liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
Wheel loader operation-Optimal control compared to real drive experience
Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
Lund University, Sweden.
Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
2016 (English)In: Control Engineering Practice, ISSN 0967-0661, E-ISSN 1873-6939, Vol. 48, 1-9 p.Article in journal (Refereed) PublishedText
Abstract [en]

Wheel loader trajectories between loading and unloading positions in a repetitive loading cycle are studied. A wheel loader model available in the literature is improved for better fuel estimation and optimal control problems are formulated and solved using it. The optimization results are analyzed in a side to side comparison with measurement data from a real world application. It is shown that the trajectory properties affect the operation productivity. However, efficient trajectories are not the only requirement for high productivity operation and all major power consuming sources such as vehicle dynamics, lifting and steering have to be included in the optimization for productivity analysis. The effect of operator steering capability is also analyzed showing that development of autonomous vehicles can be envisaged especially for repetitive cycles. (C) 2015 Elsevier Ltd. All rights reserved.

Place, publisher, year, edition, pages
Elsevier, 2016. Vol. 48, 1-9 p.
Keyword [en]
Optimal control; Modeling for control; Powertrain modeling and simulation; Trajectory optimization
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
URN: urn:nbn:se:liu:diva-126245DOI: 10.1016/j.conengprac.2015.12.015ISI: 000370906700001OAI: oai:DiVA.org:liu-126245DiVA: diva2:913457
Available from: 2016-03-21 Created: 2016-03-21 Last updated: 2016-05-30
In thesis
1. Modeling and Optimal Control of Heavy-Duty Powertrains
Open this publication in new window or tab >>Modeling and Optimal Control of Heavy-Duty Powertrains
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Heavy duty powertrains are complex systems with components from various domains, different response times during transient operations and different efficient operating ranges. To ensure efficient transient operation of a powertrain, e.g. with low fuel consumption or short transient duration, it is important to come up with proper control strategies. In this dissertation, optimal control theory is used to calculate and analyze efficient heavy duty powertrain controls during transient operations in different applications. This is enabled by first developing control ready models, usable for multi-phase optimal control problem formulations, and then using numerical optimal control methods to calculate the optimal transients.

Optimal control analysis of a wheel loader operating in a repetitive loading cycle is the first studied application. Increasing fuel efficiency or reducing the operation time in such repetitive loading cycles sums up to large savings over longer periods of time. Load lifting and vehicle traction consume almost all of the power produced by a diesel engine during wheel loader operation. Physical models are developed for these subsystems where the dynamics are described by differential equations. The model parameters are tuned and fuel consumption estimation is validated against measured values from real wheel loader operation. The sensitivity of wheel loader trajectory with respect to constrains such as the angle at which the wheel loader reaches the unloading position is also analyzed. A time and fuel optimal trajectory map is calculated for various unloading positions. Moreover, the importance of simultaneous optimization of wheel loader trajectory and the component transients is shown via a side to side comparison between measured fuel consumption and trajectories versus optimal control results.

In another application, optimal control is used to calculate efficient gear shift controls for a heavy duty Automatic Transmission system. A modeling and optimal control framework is developed for a nine speed automatic transmission. Solving optimal control problems using the developed model, time and jerk efficient transient for simultaneous disengagement of off-going and engagement of in-coming shift actuators are obtained and the results are analyzed.

Optimal controls of a diesel-electric powertrain during a gear shift in an Automated Manual Transmission system are calculated and analyzed in another application of optimal control. The powertrain model is extended by including driveline backlash angle as an extra state in the system. This is enabled by implementation of smoothing techniques in order to describe backlash dynamics as a single continuous function during all gear shift phases.

Optimal controls are also calculated for a diesel-electric powertrain corresponding to a hybrid bus during a tip-in maneuver. It is shown that for optimal control analysis of complex powertrain systems, minimizing only one property such as time pushes the system transients into extreme operating conditions far from what is achievable in real applications. Multi-objective optimal control problem formulations are suggested in order to obtain a compromise between various objectives when analyzing such complex powertrain systems.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2016. 27 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1771
Keyword
Powertrain, transmission system, optimal control, modeling for control
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-128002 (URN)10.3384/diss.diva-128002 (DOI)978-91-7685-748-9 (Print) (ISBN)
Public defence
2016-06-17, Visionen, Ingång 27, B huset, Campus Valla, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2016-05-30 Created: 2016-05-16 Last updated: 2016-05-31Bibliographically approved

Open Access in DiVA

The full text will be freely available from 2017-12-24 10:39
Available from 2017-12-24 10:39

Other links

Publisher's full text

Search in DiVA

By author/editor
Nezhadali, VaheedEriksson, Lars
By organisation
Vehicular SystemsFaculty of Science & Engineering
In the same journal
Control Engineering Practice
Electrical Engineering, Electronic Engineering, Information Engineering

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 177 hits
ReferencesLink to record
Permanent link

Direct link