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This paper will develop a novel electro-hydraulic actuator with energy saving characteristics. This system is able to work in differential configurations through the shifting algorithm of the valves, meaning that this developed system can be adjusted flexibly to obtain the desirable working requirements including the high effectiveness of energy re...
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Digital hydraulic technology as an emergent and important branch of fluid power offers good prospects for intelligence, integration, and energy saving of hydraulic systems. The high-speed on-off valve (HSV) that is a critical component of digital hydraulics has the drawbacks of specific design, narrow scope of application and high price compared to...
The new configuration of independent metering valve (NIMV) system uses three proportional valves that gave been effectively proven to be energy saving compared with a conventional independent metering valve system in the fixed load condition. However, the variable load condition completely affects the accuracy and energy consumption during the oper...
Citations
... Therefore, the power-by-wire (PBW) aircraft hydraulic system was proposed to convert the energy of the actuator from hydraulic pipeline transmission to electric power transmission. An electro-hydrostatic actuator (EHA) is a typical PBW-type hydraulic system component, which has the advantages of high efficiency, high power density, no pipeline, and easy maintenance [6,7]. ...
The development of the electrification of aircraft has prompted aviation hydraulic systems to shift from traditional centralized valve actuators (CVAs) to electro-hydrostatic actuators (EHAs). In this paper, aiming at the demand for a quantitative comparison of performance between CVAs and EHAs, CVA and EHA prototypes with the same power level and test platform were developed. Then, based on the power flow and dynamic models of the CVA and EHA, simulation and experimental comparative tests were conducted using different load spectrum test conditions and step response test conditions. The comparative test results showed that the efficiency of the EHA was better than that of the CVA, and the dynamic response of the CVA was better than that of the EHA. Finally, a power loss quantification and parameter sensitivity analysis were performed to reveal the impact of different parameters on the different power losses and to provide suggestions for improving the performance of CVAs and EHAs.
... The storage options include devices such as a battery or a supercapacitor [18,19]. When considering HERSs, it is notable that the use of hydraulic valves enables the storage of regenerated energy in a hydraulic accumulator [7,20,21]. These systems can capture and store energy that can be used to run actuators directly or assist the internal combustion engine (ICE), thus reducing energy consumption. ...
... Moreover, the IEHCVP shows a remarkable improvement of 16.1% in the energy-saving efficiency compared to that of the EHCVP II. This improvement is attributed to the reduced energy supply from the battery due to the assistance provided by the arm-lowering process, as calculated using Equation (21). As a result, the proposed IEHCVP outperforms both the conventional system and the EHCVP II, effectively enhancing energy conservation. ...
This paper presents an innovative powertrain design and an energy regeneration system for hybrid hydraulic excavators to reduce energy consumption and emissions. The proposed system is designed to maximize engine efficiency and make full use of the energy gained from boom and arm retraction. The powertrain features an innovative design that incorporates a continuously variable transmission (CVT), which drives the main pump. It enables precise control of both the engine’s speed and torque, ensuring that the engine operates within the high-efficiency range. The energy regeneration system is applied to regenerate the potential energy of the boom and arm, which can be used to either charge the battery or directly supply power to the main pump. Moreover, an energy management strategy based on an equivalent consumption minimization strategy is used to distribute the power while offering maximum engine efficiency. When compared with the existing hybrid system and conventional system, the simulation results indicated that the proposed approach achieves energy-saving efficiencies of 16.9% and 77.1%, respectively, at high velocities and 22.25% and 53.5%, respectively, at medium velocities. This research signifies a promising advancement for sustainable and efficient hydraulic excavator operations.
... Ho and Le in [2] presented a hydraulic system with high efficiency, which saves about 20% energy compared with systems without energy recovering. A high pressure hydraulic accumulator, a relief valve, an AC servo-motor, a fix displacement hydraulic pump, a hydraulic cylinder, seven directional controlled valves, a tank are the main components of the system. ...
