Theory and Application of the Internal Leakage Detection of Open-Circuit Hydraulic Systems Based on Active Hydraulic Test Technology

2018 ◽  
Vol 48 (2) ◽  
pp. 20170459
Author(s):  
Yang Chenggang ◽  
Zhao Jingyi ◽  
Sun Hao ◽  
Yang Lixuan ◽  
Zhang Ruixin
Keyword(s):  
Open Circuit ◽  
Leakage Detection ◽  
Hydraulic Systems ◽  
Hydraulic Test ◽  
Test Technology

Novel Open Circuit Displacement Control Architecture in Heavy Machinery

2014 ◽  
Author(s):  
Roman Ivantysyn ◽  
Jürgen Weber
Keyword(s):  
Large Scale ◽  
Mass Movement ◽  
Operating Cost ◽  
Open Circuit ◽  
Closed Circuit ◽  
Small Scale ◽  
Hydraulic Systems ◽  
Displacement Control ◽  
Heavy Machinery ◽  
Mobile Machinery

Motivated by the ever-stricter demands by lawmakers to lower emissions of mobile machinery and increasing fuel prices, mobile machinery has gone through a paradigm shift. Fuel efficiency has become a major selling point of machine producers. Even the heavy machinery branch, which is mainly dominated by reliability, productivity and serviceability, has started to feel this change. Hydraulic systems of large scale, as can be found in mining excavators, have typically been based on simplicity and durability. Typical architectures are open-center hydraulic systems, which were designed with robustness and productivity in mind; however they lack competiveness with other hydraulic systems in terms of energy efficiency. Displacement control has shown promising potential especially in multi-actuator machines such as excavators. The technology has so far been demonstrated in closed circuit applications on small-scale machines (below 30 t). Large scale excavators however should in general be more suitable for displacement control due to their relatively small hydraulic component cost compared to the machine and operating cost, larger energy recovery potential due to larger mass movement, more flexibility in space management and greater hydraulic power installed. Large machines feature already several smaller pumps instead of a single large pump, which is important with respect to the fact that displacement control is based on one pump per actuator. A challenge for displacement control on large-scale machinery is handling their high volumetric flow-demands on the system. Today many large excavators feature a float valve, which short-circuits the cylinder chambers and ensures rapid lowering of the attachment under aiding load. Float valves ensure fast cycle times and are essential for high productivity, however incorporating this feature in displacement control is a challenge, especially in closed circuit systems. Open circuit displacement control systems have greater flexibility than closed circuit solutions in working with float-valves and dealing with the high volumetric flows. Additionally the open circuit architecture is ideal for pump-flow-sharing, the strategy to connect two or more pumps with one actuator, which can be practiced when not all actuators move at the same time. This paper compares displacement control in open circuit form with valve-controlled actuation in a mining excavator and shows several fuel saving potentials. The Open Center system was simulated and results were validated with measurements. The proposed open circuit displacement control solutions are implemented virtually and replace the valve-controlled system. Components and system-architecture were carefully chosen in order to ensure reliability, minimal component changes and redundancy that compare to the robustness of today’s system.

Direct Driven Pump Control of Hydraulic Cylinder for Rapid Vertical Position Control of Heavy Loads: Energy Efficiency Including Effects of Damping and Load Compensation

2018 ◽  
Author(s):  
Heikki Kauranne ◽  
Teemu Koitto ◽  
Olof Calonius ◽  
Tatiana Minav ◽  
Matti Pietola
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Position Control ◽  
Open Circuit ◽  
Vertical Position ◽  
Hydraulic Systems ◽  
Heavy Load ◽  
Load Compensation ◽  
Electric Drives ◽  
Measurement Results

