plate leveler uses the Supervisory Control and Data Acquisition system, including the main operator station, the monitoring station, engineer station, etc.It also adopts Oracle 10G database system and HP 380 Server clusters to realize the management function of technical data acquisition and analysis. It is able to complete the real-time data acquisition, data analysis, model calculation and self –learning function.
9
Rezvaya, Kseniya, Irina Tynyanova, and Оleksandr Kosorukov. "APPLICATION OF THE METHOD OF AVERAGE DIMENSIONLESS PARAMETERS FOR DETERMINING THE OPTIMAL OPERATING MODE OF A HIGH-PRESSURE REVERSIBLE HYDRAULIC MACHINE." Bulletin of the National Technical University "KhPI". Series: Hydraulic machines and hydraulic units, no. 2 (December 26, 2019): 82–88. http://dx.doi.org/10.20998/2411-3441.2019.2.10.
Повний текст джерела
10
Salter, S. H., J. R. M. Taylor, and N. J. Caldwell. "Power conversion mechanisms for wave energy." Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment 216, no. 1 (June 1, 2002): 1–27. http://dx.doi.org/10.1243/147509002320382103.
Повний текст джерелаАнотація:
It is easy to make a device that will respond vigorously to the action of sea waves. Indeed, it is quite hard to make one that will not. However, the conversion of the slow, random, reversing energy flows with very high extreme values into phase-locked synchronous electricity with power quality acceptable to a utility network is very much harder. This paper describes a range of different control strategies of varying degrees of sophistication and then describes possible conversion equipment for high-pressure oil and water and low-pressure air. Like many renewable energy sources, waves would benefit from some form of energy storage, particularly if they are to be used in weak island networks. Flywheels, gas accumulators, submerged oil/vacuum accumulators, thermal stores and reversible fuel cells are discussed, with emphasis on the coupling hardware. This leads on to a description of a new type of hydraulic machine with digital control which has been specially designed for high efficiency and flexible control of multiple erratic sources. An explanation of the rather low performance of air turbines in the random air flows caused by sea waves suggests the need for a variable-pitch version of the Wells turbine and the design of a reciprocating-flow wind-tunnel with recirculating energy recovery in which it could be tested.
Дисертації з теми "Reversible hydraulic machine"
1
Рєзва, Ксенія Сергіївна. "Удосконалення проточних частин високонапірних оборотних гідромашин на основі чисельного моделювання їх гідродинамічних характеристик". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/40009.
Повний текст джерелаАнотація:
Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.05.17 – гідравлічні машини і гідропневмоагрегати. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2019 р.
Дисертацію присвячено вирішенню науково-практичної задачі удосконалення проточних частин високонапірних оборотних гідромашин за рахунок розробки методів розрахунку та аналізу їх гідродинамічних характеристик. На підставі розгляду тенденцій розвитку гідроенергетики України, з урахуванням ролі високонапірних оборотних гідромашин в об'єднаній енергетичній системі, відмічено актуальність проектування нових проточних частин. Визначено переваги та недоліки існуючих методів дослідження гідродинамічних процесів у проточних частинах оборотних гідромашин. Наведені результати розрахунку гідродинамічних характеристик елементів проточної частини на основі методу осереднених безрозмірних параметрів для оборотних гідромашин ОРО200-В-100 та ОРО500-В-100. Застосована математична модель робочого процесу гідромашини на основі блочно-ієрархічного підходу для проведення дослідження балансу енергії. Визначено вплив геометричних параметрів елементів проточної частини на показники роботи. Проведено чисельне дослідження просторової течії рідини в проточній частині високонапірних оборотних гідромашин за допомогою CFD, що дозволило визначити та візуалізувати картину течії. Складено баланси енергії гідромашин ОРО200-В-100 та ОРО500-В-100. Відмічено, що розподіл втрат по елементам проточної частини нерівномірний: для ОРО200-В-100 найбільшу частину втрат складають втрати в робочому колесі (близько 56 %), для ОРО500-В-100 – втрати у підводі (близько 62 %). Описано основні положення визначення оптимального режиму роботи оборотної гідромашини. Запропоновано та досліджено модифікований підвід для тихохідної оборотної гідромашини ОРО500-В-100, щоб підвищити її енергетичні показники: краще узгоджені елементи ПЧ та гідравлічний ККД збільшився на 2 %.Thesis for granting the Degree of Candidate of Technical sciences in speciality 05.05.17 – Hydraulic machines and hydropneumatic units. – National Technical University "Kharkiv Polytechnic Institute", 2019. The tеhesis is devoted to the solution of the scientific and