Journal articles: 'Hydraulics proportional'

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Ding, Wen Si, Jian Yuan Liao, and Lin Yan Yuan. "Design and Simulation Analysis of the Multi-Stage Linear Synchronous Expanding and Contracting Hydraulic Cylinder." Applied Mechanics and Materials 779 (July 2015): 35–41. http://dx.doi.org/10.4028/www.scientific.net/amm.779.35.

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A double-action three-stage synchronous expanding and contracting hydraulic cylinder has been designed based on the principle of synchronous expanding and contracting hydraulics cylinder. The Principle of linear synchronous expanding and contracting hydraulics cylinder and the main points of design have been discussed. Modeling and simulation are conducted in AMESim system and the result shows that the multi-stage cylinder can expand and contract synchronously and smoothly. As long as the effective area is proportional, the multi-stage cylinder can move linearly.

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Suzuki, Kenji, Sho Akazawa, and Yohichi Nakao. "Development of Cam-Drive Type Proportional Valve for Water Hydraulics." International Journal of Automation Technology 6, no. 4 (July 5, 2012): 450–56. http://dx.doi.org/10.20965/ijat.2012.p0450.

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This paper describes the development of water hydraulic proportional valves. These valves are spooltype and the spool is driven by a positive cam mechanism with an appropriate motor, such as a stepping motor or servo motor, depending on the application. The cam is placed precisely between two cam followers so that no gap is left between the cam and followers. Accordingly, no return spring is required. The rotational angle of the cam and the displacement of the spool are linear. Mathematical models of static characteristics of the valves are derived. Experimental results for the static characteristics are also shown: internal leakage and pressure gain against spool displacement, flow rate characteristics with no load, and flow rate against load pressure. Although the spool overlaps with sleeve, no dead band was observed in flow rate characteristics with no load because of leakage passing through the clearance around the spool. In addition, the nonlinearity of spool displacement against the rotational angle of the cam was below 0.2% and hysteresis was hardly observed. Feedback control of the displacement of water hydrostatic bearings is conducted as an application of the developed valve.

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Akdemir, Bayram. "Novel Intelligent and Sensorless Proportional Valve Control with Self-Learning Ability." Journal of Sensors 2016 (2016): 1–6. http://dx.doi.org/10.1155/2016/8141720.

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Linear control is widely used for any fluid or air flows in many automobile, robotics, and hydraulics applications. According to signal level, valve can be controlled linearly. But, for many valves, hydraulics or air is not easy to control proportionally because of flows dynamics. As a conventional solution, electronic driver has up and down limits. After manually settling up and down limits, control unit has proportional blind behavior between two points. This study offers a novel valve control method merging pulse width and amplitude modulation in the same structure. Proposed method uses low voltage AC signal to understand the valve position and uses pulse width modulation for power transfer to coil. DC level leads to controlling the valve and AC signal gives feedback related to core moving. Any amplitude demodulator gives core position as voltage. Control unit makes reconstruction using start and end points to obtain linearization at zero control signal and maximum control signal matched to minimum demodulated amplitude level. Proposed method includes self-learning abilities to keep controlling in hard environmental conditions such as dust, temperature, and corrosion. Thus, self-learning helps to provide precision control for hard conditions.

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AKAZAWA, Sho, Kenji SUZUKI, and Yohichi NAKAO. "G110022 Dynamic characteristics of a cam-drive type proportional valve for water hydraulics." Proceedings of Mechanical Engineering Congress, Japan 2011 (2011): _G110022–1—_G110022–4. http://dx.doi.org/10.1299/jsmemecj.2011._g110022-1.

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Zhang, Zeng Meng, and Yong Jun Gong. "Design and Simulation on Multi-Digit Numerical Control Valve in Water Hydraulics." Advanced Materials Research 422 (December 2011): 257–61. http://dx.doi.org/10.4028/www.scientific.net/amr.422.257.

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Due to the problems about Lubrication and sealing in water hydraulics, the poor performance, large leakage, extreme requirements of processing, high cost and poor anti-pollution properties exist in water hydraulic servo or proportional valves of spool structure and analogue control. A better seal is provided by the structure of the poppet valve comparing to the spool valve, however, poorer linearity and control accuracy accompanying inevitably. Aiming at improving the control performance of poppet valve, the design of the multi-digit numerical control valve is analyzed in this paper. The novel design using ball seat valves for digital bits is proposed to ensure enough seal ability and lower the cost. The simulation model of the multi-digit numerical control valve is built in AMESim software and the results show high linearity in flow control. However, large overshoot and oscillation encounter during the switching of the digits. Especially the switching process of the high digital bits requires to be regulated to reduce the large overshooting. The adjustment of the spring in the sensitive chamber of the bit valve can decrease the overshoot and improve the stability. These above contribute to the improvement of the control performance of water hydraulic control valves and applications of water hydraulics in the industry.

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Mohammed, Jamal AK, Walaa M. Hashim, and Bahaa S. Beram. "Performance Improvement of a Conventional Hydraulic Elevator by Using Electro-Hydraulic Servo Mechanism." Engineering and Technology Journal 38, no. 5A (May 25, 2020): 748–60. http://dx.doi.org/10.30684/etj.v38i5a.367.

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An electro-hydraulic elevator is a new type of enhanced elevators that are used in low-rise buildings that do not exceed more than three floors. In this paper, an electro-hydraulic servo system for controlling the speed of a hydraulic elevator prototype by using a proportional valve and PID controller was investigated theoretically and experimentally. A three floors elevator prototype model with 76cm height was built including hydraulics components and electrical components. The elevator system is fully automated using the Arduino UNO board based Data Acquisition (DAQ) system. LabVIEW software is used to control the hydraulic elevator system through L298 DC drive via the DAQ board. The best PID gains was obtained experimentally. The elevator system prototype could be emplimented for educational purposes; such as learning the undergraduate students in the Electromechanical Engineering Department in the University of Technology how to structuring the electro-hydraulic elevator as well as the appropriate control strategy.

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Osiecki, Leszek, Piotr Patrosz, Tomasz Zawistowski, Bettina Landvogt, Janusz Piechna, and Bartek Żyliński. "Compensation of Pressure Peaks in PWK-Type Hydraulic Pumps." Key Engineering Materials 490 (September 2011): 33–44. http://dx.doi.org/10.4028/www.scientific.net/kem.490.33.

