scholarly journals Study of Losses and Energy Efficiency of Hydrostatic Drives with Hydraulic Cylinder

2018 ◽  
Vol 25 (4) ◽  
pp. 114-128 ◽  
Author(s):  
Grzegorz Skorek
Keyword(s):  
Energy Efficiency ◽  
Control Valve ◽  
Hydraulic Cylinder ◽  
Mathematical Tool ◽  
Hydraulic Systems ◽  
Motor Speed ◽  
Accurate Analysis ◽  
Hydrostatic Transmissions ◽  
And Control ◽  
The Impact

Abstract Energy efficiency of hydrostatic transmissions, and especially efficiencies of drives with motor speed controlled by throttle, as well as efficiency of hydraulic servomechanisms can in fact be higher than the efficiency values most frequently given by the respective literature in this field. With the progress achieved in recent years in the development of hydraulic systems it is becoming necessary to develop methods for precise energy efficiency calculation of such systems. It is difficult to imagine that more and more, better and better machines and control elements could be used without the possibility of a mathematical tool at our disposal to enable an accurate analysis and assessment of behavior of the system in which such machines and control elements have been applied. The paper discusses energy savings using mathematical model of losses in elements, the energy efficiency of the system. There are possibilities to reduce energy losses in proportional control systems (in the pump, in the throttle control unit, especially in the cylinder), and thus to improve the energy efficiency of the throttling manifold. The considerations allow for comparison of the loss power resulting from the applied hydraulic control structure of the hydraulic cylinder and the power consumed by the pump from the electric motor that drives it, the power necessary to provide pump-driven hydraulic cylinder. The article shows the impact on the output (useful) power consumed in the considered systems, and the impact on the power consumed of the loss power in the individual elements. The paper presents also formulas of loss power, formulas of energy efficiency connected with investigated hydrostatic drives, two schematic diagrams of hydraulic systems, their principle of operation and problems of studying losses in elements and energy efficiency characteristics of systems consisting of a feed assembly, control set and cylinder. It also includes a subject matter connected with an energy loss power of hydrostatic systems with hydraulic cylinder controlled by proportional directional control valve. Diagrams of loss power of two hydraulic systems worked at the same parameters of speed and load of a cylinder, which were different due to structure and ability of energy saving, were presented and compared.

scholarly journals Energy efficiency of a hydrostatic drive with proportional control compared with volumetric control

2013 ◽  
Vol 20 (3) ◽  
pp. 14-19 ◽  
Author(s):  
Grzegorz Skorek
Keyword(s):  
Energy Efficiency ◽  
Hydraulic Systems ◽  
System Quality ◽  
Motor Speed ◽  
Complete Evaluation ◽  
Proportional Control ◽  
Variable Capacity ◽  
Low Efficiency ◽  
Hydrostatic Transmissions ◽  
Drive Systems

Abstract There are uninvestigated areas connected with behaviour of elements in hydraulic systems with different structures. Unawareness of proportions of the energy, volumetric, pressure and mechanical losses in elements is often the case. Problems connected with energy efficiency are essential for improvement of functionality and quality of hydrostatic drive systems, characterised by unquestioned advantages but also by relatively low efficiency in comparison with other types of drive. Energy efficiency of hydrostatic transmissions, particularly those with throttling control of the motor speed, and also efficiency of the hydraulic servo-mechanism systems may be in fact higher than the values most often quoted in publications on the subject. Possibility of calculating the real value of the hydraulic system overall efficiency as a function of many parameters influencing it, becomes a tool of complete evaluation of the designed system quality. The paper compares efficiencies of systems with cylinder proportional control and efficiency of the system volumetric control by a variable capacity pump. Presented are also two schematic diagrams of the investigated hydrostatic systems, their principle of operation and problems of studying losses in elements and energy efficiency of systems consisting of a feed assembly, control set and cylinder.

scholarly journals A Self-Contained Electro-Hydraulic Cylinder with Passive Load-Holding Capability