practical problem of improvement of the water passages of the high-pressure reversible hydraulic due to calculation and analysis their hydrodynamic characteristics. Based on the review of the trends in the development of hydropower engineering in Ukraine and given the role of high-pressure reversible hydraulic machines in the United Power System, it was noted that the designing a new flow parts is topical task. Advantages and disadvantages of the existing methods for research hydrodynamic processes in water passages of reversible hydraulic machines were identified after their analysis. The results of the calculation of the hydrodynamic characteristics of the elements of the water passages based on the method of averaged dimensionless parameters using the example of reversible hydraulic machines OPO200-B-100 and OPO500-B-100 were demonstrated. The mathematical model of the hydraulic machine working process based on a block-hierarchical approach was used to study the energy balance in the turbine and pump modes of hydraulic machines. The influence of the geometrical parameters of the elements of the water passage on the performance was determined: how the angle of flow in the spiral casing (cп ), the height of the wicket gate (b0 D) and the shape of the wicket gate profile influence the value of the coefficient resistance in the wicket gate. A numerical study of the three-dimensional flow of fluid in the water passage of high-pressure reversible hydraulic machines was carried out using the CFD software. This program allows determining the character of the flow and presenting the fields of distribution of velocity components, pressure and streamlines. The balances of energy were compiled: for the OPO200-B-100 in the turbine and pump operation modes, for the OPO500-B-100 in the turbine operation mode. It is noted that the distribution of losses on the elements of the water passage is not uniform: for the OPO200-B-100, the greatest part of the total losses are losses in the runner (about 56%), for OPO500-B-100 - losses in the inlet (about 62%). The main points for determining the optimal operating mode of the reversible hydraulic machine are described. The modified inlet for low-speed high-pressure hydraulic machine OPO500-B-100 was proposed and investigated to increase energy performance of hydraulic machine. The spiral casing was expanded, the number of stay vane blades and wicket gate blades were reduced to 16. As a result of the calculations of the modified inlet, the obtained results showed that the second variant made it possible to better align the elements of the water passage and the hydraulic efficiency increased by 2 %.
2
Рєзва, Ксенія Сергіївна. "Удосконалення проточних частин високонапірних оборотних гідромашин на основі чисельного моделювання їх гідродинамічних характеристик". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/40011.
Повний текст джерелаАнотація:
Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.05.17 – гідравлічні машини і гідропневмоагрегати. – Національний технічний університет "Харківський політехнічний інститут", Харків, 2019 р.
Дисертацію присвячено вирішенню науково-практичної задачі удосконалення проточних частин високонапірних оборотних гідромашин за рахунок розробки методів розрахунку та аналізу їх гідродинамічних характеристик. На підставі розгляду тенденцій розвитку гідроенергетики України, з урахуванням ролі високонапірних оборотних гідромашин в об'єднаній енергетичній системі, відмічено актуальність проектування нових проточних частин. Визначено переваги та недоліки існуючих методів дослідження гідродинамічних процесів у проточних частинах оборотних гідромашин. Наведені результати розрахунку гідродинамічних характеристик елементів проточної частини на основі методу осереднених безрозмірних параметрів для оборотних гідромашин ОРО200-В-100 та ОРО500-В-100. Застосована математична модель робочого процесу гідромашини на основі блочно-ієрархічного підходу для проведення дослідження балансу енергії. Визначено вплив геометричних параметрів елементів проточної частини на показники роботи. Проведено чисельне дослідження просторової течії рідини в проточній частині високонапірних оборотних гідромашин за допомогою CFD, що дозволило визначити та візуалізувати картину течії. Складено баланси енергії гідромашин ОРО200-В-100 та ОРО500-В-100. Відмічено, що розподіл втрат по елементам проточної частини нерівномірний: для ОРО200-В-100 найбільшу частину втрат складають втрати в робочому колесі (близько 56 %), для ОРО500-В-100 – втрати у підводі (близько 62 %). Описано основні положення визначення оптимального режиму роботи оборотної гідромашини. Запропоновано та досліджено модифікований підвід для тихохідної оборотної гідромашини ОРО500-В-100, щоб підвищити її енергетичні показники: краще узгоджені елементи ПЧ та гідравлічний ККД збільшився на 2 %.Thesis for granting the Degree of Candidate of Technical sciences in