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Hydraulic axial pumps equipped with cam-driven commutation unit (PWK pumps) proved their high efficiency up to 55 MPa and ability to work self-sucking, even at high speed. Displacement of PWK pump may easily be changed by moving its control cam. Full discharge from hydrostatic forces makes such control possible by direct action of a low-energy actuator like proportional electromagnet or stepping motor. That eliminates heavy and costly hydraulic servomechanism, necessary in other variable displacement machines. Such a control mechanism was positively evaluated in prototype tests in Department of Hydraulics and Pneumatics of Gdańsk University of Technology. The new commutation unit generates however harmful pressure peaks. The paper presents the compensation method for pressure peaks by use of the elastic compensation chamber. It shows also results of multidisciplinary FEA and CFD analysis necessary to properly design the compensation chamber.

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Zhang, Shuzhong, Tianyi Chen, and Fuquan Dai. "Adaptive Backstepping Sliding Mode Control for Direct Driven Hydraulics." Proceedings 64, no. 1 (November 20, 2020): 1. http://dx.doi.org/10.3390/iecat2020-08496.

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Due to the advantages of high energy efficiency and environmental friendliness, the electro-hydraulic actuator (EHA) plays a vital role in fluid power control. One variant of EHA, double pump direct driven hydraulics (DDH), is proposed, which consists of double fixed-displacement pumps, a servo motor, an asymmetric cylinder and auxiliary components. This paper proposes an adaptive backstepping sliding mode control (ABSMC) strategy for DDH to eliminate the adverse effect produced by parametric uncertainty, nonlinear characteristics and the uncertain external disturbance. Based on theoretical analysis, the nonlinear system model is built and transformed. Furthermore, by defining the sliding manifold and selecting a proper Lyapunov function, the nesting problems (of the designed variable and adaptive law) caused by uncertain coefficients are solved. Moreover, the adaptive backstepping control and the sliding mode control are combined to boost system robustness. At the same time, the controller parameter adaptive law is derived from Lyapunov analysis to guarantee the stability of the system. Simulations of the DDH are performed with the proposed control strategy and proportional–integral–differential (PID), respectively. The results show that the proposed control strategy can achieve better position tracking and stronger robustness under parameter changing compared with PID.

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AKAZAWA, Sho, Kenji SUZUKI, and Yohichi NAKAO. "1709 Study on improvement of dynamic characteristics of cam-drive type proportional valve for water hydraulics." Proceedings of Conference of Kanto Branch 2012.18 (2012): 21–22. http://dx.doi.org/10.1299/jsmekanto.2012.18.21.

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Brown, F. T., S. C. Tentarelli, and S. Ramachandran. "A Hydraulic Rotary Switched-Inertance Servo-Transformer." Journal of Dynamic Systems, Measurement, and Control 110, no. 2 (June 1, 1988): 144–50. http://dx.doi.org/10.1115/1.3152664.

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Switched-reactance hydraulics represents a radically novel approach to the control of fluid power, since the proportional metering of flow through adjustable orifices is eliminated, and the inertive properties of the fluid substituted. Potential advantages in bandwidth, linearity, and efficiency have been indicated. This paper presents the first steady-state theory and experiments with a rotary fluid switch, which accomplishes the needed pulse-width modulation at a desirably high frequency. Cavitation problems are observed, means of their partial solution are implemented, and means of a more complete solution are indicated.

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Zhang, Shuzhong, Angen Wu, and Fuquan Dai. "Active Disturbance Rejection Control for Double-Pump Direct-Driven Hydraulics." Proceedings 64, no. 1 (November 20, 2020): 14. http://dx.doi.org/10.3390/iecat2020-08497.

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As a result of the energy crisis and further development of the electro-hydraulic actuator, double-pump direct driven hydraulics (DDH) was brought forward, which mainly comprises a servo motor, double fixed displacement pumps, a differential cylinder, a low-pressurized tank and auxiliary valves. To address the problems caused by uncertain parameters and unknown external disturbances of DDH, this paper proposed a control method adopting active disturbance rejection control (ADRC). Firstly, a mathematical model, including a DDH unit and a micro-crane, was created and modelled in MATLAB/Simulink. Further, the model was verified by measurement. After that, the state-space equation model of the system was derived based on its mathematical model and a third-order ADRC was designed using the constructed system state-space equation. Additionally, tracking-differentiator (TD) was employed to process the input signal transiently to avoid unnecessary oscillations, and the extended state observer (ESO) was used to accurately estimate the influence of the uncertainty and compensate by nonlinear feedback control law (NFCL). Moreover, the proposed ADRC or Proportional–Integral–Differential (PID) control was combined with the mathematical model of a micro-crane. Finally, the simulations were performed under varying loads, and the system position tracking performance were analyzed and compared. The results show that the ADRC can sufficiently suppress the unknown external disturbance, has the advantages of robustness, and improves the position tracking precision.

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Wu, Jin Jun, You Sheng Yang, Jing Yuan Li, Ge Gang Yu, and Zong Xia Jiao. "Numerical Study of the Characteristics of Rotary Spool Orifice in Water Hydraulics." Applied Mechanics and Materials 716-717 (December 2014): 662–69. http://dx.doi.org/10.4028/www.scientific.net/amm.716-717.662.

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The rotary control orifice, in which the relative angular openings are adjusted by the rotary motion of the spool, thus controlling the flow area and the flow passing through, is a basic control element of hydraulic control valve. It has several advantages, such as little minimal steady flow rate, good anti-contamination, small driving power, small opening and shutting shock, and etc., over the translational control orifice. The working medium is tap water. A model is developed and numerical studies are carried out to investigate the hydrodynamic characteristics of the rotary control orifice, including flow and pressure field, flow characteristics, flow torque. The relationships between the flow and the pressure drops, the efflux angle and the angular openings, the steady-state flow torque and the pressure drops as well as the angular openings are obtained. The results show that a) the orifice geometries have great effects on the efflux angle and the steady-state flow torque; b) Under the same openings and flow direction, the efflux angle is almost constant under different pressure drops. It is larger for meter-in flow than for meter-out flow and decreases with the increase of openings; c) The steady-state flow torque (including meter-in flowTsfinand meter-out flowTsfout) is proportional to the pressure drops and first increases and then decreases with the increase of openings, finally reaches zero at the fully opened position; d) The friction moment is proportional to the rotary speed so as the transient flow induced moment to the rotary acceleration. The in-depth study of the drag moment of rotary control orifice helps to design high performance rotary servo valve for robots. The in-depth study of the rotary control orifice provides a basis for developing high performance rotary control valve.

