Stability and Energy Efficiency Improvement of Hydraulic Excavator Arm Control System With a Novel Asymmetric Pump

2017 ◽  
Author(s):  
Long Quan ◽  
Lei Ge ◽  
Jing Yang ◽  
Bin Zhao ◽  
Zhen Lu ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Control Strategies ◽  
Open Loop ◽  
Load Force ◽  
Cooling Power ◽  
Operating Characteristics ◽  
Flow Rates ◽  
Energy Efficiency Improvement ◽  
Working Cycle ◽  
Efficient Alternative

Pump controlled hydraulic circuit is an energy efficient alternative to valve controlled system, as they eliminate the throttling loss and require less cooling power. In all pump controlled systems, the internal and external leakages of the pump and actuator, especially the unequal flow rates of the single rod cylinder must be compensated. In presently existing solutions, an additional pump or some valves are used to compensate the unequal flow rates, leakages and to pressurize the system. However, these approaches increase the system complexity and complex control strategies are required to improve the overall system dynamic performances. Also, some of them suffer from undesired and uncontrolled pressure and velocity oscillations when the load force is small or its direction changes. This paper addresses the unequal flow rates compensation problem and stability problem of pump controlled single rod cylinder system, and proposes a novel solution for it. The system under consideration utilizes a new designed asymmetric pump which can match the unequal flow rates of the single rod cylinder basically. The feasibility of the new circuit is validated by both mathematics and multi-body simulation model. The results show that the undesired velocity oscillations can be removed up. Furthermore, the operating characteristics and energy efficiency of the arm cylinder with the new scheme based on the designed open-loop and closed-loop strategies are studied on a real excavator. The results show that there is no obvious velocity fluctuation with the asymmetric pump and the position controlled precision is satisfied. Compared with the independent metering circuit, the energy-saving ratio reaches to 57% during a working cycle.

Process control for nutrients removal using lamella sedimentation and floating media filtration

1998 ◽  
Vol 38 (3) ◽  
pp. 227-235
Author(s):  
Slim Zeghal ◽  
Nelu Puznava ◽  
Jean Philippe Subra ◽  
Patrick Sauvegrain
Keyword(s):  
Closed Loop ◽  
Control Strategies ◽  
Open Loop ◽  
Nutrients Removal ◽  
Flow Rates ◽  
Complete Treatment ◽  
Treatment Train ◽  
On Line ◽  
Future Work ◽  
Process Transfer

The objective of this work is to provide an efficient method to control the dosing of chemicals in order to optimise the operation of the complete treatment train associating phosphorus precipitation in a lamellae separator followed by nitrogen removal in a Biostyr® filter with methanol addition. Four coagulation-flocculation tanks of 1.54 m3 total volume were used, followed by a lamellae primary tank of 0.65 m2 footprint and 5.4 m2 total settling surface. On-line measurements were used. The pilot was operated initially with no chemicals, at constant and variable flow. Different control strategies were sought. To help tune the controllers, step changes in chemicals dosing were made to identify the open-loop process transfer function at different flow rates. The system was then operated in closed loop. This proved to be an efficient means of operating the system. Future work will continue to test various control strategies.

Additional methods to improve the energy efficiency of oil pipeline transportation

2020 ◽  
Vol 10 (5) ◽  
pp. 558-565
Author(s):  
Marat R. Lukmanov ◽  
◽  
Sergey L. Semin ◽  
Pavel V. Fedorov ◽  
◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Energy Saving ◽  
Pipeline System ◽  
Energy Costs ◽  
Improvement Program ◽  
Oil Pipeline ◽  
Energy Efficiency Improvement ◽  
Oil Transportation ◽  
Pumping Equipment ◽  
Preparatory Work

The challenges of increasing the energy efficiency of the economy as a whole and of certain production sectors in particular are a priority both in our country and abroad. As part of the energy policy of the Russian Federation to reduce the specific energy intensity of enterprises in the oil transportation system, Transneft PJSC developed and implements the energy saving and energy efficiency improvement Program. The application of energy-saving technologies allowed the company to significantly reduce operating costs and emissions of harmful substances. At the same time, further reduction of energy costs is complicated for objective reasons. The objective of this article is to present additional methods to improve the energy efficiency of oil transportation by the example of the organizational structure of Transneft. Possibilities to reduce energy costs in the organization of the operating services, planning and execution of work to eliminate defects and preparatory work for the scheduled shutdown of the pipeline, the use of pumping equipment, including pumps with variable speed drive, the use of various pipelines layouts, changing the volume of oil entering the pipeline system and increase its viscosity.

