Research

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33 pages, 5319 KiB

Open AccessArticle

Electro-Hydraulic Variable-Speed Drive Networks—Idea, Perspectives, and Energy Saving Potentials

by Lasse Schmidt and Kenneth Vorbøl Hansen

Energies 2022, 15(3), 1228; https://0-doi-org.brum.beds.ac.uk/10.3390/en15031228 - 08 Feb 2022

Cited by 13 | Viewed by 2689

Electro-hydraulic differential cylinder drives with variable-speed displacement units as their central transmission element are subject to an increasing focus in both industry and academia. A main reason is the potential for substantial efficiency increases due to avoidance of throttling of the main flows. [...] Read more.

Electro-hydraulic differential cylinder drives with variable-speed displacement units as their central transmission element are subject to an increasing focus in both industry and academia. A main reason is the potential for substantial efficiency increases due to avoidance of throttling of the main flows. Research contributions have mainly been focusing on appropriate compensation of volume asymmetry and the development of standalone self-contained and compact solutions, with all necessary functions onboard. However, as many hydraulic actuator systems encompass multiple cylinders, such approaches may not be the most feasible ones with respect to efficiency or commercial feasibility. This article presents the idea of multi-cylinder drives, characterized by electrically and hydraulically interconnected variable-speed displacement units essentially allowing for completely avoiding throttle elements, while allowing for hydraulic and electric power sharing as well as the sharing of auxiliary functions and fluid reservoir. With drive topologies taking offset in communication theory, the concept of electro-hydraulic variable-speed drive networks is introduced. Three different drive networks are designed for an example application, including component sizing and controls in order to demonstrate their potentials. It is found that such drive networks may provide simple physical designs with few building blocks and increased energy efficiencies compared to standalone drives, while exhibiting excellent dynamic properties and control performance. Full article

(This article belongs to the Special Issue Intelligent Fluid Power Drive Technology)

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22 pages, 895 KiB

Open AccessArticle

Hysteresis Control in Pump-Controlled Systems—A Way to Reduce Mode-Switch Oscillations in Closed and Open Circuits

by Samuel Kärnell and Liselott Ericson

Energies 2022, 15(2), 424; https://0-doi-org.brum.beds.ac.uk/10.3390/en15020424 - 07 Jan 2022

Cited by 2 | Viewed by 2021

Abstract

There is growing interest in using electric motors as prime movers in mobile hydraulic systems. This increases the interest in so-called pump-controlled systems, where each actuator has its own drive unit. Such architectures are primarily appealing in applications where energy efficiency is important [...] Read more.

There is growing interest in using electric motors as prime movers in mobile hydraulic systems. This increases the interest in so-called pump-controlled systems, where each actuator has its own drive unit. Such architectures are primarily appealing in applications where energy efficiency is important and electric recuperation is relevant. An issue with pump-controlled systems is, however, mode-switch oscillations which can appear when the pressure levels in the system are close to the switching condition. In this paper, the mode-switching behavior of different generalized closed and open circuit configurations is investigated. The results show that the choice of where to sense the pressures has a huge impact on the behavior. They also show that, if the pressure sensing components are properly placed, closed and open circuits can perform very similarly, but that mode-switch oscillations still can occur in all circuits. Active hysteresis control is suggested as a solution and its effectiveness is analyzed. The outcome from the analysis shows that active hysteresis control can reduce the risk for mode-switch oscillations significantly. Full article

(This article belongs to the Special Issue Intelligent Fluid Power Drive Technology)

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27 pages, 4468 KiB

Open AccessArticle

Novel Concept for Electro-Hydrostatic Actuators for Motion Control of Hydraulic Manipulators

by Konrad Johan Jensen, Morten Kjeld Ebbesen and Michael Rygaard Hansen

Energies 2021, 14(20), 6566; https://0-doi-org.brum.beds.ac.uk/10.3390/en14206566 - 12 Oct 2021

Cited by 10 | Viewed by 2717

Abstract

Self-contained hydraulic cylinders have gained popularity in the recent years but have not been implemented for high power articulated hydraulic manipulators. This paper presents a novel concept for an electro-hydrostatic actuator applicable to large hydraulic manipulators. The actuator is designed and analyzed to [...] Read more.

