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

Direct link
BETA
Åslund, Jan
Alternative names
Publications (10 of 57) Show all publications
Albrektsson, J. & Åslund, J. (2019). Fuel Optimal Control of an Articulated Hauler Utilising a Human Machine Interface. In: Donnellan, Brian; Klein, Cornel; Helfert, Markus; Gusikhin, Oleg; Pascoal, António (Ed.), Smart Cities, Green Technologies, and Intelligent Transport Systems: . Paper presented at 6th International Conference, SMARTGREENS 2017 and Third International Conference, VEHITS 2017, Porto, Portugal, April 22–24, 2017 (pp. 190-208). Springer International Publishing
Open this publication in new window or tab >>Fuel Optimal Control of an Articulated Hauler Utilising a Human Machine Interface
2019 (English)In: Smart Cities, Green Technologies, and Intelligent Transport Systems / [ed] Donnellan, Brian; Klein, Cornel; Helfert, Markus; Gusikhin, Oleg; Pascoal, António, Springer International Publishing , 2019, p. 190-208Conference paper, Published paper (Refereed)
Abstract [en]

Utilising optimal control presents an opportunity to increase the fuel efficiency in an off-road transport mission conducted by an articulated hauler. A human machine interface (HMI) instructing the hauler operator to follow the fuel optimal vehicle speed trajectory has been developed and tested in real working conditions. The HMI implementation includes a Dynamic Programming based method to calculate the optimal vehicle speed and gear shift trajectories. Input to the optimisation algorithm is road related data such as distance, road inclination and rolling resistance. The road related data is estimated in a map module utilising an Extended Kalman Filter (EKF), a Rauch-Tung-Striebel smoother and a data fusion algorithm. Two test modes were compared: (1) The hauler operator tried to follow the optimal vehicle speed trajectory as presented in the HMI and (2) the operator was given a constant target speed to follow. The objective of the second test mode is to achieve an approximately equal cycle time as for the optimally controlled transport mission, hence, with similar productivity. A small fuel efficiency improvement was found when the human machine interface was used.

Place, publisher, year, edition, pages
Springer International Publishing, 2019
Series
Communications in Computer and Information Science book series (CCIS), ISSN 1865-0929, E-ISSN 1865-0937 ; 921
Keywords
Off-road, Construction equipment, Human machine interface, Optimal control, Dynamic programming, Kalman filters
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:liu:diva-153311 (URN)10.1007/978-3-030-02907-4_10 (DOI)978-3-030-02906-7 (ISBN)978-3-030-02907-4 (ISBN)
Conference
6th International Conference, SMARTGREENS 2017 and Third International Conference, VEHITS 2017, Porto, Portugal, April 22–24, 2017
Available from: 2018-12-12 Created: 2018-12-12 Last updated: 2018-12-12
Albrektsson, J. & Åslund, J. (2018). Fuel optimal control of an off-road transport mission. In: 2018 IEEE International Conference on Industrial Technology (ICIT): . Paper presented at 2018 IEEE International Conference on Industrial Technology (ICIT), 19-22 Feb.,Lyon, France (pp. 175-180).
Open this publication in new window or tab >>Fuel optimal control of an off-road transport mission
2018 (English)In: 2018 IEEE International Conference on Industrial Technology (ICIT), 2018, p. 175-180Conference paper, Published paper (Refereed)
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-151856 (URN)10.1109/ICIT.2018.8352172 (DOI)978-1-5090-5949-2 (ISBN)
Conference
2018 IEEE International Conference on Industrial Technology (ICIT), 19-22 Feb.,Lyon, France
Available from: 2018-10-06 Created: 2018-10-06 Last updated: 2018-11-22
Nilsson, T., Fröberg, A. & Åslund, J. (2015). Development of look-ahead controller concepts for a wheel loader application: [Développement de concepts d’une commande prédictive, destinée à une application pour chargeur sur pneus]. Oil & gas science and technology, 70(1), 159-178
Open this publication in new window or tab >>Development of look-ahead controller concepts for a wheel loader application: [Développement de concepts d’une commande prédictive, destinée à une application pour chargeur sur pneus]
2015 (English)In: Oil & gas science and technology, ISSN 1294-4475, E-ISSN 1953-8189, Vol. 70, no 1, p. 159-178Article in journal (Refereed) Published
Abstract [en]

This paper presents two conceptual methods, based on dynamic programming, for one-step look-ahead control of a Continuously Variable Transmission (CVT) in a wheel loader. The first method developed, designated Stochastic Dynamic Programming (SDP), uses a statistical load prediction and stochastic dynamic programming for minimizing fuel use. The second method developed, designated Free-Time Dynamic Programming (FTDP), has vehicle speed as a state and introduces a fixed 0.1 s delay in the bucket controls in a combined minimization of fuel and time. The methods are evaluated using a set of 34 measured loading cycles, used in a ‘leave one out’ manner.

