Topic
Hydraulic machinery
About: Hydraulic machinery is a research topic. Over the lifetime, 34190 publications have been published within this topic receiving 153453 citations. The topic is also known as: hydraulic equipment & fluid energy machine.
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TL;DR: In this paper, the authors summarized the recent progress for the cavitation study in the hydraulic machinery including turbo-pumps, hydro turbines, etc., and identified the 1-D analysis method, which is identified to be very useful for engineering applications regarding the cavitating flows in inducers, turbine draft tubes, etc.
Abstract: This paper mainly summarizes the recent progresses for the cavitation study in the hydraulic machinery including turbo-pumps, hydro turbines, etc.. Especially, the newly developed numerical methods for simulating cavitating turbulent flows and the achievements with regard to the complicated flow features revealed by using advanced optical techniques as well as cavitation simulation are introduced so as to make a better understanding of the cavitating flow mechanism for hydraulic machinery. Since cavitation instabilities are also vital issue and rather harmful for the operation safety of hydro machines, we present the 1-D analysis method, which is identified to be very useful for engineering applications regarding the cavitating flows in inducers, turbine draft tubes, etc. Though both cavitation and hydraulic machinery are extensively discussed in literatures, one should be aware that a few problems still remains and are open for solution, such as the comprehensive understanding of cavitating turbulent flows especially inside hydro turbines, the unneglectable discrepancies between the numerical and experimental data, etc.. To further promote the study of cavitation in hydraulic machinery, some advanced topics such as a Density-Based solver suitable for highly compressible cavitating turbulent flows, a virtual cavitation tunnel, etc. are addressed for the future works.
296 citations
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TL;DR: In this paper, a gas accumulator is employed as an energy storage device that provides a smoothing effect to the electric power output of a wave energy converter for power take-off.
257 citations
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TL;DR: An adaptive backstepping controller is proposed for precise tracking control of hydraulic systems to handle parametric uncertainties along with nonlinear friction compensation, and the robustness against unconsidered dynamics, as well as external disturbances is also ensured via Lyapunov analysis.
Abstract: This paper concerns high-accuracy tracking control for hydraulic actuators with nonlinear friction compensation Typically, LuGre model-based friction compensation has been widely employed in sundry industrial servomechanisms However, due to the piecewise continuous property, it is difficult to be integrated with backstepping design, which needs the time derivation of the employed friction model Hence, nonlinear model-based hydraulic control rarely sets foot in friction compensation with nondifferentiable friction models, such as LuGre model, Stribeck effects, although they can give excellent friction description and prediction In this paper, a novel continuously differentiable nonlinear friction model is first derived by modifying the traditional piecewise continuous LuGre model, then an adaptive backstepping controller is proposed for precise tracking control of hydraulic systems to handle parametric uncertainties along with nonlinear friction compensation In the formulated nonlinear hydraulic system model, friction parameters, servovalve null shift, and orifice-type internal leakage are all uniformly considered in the proposed controller The controller theoretically guarantees asymptotic tracking performance in the presence of parametric uncertainties, and the robustness against unconsidered dynamics, as well as external disturbances, is also ensured via Lyapunov analysis The effectiveness of the proposed controller is demonstrated via comparative experimental results
255 citations
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TL;DR: This paper presents the derivation, simulation, and implementation of a nonlinear tracking control law for a hydraulic servosystem that provides for exponentially stable force trajectory tracking and is extended to provide position tracking.
Abstract: This paper presents the derivation, simulation, and implementation of a nonlinear tracking control law for a hydraulic servosystem. An analysis of the nonlinear system equations is used in the derivation of a Lyapunov function that provides for exponentially stable force trajectory tracking. This control law is then extended to provide position tracking. The proposed controller is simulated and then implemented on an experimental hydraulic system to test the limits of its performance and the realistic effects of friction.
251 citations
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TL;DR: In this paper, a method of phase control by latching is proposed for a single-degree-of-freedom oscillating body in regular and irregular waves, where the body remains stationary for as long as the hydrodynamic forces on its wetted surface are unable to overcome the resisting force introduced by the hydraulic power take-off mechanism.
225 citations