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Tóth, Sándor Gergő, and György Takács. "Introduction of active and passive control options for hydrostatic pressure chambers." Design of Machines and Structures 10, no. 2 (2020): 155–59. http://dx.doi.org/10.32972/dms.2020.027.

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One of the critical points in the design of hydrostatic bearings is the proper selection of the pressure control of the bearing recess, yet the design methods do not pay much attention to this. In addition to conventional solutions, the control of the pressure recesses can be accomplished by the use of volumetric and pressure-sensitive valves in the hydraulics to achieve greater bearing stiffness. A new way of regulating can also be the regulation of the recess with proportional valves.

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Liu, Zhiyu, S. A. Thorpe, and W. D. Smyth. "Instability and hydraulics of turbulent stratified shear flows." Journal of Fluid Mechanics 695 (February 20, 2012): 235–56. http://dx.doi.org/10.1017/jfm.2012.13.

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AbstractThe Taylor–Goldstein (T–G) equation is extended to include the effects of small-scale turbulence represented by non-uniform vertical and horizontal eddy viscosity and diffusion coefficients. The vertical coefficients of viscosity and diffusion, ${A}_{V} $ and ${K}_{V} $, respectively, are assumed to be equal and are expressed in terms of the buoyancy frequency of the flow, $N$, and the dissipation rate of turbulent kinetic energy per unit mass, $\varepsilon $, quantities that can be measured in the sea. The horizontal eddy coefficients, ${A}_{H} $ and ${K}_{H} $, are taken to be proportional to the dimensionally correct form, ${\varepsilon }^{1/ 3} {l}^{4/ 3} $, found appropriate in the description of horizontal dispersion of a field of passive markers of scale $l$. The extended T–G equation is applied to examine the stability and greatest growth rates in a turbulent shear flow in stratified waters near a sill, that at the entrance to the Clyde Sea in the west of Scotland. Here the main effect of turbulence is a tendency towards stabilizing the flow; the greatest growth rates of small unstable disturbances decrease, and in some cases flows that are unstable in the absence of turbulence are stabilized when its effects are included. It is conjectured that stabilization of a flow by turbulence may lead to a repeating cycle in which a flow with low levels of turbulence becomes unstable, increasing the turbulent dissipation rate and so stabilizing the flow. The collapse of turbulence then leads to a condition in which the flow may again become unstable, the cycle repeating. Two parameters are used to describe the ‘marginality’ of the observed flows. One is based on the proximity of the minimum flow Richardson number to the critical Richardson number, the other on the change in dissipation rate required to stabilize or destabilize an observed flow. The latter is related to the change needed in the flow Reynolds number to achieve zero growth rate. The unstable flows, typical of the Clyde Sea site, are relatively further from neutral stability in Reynolds number than in Richardson number. The effects of turbulence on the hydraulic state of the flow are assessed by examining the speed and propagation direction of long waves in the Clyde Sea. Results are compared to those obtained using the T–G equation without turbulent viscosity or diffusivity. Turbulence may change the state of a flow from subcritical to supercritical.

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Ranawana, S. R. W. M. C. J. K., K. H. M. Siddique, J. A. Palta, K. Stefanova, and H. Bramley. "Stomata coordinate with plant hydraulics to regulate transpiration response to vapour pressure deficit in wheat." Functional Plant Biology 48, no. 9 (2021): 839. http://dx.doi.org/10.1071/fp20392.

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Genotypic variation in transpiration (Tr) response to vapour pressure deficit (VPD) has been studied in many crop species. There is debate over whether shoots or roots drive these responses. We investigated how stomata coordinate with plant hydraulics to mediate Tr response to VPD and influence leaf water status in wheat (Triticum aestivum L.). We measured Tr and stomatal conductance (gs) responses to VPD in well-watered, water-stressed and de-rooted shoots of eight wheat genotypes. Tr response to VPD was related to stomatal sensitivity to VPD and proportional to gs at low VPD, except in the water-stressed treatment, which induced strong stomatal closure at all VPD levels. Moreover, gs response to VPD was driven by adaxial stomata. A simple linear Tr response to VPD was associated with unresponsive gs to VPD. In contrast, segmented linear Tr to VPD response was mostly a function of gs with the breakpoint depending on the capacity to meet transpirational demand and set by the shoots. However, the magnitude of Tr response to VPD was influenced by roots, soil water content and stomatal sensitivity to VPD. These findings, along with a theoretical model suggest that stomata coordinate with plant hydraulics to regulate Tr response to VPD in wheat.

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Liu, Yanlan, Nataniel M. Holtzman, and Alexandra G. Konings. "Global ecosystem-scale plant hydraulic traits retrieved using model–data fusion." Hydrology and Earth System Sciences 25, no. 5 (May 10, 2021): 2399–417. http://dx.doi.org/10.5194/hess-25-2399-2021.