The evaluation shows that the SDP method requires about 1/10th of the computational effort of FTDP and has a more transparent impact of differences in the cycle prediction. The FTDP method, on the other hand, shows a 10% lower fuel consumption, which is close to the actual optimum, at the same cycle times, and is able to complete a much larger part of the evaluation cycles.

Abstract [fr]

Ce document présente deux méthodes de conception, basées sur la programmation dynamique, pour la commande à un pas de prédiction d’une transmission continûment variable (Continuously Variable Transmission, CVT) d’un chargeur sur pneus. La première méthode développée, appelée programmation dynamique stochastique (Stochastic Dynamic Programming, SDP) utilise une prédiction statistique de la charge et la programmation dynamique stochastique pour minimiser l’utilisation de carburant. La seconde méthode développée, appelée programmation dynamique à temps libre (Free-Time Dynamic Programming, FTDP), établit la vitesse du véhicule en tant qu’état et introduit un retard de 0:1 s dans les commandes du godet pour minimiser à la fois l’utilisation de carburant et le temps nécessaire à l’opération.

Les méthodes sont évaluées en s’appuyant sur 34 cycles de chargement mesurés, utilisés selon la méthode de validation croisée « leave-one-out ».

L’évaluation montre que la méthode SDP requiert environ 1 dixième de l’effort de calcul de la méthode FTDP, et qu’elle a un impact plus transparent sur les écarts dans la prédiction du cycle. D’un autre côté, avec la méthode FTDP on obtient une réduction de 10% de la consommation de carburant, ce qui est proche de l’optimum réel, pour les mêmes durées de cycle, et elle permet de réaliser une plus grande partie des cycles d’évaluation.

Place, publisher, year, edition, pages
EDITIONS TECHNIP, 2015
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-112719 (URN)10.2516/ogst/2014022 (DOI)000351444400011 ()
Available from: 2014-12-09 Created: 2014-12-09 Last updated: 2017-12-05
Nilsson, T., Fröberg, A. & Åslund, J. (2015). Predictive control of a diesel electric wheel loader powertrain. Control Engineering Practice, 41, 47-56
Open this publication in new window or tab >>Predictive control of a diesel electric wheel loader powertrain
2015 (English)In: Control Engineering Practice, ISSN 0967-0661, E-ISSN 1873-6939, Vol. 41, p. 47-56Article in journal (Refereed) Published
Abstract [en]

Wheel loaders often have a highly repetitive pattern of operation, which can be used for creating a rough prediction of future operation. As the present torque converter based transmission is replaced with an infinitely variable device, such as an electric or hydraulic transmission, a freedom in the choice of engine speed is introduced. This choice is far from trivial in the extremely transient operation of these machines, but the availability of a load prediction should be utilized.

In this paper, a predictive engine and generator controller, based on stochastic dynamic programming, is described, implemented and evaluated. The evaluation is performed against non-predictive controllers in the same system, to lift out any possible benefits of utilizing the repetition based prediction. Simulations and field tests show that the controllers are able to handle disturbances introduced from model errors, the machine environment and the human operator, and that the predictive controller gives around 5% lower fuel consumption than the non-predictive reference controllers.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Diesel engine; Continuously variable transmission; Predictive control; Stochastic dynamic programming
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-112891 (URN)10.1016/j.conengprac.2015.04.008 (DOI)000357546200005 ()
Available from: 2014-12-19 Created: 2014-12-19 Last updated: 2017-12-05Bibliographically approved
Larsson, E., Åslund, J., Frisk, E. & Eriksson, L. (2014). Gas Turbine Modeling for Diagnosis and Control. Journal of engineering for gas turbines and power, 136(7), 071601
Open this publication in new window or tab >>Gas Turbine Modeling for Diagnosis and Control
2014 (English)In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 136, no 7, p. 071601-Article in journal (Refereed) Published
Abstract [en]

The supervision of performance in gas turbine applications is crucial in order to achieve: (i) reliable operations, (ii) low heat stress in components, (iii) low fuel consumption, and (iv) efficient overhaul and maintenance. To obtain a good diagnosis of performance it is important to have tests which are based on models with high accuracy. A main contribution is a systematic design procedure to construct a fault detection and isolation (FDI) system for complex nonlinear models. To fulfill the requirement of an automated design procedure, a thermodynamic gas turbine package (GTLib) is developed. Using the GTLib framework, a gas turbine diagnosis model is constructed where component deterioration is introduced. In the design of the test quantities, equations from the developed diagnosis model are carefully selected. These equations are then used to implement a constant gain extended Kalman filter (CGEKF)-based test quantity. The test quantity is used in the FDI-system to supervise the performance and in the controller to estimate the flame temperature. An evaluation is performed using experimental data from a gas turbine site. The case study shows that the designed FDI-system can be used when the decision about a compressor wash is taken. Thus, the proposed model-based design procedure can be considered when an FDI-system of an industrial gas turbine is constructed.