speciality 05.05.17 – Hydraulic machines and hydropneumatic units. – National Technical University "Kharkiv Polytechnic Institute", 2019. The tеhesis is devoted to the solution of the scientific and practical problem of improvement of the water passages of the high-pressure reversible hydraulic due to calculation and analysis their hydrodynamic characteristics. Based on the review of the trends in the development of hydropower engineering in Ukraine and given the role of high-pressure reversible hydraulic machines in the United Power System, it was noted that the designing a new flow parts is topical task. Advantages and disadvantages of the existing methods for research hydrodynamic processes in water passages of reversible hydraulic machines were identified after their analysis. The results of the calculation of the hydrodynamic characteristics of the elements of the water passages based on the method of averaged dimensionless parameters using the example of reversible hydraulic machines OPO200-B-100 and OPO500-B-100 were demonstrated. The mathematical model of the hydraulic machine working process based on a block-hierarchical approach was used to study the energy balance in the turbine and pump modes of hydraulic machines. The influence of the geometrical parameters of the elements of the water passage on the performance was determined: how the angle of flow in the spiral casing (cп ), the height of the wicket gate (b0 D) and the shape of the wicket gate profile influence the value of the coefficient resistance in the wicket gate. A numerical study of the three-dimensional flow of fluid in the water passage of high-pressure reversible hydraulic machines was carried out using the CFD software. This program allows determining the character of the flow and presenting the fields of distribution of velocity components, pressure and streamlines. The balances of energy were compiled: for the OPO200-B-100 in the turbine and pump operation modes, for the OPO500-B-100 in the turbine operation mode. It is noted that the distribution of losses on the elements of the water passage is not uniform: for the OPO200-B-100, the greatest part of the total losses are losses in the runner (about 56%), for OPO500-B-100 - losses in the inlet (about 62%). The main points for determining the optimal operating mode of the reversible hydraulic machine are described. The modified inlet for low-speed high-pressure hydraulic machine OPO500-B-100 was proposed and investigated to increase energy performance of hydraulic machine. The spiral casing was expanded, the number of stay vane blades and wicket gate blades were reduced to 16. As a result of the calculations of the modified inlet, the obtained results showed that the second variant made it possible to better align the elements of the water passage and the hydraulic efficiency increased by 2 %.
Частини книг з теми "Reversible hydraulic machine"
1
Nakamura, T., H. Nishizawa, M. Yasuda, T. Suzuki, and H. Tanaka. "Study on High Speed and High Head Reversible Pump -Turbine." In Hydraulic Machinery and Cavitation, 210–19. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-010-9385-9_20.
Повний текст джерела
2
Jernsletten, Jo. "Non-Stationary Flow in Reversible Francis Turbine Runner Due to Wakes Trailing the Guide Vanes." In Hydraulic Machinery and Cavitation, 865–74. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-010-9385-9_88.
Повний текст джерелаТези доповідей конференцій з теми "Reversible hydraulic machine"
1
Ješe, Uroš, Regiane Fortes-Patella, and Matevž Dular. "Numerical Study of Pump-Turbine Instabilities Under Pumping Mode Off-Design Conditions." In ASME/JSME/KSME 2015 Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/ajkfluids2015-33501.
Повний текст джерелаАнотація:
Pumped storage power plants, using reversible pump-turbines, are a great solution to maintain the stability of an electrical network. The continuous operating area of reversible pump-turbines machines is usually delimited by cavitation or a hydraulic instability called hump phenomena at part load. If the machine operates under these off-design conditions, it might be exposed to vibrations and performance losses. The paper focuses on the numerical analysis of the pumping mode regime and pays special attention to the prediction of the hump shaped characteristic curve and associated rotating stall. The investigations were made on a high head pump-turbine design (nq=27) at model scale for four different guide vane opening angles and a wide range of flow rates. Numerical simulations were performed and analyzed in LEGI and were compared to the global experimental data, provided by Alstom Hydro.
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Kerner, Alexander, Anselm Schaefer, and Kan Chen. "Parameter Adaptation Techniques for the Best-Estimate Thermal-Hydraulic Code ATHLET." In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75705.
