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

Author(s):  
Heikki Kauranne ◽  
Teemu Koitto ◽  
Olof Calonius ◽  
Tatiana Minav ◽  
Matti Pietola

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.

Author(s):  
Jin Mengren ◽  
Wang Qingfeng

In hydraulic systems under negative loads, counterbalance valves are widely employed, which introduce instability and sizable energy consumption. This article focuses on the electrohydraulic system with meter-out orifice and variable pump, which allows flexible control structure. The target is to reduce inlet pressure level as well as diminish oscillation caused by time-varying loads. An extended load observer is constructed to estimate the external load. Accordingly, a robust back-stepping controller with integral part and disturbance compensation is proposed to regulate the meter-out orifice, achieving velocity-oriented control. Also, a model-based pressure-oriented controller is developed to determine pump displacement. The target is set to 3 bar in this work, while the pressure losses in conventional systems are more than 12 bar. The stabilities of these two independent controllers are both proved by Lyapunov theory. Experiments focusing on energy consumption, load compensation, and velocity tracking are carried out verifying the controller effectiveness. Discussions of results illustrate that the whole proposed controller succeeds in velocity tracking and reducing energy consumption in the presence of time-varying negative load.


2010 ◽  
Vol 118-120 ◽  
pp. 640-644
Author(s):  
Jian Xin Liu ◽  
Yu Liu ◽  
Ping Tan

This paper presents a kind of all-digital integrated hydraulic actuator (IHA) unit to drive heavy load object without centralized oil tank. In order to improve the control quality of the actuation system while eliminating or reducing the disturbance, and also to solve the problem of flow rate mismatch existed in IHA with single-rod cylinder actuator, a fuzzy PID PWM controller is suggested. Simulations on the integrated hydraulic actuator unit are carried out to evaluate the effectiveness of the proposed control method when applied to hydraulic systems with various external disturbances encountered in real working conditions. Simulation results are discussed and some conclusions are given.


2016 ◽  
Vol 821 ◽  
pp. 620-625
Author(s):  
Kamil Šubrt ◽  
Radek Knoflíček ◽  
Pavel Houška

Presently, production machines and mainly contemporary machining centers are subjected to ever increasing pressure to enhance energy efficiency, both from the side of customers and also in terms of legislative regulations. A selection of drives for the individual axes is primarily a compromise between achievable dynamics, precision and price. The electrical efficiency and energy consumption is not usually taken into consideration during the design of the axis. In this paper, the electricity consumption of single drive axis actuator and redundant actuation through two drives is compared under various operating conditions. The measurement results are used to assess the benefits of redundant actuation of positioning axes with emphasis on energy efficiency, which is consistent with the current trend of the so-called Ecodesign.


2020 ◽  
Vol 14 ◽  
Author(s):  
M. Sivaram ◽  
V. Porkodi ◽  
Amin Salih Mohammed ◽  
S. Anbu Karuppusamy

Background: With the advent of IoT, the deployment of batteries with a limited lifetime in remote areas is a major concern. In certain conditions, the network lifetime gets restricted due to limited battery constraints. Subsequently, the collaborative approaches for key facilities help to reduce the constraint demands of the current security protocols. Aim: This work covers and combines a wide range of concepts linked by IoT based on security and energy efficiency. Specifically, this study examines the WSN energy efficiency problem in IoT and security for the management of threats in IoT through collaborative approaches and finally outlines the future. The concept of energy-efficient key protocols which clearly cover heterogeneous IoT communications among peers with different resources has been developed. Because of the low capacity of sensor nodes, energy efficiency in WSNs has been an important concern. Methods: Hence, in this paper, we present an algorithm for Artificial Bee Colony (ABC) which reviews security and energy consumption to discuss their constraints in the IoT scenarios. Results: The results of a detailed experimental assessment are analyzed in terms of communication cost, energy consumption and security, which prove the relevance of a proposed ABC approach and a key establishment. Conclusion: The validation of DTLS-ABC consists of designing an inter-node cooperation trust model for the creation of a trusted community of elements that are mutually supportive. Initial attempts to design the key methods for management are appropriate individual IoT devices. This gives the system designers, an option that considers the question of scalability.


2015 ◽  
Vol 8 (1) ◽  
pp. 206-210 ◽  
Author(s):  
Yu Junyang ◽  
Hu Zhigang ◽  
Han Yuanyuan

Current consumption of cloud computing has attracted more and more attention of scholars. The research on Hadoop as a cloud platform and its energy consumption has also received considerable attention from scholars. This paper presents a method to measure the energy consumption of jobs that run on Hadoop, and this method is used to measure the effectiveness of the implementation of periodic tasks on the platform of Hadoop. Combining with the current mainstream of energy estimate formula to conduct further analysis, this paper has reached a conclusion as how to reduce energy consumption of Hadoop by adjusting the split size or using appropriate size of workers (servers). Finally, experiments show the effectiveness of these methods as being energy-saving strategies and verify the feasibility of the methods for the measurement of periodic tasks at the same time.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2703
Author(s):  
Robert Sekret ◽  
Przemysław Starzec

The paper presents the investigation of a prototype cold accumulator using water–ice latent heat for the cold storage process. The concept of the cold accumulator was based on a 200-L-capacity cylindrical storage tank in which spherical capsules filled with water were placed. Beds of polypropylene capsules with diameters of 80 mm, 70 mm, and 60 mm were used in the tests. The cold accumulator operated with a water–air heat pump. Based on the test results, the following parameters were calculated: the cooling capacity, cooling power, energy efficiency of the cold storage, and energy efficiency ratio (EER) of the accumulator. The obtained measurement results were described with mathematical relationships (allowing for measurement error) using criterial numbers and the developed “Research Stand Factor Number” (RSFN) index. It has been found that, for the prototype cold accumulator under investigation, the maximum values of the cooling capacity (17 kWh or 85.3 kWh per cubic meter of the accumulator), energy efficiency (0.99), and EER (4.8) occur for an RSFN of 144·10−4. The optimal conditions for the operation of the prototype cold accumulator were the closest to laboratory tests conducted for a bed with capsules with a diameter of 70 mm and a mass flow of the water–glycol mixture flowing between the accumulator and the heat pump of 0.084 kg/s. During the tests, no significant problems with the operation of the prototype cold accumulator were found.