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 292 ◽  
Author(s):  
Damiano Padovani ◽  
Søren Ketelsen ◽  
Daniel Hagen ◽  
Lasse Schmidt
Keyword(s):  
Energy Efficiency ◽  
Cost Efficiency ◽  
Tracking Error ◽  
Hydraulic Cylinder ◽  
Position Tracking ◽  
Hydraulic Systems ◽  
Practical Applications ◽  
Hydraulic Cylinders ◽  
External Loads ◽  
Boom Crane

Self-contained electro-hydraulic cylinders have the potential to replace both conventional hydraulic systems and the electro-mechanical counterparts enhancing energy efficiency, plug-and-play installation, and reduced maintenance. Current commercial solutions of this technology are limited and typically tailor-made, whereas the research emphasis is primarily on cost efficiency and power applications below five [kW]. Therefore, there is the need of developing more flexible systems adaptable to multiple applications. This research paper offers a contribution in this regard. It presents an electro-hydraulic self-contained single-rod cylinder with passive load-holding capability, sealed tank, capable of recovering energy, and scalable up to about eighty [kW]. The system implementation on a single-boom crane confirms its feasibility: The position tracking error remains well within ±2 [mm], oscillations are limited, and the overall energy efficiency is about 60 [%] during actuation. Concerning the passive load-holding devices, it is shown that both vented and non-vented pilot-operated check valves achieve the desired functioning and can hold the actuator position without consuming energy. Additional observations about the size and the arrangement of the load-holding valves are also provided. In conclusion, this paper demonstrates that the proposed self-contained cylinder can be successfully extended to several practical applications, especially to those characterized by overrunning external loads and the need of securing the actuator position.

scholarly journals DYNAMICS OF PROPORTIONAL SPEED CONTROL VERSUS SERVO SPEED CONTROL OF A HOSE / CABLE SPOOLING DEVICE FOR WINCH

2020 ◽  
Vol 61 (2) ◽  
pp. 350-359
Author(s):  
Alexandru-Polifron Chirita ◽  
Marian Blejan ◽  
Teodor-Costinel Popescu ◽  
Ana-Maria Popescu
Keyword(s):  
Closed Loop ◽  
Dynamic Performance ◽  
Control Valve ◽  
Speed Control ◽  
Hydraulic Cylinder ◽  
Directional Control ◽  
First Case ◽  
Control Versus ◽  
And Control ◽  
Directional Control Valve

This article presents and analyses in two cases the dynamic performance of regulation and control of the linear speed of an electro-hydraulically driven mechatronic axis. In the first case, the flow control is performed with a proportional hydraulic directional control valve, while in the second case the control is performed with a servo-valve. The linear mechatronic axis is part of a complex subsystem used in both agriculture and industry, that allows the precise winding of a hose / cable on a drum with the help of a spooling device, which conditions the positioning of the hose. The speed control of the hydraulic cylinder with bilateral rod on whose liner the spooling device is fixed is performed in a closed loop with the help of transducers and a programmable controller (PLC).

scholarly journals Development and Control of an Electro-Hydraulic Actuator System for an Exoskeleton Robot

2019 ◽  
Vol 9 (20) ◽  
pp. 4295 ◽  
Author(s):  
Dongyoung Lee ◽  
Buchun Song ◽  
Sang Yong Park ◽  
Yoon Su Baek
Keyword(s):  
Gait Cycle ◽  
Sliding Mode ◽  
Control Valve ◽  
Hydraulic Cylinder ◽  
Hydraulic Actuator ◽  
Directional Control ◽  
Robot Systems ◽  
Actuator System ◽  
And Control ◽  
Directional Control Valve

Exoskeleton robots have been developed in various fields and are divided into electric and hydraulic exoskeletons according to the actuator type. In the case of hydraulic robots, because a unidirectional pump is applied, there are limitations to the wearer’s walking. In addition, robot systems are complicated, because a directional control valve is required to change the direction of the actuator. To solve these problems, we designed the electro-hydraulic actuator (EHA) system which has both the hydraulic and electric advantages. The EHA system consists of a hydraulic bidirectional pump, a motor, a hydraulic cylinder, and various valves. For the development of the piston pump, we analyzed the gait cycle and considered the flow rate and pulsation rate. In order to reduce the size and weight of the EHA system, the valves were made from one manifold, and the hydraulic circuit was simplified. We verified that the developed EHA system is applicable to robots through position and force control experiments. Because the hydraulic system is nonlinear, we designed a sliding mode control (SMC) and compared it with the proportional integral derivative (PID) controller.