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Abstract. Droughts are expected to become more frequent and severe under climate change, increasing the need for accurate predictions of plant drought response. This response varies substantially, depending on plant properties that regulate water transport and storage within plants, i.e., plant hydraulic traits. It is, therefore, crucial to map plant hydraulic traits at a large scale to better assess drought impacts. Improved understanding of global variations in plant hydraulic traits is also needed for parameterizing the latest generation of land surface models, many of which explicitly simulate plant hydraulic processes for the first time. Here, we use a model–data fusion approach to evaluate the spatial pattern of plant hydraulic traits across the globe. This approach integrates a plant hydraulic model with data sets derived from microwave remote sensing that inform ecosystem-scale plant water regulation. In particular, we use both surface soil moisture and vegetation optical depth (VOD) derived from the X-band Japan Aerospace Exploration Agency (JAXA) Advanced Microwave Scanning Radiometer for Earth Observing System (EOS; collectively AMSR-E). VOD is proportional to vegetation water content and, therefore, closely related to leaf water potential. In addition, evapotranspiration (ET) from the Atmosphere–Land Exchange Inverse (ALEXI) model is also used as a constraint to derive plant hydraulic traits. The derived traits are compared to independent data sources based on ground measurements. Using the K-means clustering method, we build six hydraulic functional types (HFTs) with distinct trait combinations – mathematically tractable alternatives to the common approach of assigning plant hydraulic values based on plant functional types. Using traits averaged by HFTs rather than by plant functional types (PFTs) improves VOD and ET estimation accuracies in the majority of areas across the globe. The use of HFTs and/or plant hydraulic traits derived from model–data fusion in this study will contribute to improved parameterization of plant hydraulics in large-scale models and the prediction of ecosystem drought response.

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Tamburrano, Paolo, Pietro De Palma, Andrew R. Plummer, Elia Distaso, Francesco Sciatti, and Riccardo Amirante. "Simulation of a high frequency on/off valve actuated by a piezo-ring stack for digital hydraulics." E3S Web of Conferences 312 (2021): 05008. http://dx.doi.org/10.1051/e3sconf/202131205008.

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Despite being widely used in several applications, commercially available spool valves, both servovalves and proportional valves, are inefficient components because they cause high power consumption due to the large pressure drops across the metering orifices. A recent research field aims at substituting spool valves with on/off valves having high switching frequency (changing state between open and closed in a few milliseconds or less) and producing low pressure drops, in order to make the so-called digital hydraulics possible. In spite of the advantages that it could provide, digital hydraulics does not have significative industrial applications yet, because of the difficulty in manufacturing such high frequency on/off valves. Hence, this paper performs a feasibility study of an on/off poppet-type valve actuated directly by a commercially available ring stack, which is a multilayer piezo-actuator capable of generating very high actuation forces needed for this application. Modulation of the average flow can be achieved by changing the duty cycle of the pulse width modulation (PWM) signal driving the piezostack. An inertance tube could also be used to smooth flow pulsation. The simulations obtained using a detailed Simulink model show that high switching frequency and very effective flow modulation can be obtained with this valve architecture along with low pressure drops and high flow rates, thus making it potentially suitable for digital hydraulics. The disadvantages of this single stage architecture are the large dimensions of the piezo stacks, and the high current generated because of both the high capacitance of the piezo stack and the high frequency switching. However, large-scale production of these components could help to reduce the costs, and the simulations show that limiting the maximum current to 10 A still provides good regulation.

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Liu, Chunyu, Xiaodong Li, Run Luo, and Rafael Macian-Juan. "Thermal Hydraulics Analysis of the Distribution Zone in Small Modular Dual Fluid Reactor." Metals 10, no. 8 (August 6, 2020): 1065. http://dx.doi.org/10.3390/met10081065.

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The Small Modular Dual Fluid Reactor (SMDFR) is a novel molten salt reactor based on the dual fluid reactor concept, which employs molten salt as fuel and liquid lead/lead-bismuth eutectic (LBE) as coolant. A unique design of this reactor is the distribution zone, which locates under the core and joins the core region with the inlet pipes of molten salt and coolant. Since the distribution zone has a major influence on the heat removal capacity in the core region, the thermal hydraulics characteristics of the distribution zone have to be investigated. This paper focuses on the thermal hydraulics analysis of the distribution zone, which is conducted by the numerical simulation using COMSOL Multiphysics with the CFD (Computational Fluid Dynamics) module and the Heat Transfer module. The energy loss and heat exchange in the distribution zone are also quantitatively analyzed. The velocity and temperature distributions of both molten salt and coolant at the outlet of the distribution zone, as inlet of the core region, are produced. It can be observed that the outlet velocity profiles are proportional in magnitude to the inlet velocity ones with a similar shape. In addition, the results show that the heat transfer in the center region is enhanced due to the velocity distribution, which could compensate the power peak and flatten the temperature distribution for a higher power density.

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Muchtar, Masjono, Salama Manjang, Dadang A. Suriamiharja, and M. Arsyad Thaha. "Kinerja Model Fisik Konverter Energi Ombak Rangkaian Gear Searah pada Periode Ombak yang Bervariasi." MEDIA KOMUNIKASI TEKNIK SIPIL 22, no. 2 (December 27, 2016): 71. http://dx.doi.org/10.14710/mkts.v22i2.12871.

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To date there were few research on the effect of non-linearity properties of the ocean waves on the performance of wave energy converter (WEC), which uses a series of unidirectional gear. One such parameter is the variation of wave period. The influence of wave period variations on the performance of physical model of the wave energy converters have been investigated at the Hydraulics Laboratory, Department of Civil Engineering, Hasanuddin University Indonesia. This WEC physical model was fabricated and assembled at Politeknik ATI Makassar Indonesia. The investigation steps consists of physical model development, physical model investigation at wave flume prior to the wave period variation, measuring input output parameters of the physical model under test and empirical model formulation based on observed data analysis. Physical model test carried out on the wave flume at the Hydraulics Laboratory of the Department of Civil Hasanuddin University, at a water depth of 25 cm, wave height between 5-9 cm and wave period between 1.2 - 2.2 seconds. Investigation result based on flywheel radial speed (RPM) and torque (Nm) indicated that calculated harvested power was inversely proportional with the wave period. The longer the period of the waves, the energy produced is getting smaller. The derived empirical formula was y = -85.598x + 208.53 and R² = 0.8881. Y is energy produced (Watt) and X is the wave period (Second). Formulations generated from this study could be used as a reference for future research in dealing with wave period variations on a design one way gear wave energy converter as a source of renewable energy.

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Wang, Yalin, Xueliang Ju, Shijiang Zhu, and Meng Li. "Simulation of local head loss of drip-irrigation tape with integrated in-line emitters as a function of cross section." Spanish Journal of Agricultural Research 18, no. 4 (November 23, 2020): e0210. http://dx.doi.org/10.5424/sjar/2020184-15767.