Self-contained hydraulic cylinders have gained popularity in the recent years but have not been implemented for high power articulated hydraulic manipulators. This paper presents a novel concept for an electro-hydrostatic actuator applicable to large hydraulic manipulators. The actuator is designed and analyzed to comply with requirements such as load holding, overload handling, and differential flow compensation. The system is analyzed during four quadrant operation to investigate energy efficiency and regenerative capabilities. Numerical simulation is carried out using path control and 2DOF anti-swing of a hydraulic crane as a load case to illustrate a real world scenario. A comparison with traditional valve-controlled actuators is conducted, showing significantly improved efficiency and with similar dynamic response, as well as the possibility for regenerating energy. Full article

(This article belongs to the Special Issue Intelligent Fluid Power Drive Technology)

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29 pages, 4675 KiB

Open AccessArticle

Thermo-Hydraulic Modelling and Experimental Validation of an Electro-Hydraulic Compact Drive

by Søren Ketelsen, Sebastian Michel, Torben O. Andersen, Morten Kjeld Ebbesen, Jürgen Weber and Lasse Schmidt

Energies 2021, 14(9), 2375; https://0-doi-org.brum.beds.ac.uk/10.3390/en14092375 - 22 Apr 2021

Cited by 12 | Viewed by 2614

Abstract

Electro-hydraulic compact drives (ECDs) are an emerging technology for linear actuation in a wide range of applications. Especially within the low power range of 5–10 kW, the plug-and-play capability, good energy efficiency and small space requirements of ECDs render this technology a promising [...] Read more.

Electro-hydraulic compact drives (ECDs) are an emerging technology for linear actuation in a wide range of applications. Especially within the low power range of 5–10 kW, the plug-and-play capability, good energy efficiency and small space requirements of ECDs render this technology a promising alternative to replace conventional valve-controlled linear drive solutions. In this power range, ECDs generally rely on passive cooling to keep oil and system temperatures within the tolerated range. When expanding the application range to larger power classes, passive cooling may not be sufficient. Research investigating the thermal behaviour of ECDs is limited but indeed required for a successful expansion of the application range. In order to obtain valuable insights into the thermal behaviour of ECDs, thermo-hydraulic simulation is an important tool. This may enable system design engineers to simulate thermal behaviour and thus develop proper thermal designs during the early design phase, especially if such models contain few parameters that can be determined with limited information available. Our paper presents a lumped thermo-hydraulic model derived from the conservation of mass and energy. The derived model was experimentally validated based on experimental data from an ECD prototype. Results show good accuracy between measured and simulated temperatures. Even a simple thermal model containing only a few thermal resistances may be sufficient to predict steady-state and transient temperatures with reasonable accuracy. The presented model may be used for further investigations into the thermal behaviour of ECDs and thus toward proper thermal designs required to expand the application range. Full article

(This article belongs to the Special Issue Intelligent Fluid Power Drive Technology)

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17 pages, 31118 KiB

Open AccessArticle

The Hydraulically Controlled Oscillating Piston Converter

by Rudolf Scheidl

Energies 2021, 14(8), 2156; https://0-doi-org.brum.beds.ac.uk/10.3390/en14082156 - 13 Apr 2021

Cited by 2 | Viewed by 1559

Abstract

One way to realize inertia in energy saving hydraulic switching converters is a mechanical oscillator connected to a piston. Its two basic advantages over the use of fluid in an inductance pipe are higher compactness and a better decoupling of inductance and capacitance; [...] Read more.

One way to realize inertia in energy saving hydraulic switching converters is a mechanical oscillator connected to a piston. Its two basic advantages over the use of fluid in an inductance pipe are higher compactness and a better decoupling of inductance and capacitance; these are opposed by a more complex valve system, which raises costs if electric control is applied. This paper presents and studies an oscillating mass converter with pure hydraulic control. It features a pressure control function and constitutes a step-up converter. A simple model is established to elucidate the basic properties of the function principle under idealized conditions. The complete system with the hydraulic control concept is studied by an elaborate dynamical model. It is shown that the converter is able to operate in the intended way under the conditions of the mathematical model. A potential application for a load sensing type meter out control of a cylinder drive is sketched. Full article

(This article belongs to the Special Issue Intelligent Fluid Power Drive Technology)

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27 pages, 6985 KiB

Open AccessArticle

Active Vehicle Suspension with Anti-Roll System Based on Advanced Sliding Mode Controller

by Jarosław Konieczny, Marek Sibielak and Waldemar Rączka

Energies 2020, 13(21), 5560; https://0-doi-org.brum.beds.ac.uk/10.3390/en13215560 - 23 Oct 2020

Cited by 17 | Viewed by 2283

Abstract

In the paper authors consider the active suspension of the wheeled vehicle. The proposed controller consists of a sliding mode controller used to roll reduction and linear regulators with quadratic performance index (LQRs) for struts control was shown. The energy consumption optimization was [...] Read more.

