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Mode Shifting in Hybrid Hydromechanical Transmissions
Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.
Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering. Volvo Construction Equipment.
Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.ORCID iD: 0000-0002-2315-0680
2015 (English)In: ASME/BATH 2015 Symposium on Fluid Power and Motion Control, ASME Press, 2015, p. 13-Conference paper, Published paper (Refereed)
Abstract [en]

Demands for low cost sustainable solutions have increased the use of and interest in complex hydromechanical transmissions for heavy off-road vehicles. In transmissions with multiplemodes, an important condition is to maintain the tractive force during the mode shifting event. For hybrid hydromechanical transmissions, with a direct connection to a hydraulic accumulator, the impressed system pressure caused by the hydraulic accumulator has not yet been observed to interfere with this condition. In this paper, a black box model approach is used to modify the hydraulic system after obtaining knowledge regarding how it is affected by a mode shift. A comparative study is carried out where a full vehicle model of a mobile working machine is simulated with two different hydraulic systems. The results show that different system solutions imply different demands on the included components, and that the mode shifting event is not a negligible factor in heavy hydraulic hybrid vehicles.

Place, publisher, year, edition, pages
ASME Press, 2015. p. 13-
Keywords [en]
Mode shifting, hydromechanical transmissions, fluid power, heavy construction machinery
National Category
Other Mechanical Engineering
Identifiers
URN: urn:nbn:se:liu:diva-126556DOI: 10.1115/FPMC2015-9583ISI: 000373970500045ISBN: 978-0-7918-5723-6 (print)OAI: oai:DiVA.org:liu-126556DiVA, id: diva2:915457
Conference
ASME/BATH 2015 Symposium on Fluid Power and Motion Control, Chicago, Illinois, USA, October 12–14, 2015
Projects
Research on Hydromechanical Transmissions and Hybrid Motion systems, RHYTHM
Funder
Swedish Energy Agency, P39367-1Available from: 2016-03-30 Created: 2016-03-30 Last updated: 2017-11-09
In thesis
1. Control Aspects of Complex Hydromechanical Transmissions: with a Focus on Displacement Control
Open this publication in new window or tab >>Control Aspects of Complex Hydromechanical Transmissions: with a Focus on Displacement Control
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis deals with control aspects of complex hydromechanical transmissions. The overall purpose is to increase the knowledge of important aspects to consider during the development of hydromechanical transmissions to ensure transmission functionality. These include ways of evaluating control strategies in early design stages as well as dynamic properties and control aspects of displacement controllers, which are key components in these systems.

Fuel prices and environmental concerns are factors that drive research on propulsion in heavy construction machinery. Hydromechanical transmissions are strong competitors to conventional torque-converter transmissions used in this application today. They offer high efficiency and wide speed/torque conversion ranges, and may easily be converted to hybrids that allow further fuel savings through energy recuperation. One challenge with hydromechanical transmissions is that they offer many different configurations, which in turn makes it important to enable evaluation of control aspects in early design stages. In this thesis, hardware-in-the-loop simulations, which blend hardware tests and standard software-based simulations, are considered to be a suitable method. A multiple-mode transmission applied to a mid-sized construction machine is modelled and evaluated in offline simulations as well as in hardware-in-the-loopsimulations.

Hydromechanical transmissions rely on efficient variable pumps/motors with fast, accurate displacement controllers. This thesis studies the dynamic behaviour of the displacement controller in swash-plate axial-piston pumps/motors. A novel control approach in which the displacement is measured with an external sensor is proposed. Performance and limitations of the approach are tested in simulations and in experiments. The experiments showed a significantly improved performance with a controller that is slightly more advanced than a standard proportional controller. The implementation of the controller allows simple tuning and good predictability of the displacement response.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2017. p. 55
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1781
National Category
Control Engineering Other Electrical Engineering, Electronic Engineering, Information Engineering Robotics Computer Engineering Vehicle Engineering
Identifiers
urn:nbn:se:liu:diva-139855 (URN)10.3384/lic.diva-139855 (DOI)978-91-7685-483-9 (ISBN)
Presentation
2017-09-08, ACAS, Campus Valla, Linköping, 10:15 (Swedish)
Opponent
Supervisors
Available from: 2017-08-17 Created: 2017-08-17 Last updated: 2018-01-13Bibliographically approved
2. Conceptual Design of Complex Hydromechanical Transmissions
Open this publication in new window or tab >>Conceptual Design of Complex Hydromechanical Transmissions
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis explores the conceptual design process of complex hydromechanical transmissions for mobile working machines. Efficient methods for design optimisation and controller development are presented to support the final concept selection.

In the endeavour to develop new fuel-efficient driveline solutions for construction machines and off-road equipment new complex hydromechanical transmission concepts are being investigated. This pursuit is driven by stricter emission legislation, high fuel prices and a desire for a greener image both for customers and manufacturers. The trend towards more complex transmission architectures increases the need for more sophisticated product development methods. Complex multiple-mode transmissions are difficult to design and prototype and can be realised in a great number of architectures. By introducing a secondary energy storage in the machine the design space expands further for both hardware and software. There is accordingly a need for more reliable concept assessment in early design stages and the possibility to support concurrent engineering throughout the development process.

Previous research on the design and development of hydromechanical transmissions has been limited to analysis of fixed concept designs or design optimization using very simple performance indicators. Existing methodologies for electrified on-road vehicles are not suitable for off-road working machines with hydromechanical transmissions and hydraulic energy storage.

The proposed conceptual design process uses detailed quasi-static simulation models and targets to optimise the fuel efficiency of the specific machine specifications and operations. It is also shown how high-speed dynamic simulations can be used for controller development and hardware-in-the-loop simulations to support an efficient product design process. The methods are demonstrated for typical use cases targeting new transmission development for construction machines. Software control development is also treated using control optimisation and real-time simulation. Finally a novel hybrid hydromechanical motion system is presented for which an efficient design process is crucial to its end performance.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2017. p. 70
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1883
National Category
Embedded Systems
Identifiers
urn:nbn:se:liu:diva-142895 (URN)10.3384/diss.diva-142895 (DOI)9789176854471 (ISBN)
Public defence
2017-12-08, ACAS, Hus A, Campus Valla, Linköping, 10:15 (English)
Opponent
Supervisors
Note

In the printed verison the series name Linköping studies in Arts and Science is incorrect. The correct series name is Linköping studies in science and technology. Dissertations.

Available from: 2017-11-09 Created: 2017-11-09 Last updated: 2017-11-30Bibliographically approved

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Larsson, L. ViktorPettersson, KarlKrus, Petter

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