Повний текст джерелаАнотація:
Parameter adaptation can be used for automated adjustment of real time simulation according to measured data from the simulated plant. It is able to prevent that model uncertainties lead to an increasing deviation between simulation results and real plant behaviour. The objective is to ensure that the simulation corresponds with reality even over a longer period. The present investigation deals with the application of parameter adaptation techniques to best-estimate simulation. This opens a range of new applications including the use of best-estimate codes for improving process diagnostics, signal validation and the man-machine-interface. The adaptation of ATHLET poses several challenges. Among them are non-linear dependencies within the equation system to be solved, the interference of a sophisticated time integration technique, and the identification and proper consideration of those code uncertainties which are most influential with regard to deviations between simulation and real plant behaviour. To overcome these problems a set of new techniques has been developed: - A refined method for the definition of the parameters to be adapted is based on the consideration of the parameter’s uncertainty and sensitivity to the results. Statistic sensitivity analysis is used to validate and improve parameters obtained by expert judgement. - Different parameter adaptation techniques (e.g. based on standard controllers or parameter estimation techniques) are applied to produce feasible solutions for the large systems to be modeled. - In view of preventing non-reversible propagation of simulation inaccuracies decomposition techniques are applied assuring that such temporary inaccuracies do not spread over subsystem boundaries. Results of adaptation based on these techniques are shown for an experiment performed at the test facility PKL III. It turns out that adaptive simulation is feasible for such facilities and that it offers possibilities to improve prediction of experiments by code calculations.
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Humphreys, Heather C., and Wayne J. Book. "Advanced Hydraulically Actuated Patient Transfer Assist Device." In 8th FPNI Ph.D Symposium on Fluid Power. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fpni2014-7821.
Повний текст джерелаАнотація:
A new, advanced patient transfer device is being developed for moving mobility limited patients, for example, from a wheelchair to a bed or a floor into a chair. Current market patient lift devices are antiquated and insufficient for customer needs, with only one actuated degree of freedom. The high power to size ratio of hydraulic actuation makes it suitable for moving larger, heavier patients. We have developed a prototype pump-controlled hydraulically actuated patient transfer device that is more maneuverable and agile, using multiple actuated degrees of freedom. We are also working toward developing a more intuitive and safe caretaker interface and control strategy. We have performed an extensive needs assessment; these are a few associated key design requirements relevant to this presented work. A compact package is needed for ease of maneuvering the patient around obstacles in an uncertain environment. The device is capable of producing large forces, so it is desirable for the controller to minimize any unintentional large external contact forces, or provide force feedback. In this system, the caretaker and device work together to maneuver a complex payload, a human body; the operator’s mental workload must be minimized. With humans in the device workspace, safety and stability are necessary, including environment interactions. This new application presents several challenges related to the hydraulic control. First, we are using a separate bidirectional fixed displacement pump with a reversible brushed DC motor for each degree of freedom. The low level control involves obtaining desirable response from each motor-pump-actuator system, while compensating for significant static friction. At a higher level, we are testing several approaches to attain the desired intuitive control and desired dynamics, and minimize the operator workload. First, we are developing a coordinated control using a force input, such that the operator simply pushes on the device in the desired direction of motion. We are testing several different controllers to attain the desired dynamics. This paper presents the design of the machine, the proposed control structures as applied to this application, operator interface options, some preliminary results, and future work.
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Morselli, Serena, Pietro Marani, Cesare Dolcin, Mattia Scolari, and Cristian Ferrari. "Efficiency Analysis of an Electro-Hydraulic Drive for Mobile Lifting Machines." In BATH/ASME 2020 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/fpmc2020-2794.
Повний текст джерелаАнотація:
Abstract Environmental issues have become a critical topic at all levels and the Fluid Power industry is no exception. One of the most important research trends is aimed at improving efficiency through electrification, the availability of new electric motors and drive solutions is expected to promote the introduction of speed-controlled pump systems in mobile applications, nowadays dominated by conventional valve-controlled solutions. The paper will firstly present a collection of tests carried out on a lifting application, powered by an inverter-controlled electric motor moving a reversible gear pump/motor. The lowering phase is carried out in two alternative modes, the first one is the electric regenerative mode, the second one is the throttle-controlled mode. The analysis of the results will highlight different energy efficiencies of the system at different operating conditions. In particular the losses of volumetric unit, piping, throttle elements, hydraulic cylinder and electric components can change dramatically depending on operating conditions. In the second part of the paper, a lumped parameters model will be presented, using a commercial software. Firstly, the model will be able to catch the behavior of the test bench and secondarily it will be used to predict the expected performances of alternative design choices. Particular attention will be focused on low speed operation. In fact, there is more uncertainty and much less well-established knowledge on the behavior of the volumetric units at low speed, concerning the large body of work available for the nominal speed conditions. Finally an outlook will be drawn of expected advantages and limitations arising from the implementation of variable speed pumps on mobile machines. Such benefits will be presented with practical figures of merit such as the energy recovery performance, the increase of cycles and the cooling system size reduction.