Improving Energy Efficiency of the Hydraulic Power Systems in Heavy Machinery

2020 ◽  
Vol 22 (1-2) ◽  
pp. 72-78
Author(s):  
Dejvid Anastasovski ◽  
◽  
Emil Zaev ◽  
Darko Babunski ◽  
Gerhard Rath ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Power Systems ◽  
Hydraulic System ◽  
Experimental Studies ◽  
Pressure Control ◽  
Hydraulic Systems ◽  
Hydraulic Power ◽  
Servo Systems ◽  
Scada System ◽  
And Control

The main goal of the research done in this paper is to examine possible improvements in energy efficiency of the hydraulic power systems and with this lower gas emission from working machinery. It is here given a brief explanation of the existing hydraulic systems putting special attention on a hydraulic system with separate meter-in and separate meter-out (SMISMO). While the aim of this research is to improve the hydraulic energy efficiency mainly using the SMISMO system, additional research on using those systems for simultaneous speed and pressure control of the cylinders is also observed. The results obtained through experimental studies will be used to further improve the hydraulic system. Further upgrade of this system is to design automated SCADA system for improved data acquisition and control the valves in servo systems.

Impact of Long Hydraulic Pipeline upon Performance of Hydraulic Control System

2011 ◽  
Vol 328-330 ◽  
pp. 2148-2151
Author(s):  
Ya Nan Zhao ◽  
Hong Wang Du ◽  
Yu Mei Li ◽  
Xiang Luo ◽  
Gang Liu
Keyword(s):  
Pressure Sensors ◽  
Control Valve ◽  
Hydraulic Cylinder ◽  
Hydraulic Control ◽  
Relief Valve ◽  
Supply Pressure ◽  
Directional Control ◽  
Cylinder Piston ◽  
The Impact ◽  
Directional Control Valve

In ocean exploitation, long hydraulic pipelines are usually applied. Using SimHydraulic software, the model of hydraulic system including hydraulic fluid, pump, hydraulic cylinder, directional control valve, relief valve, accumulator, long supply pipeline and return pipeline, is established. The position of the cylinder piston is measured by position sensor, while the supply pressure of the cylinder and the system supply pressure are measured by pressure sensors, the directional control valve is controlled by an on-off signal. The simulation was carried out, the impact of long hydraulic pipeline on system performance is also analyzed.

scholarly journals Design and control of mechatronic systems with pneumatic and hydraulic drive

2021 ◽  
Author(s):  
Željko Šitum ◽  
Juraj Benić ◽  
Klara Pejić ◽  
Marko Miroslav Bača ◽  
Ivan Radić ◽  
...  
Keyword(s):  
Position Control ◽  
Vision System ◽  
Hydraulic Drive ◽  
Control Valve ◽  
Mobile Systems ◽  
Motor Speed ◽  
Mechatronic Systems ◽  
Precise Position ◽  
Bar Code ◽  
And Control

This paper presents four handmade laboratory systems with pneumatic and hydraulic drive. The article first presents an example of a pneumatic motor speed control using a proportional directional control valve. Then the paper presents the design and control of a test device with pneumatic drive for determining the dynamic strength of materials, on which the fracture mechanics of materials due to the action of dynamic stress can be experimentally demonstrated and the resistance of materials to cyclic stress can be analyzed. The article then describes the design, construction and control of a pneumatically driven system for sorting products marked with a bar code using a vision system. The final section of the article describes an experimental setup for precise position control of a hydraulic cylinder using 2/2 cartridge valves, which can clearly demonstrate the application possibilities of these valves in industrial plants and mobile systems.

scholarly journals Variable Gap Sealing Technology of a Hydraulic Cylinder Based on Magnetic Shape Memory Alloy

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 950
Author(s):  
Xiaolan Chen ◽  
Fuquan Tu ◽  
Feng Gao ◽  
Heming Cheng ◽  
Shixiong Xing
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Active Role ◽  
Hydraulic Cylinder ◽  
Hydraulic Systems ◽  
Magnetic Shape Memory ◽  
The Impact ◽  
The Magnetic Field ◽  
Sealing Gap