The ever-tightening government-enforced regulations for more energy efficient and less polluting machines and the simultaneous fast development of electric drives have caused hydraulic systems to lose ground to electric drives. One promising solution to improve the status of hydraulics in this competition are the Direct Driven Hydraulic (DDH) systems, aka electro-hydraulic actuators (EHAs), which are characterized by a closed circuit type and a servo motor driven speed-controlled pump controlling the actuator. Due to this topology, they offer a possibility of reaching higher energy efficiencies compared to traditional open circuit type valve-controlled systems and simultaneously they offer the high accuracy and dynamics of these. Typical applications where DDHs have been used are, in the area of mobile equipment, modern commercial and military aircrafts and some lift trucks, and in the area of stationary applications, mostly presses. In all of these, the actuators produce relatively slow motions. In this experimental study, a DDH system is applied to a stationary industrial vertical position control application where a very rapid movement of a heavy load is required. This brings out some unwanted fluctuation phenomena not encountered with slower motion velocities. Here we are striving for avoiding these phenomena by adding damping to the system. In addition, it is studied whether the good energy efficiency of DDH systems could be enhanced with load-compensation. The presented measurement results include the system behavior regarding the smoothness of positioning, the fluctuations of pressures, forces, and power, and finally the energy consumption with three different system configurations: basic DDH, load-compensated DDH, and load-compensated and damped DDH. The measured energy consumptions are compared against results gained in simulating a conventional valve-controlled system driving the same application. The measurement results manifest that energy consumption wise significant benefits are achievable with DDH, especially in combination with hydraulic load compensation. However, without added damping the motion involved marked vibrations in the end of the upward and downward strokes. Added damping eliminated these vibrations, but at the cost of reduced energy efficiency. Due to this, the solution for the fluctuation and vibration problem should be sought by developing a control strategy that produces a smoother but as fast motion.

scholarly journals Sensor and Component Fault Detection and Diagnosis for Hydraulic Machinery Integrating LSTM Autoencoder Detector and Diagnostic Classifiers

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 433
Author(s):  
Ahlam Mallak ◽  
Madjid Fathi
Keyword(s):  
Fault Detection ◽  
Fault Detection And Diagnosis ◽  
Behavioral Changes ◽  
Sensor Faults ◽  
Hydraulic Systems ◽  
Hydraulic Test ◽  
Economic Implications ◽  
Hydraulic Machinery ◽  
Detection And Diagnosis ◽  
Two Phases

Anomaly occurrences in hydraulic machinery might lead to massive system shut down, jeopardizing the safety of the machinery and its surrounding human operator(s) and environment, and the severe economic implications following the faults and their associated damage. Hydraulics are mostly placed in ruthless environments, where they are consistently vulnerable to many faults. Hence, not only are the machines and their components prone to anomalies, but also the sensors attached to them, which monitor and report their health and behavioral changes. In this work, a comprehensive applicational analysis of anomalies in hydraulic systems extracted from a hydraulic test rig was thoroughly achieved. First, we provided a combination of a new architecture of LSTM autoencoders and supervised machine and deep learning methodologies, to perform two separate stages of fault detection and diagnosis. The two phases were condensed by—the detection phase using the LSTM autoencoder. Followed by the fault diagnosis phase represented by the classification schema. The previously mentioned framework was applied to both component and sensor faults in hydraulic systems, deployed in the form of two in-depth applicational experiments. Moreover, a thorough literature review of related work from the past decade, for autoencoders related fault detection and diagnosis in hydraulic systems, was successfully conducted in this study.

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

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 424
Author(s):  
Samuel Kärnell ◽  
Liselott Ericson
Keyword(s):  
Open Circuit ◽  
Switching Behavior ◽  
Mode Switching ◽  
Hydraulic Systems ◽  
Mode Switch ◽  
Pressure Sensing ◽  
Controlled Systems ◽  
Huge Impact ◽  
Prime Movers ◽  
Hysteresis Control

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.

A Cost-Effective Electro-Hydraulic Actuator Solution with Open Circuit Architecture

2021 ◽  
Author(s):  
Shaoyang Qu ◽  
David Fassbender ◽  
Andrea Vacca ◽  
Enrique Busquets
Keyword(s):  
Hydraulic Drive ◽  
Cost Effective ◽  
Efficient Solutions ◽  
Open Circuit ◽  
Hydraulic Systems ◽  
Hydraulic Actuator ◽  
Machine Performance ◽  
Duty Cycles ◽  
Full Speed ◽  
Four Quadrant

With the recent electrification trend in the fluid power area, more research has been incentivized to propose cost-effective and energy-efficient solutions for hydraulic systems. Hence, electro-hydraulic actuator (EHA) architectures receive increasing attention. The paper proposes a novel open-circuit EHA architecture, with the goal to obtain a cost-effective solution for mobile applications while maximizing the overall system efficiency. The proposed EHA is capable of meeting or exceeding traditional off-road machine performance, therefore enabling further electrification of off-road machines. Four-quadrant functionality, covering the full speed range, is achieved by a combination of a variable electro-hydraulic drive and valves with different functions. Focusing on the steady-state performance, the functionality is validated by numerical as well as experimental methods. A simulation model based on the Amesim environment and a dedicated test setup was developed to verify the performance. The good match between simulation and experimental results confirms the potential of the formulation approach of the proposed EHA for applications with different duty cycles and power levels.