In the paper authors consider the active suspension of the wheeled vehicle. The proposed controller consists of a sliding mode controller used to roll reduction and linear regulators with quadratic performance index (LQRs) for struts control was shown. The energy consumption optimization was taken into account at the stage of strut controllers synthesis. The studied system is half of the active vehicle suspension using hydraulic actuators to increase the ride comfort and keeping safety. Instead of installing additional actuators in the form of active anti-roll bars, it has been decided to expand the active suspension control algorithm by adding extra functionality that accounts for the roll. The suggested algorithm synthesis method is based on the object decomposition into two subsystems whose controllers can be synthesized separately. Individual suspension struts are controlled by actuators that use the controllers whose parameters have been calculated with the LQR method. The mathematical model of the actuator applied in the work takes into account its nonlinear nature and the dynamics of the servovalve. The simulation tests of the built active suspension control system have been performed. In the proposed solution, the vertical displacements caused by uneven road surface are reduced by controllers related directly to suspension strut actuators. Full article

(This article belongs to the Special Issue Intelligent Fluid Power Drive Technology)

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18 pages, 9008 KiB

Open AccessArticle

A Piston-Swiveling-Cylinder Pair in a High Water-Based Hydraulic Motor with Self-Balanced Distribution Valves

by Jiyun Zhao, Bingjing Qiu and Jiaxiang Man

Energies 2020, 13(12), 3175; https://0-doi-org.brum.beds.ac.uk/10.3390/en13123175 - 19 Jun 2020

Cited by 6 | Viewed by 3243

Abstract

To improve the low viscosity and poor lubrication characteristics of high-water-based hydraulic liquid, the abrasion and leakage problems in hydraulic components need to be addressed. In a high water-based hydraulic motor with self-balanced distribution valve (HWBHM-SDV), there are two key friction pairs: the [...] Read more.

To improve the low viscosity and poor lubrication characteristics of high-water-based hydraulic liquid, the abrasion and leakage problems in hydraulic components need to be addressed. In a high water-based hydraulic motor with self-balanced distribution valve (HWBHM-SDV), there are two key friction pairs: the piston-crankshaft pair and piston-swivelling-cylinder (PSC) pair. To study the working performance of the PSC pair in HWBHM-SDV, we firstly designed the structural parameters. We found that, within the working speed 0–100 rpm, the leakage in the PSC pair is mainly caused by pressure-gradient flow, and the influence of the seal will not be significant when the seal length is 24 mm. Then, the friction coefficients of different matching materials were tested. It was found that the friction coefficient of 316L stainless steel with OVINO-GIC (OVINO-graphite intercalated compound) coating (316L-GIC)/PEEK reinforced with 30% carbon fibre (PEEK-30CF) is about 0.02~0.04, and the friction coefficient of 316L-GIC/316L-GIC is about 0.05–0.07. Finally, the influences of factors (clearance, temperature, pressure, and material) on leakage performance were analysed based on an orthogonal test method considering fluid-structure interaction. It was found that clearance has the most significant influence on leakage, followed by pressure and liquid temperature, and the difference between matching materials 316L-GIC/316L-GIC and 316L-GIC/PEEK-30CF is insignificant when the clearance is less than 8 μm and the working pressure is less than 10 MPa. Moreover, the difference in volume efficiency loss between theoretical analysis and calculated result considering fluid-structure interaction increases with the increase of working pressure and working speed. To ensure good working performance of a PSC pair, matching materials 316L-GIC/PEEK-30CF could be selected for pressures below 15 MPa, while 316L-GIC/316L-GIC could be used at 28 MPa. Full article

(This article belongs to the Special Issue Intelligent Fluid Power Drive Technology)

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20 pages, 5329 KiB

Open AccessArticle

Performance Improvement of a Hydraulic Active/Passive Heave Compensation Winch Using Semi Secondary Motor Control: Experimental and Numerical Verification

by Geir-Arne Moslått, Michael Rygaard Hansen and Damiano Padovani

Energies 2020, 13(10), 2671; https://0-doi-org.brum.beds.ac.uk/10.3390/en13102671 - 25 May 2020

Cited by 7 | Viewed by 3791

Abstract

In this paper, a newly developed controller for active heave compensated offshore cranes is compared with state-of-the-art control methods. The comparison is divided into a numerical part on stability margins as well as operational windows and an experimental validation of the expected performance [...] Read more.