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Aim of study: To investigate how the cross section of a drip-irrigation tape affects local head loss.Area of study: The work was carried out in the laboratory of Irrigation hydraulics, College of Water Conservancy and Environment, Three Gorges University, Yichang, Hubei province.Material and methods: Tapes with six different wall thicknesses were studied experimentally to determine the relationship between cross-section deformation, wall thickness, and pressure. Based on the experimental results, we determined the factors that influence local head loss in drip-irrigation tapes by numerical simulation and dimensional analysis.Main results: The cross-sectional shape of the drip-irrigation tape varied with pressure: under low pressure, the cross section was nearly elliptical. The cross-sectional shape of the tape strongly influenced the local head loss, which was inversely proportional to the 0.867th power of the flattening coefficient of the drip irrigation tape. We expressed the local head loss of a drip-irrigation tape equipped with integrated in-line emitters by considering the deformation of the cross section. Under the conditions used in this study, when the cross section is circular, the ratio of local head loss to frictional head loss was about 10% but, when the cross section is elliptical, this ratio increased to 15%.Research highlights: The shape of the cross section of a drip-irrigation tape is nearly elliptical under low pressure. Local head loss is inversely proportional to the 0.867th power of that is the flatting coefficient of the drip-irrigation tape. Local head loss is about 1.5 times for elliptical tape than circular tape.

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Beer, A. R., and J. M. Turowski. "Bedload transport controls intra-event bedrock erosion." Earth Surface Dynamics Discussions 3, no. 1 (January 6, 2015): 53–82. http://dx.doi.org/10.5194/esurfd-3-53-2015.

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Abstract. Fluvial bedrock incision constrains the pace of mountainous landscape evolution. Fluvial erosion processes have been described with incision models that are widely applied in river reach and catchment scale studies. However, so far, no linked field data set at the process scale had been published that allows to assess model requirements and adequacy. Here, we evaluate the predictive power of various incision models on data on hydraulics, bedload transport and erosion recorded on an artificial bedrock slab installed in a steep mountain stream for a single bedload transport event. The influence of transported bedload on erosion rate (the "tools effect") is shown to be dominant while other effects are of minor importance. Hence, a simple temporal distributed incision model in which erosion rate is proportional to bedload transport rate is proposed for transient local studies. This model can be site-calibrated with temporally lumped bedload and erosion data and its applicability can be assessed by visual inspection of the study site. Basic discharge-based models like derivatives of the stream power model family however, are adequate to reproduce the overall trend of the observed erosion rate, at least for the event on hand. This is relevant for long-term studies of e.g. landscape evolution with no interest in transient local behaviour.

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Liu, Guoqiang, Guanghua Guan, and Changde Wang. "Transition mode of long distance water delivery project before freezing in winter." Journal of Hydroinformatics 15, no. 2 (October 9, 2012): 306–20. http://dx.doi.org/10.2166/hydro.2012.167.

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In order to automatically and safely control long distance water delivery projects in winter, there is a need for a reasonable and feasible transition mode to avoid the emergence of ice jam. Based on open canal hydraulics, a mathematical model of canal system operated by constant downstream depth method is developed. The principle of combining feed-forward control of discharges with feedback control of water level is adopted for operation of check gates and a simulation model of multiple serial canal sections is established. Also, reasonable parameters of proportional-integral (PI) controller and logical dead band are obtained by trial and optimizing. The model is applied to simulate the operation process of the canal sections part of the main canal of the middle route of the South-to-North Water Transfer Project in China. Flow velocities are reduced to less than 0.4 m/s by decreasing discharges of canal pools and turnouts in terms of 3 days' cold current forecast in advance. As a result, discharge in canal was reduced from 70% designed capacity to less than 30%, which is a big challenge for the controller. This paper tests the suggested transition mode from open-channel water transfer state to a low flow ice-forming state at the MATLAB platform, and the results show that this model can achieve the expected goals.

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De Persis, Claudio, and Carsten Skovmose Kallesøe. "Proportional and Proportional-Integral Controllers for a Nonlinear Hydraulic Network." IFAC Proceedings Volumes 41, no. 2 (2008): 319–24. http://dx.doi.org/10.3182/20080706-5-kr-1001.00054.

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Cheng, Chin Yi, Jyh Chyang Renn, Yi Zhe Xie, Yi Kai Huang, and Chun Bin Yang. "FEM design of proportional solenoid for hydraulic proportional suspension damper." IOP Conference Series: Materials Science and Engineering 1113, no. 1 (March 1, 2021): 012009. http://dx.doi.org/10.1088/1757-899x/1113/1/012009.

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Li, Ke, M. A. Mannan, Mingqian Xu, and Ziyuan Xiao. "Electro-hydraulic proportional control of twin-cylinder hydraulic elevators." Control Engineering Practice 9, no. 4 (April 2001): 367–73. http://dx.doi.org/10.1016/s0967-0661(01)00003-x.

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Jiang Yongmei. "Design on Electro-hydraulic Proportional Controller." INTERNATIONAL JOURNAL ON Advances in Information Sciences and Service Sciences 4, no. 2 (February 15, 2012): 101–9. http://dx.doi.org/10.4156/aiss.vol4.issue2.13.

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Ruan, Jian, R. Burton, P. Ukrainetz, and D. Bitner. "ELECTRO-HYDRAULIC (PNEUMATIC) STAGE PROPORTIONAL CONTROL." Proceedings of the JFPS International Symposium on Fluid Power 2002, no. 5-2 (2002): 585–90. http://dx.doi.org/10.5739/isfp.2002.585.

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Beer, A. R., and J. M. Turowski. "Bedload transport controls bedrock erosion under sediment-starved conditions." Earth Surface Dynamics 3, no. 3 (July 13, 2015): 291–309. http://dx.doi.org/10.5194/esurf-3-291-2015.