2021 ◽  
Vol 236 ◽  
pp. 110772
Author(s):  
Carmela Vetromile ◽  
Antonio Spagnuolo ◽  
Antonio Petraglia ◽  
Antonio Masiello ◽  
Maria Rosa di Cicco ◽  
...  

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4089
Author(s):  
Kaiqiang Zhang ◽  
Dongyang Ou ◽  
Congfeng Jiang ◽  
Yeliang Qiu ◽  
Longchuan Yan

In terms of power and energy consumption, DRAMs play a key role in a modern server system as well as processors. Although power-aware scheduling is based on the proportion of energy between DRAM and other components, when running memory-intensive applications, the energy consumption of the whole server system will be significantly affected by the non-energy proportion of DRAM. Furthermore, modern servers usually use NUMA architecture to replace the original SMP architecture to increase its memory bandwidth. It is of great significance to study the energy efficiency of these two different memory architectures. Therefore, in order to explore the power consumption characteristics of servers under memory-intensive workload, this paper evaluates the power consumption and performance of memory-intensive applications in different generations of real rack servers. Through analysis, we find that: (1) Workload intensity and concurrent execution threads affects server power consumption, but a fully utilized memory system may not necessarily bring good energy efficiency indicators. (2) Even if the memory system is not fully utilized, the memory capacity of each processor core has a significant impact on application performance and server power consumption. (3) When running memory-intensive applications, memory utilization is not always a good indicator of server power consumption. (4) The reasonable use of the NUMA architecture will improve the memory energy efficiency significantly. The experimental results show that reasonable use of NUMA architecture can improve memory efficiency by 16% compared with SMP architecture, while unreasonable use of NUMA architecture reduces memory efficiency by 13%. The findings we present in this paper provide useful insights and guidance for system designers and data center operators to help them in energy-efficiency-aware job scheduling and energy conservation.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4209
Author(s):  
Rita Remeikienė ◽  
Ligita Gasparėnienė ◽  
Aleksandra Fedajev ◽  
Marek Szarucki ◽  
Marija Đekić ◽  
...  

The main goal of setting energy efficiency priorities is to find ways to reduce energy consumption without harming consumers and the environment. The renovation of buildings can be considered one of the main aspects of energy efficiency in the European Union (EU). In the EU, only 5% of the renovation projects have been able to yield energy-saving at the deep renovation level. No other study has thus far ranked the EU member states according to achieved results in terms of increased usage in renewable sources, a decrease in energy usage and import, and reduction in harmful gas emissions due to energy usage. The main purpose of this article is to perform a comparative analysis of EU economies according to selected indicators related to the usage of renewable resources, energy efficiency, and emissions of harmful gasses as a result of energy usage. The methodological contribution of our study is related to developing a complex and robust research method for investment efficiency assessment allowing the study of three groups of indicators related to the usage of renewable energy sources, energy efficiency, and ecological aspects of energy. It was based on the PROMETHEE II method and allows testing it in other time periods, as well as modifying it for research purposes. The EU member states were categorized by such criteria as energy from renewables and biofuels, final energy consumption from renewables and biofuels, gross electricity generation from renewables and biofuels and import dependency, and usage of renewables and biofuels for heating and cooling. The results of energy per unit of Gross Domestic Product (GDP), Greenhouse gasses (GHG) emissions per million inhabitants (ECO2), energy per capita, the share of CO2 emissions from public electricity, and heat production from total CO2 emissions revealed that Latvia, Sweden, Portugal, Croatia, Austria, Lithuania, Romania, Denmark, and Finland are the nine most advanced countries in the area under consideration. In the group of the most advanced countries, energy consumption from renewables and biofuels is higher than the EU average.


2021 ◽  
Vol 11 (5) ◽  
pp. 2342
Author(s):  
Long Li ◽  
Zhongqu Xie ◽  
Xiang Luo ◽  
Juanjuan Li

Gait pattern generation has an important influence on the walking quality of biped robots. In most gait pattern generation methods, it is usually assumed that the torso keeps vertical during walking. It is very intuitive and simple. However, it may not be the most efficient. In this paper, we propose a gait pattern with torso pitch motion (TPM) during walking. We also present a gait pattern with torso keeping vertical (TKV) to study the effects of TPM on energy efficiency of biped robots. We define the cyclic gait of a five-link biped robot with several gait parameters. The gait parameters are determined by optimization. The optimization criterion is chosen to minimize the energy consumption per unit distance of the biped robot. Under this criterion, the optimal gait performances of TPM and TKV are compared over different step lengths and different gait periods. It is observed that (1) TPM saves more than 12% energy on average compared with TKV, and the main factor of energy-saving in TPM is the reduction of energy consumption of the swing knee in the double support phase and (2) the overall trend of torso motion is leaning forward in double support phase and leaning backward in single support phase, and the amplitude of the torso pitch motion increases as gait period or step length increases.


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