In this paper, a newly developed controller for active heave compensated offshore cranes is compared with state-of-the-art control methods. The comparison is divided into a numerical part on stability margins as well as operational windows and an experimental validation of the expected performance improvement based on a full-scale testing on site with a crane rated to 250 metric tons. Such a crane represents the typical target for the new control method using a combination of active and passive hydraulic actuation on the main winch. The active hydraulic actuation is a hydrostatic transmission with variable-displacement pumps and variable-displacement motors. The new controller employs feedforward control of the motors’ displacement so that the window of operation is increased and, simultaneously, oscillations in the system are markedly reduced. Full article

(This article belongs to the Special Issue Intelligent Fluid Power Drive Technology)

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Review

Jump to: Research

22 pages, 3904 KiB

Open AccessReview

A Comparison of Adaptive Ultrasound Reflectometry Calibration Methods for Use in Lubrication Films

by Elias Vagn Hansen and Per Johansen

Energies 2022, 15(9), 3240; https://0-doi-org.brum.beds.ac.uk/10.3390/en15093240 - 28 Apr 2022

Cited by 3 | Viewed by 1146

Abstract

Adaptive calibration for ultrasound reflectometry methods used in the detection of lubrication film thickness is of great research interest. This is mainly due to the versatile non-destructive implementation of the technology in industrial applications, allowing for measurements of the lubrication film thickness, which [...] Read more.

Adaptive calibration for ultrasound reflectometry methods used in the detection of lubrication film thickness is of great research interest. This is mainly due to the versatile non-destructive implementation of the technology in industrial applications, allowing for measurements of the lubrication film thickness, which directly relates to the friction, wear, and overall efficiency of the system. This study reviews and compares a curve fitting, extended Kalman filter, and resonance frequency detection adaptive calibration approach. Furthermore, the study compares two different regression models, used for the curve fitting and the extended Kalman filter approach. The study compares the methods and regression models based on both a theoretical and experimental analysis. The experimental analysis is based on data with varying lubrication film thickness. The lubrication film thickness is varied such that the resonance frequency is both detectable and non-detectable within the ultrasound transducer bandwidth. It is found that all three methods give results very similar to those achieved through manual calibration. However, since the extended Kalman filter approach is the only method that allows for continuous calibration, this method is found to have the greatest potential of the methods compared. Full article

(This article belongs to the Special Issue Intelligent Fluid Power Drive Technology)

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15 pages, 312 KiB

Open AccessReview

Fault Detection and Diagnosis Methods for Fluid Power Pitch System Components—A Review

by Magnus F. Asmussen, Jesper Liniger and Henrik C. Pedersen

Energies 2021, 14(5), 1305; https://0-doi-org.brum.beds.ac.uk/10.3390/en14051305 - 27 Feb 2021

Cited by 7 | Viewed by 2190

Abstract

Wind turbines have become a significant part of the global power production and are still increasing in capacity. Pitch systems are an important part of modern wind turbines where they are used to apply aerodynamic braking for power regulation and emergency shutdowns. Studies [...] Read more.

Wind turbines have become a significant part of the global power production and are still increasing in capacity. Pitch systems are an important part of modern wind turbines where they are used to apply aerodynamic braking for power regulation and emergency shutdowns. Studies have shown that the pitch system is responsible for up to 20% of the total down time of a wind turbine. Reducing the down time is an important factor for decreasing the total cost of energy of wind energy in order to make wind energy more competitive. Due to this, attention has come to condition monitoring and fault detection of such systems as an attempt to increase the reliability and availability, hereby the reducing the turbine downtime. Some methods for fault detection and condition monitoring of fluid power systems do exists, though not many are used in today’s pitch systems. This paper gives an overview of fault detection and condition monitoring methods of fluid power systems similar to fluid power pitch systems in wind turbines and discuss their applicability in relation to pitch systems. The purpose is to give an overview of which methods that exist and to find areas where new methods need to be developed or existing need to be modified. The paper goes through the most important components of a pitch system and discuss the existing methods related to each type of component. Furthermore, it is considered if existing methods can be used for fluid power pitch systems for wind turbine. Full article

(This article belongs to the Special Issue Intelligent Fluid Power Drive Technology)

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