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Abstract. Fluvial bedrock incision constrains the pace of mountainous landscape evolution. Bedrock erosion processes have been described with incision models that are widely applied in river-reach and catchment-scale studies. However, so far no linked field data set at the process scale had been published that permits the assessment of model plausibility and accuracy. Here, we evaluate the predictive power of various incision models using independent data on hydraulics, bedload transport and erosion recorded on an artificial bedrock slab installed in a steep bedrock stream section for a single bedload transport event. The influence of transported bedload on the erosion rate (the "tools effect") is shown to be dominant, while other sediment effects are of minor importance. Hence, a simple temporally distributed incision model, in which erosion rate is proportional to bedload transport rate, is proposed for transient local studies under detachment-limited conditions. This model can be site-calibrated with temporally lumped bedload and erosion data and its applicability can be assessed by visual inspection of the study site. For the event at hand, basic discharge-based models, such as derivatives of the stream power model family, are adequate to reproduce the overall trend of the observed erosion rate. This may be relevant for long-term studies of landscape evolution without specific interest in transient local behavior. However, it remains to be seen whether the same model calibration can reliably predict erosion in future events.

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Liu, Ming, and Yao Yao. "Application of Matlab/Simulink in Hydraulic Proportional System." Applied Mechanics and Materials 341-342 (July 2013): 1062–65. http://dx.doi.org/10.4028/www.scientific.net/amm.341-342.1062.

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This paper introduces the features of Simulink software and presents a method for the dynamic simulation of hydraulic proportional system by Simulink. It establishes a mathematical model for hydraulic proportional system based on four-way valve controlled asymmetric hydraulic cylinder. Based on the simulation model, the paper introduces how to use Simulink to simulate the dynamic characteristics of the hydraulic proportional system, and then obtains the main parameters of the dynamic characteristics of the system. The simulation results show that Simulink is an effective way for the dynamic simulation of the hydraulic proportional system.

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LI, Sheng. "Two-dimensional Electro-hydraulic Proportional Directional Valve." Journal of Mechanical Engineering 52, no. 2 (2016): 202. http://dx.doi.org/10.3901/jme.2016.02.202.

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TAKAHASHI, Tamami, Chishiro YAMASHINA, and Simpei MIYAKAWA. "DEVELOPMENT OF WATER HYDRAULIC PROPORTIONAL CONTROL VALVE." Proceedings of the JFPS International Symposium on Fluid Power 1999, no. 4 (1999): 549–54. http://dx.doi.org/10.5739/isfp.1999.549.

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Ba, Xin, Xiao Hui Luo, Xu Feng Zhao, and Yu Quan Zhu. "PI Control of Proportional Valve-Cylinder Water Hydraulic System." Applied Mechanics and Materials 548-549 (April 2014): 977–84. http://dx.doi.org/10.4028/www.scientific.net/amm.548-549.977.

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Water hydraulic components have been developed rapidly in recent years. However many problems such as low lubricity and leakage limited the performance of them, especially water proportional valves. A proportional valve- hydraulic cylinder system with tap water as working medium is chosen as object to investigate the performance of water hydraulic system. With regarding to the weaknesses of the selected 4/3 proportional valve including lag, dead zone and nonlinearity, an integral separation PI arithmetic based close-loop controller is developed. Experiments results verified the electro-hydraulic proportional system of fast response speed and high accuracy.

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Raghuraman, D. R. S., S. Senthil Kumar, and G. Kalaiarasan. "Simulation of proportional control of hydraulic actuator using digital hydraulic valves." IOP Conference Series: Materials Science and Engineering 263 (November 2017): 062080. http://dx.doi.org/10.1088/1757-899x/263/6/062080.

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Park, S.-H. "Development of a proportional poppet-type water hydraulic valve." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 223, no. 9 (June 2, 2009): 2099–107. http://dx.doi.org/10.1243/09544062jmes1380.

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To address the environmental problems and the safety of hydraulic systems, the development of novel water hydraulic systems using working fluids such as tap water are being developed successfully. In this study, we aim to develop a proportional water hydraulic valve using a proportional poppet as the main valve, which has an on—off function as well as a proportional function. The proposed proportional poppet-type water hydraulic valve has a simple structure with a control orifice that passes to the pilot orifice at both sides of the conventional poppet. Experiments verified that the relation between the main flowrate and pilot flowrate of the developed valve is linear and that the dynamic characteristics of the proportional poppet are satisfactory. Also, the developed valve was verified to be suitable for pulse width modulation (PWM) control and practical use for the control of water hydraulic systems.

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Balan, Isabela, Loredana Crenganiş, Flaviana Corduneanu, Claudiu Pricop, and Loredana Andreea Popoiu. "Infiltration Losses Calculated for the Flash Flood in the Upper Catchment of Geru River, Galaţi County, Romania." Present Environment and Sustainable Development 10, no. 2 (October 1, 2016): 219–34. http://dx.doi.org/10.1515/pesd-2016-0039.

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Abstract MIKE software created by Danish Institute of Hydraulics can be used to perform mathematical modelling of rainfall-runoff process on the hillslopes, resulting in a runoff hydrograph in the closing section of a catchment. The software includes a unitary hydrograph method - UHM in the hydrological module Rainfall - Runoff. Excess rainfall is routed to the river and transited through unit hydrograph method. The model divides the flood generating precipitation in excess rainfall (net rainfall) and losses (infiltration). This paper analyzes data from the flash flood that occurred between the 11th and 13th of September 2013 in the upper catchment of the river Geru. The catchment chosen for study, is controlled by the hydrometric station located in the village Cudalbi. Simulations of this flash flood were performed with MIKE by DHI –UHM software, alternatively using as input data the precipitations recorded by AHSS (Automated Hydrological Sensor Station) Cudalbi and radar precipitations generated by ROFFG (Romanian Flash Flood Guidance) software system in ArcGIS module for determining the areas affected by flash floods. The Unitary Hydrograph Method - UHM from the hydrological module Rainfall – Runoff calculates excess rainfall and determines infiltration losses by four methods. For each set of input data, the four methods for calculating infiltration losses were subsequently used. The comparison between the results highlights that the amplitude and phase errors for the maximum discharge are smaller when the model uses for simulation radar precipitations as input data, and calculates infiltration losses with the Proportional Loss method. This method reproduces with a better accuracy the peaks of the discharge hydrograph. The model can be used in the future to forecast a discharge hydrograph based on estimated radar precipitations in the catchment

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Li, Yao, and Jian Gang Yi. "Research on Hydraulic Components Test System Based on Proportional Control Technology." Advanced Materials Research 912-914 (April 2014): 744–47. http://dx.doi.org/10.4028/www.scientific.net/amr.912-914.744.