In hydraulic systems, energy dissipation can be significant. The pressure drops that can occur in the hydraulic circuit, influenced by the adopted drive architecture, result in an absorbed power often significantly greater than that required by the mechanical system. In this paper, a comparative study of energy efficiency among five drive common architectures in industrial hydraulic axes is carried out. The analysis is applied to a hydraulic blanking press with variable speed and force, a fairly frequent industrial system, e.g. in the production of semi-finished brass products. Standard, regenerative, high-low, variable displacement pump and variable speed drive for a fixed displacement pump configurations have been analysed and compared. An adequate and optimized sizing of the various components of the system has been carried out in each case and subsequently the energy consumption has been estimated for a load cycle common to all the considered cases. The results show that the choice of power generation architecture of the hydraulic system has a very significant impact on energy efficiency and consequently operating costs and carbon footprint. The performed quantification of the potential energy efficiency of the considered drive architectures can be very useful in guiding energy-conscious choices.
... Pump-controlled hydraulic actuators (PHAs) have been widely used in industrial applications [1][2][3] due to their high power-to-weight ratio, energetic efficiency, simple structure, compactness, and ease of maintenance [4][5][6]. However, ensuring highperformance output tracking control is a primary demand for PHAs. ...
Pump-controlled hydraulic actuators (PHAs) contain slow mechanical and fast hydraulic dynamics, and thus singular perturbation theory can be adopted in the control strategies of PHAs. In this article, we develop a singular perturbation theory-based composite control approach for a PHA with position tracking error constraint. Disturbance observers (DOBs) are used to estimate the matched and mismatched uncertainties for online compensation. A sliding surface-like error variable is proposed to transform the second-order mechanical subsystem into a first-order error subsystem. Consequently, the position tracking error constraint of the PHA is decomposed into the output constraint of the first-order error subsystem and the stabilizing of the first-order hydraulic subsystem. Slow and fast control laws can be easily designed without using the backstepping technique, thus simplifying the control design and reducing the computational burden to a large extent. Theoretical analysis verifies that desired stability properties can be achieved by an appropriate selection of the control parameters. Simulations and experiments are performed to confirm the efficacy and practicability of the proposed control strategy.
This review article deals with hydro-pneumatic accumulators (HPAs) charged with nitrogen. The focus is on HPA models used in the study of the energy efficiency of hydraulic systems. Hydraulic circuits with HPA are presented along with their various applications for delivering the required volume of fluid, maintaining the required pressure, ensuring safe operation, safety stop, leak compensation, fluid volume change compensation, pulsation damping, and pressure shock absorption. A general regenerative hydraulic system and a general hybrid hydraulic system are also presented. The review focuses primarily on HPA computational, dynamic, and simulation models. Basic HPA calculation parameters and computational models of energy storage and thermodynamic cycle are presented. Various computational and dynamic models of HPA have been defined, such as the thermodynamic model, simulation model, dynamic model, pulsation damper model, and shock pulse damper model. Research projects that have used HPA in industrial hydraulic systems are reviewed, such as those maintaining operating pressure in an industrial 80 MN open-die hydraulic forging press and acting as a shock pulse absorber in the lifting and levelling module of a tracked mobile robotic bricklaying system. The development of energy storage technology in HPA from various sources is now a global challenge.
In hydraulic systems, energy dissipation can be significant. The pressure losses that can occur in the hydraulic circuit, which are influenced by the adopted drive architecture, result in power consumption that is often significantly higher than that required by the mechanical system. This paper presents a comparative study of the energy efficiency of five common drive architectures in industrial hydraulic axes. The analysis is applied to a variable speed and force hydraulic blanking press, a fairly common industrial system, e.g., in the manufacture of semi-finished brass products. Standard, regenerative, high–low, variable-displacement pumps and variable speed drive configurations for a fixed-displacement pump were analyzed and compared. In each case, an appropriate and optimized sizing of the different components of the system was performed, and then the energy consumption was estimated for a load cycle common to all the considered cases. The results show that the choice of the power generation architecture of the hydraulic system has a very significant impact on the energy efficiency and consequently on the operating costs and the carbon footprint. The performed quantification of the potential energy efficiency of the considered drive architectures can be very useful in helping to make energy-conscious decisions.