scholarly journals Control Strategies for Daylight and Artificial Lighting in Office Buildings—A Bibliometrically Assisted Review

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3852
Author(s):  
Daniel Plörer ◽  
Sascha Hammes ◽  
Martin Hauer ◽  
Vincent van Karsbergen ◽  
Rainer Pfluger
Keyword(s):  
Energy Efficiency ◽  
Energy Demand ◽  
Control Strategies ◽  
Significant Proportion ◽  
Decisive Role ◽  
Future Trend ◽  
Office Buildings ◽  
Total Energy Consumption ◽  
Integral Control ◽  
Artificial Lighting

A significant proportion of the total energy consumption in office buildings is attributable to lighting. Enhancements in energy efficiency are currently achieved through strategies to reduce artificial lighting by intelligent daylight utilization. Control strategies in the field of daylighting and artificial lighting are mostly rule-based and focus either on comfort aspects or energy objectives. This paper aims to provide an overview of published scientific literature on enhanced control strategies, in which new control approaches are critically analysed regarding the fulfilment of energy efficiency targets and comfort criteria simultaneously. For this purpose, subject-specific review articles from the period between 2015 and 2020 and their research sources from as far back as 1978 are analysed. Results show clearly that building controls increasingly need to address multiple trades to achieve a maximum improvement in user comfort and energy efficiency. User acceptance can be highlighted as a decisive factor in achieving targeted system efficiencies, which are highly determined by the ability of active user interaction in the automatic control system. The future trend is moving towards decentralized control concepts including appropriate occupancy detection and space zoning. Simulation-based controls and learning systems are identified as appropriate methods that can play a decisive role in reducing building energy demand through integral control concepts.

scholarly journals Developing a Cold Accumulator with a Capsule Bed Containing Water as a Phase-Change Material

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2703
Author(s):  
Robert Sekret ◽  
Przemysław Starzec
Keyword(s):  
Energy Efficiency ◽  
Heat Pump ◽  
Cold Storage ◽  
Cooling Capacity ◽  
Cooling Power ◽  
Storage Process ◽  
Water Ice ◽  
Measurement Results ◽  
Mathematical Relationships ◽  
Change Material

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.

scholarly journals An integrodifferential approach to modeling, control, state estimation and optimization for heat transfer systems

2016 ◽  
Vol 26 (1) ◽  
pp. 15-30 ◽  
Author(s):  
Andreas Rauh ◽  
Luise Senkel ◽  
Harald Aschemann ◽  
Vasily V. Saurin ◽  
Georgy V. Kostin
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Control Strategies ◽  
Open Loop ◽  
Distributed Parameter ◽  
Dimensional System ◽  
State Equations ◽  
Large Space ◽  
Finite Dimensional ◽  
Spatially Distributed

Abstract In this paper, control-oriented modeling approaches are presented for distributed parameter systems. These systems, which are in the focus of this contribution, are assumed to be described by suitable partial differential equations. They arise naturally during the modeling of dynamic heat transfer processes. The presented approaches aim at developing finite-dimensional system descriptions for the design of various open-loop, closed-loop, and optimal control strategies as well as state, disturbance, and parameter estimation techniques. Here, the modeling is based on the method of integrodifferential relations, which can be employed to determine accurate, finite-dimensional sets of state equations by using projection techniques. These lead to a finite element representation of the distributed parameter system. Where applicable, these finite element models are combined with finite volume representations to describe storage variables that are—with good accuracy—homogeneous over sufficiently large space domains. The advantage of this combination is keeping the computational complexity as low as possible. Under these prerequisites, real-time applicable control algorithms are derived and validated via simulation and experiment for a laboratory-scale heat transfer system at the Chair of Mechatronics at the University of Rostock. This benchmark system consists of a metallic rod that is equipped with a finite number of Peltier elements which are used either as distributed control inputs, allowing active cooling and heating, or as spatially distributed disturbance inputs.

Energy efficiency improvement and GHG abatement in the global production of primary aluminium

2014 ◽  
Vol 8 (4) ◽  
pp. 629-666 ◽  
Author(s):  
Katerina Kermeli ◽  
Peter-Hans ter Weer ◽  
Wina Crijns-Graus ◽  
Ernst Worrell
Keyword(s):  
Energy Efficiency ◽  
Efficiency Improvement ◽  
Energy Efficiency Improvement ◽  
Primary Aluminium
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