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Proportional control technology is widely used in many hydraulic systems. In order to measure the characteristics of hydraulic components, it is necessary to establish hydraulic components test system based on proportional control technology. In this paper, the test contents of hydraulic components are analyzed, the performance testing system is designed, the system construction is presented, and the computer test software is developed. The application results showed that the developed system has good value, which can not only be used directly in enterprise to solve the production problem, but also improve the utilization and reliability of hydraulic components.

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Jia, Wen Hua, Chen Bo Yin, and Dong Hui Cao. "Research of Median-Nonlinear Flow of Proportional Valve." Applied Mechanics and Materials 488-489 (January 2014): 1231–34. http://dx.doi.org/10.4028/www.scientific.net/amm.488-489.1231.

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In the traditional proportional valve mathematical model, the nonlinear flow characteristics induced by the geometrical features in various flow areas were often ignored. To overcome this problem, the uniform nonlinear flow mathematical model for the electro-hydraulic proportional valve is constructed. The relational expression between the orifice flow of the proportional valve and the geometrical future and physical characteristics of spool is constructed to obtain a series continuous nonlinear flow equations of median positive overlap, negative overlap and zero overlap proportional valve. The experiment validates that, for positive overlap, the flow input into the hydraulic tank is proportional to the displacement of the spool in the dead zone. For negative overlap, even though the spool located at the median, the flow output also exists, and induces the piston movement of hydraulic tank. This situation is consistent with the non-matching overlap response of actual negative proportional valve.

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Gao, Tian Xiang, Qiang Gao, and Yan Li. "Hydraulic Leveling Technology for Electro-Hydraulic Proportional Control Based on Fuzzy PID." Applied Mechanics and Materials 551 (May 2014): 503–8. http://dx.doi.org/10.4028/www.scientific.net/amm.551.503.

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In modern military and civil technologies, platforms with equipment on them are often needed to be adjusted to horizontal position rapidly and precisely and keep the platforms stable at the same time. Most leveling systems are implemented with hydraulic system, and they are time-variant nonlinear systems. To leveling both rapidly and steadily with required precision, a PID control strategy based on fuzzy theory was proposed. Electro-hydraulic proportional valve control hydraulic system model was created and analyzed, transfer function of hydraulic legs was obtained and fuzzy PID controller was created in this paper. The proposed method is simulated in Simulink. The simulation result shows that fuzzy PID controller can adjust the platform to horizontal position rapidly and steadily, and improve system performance.

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Tanaka, Hirohisa, and Kenji Masuda. "ELECTRO-HYDRAULIC TWO STAGE PROPORTIONAL PRESSURE CONTROL VALVE." Proceedings of the JFPS International Symposium on Fluid Power 1989, no. 1 (1989): 381–86. http://dx.doi.org/10.5739/isfp.1989.381.

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Liu, Wei, Jianhua Wei, Jinhui Fang, and Shizhen Li. "Hydraulic-feedback proportional valve design for construction machinery." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 229, no. 17 (February 5, 2015): 3162–78. http://dx.doi.org/10.1177/0954406214568822.

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Due to the increasing demand for large-tonnage construction machinery, the manufacturers call for a reliable and inexpensive proportional control valve with large flow capacity. In this work, a novel throttle poppet valve based on hydraulic-feedback principle has been studied comprehensively and optimized to meet the requirements of the construction machinery. A detailed and precise mathematical model has been developed and validated through experiments. According to the model, basic status of the valve under different working conditions has been analyzed, and the impacts of the parameters on the performances of response speed and the pressure stiffness have been studied through the root locus method. To find the optimal parameters suitable for construction machinery, an optimization based on non-dominated sorting genetic algorithm II was carried out, and the performances have been significantly improved. Finally, by adopting the analysis on the parameters and the optimization results, guidelines for designing the hydraulic-feedback proportional valve in various sizes are presented.

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41

Cao, Qing Hua. "Digital Electro-Hydraulic Proportional Control for Bulldozer Working Device." Applied Mechanics and Materials 40-41 (November 2010): 771–73. http://dx.doi.org/10.4028/www.scientific.net/amm.40-41.771.

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In order to improve the steering and braking of the bulldozers, electro-hydraulic proportional control technology is adopted without change the transmission system of bulldozer, two hydraulic rams are used to control the steering and braking valves in both sides of bulldozer, one electromagnetic direction valve to select controlling side, and proportional reduced valve to control the pressure of hydraulic ram. Then Matlab/Simulink to imitate the dynamic characteristic is used, The single stick steering and braking control system designed improve the maneuverability and operating condition of bulldozer. The result of this paper can apply to practice directly and use for reference for other engineering machine as to single stick centralized control.

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Peng, Zhi Fei, Rui Bo Yuan, Jing Luo, and Rong Li. "The Research of Electro-Hydraulic Proportional Control on Copper Anode Lifting Platform." Applied Mechanics and Materials 233 (November 2012): 172–76. http://dx.doi.org/10.4028/www.scientific.net/amm.233.172.

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This paper introduces the structure and working principle of the designed copper anode lifting platform. According to the actual working conditions and the structure of the lifting device, hydraulic system of electro-hydraulic proportional synchronous lifting device is designed and its working principle is analyzed. This paper takes the electro-hydraulic synchronization system as a research subject, whose mathematic model is established. To solve the synchronization accuracy of the hydraulic cylinder movement in the lifting process, a model reference adaptive controller is designed which is based on hyperstability theory. Both system simulation models of traditional PID control and adaptive control are established respectively in the software of Matlab/Simulink. Through the simulation result we can learn that adaptive control is batter than the PID control. Two hydraulic cylinders synchronization error is less than 0.02mm.

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Chang, Lin Jiang, Shu Zhong Lin, and Hong Wu Zheng. "Hydraulic System Research of the Pumping Unit Based on Electro-Hydraulic Proportional Control Technology." Applied Mechanics and Materials 373-375 (August 2013): 1340–44. http://dx.doi.org/10.4028/www.scientific.net/amm.373-375.1340.

