Comparative analysis of forward-facing models vs backward-facing models in powertrain component sizing

Mohan, Ganesh; Assadian, Francis; Longo, Stefano

doi:10.1049/cp.2013.1920

Cited by 59 publications

(35 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Figure 1 shows a diagram of these modeling techniques. The literature contains some discussion of the merits and disadvantages of the two [8,9]: "forward-facing" models can contain considerably more detail (in particular dynamics), but this has to be traded-off against the fact that quasi-static; "backwards-facing" models execute much more quickly. In some sources, the models which must be free from dynamics are expressed as algebraic equations [6]: if the driving cycle is fixed, it is often possible to express the energy consumed as a pure function of several parameters:…”

Section: Introductionmentioning

confidence: 99%

Sensitivity Analyses for Cross-Coupled Parameters in Automotive Powertrain Optimization

2014

View full text Add to dashboard Cite

When vehicle manufacturers are developing new hybrid and electric vehicles, modeling and simulation are frequently used to predict the performance of the new vehicles from an early stage in the product lifecycle. Typically, models are used to predict the range, performance and energy consumption of their future planned production vehicle; they also allow the designer to optimize a vehicle's configuration. Another use for the models is in performing sensitivity analysis, which helps us understand which parameters have the most influence on model predictions and real-world behaviors. There are various techniques for sensitivity analysis, some are numerical, but the greatest insights are obtained analytically with sensitivity defined in terms of partial derivatives. Existing methods in the literature give us a useful, quantified measure of parameter sensitivity, a first-order effect, but they do not consider second-order effects. Second-order effects could give us additional insights: for example, a first order analysis might tell us that a limiting factor is the efficiency of the vehicle's prime-mover; our new second order analysis will tell us how quickly the efficiency of the powertrain will become of greater significance. In this paper, we develop a method based on formal optimization mathematics for rapid second-order sensitivity analyses and illustrate these through a case study on a C-segment electric vehicle.

show abstract

Section: Introductionmentioning

confidence: 99%

Sensitivity Analyses for Cross-Coupled Parameters in Automotive Powertrain Optimization

2014

View full text Add to dashboard Cite

show abstract

“…A similar approach is also found in [121]. In fact, Assadian et al [122] state that powertrain component size optimisation could be possible with forward-facing simulations when integrating the driver model control parameters into the optimisation. The premise, however, is that both the driver and the load side are easily modelled and that the increased computational effort can be handled.…”

Section: Conceptual Design Of Complex Hydromechanical Transmissionsmentioning

confidence: 87%

Conceptual Design of Complex Hydromechanical Transmissions

Uebel¹

View full text Add to dashboard Cite

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 optimisation 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. i ii Populärvetenskaplig SammanfattningI denna avhandling presenteras nya metoder för utveckling av energieffektiva transmissioner för tunga arbetsfordon och entreprenadmaskiner. Genom att kombinera numerisk optimering av hårdvara och mjukvara tillsammans med detaljerade simuleringar av maskinens bränsleförbrukning kan designprocessen göras mer effektiv.Idag finns det en trend mot utveckling av nya energieffektiva hydraulmekaniska transmissioner och hybridisering av mobila arbetsfordon som exempelvis hjullastare, skogsmaskiner och jordbrukstraktorer. Motiven är bland annat höga bränslekostnader, hårdare lagstiftning på utsläpp och företagens önskan om en grönare profil. En hydraulmekanisk transmission kombinerar hydraulisk och mekanisk effektöverföring och har kontinuerligt varierbar utväxling som möjliggör en effektivare framdrivn...

show abstract

“…In contrast, forward-facing models contain a driver representation, components are operated based on control inputs and sufficient vehicle performance is not guaranteed. Backward-facing models can typically be simulated quicker, while the forward-facing approach can amongst others capture system dynamics and the actual vehicle performance and the effect of a control strategy [69,70]. Common simulation software products to model in particular HHV transmissions include Matlab/Simulink [71], Advisor [72,69,73,74], an analysis-focused tool based on the former, which was developed by the National Renewable Energy Laboratory, and Amesim [75], a commercial software for modelling multi-domain systems.…”

Section: Modelling Of a Series Hydraulic Hybrid Vehicle Transmissionmentioning

confidence: 99%

“…Dynamic models in Hopsan are typically one-dimensional and apply the forward-facing simulation principle. These kinds of models can offer better understanding of the physical system than their backward-facing counterparts [70,73], but require smaller simulation time steps. In principle, the use of Transmission Line Modelling (TLM) [78] in Hopsan should, however, allow for increased simulation performance on multi-core processors [79]; this has not been analysed or targeted within the scope of this thesis.…”

Section: Modelling Of a Series Hydraulic Hybrid Vehicle Transmissionmentioning

confidence: 99%

“…Due to the forward-facing nature of the simulation model, however, it needs to be guaranteed that the vehicle actually performs the driving task sufficiently [70]. Absolute deviation limits as employed in [28] (somewhat modulated in [50]) can be systematically abused; to prevent this, the total deviation of the vehicle speed v veh from the reference drive cycle v ref is related to the total distance covered, x cycle , in the dimensionless Average Relative Velocity Deviation (ARVD) measure to quantify the tracking.…”

Section: Framework For Simulation-based Optimizationmentioning

confidence: 99%

See 1 more Smart Citation

Simulation-Based Optimization of a Series Hydraulic Hybrid Vehicle

Bær¹

View full text Add to dashboard Cite

"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...

show abstract

Comparative analysis of forward-facing models vs backward-facing models in powertrain component sizing

Cited by 59 publications

References 14 publications

Sensitivity Analyses for Cross-Coupled Parameters in Automotive Powertrain Optimization

Sensitivity Analyses for Cross-Coupled Parameters in Automotive Powertrain Optimization

Conceptual Design of Complex Hydromechanical Transmissions

Simulation-Based Optimization of a Series Hydraulic Hybrid Vehicle

Contact Info

Product

Resources

About