scholarly journals Sensor and Component Fault Detection and Diagnosis for Hydraulic Machinery Integrating LSTM Autoencoder Detector and Diagnostic Classifiers

2020 ◽  
Author(s):  
Ahlam Mallak ◽  
Madjid Fathi
Keyword(s):  
Fault Detection ◽  
Fault Detection And Diagnosis ◽  
Behavioral Changes ◽  
Hydraulic Systems ◽  
Hydraulic Test ◽  
Economic Implications ◽  
Hydraulic Machinery ◽  
Detection And Diagnosis ◽  
Two Phases ◽  
Two Stages

Anomaly occurrences in hydraulic machinery may lead to massive systems shut down, jeopardizing the safety of the machinery and its surrounding human operator(s) and environment, and the severe economic implications succeeding the faults and their associated damage. Hydraulics are mostly placed in ruthless environments, where they are consistently vulnerable to many faults. Hence, not only the machines and their components are prone to anomalies, but also the sensors attached to them, which monitor and report their health and behavioral changes. In this work, a comprehensive applicational analysis of anomalies in hydraulic systems extracted from a hydraulic test rig is thoroughly achieved. Firstly, we provided a combination of a new architecture of LSTM autoencoders and supervised machine and deep learning methodologies to perform two separate stages of fault detection and diagnosis. The two phases are condensed by: the detection phase using the LSTM autoencoder. Followed by the fault diagnosis phase represented by the classification schema. The previously mentioned framework is applied to both component and sensor faults in hydraulic systems, deployed in the form of two in-depth applicational experiments. Moreover, a thorough literature review of the past decade related work for the two stages separately is successfully conducted in this paper.

Development of Glycerin/Chitosan-Based Fluids for Stationary and Mobile Hydraulic Drives

2021 ◽  
Author(s):  
Malte Otten ◽  
Deniz Bulutcu ◽  
Ludger Frerichs
Keyword(s):  
Laboratory Tests ◽  
Test Bench ◽  
Hydraulic Fluid ◽  
Hydraulic Systems ◽  
Hydraulic Test ◽  
Wide Range ◽  
Fluid Properties ◽  
Endurance Tests ◽  
Water Glycerol ◽  
Further Development

Abstract A hydraulic fluid based on water, glycerol and the thickener chitosan was developed in preliminary tests at Technische Universität Braunschweig. In terms of fluid properties, the fluid is comparable to those of conventional fluids. Due to the promising properties of the fluid, further development of the fluid is now being worked on. The focus is on further development for practical use in mobile hydraulic systems, e.g. in agricultural and forestry machinery. The aim here is to optimize various fluid variants for different applications and to define the possible range of uses in general. This paper presents interim results from the development of the fluids and the investigations of the fluids in a wide range of laboratory tests and endurance tests in a hydraulic test bench.

scholarly journals The International Experimental Thermal Hydraulic Systems Database (TIETHYS): A New NEA Validation Tool

2018 ◽  
Author(s):  
Upendra Rohatgi ◽  
James Dyrda ◽  
Nicolas Soppera
Keyword(s):  
Test Data ◽  
Relational Database ◽  
Nuclear Reactor ◽  
Public Access ◽  
System Level ◽  
Hydraulic Systems ◽  
Cfd Modelling ◽  
Hydraulic Test ◽  
Energy Agency ◽  
Integral Effect

Nuclear reactor codes require validation with appropriate data representing the plant for specific scenarios. The thermal-hydraulic data is scattered in different locations and in different formats. Some of the data is in danger of being lost. A relational database is being developed to organize the international thermal hydraulic test data for various reactor concepts and different scenarios. At the reactor system level, that data is organized to include separate effect tests and integral effect tests for specific scenarios and corresponding phenomena. The database relies on the phenomena identification sections of expert developed PIRTs. The database will provide a summary of appropriate data, review of facility information, test description, instrumentation, references for the experimental data and some examples of application of the data for validation. The database has expandable platform and will accommodate different types of reactors and thermal-hydraulic tests. The current database platform includes scenarios for PWR, BWR, VVER, and specific benchmarks for CFD modelling data and is to be expanded to include references for molten salt reactors. There are place holders for high temperature gas cooled reactors, CANDU and liquid metal reactors. This relational database is called The International Experimental Thermal Hydraulic Systems database – TIETHYS and currently resides at Nuclear Energy Agency (NEA) of the OECD and is freely open to public access. Going forward the database will be extended to include additional links and data as they become available. The organizations conducting thermal-hydraulic tests are encouraged to submit their test data for inclusion in database for wider exposure and for preservation. https://www.oecd-nea.org/tiethysweb/

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