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Trapezoidal curve is selected as the hydraulic pumping unit load running speed curve. Designed a new hydraulic system of hydraulic pumping unit according to the electro hydraulic proportional control technology and then expounded its working principle, in which the electro-hydraulic proportional directional throttle valve have been used. The system is feasible on the theory by analyzing its mathematical model. It would meet the requirement of hydraulic pumping unit and realize the advantages of it via controlling the input current signal of the amplifier.

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Cheng, Da Wei, Xia Jie Jin, and Ke Li Xing. "GUI Design for Electro-Hydraulic Proportional Controller Based on Qt." Advanced Materials Research 466-467 (February 2012): 474–78. http://dx.doi.org/10.4028/www.scientific.net/amr.466-467.474.

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In order to meet the requirements of electro-hydraulic proportional controller interface in embedded system, a GUI design method based on Qt Embedded is developed in this paper. Furthermore, the vital techniques, including installation, design, are analyzed in detail. This GUI system is employed in the embedded electro-hydraulic proportional controller. It shows the graphical user interface is friendly with stable performance.

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Li, Lan, Jiang Ye, and Xue Fei Zheng. "The Electro-Hydraulic Proportional Control and Simulation of the Radial Piston Pump Based on Proportional-Integral-Derivative Neural Network." Advanced Materials Research 139-141 (October 2010): 1749–52. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.1749.

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In this paper a new control method has been studied in which PID control system was integrated into the neural network. It could overcome some disadvantages such as neural network’s slow rate of convergence and PID’s difficulty in application of multivariate nonlinear systems. A controller of the Electro-hydraulic proportional control stroking mechanism for radial piston pump was designed based on the PID neural network control algorithm. The system responses of system variable control signal of system track were achieved by computer simulation. It was found by PIDNN that the control system could reach steady state in a shorter time, compared with PID control system response time by 65% to 80%. The simulation results showed that the controller for the Electro-hydraulic proportional Radial Piston Pump based PID neural network control algorithm would have a good controlling performance.

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Kang, Guang Qing, Xuan Qin, Xiang Gao, and Chao Wang. "Fuzzy PID Control and SIMULINK Simulation of Electro Hydraulic Proportional Relief Valve Loading System." Applied Mechanics and Materials 851 (August 2016): 503–9. http://dx.doi.org/10.4028/www.scientific.net/amm.851.503.

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This paper mainly studys the open valve control hydraulic motor loading system.For the electro hydraulic proportional relief valve loading system, the electro hydraulic proportional relief valve and the quadratic component DS1 are modeled, then the mathematical model of the electro hydraulic proportional relief valve loading system is obtained. The dynamic and steady state characteristics of the loading system are stabilized by fuzzy PID control technique. Finally modeling and Simulating the electro-hydraulic proportional relief valve loading fuzzy PID control system by SIMULINK.

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Kong, Xiangzhen, Hasan Majumdar, Faye Zang, Shouyong Jiang, Qingzhen Wu, and Wenjun Zhang. "A multi-switching mode intelligent hybrid control of electro-hydraulic proportional systems." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 1 (February 5, 2018): 120–31. http://dx.doi.org/10.1177/0954406218756446.

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The electro-hydraulic proportional system is a highly non-linear system owing to the fact that the system is composed of components from different disciplines such as electric, hydraulic and mechanical disciplines. In general, a switching-based controller is suitable to the control of such a system. In this paper, a switching-based controller is proposed, which is called multi-switching mode intelligent hybrid control, for electro-hydraulic proportional systems. The novelty of the multi-switching mode intelligent hybrid control is that it integrates the PID control law, the neural-fuzzy control law, and the expert-based control law. To demonstrate the effectiveness of the proposed multi-switching mode intelligent hybrid control, both experiment and simulation were conducted. It is shown that the experimental result corresponds well with the simulation result. Further, the proposed control system was compared with the traditional ones such as PID and neural-fuzzy controller for a trajectory tracking task with an electro-hydraulic proportional, which shows that the proposed one is far superior to these traditional ones. Overall, there is evidence that the proposed multi-switching mode intelligent hybrid control is very effective. It is noted that though the idea of the switching-based control system to electro-hydraulic proportional systems may not be new, the specific integration of the member control laws along with specific control laws developed in this work to electro-hydraulic proportional systems is not reported in the literature and multi-switching mode intelligent hybrid control is potentially useful to other electro-hydraulic proportional systems.

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Avram, Mihai, Despina Duminică, and Tudor Cătălin Apostolescu. "Proportional Hydraulic Directional Control Valve with Planar Distribution and Differential Control." Applied Mechanics and Materials 772 (July 2015): 324–28. http://dx.doi.org/10.4028/www.scientific.net/amm.772.324.

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The paper presents an original solution of hydraulic proportional directional control valve with planar distribution and differential control. The characteristic of the flow section is established and an example of such directional control valve integrated in the structure of a hydraulic positioning system with mechanical feedback is given.

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MURAO, Takuji, Yoshiaki KOKOSHIMA, Tohru KATAYAMA, David N. WORMLEY, Yukio TOMITA, and Jiro SEKI. "Characteristics of Laminar Proportional Amplifier Operated with Hydraulic Oil." Transactions of the Society of Instrument and Control Engineers 22, no. 2 (1986): 244–46. http://dx.doi.org/10.9746/sicetr1965.22.244.

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Sun, Chun Geng, Jing Luo, Sen Liu, and Peng Zhang. "Electro-Hydraulic Proportional Speed Control on Walking-Beam Conveyer." Applied Mechanics and Materials 44-47 (December 2010): 3502–7. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.3502.

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Experimental analysis has been done for vibration and noise found in Walking-beam conveyer. Two possible solutions design have been proposed, which integrate with physical components on the speed control system. Because of the determine frequency of the valve, the only way to reducing the opening rate of the valve is using complex signal, which is not what I expect. My research is finding out how to use a simple signal to do complex speed control on Walking-beam conveyer. Through anglicizing the simulation of above design, select the appropriate system for speed control of the Walking-beam conveyer, which provides a theoretical basis and engineering practice for the electro-hydraulic proportional speed control and equipment in the application of non-ferrous metallurgy equipment.

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Journal articles on the topic 'Hydraulics proportional'

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