The synergistic control of resistance reduction and sealing poses challenges to enhancing the rapid dynamic response ability of servo hydraulic cylinders; the key to solving this problem is effectively controlling the sealing gap value. In this study, a micro-variation between the hydraulic cylinder and the piston based on the disadvantage of conventional seals, constant gap seals, and lip gap seals was constructed; MSMA assist support blocks were designed on the piston to form a gap seal strip; then, the sealing gap value could be changed by controlling the magnetic field intensity. Simultaneously, the effects of magnetic field strength, parts-manufacturing precision, temperature, and hysteresis on the micro-variation in the MSMA were analyzed, and effective solutions were proposed. Finally, experiments on the magnetic field, temperature, and hysteresis were conducted by the measurement system. The results showed that the variable value of the sealing gap with the MSMA is feasible under ideal conditions, and can effectively change the amount of MSMA expansion by controlling the magnetic field strength, temperature, preload, etc., and then change the amount of the sealing gap of the hydraulic cylinder. This is the key to achieving friction and sealing control, which plays a crucial and active role in improving the efficiency of hydraulic systems. However, the impact of hysteresis effects cannot be ignored, which will be the main problem to be solved in the future.

Simulation of fluid power circuits using artificial network models: Part 2: Circuit simulation

1997 ◽  
Vol 211 (6) ◽  
pp. 429-437 ◽  
Author(s):  
Y Xue ◽  
J Watton
Keyword(s):  
Computer Simulation ◽  
Initial Conditions ◽  
Circuit Simulation ◽  
Control Valve ◽  
Network Models ◽  
Fluid Power ◽  
Motor Speed ◽  
Relief Valve ◽  
Artificial Network ◽  
And Control

A variety of fluid power components, modelled by artificial networks, are brought together to form a motor speed control system. The dynamic behaviour of the system is predicted with the support of additional artificial networks to define the initial conditions. The effect of changing the volume between the pump and control valve is then considered using computer simulation and verified by experiment. A novel feature is the use of the pressure relief valve to determine supply pressure rather than fluid compressibility using the conventional computer simulation approach.

An Inchworm Bionic Stepping Actuator Based on PZT/ER Hybrid Dive and Control

2013 ◽  
Vol 461 ◽  
pp. 330-341
Author(s):  
Guo Jun Liu ◽  
Jian Fang Liu ◽  
Jian Qiao Li ◽  
Zhi Gang Yang ◽  
Jia Zhu
Keyword(s):  
Linear Relationship ◽  
Control Valve ◽  
Control Unit ◽  
Hydraulic Cylinder ◽  
Step Size ◽  
Driving Speed ◽  
Drive Speed ◽  
New Type ◽  
Er Fluids ◽  
And Control

An unconventional inchworm stepping actuator based on bionics is presented, which consists of driving unit (PZT stack pump), fluid control unit (ER fluids valve), actuating mechanism (precision hydraulic cylinder). As a new type of precision force/ displacement driving and positioning system, it inherits the advantages of conventional inchworm actuators, and also has its own remarkable characteristics, such as that stepping displacement can be adjusted precisely through varying the working voltage and frequency, etc. The driving unit is actuated jointly by double PZT stacks; Multi-channel parallel cylindrical ER fluids valve is designed as the control valve. In the lab, the inchworm bionic stepping actuator based on PZT/ ER hybrid dive and control is designed and manufactured, and the related performances are testedsystematically. The maximum driving force reaches 49N, and the step size and driving speed VS the working voltage shows a good linear relationship under three different signal waveforms. At the same time, in the frequency range less than 40Hz, the driving speed VS the frequency approximately shows a linear relationship. When working voltage is 100V and rectangle wave signal inputs, the step size reaches 12.6μm. When the working voltage and frequency is 100V, 40Hz, respectively, the driving speed reaches 420μm/s. The maximum drive speed of test prototype reaches 1051 μm/s, when working in frequency 75 Hz. The systematic test shows that the method using PZT and ER hybrid drive and control technology to develop a new type of inchworm bionic stepping actuator is feasible, which provides a reference for the future development of new type of actuator.

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