Conceptual Design of Complex Hydromechanical Transmissions

Uebel, Karl

doi:10.3384/diss.diva-142895

Cited by 3 publications

(12 citation statements)

References 69 publications

(74 reference statements)

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“…These systems combine a Hydrostatic Transmission (HST) with planetary gear trains, thereby enabling high efficiency and optimal engine operation [20]. Usually, multiple-mode HMTs with clutches are required for sufficient conversion range, efficiency, and power density [21]. Each mode then consists of one of the commonly-mentioned single-mode configurations; Input-Coupled Power-Split (ICPS), Output-Coupled-Power-Split (OCPS), and compound [22].…”

Section: Wheel Loadersmentioning

confidence: 99%

Low-Level Control of Hybrid Hydromechanical Transmissions for Heavy Mobile Working Machines

et al. 2019

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Fuel efficiency has become an increasingly important property of heavy mobile working machines. As a result, Hybrid Hydromechanical Transmissions (HMTs) are often considered for the propulsion of these vehicles. The introduction of hybrid HMTs does, however, come with a number of control-related challenges. To date, a great focus in the literature has been on high-level control aspects, concerning optimal utilization of the energy storage medium. In contrast, the main topic of this article is low-level control, with the focus on dynamic response and the ability to realize requested power flows accurately. A static decoupled Multiple-Input-Multiple-Output (MIMO) control strategy, based on a linear model of a general hybrid HMT, is proposed. The strategy is compared to a baseline approach in Hardware-In-the-Loop (HWIL) simulations of a reference wheel loader for two drive cycles. It was found that an important benefit of the decoupled control approach is that the static error caused by the system’s cross-couplings is minimized without introducing integrating elements. This feature, combined with the strategy’s general nature, motivates its use for multiple-mode transmissions in which the transmission configuration changes between the modes.

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Section: Wheel Loadersmentioning

confidence: 99%

Low-Level Control of Hybrid Hydromechanical Transmissions for Heavy Mobile Working Machines

et al. 2019

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“…The driveline of a modern working machine is most often of the hydrodynamic (torque converter) or hydrostatic type, depending on the machine's power level [5,6]. For hybridisation, complex hybrid hydromechanical transmissions are often required to fulfil demands for wide speed conversion ranges, high power density and acceptable cost.…”

Section: Hydraulic Hybrid Working Machinesmentioning

confidence: 99%

Control of Hybrid Hydromechanical Transmissions

Larsson

2019

Linköping Studies in Science and Technology. Dissertations

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“…This approach is also applied to hydro-mechanical and hydraulic hybrid transmissions (see e.g. [29], and in the context of preliminary sizing in [53]). In [54], however, a need for sizing for sufficient power at low pressure, which leads to large systems, is raised.…”

Section: Design Of Hydraulic Hybrid Transmissionsmentioning

confidence: 99%

“…In relation to a typical design process, as shown for example in [53], this integrates elements of both early and later design stages. It is, however, to be pointed out that the overall aim of the framework is not to obtain a final design, but to explore design options.…”

Section: Framework For Simulation-based Optimizationmentioning

confidence: 99%

“…A comparative study of the different system and control optimization approaches was conducted by Uebel [53] for a parallel hydraulic hybrid wheel loader transmission. Limited to three component-related parameters, dynamic programming is used for control optimization in the bi-level and iterative approaches, while sequential and simultaneous strategy are conducted with different simple rule-based control schemes.…”

Section: Simulation-based Optimization Of a Series Hydraulic Hybrid Vmentioning

confidence: 99%

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Simulation-Based Optimization of a Series Hydraulic Hybrid Vehicle

Bær¹

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"The brick walls are there for a reason. (...) [They] are there to give us a chance to show how badly we want something. Randy Pausch AbstractHybrid transmissions are characterized by their utilization of more than one form of energy storage. They have the potential to help reduce overall fuel consumption and vehicle emissions by providing the possibility of brake energy recuperation and prime mover operation management. Electric hybrids and electric vehicle drives are nowadays ubiquitous, and mechanical energy storage in flywheel has been investigated in the past. The use of fluid power technology with a combustion engine has also been investigated since the late 1970s, and is frequently revisited.Hydraulic hybridization is especially attractive for heavy vehicles with frequent braking and acceleration which benefit most from fluid power components' high power density, typically busses, delivery or refuse vehicles, and vehicles with existing hydraulic circuits and transmissions, such as forest and construction machinery, but have been considered for smaller vehicles as well.Due to the characteristic discharge profile of hydraulic energy storage, special attention needs to be paid to control aspects in the design process to guarantee drivability of the vehicle. In this respect, simulation models can be of use in early design process stages for cheaper and faster evaluation of concepts and designs than physical experiments and prototyping, and to generate better understanding of the system studied. Engineering optimization aids in the systematic exploration of a given design space, to determine limits and potentials, evaluate trade-offs and potentially find unexpected solutions. In the optimization of a hydraulic hybrid transmission, the integration of component and controller design is of importance, and different strategies (sequential, iterative, bi-level and simultaneous approaches) are conceivable, with varying consequences for the implementation.This thesis establishes a simulation-based optimization framework for a hydraulic hybrid transmission with series architecture. Component and control parameter optimization are addressed simultaneously, using a rule-based supervisory control strategy. The forward-facing dynamic simulation model at the centre of the framework is built in Hopsan, a multi-disciplinary open-source tool developed at Linköping University. The optimization is set up and conducted for an example application of an on-road light-duty truck over standard drive i cycles. Both results from these experiments as well as the framework itself are studied and evaluated. Relevant design aspects, such as explicit design relations to be considered and performance requirements for more robust design, are identified and addressed, and the optimization problem is analysed with regard to algorithm performance and problem formulation. The final result is an optimization framework that can be adjusted for further in-depth studies, for example through the inclusion of additional components or optimization obj...

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Conceptual Design of Complex Hydromechanical Transmissions

Cited by 3 publications

References 69 publications

Low-Level Control of Hybrid Hydromechanical Transmissions for Heavy Mobile Working Machines

Low-Level Control of Hybrid Hydromechanical Transmissions for Heavy Mobile Working Machines

Control of Hybrid Hydromechanical Transmissions

Simulation-Based Optimization of a Series Hydraulic Hybrid Vehicle

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