Place, publisher, year, edition, pages
American Society of Mechanical Engineers (ASME), 2014
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-109175 (URN)10.1115/1.4026598 (DOI)000337938700008 ()
Available from: 2014-08-12 Created: 2014-08-11 Last updated: 2018-01-30Bibliographically approved
Nilsson, T., Fröberg, A. & Åslund, J. (2014). Minimizing Fuel Use During Power Transients for Naturally Aspirated and Turbo Charged Diesel Engines.
Open this publication in new window or tab >>Minimizing Fuel Use During Power Transients for Naturally Aspirated and Turbo Charged Diesel Engines
2014 (English)Report (Other academic)
Abstract [en]

Recent development has renewed the interest in drivetrain concepts which gives a higher degree offreedom by disconnecting the engine and vehicle speeds. This freedom raises the demand for activecontrol, which especially during transients is not trivial, but of which the quality is crucial for the successof the drivetrain concept. In this work the fuel optimal engine operating point trajectories for a naturallyaspirated and a turbocharged diesel engine, connected to a load which does not restrict the engine speed,is derived, analysed and utilized for finding a suboptimal operating point trajectory. The analysis andoptimization is made with dynamic programming, Pontryagin’s maximum principle and a suboptimalstrategy based on the static optimal operating points. Methods are derived for using Pontryagin’smaximum principle for finding the optimal operating point trajectories, for simple load cases. The timeneeded for computation is reduced a factor 1000−100, depending on engine layout, compared to dynamicprogramming. These methods are only applicable to very simple load cases though. Finally, a suboptimalcalculation method which reduce the time needed for computation a factor > 1000 compared to dynamicprogramming, while showing a < 5% increase in fuel consumption compared to the optimal, is presented.

Publisher
p. 13
Series
LiTH-ISY-R, ISSN 1400-3902 ; 3077
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-112720 (URN)LiTH-ISY-R-3077 (ISRN)
Available from: 2014-12-09 Created: 2014-12-09 Last updated: 2015-01-19Bibliographically approved
Lundahl, K., Olofsson, B., Berntorp, K., Åslund, J. & Nielsen, L. (2014). Towards Lane-Keeping Electronic Stability Control for Road-Vehicles. In: Boje, Edward, Xia, Xiaohua (Ed.), Proceedings of the 19th IFAC World Congress, 2014: . Paper presented at 19th IFAC World Congress, August 24-28, Cape Town, South Africa (pp. 6319-6325). International Federation of Automatic Control, 19
Open this publication in new window or tab >>Towards Lane-Keeping Electronic Stability Control for Road-Vehicles
Show others...
2014 (English)In: Proceedings of the 19th IFAC World Congress, 2014 / [ed] Boje, Edward, Xia, Xiaohua, International Federation of Automatic Control , 2014, Vol. 19, p. 6319-6325Conference paper, Published paper (Refereed)
Abstract [en]

The emerging new idea of lane-keeping electronic stability control is investigated. In a critical situation, such as entering a road curve at excessive speed, the optimal behavior may differ from the behavior of traditional ESC, for example, by prioritizing braking over steering response. The important question that naturally arises is if this has a significant effect on safety. The main contribution here is to give a method for some first quantitative measures of this. It is based on optimal control, applied to a double-track chassis model with wheel dynamics and high-fidelity tire-force modeling. The severity of accidents grows with the square of the kinetic energy for high velocities, so using kinetic energy as a measure will at least not overestimate the usefulness of the new safety system principle. The main result is that the safety gain is significant compared to traditional approaches based on yaw rotation, for several situations and different road-condition parameters.

Place, publisher, year, edition, pages
International Federation of Automatic Control, 2014
Series
World Congress, ISSN 1474-6670 ; Volume 19, Issue 1
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:liu:diva-127795 (URN)10.3182/20140824-6-ZA-1003.02578 (DOI)
Conference
19th IFAC World Congress, August 24-28, Cape Town, South Africa
Available from: 2016-05-12 Created: 2016-05-12 Last updated: 2016-05-25Bibliographically approved
Larsson, E., Åslund, J., Frisk, E. & Eriksson, L. (2013). Fault Tolerant Supervision of an Industrial Gas Turbine. In: Proceedings of ASME Turbo Expo: . Paper presented at ASME 2013 Turbo Expo: Turbine Technical Conference and Exposition (GT2013), June 3-7, 2013, San Antonio, Texas, USA..
Open this publication in new window or tab >>Fault Tolerant Supervision of an Industrial Gas Turbine
2013 (English)In: Proceedings of ASME Turbo Expo, 2013Conference paper, Published paper (Refereed)
Abstract [en]

Supervision of the performance of an industrial gas turbine is important since it gives valuable information of the process health and makes efficient determination of compressor wash intervals possible. Slowly varying sensor faults can easily be misinterpreted as performance degradations and result in an unnecessary compressor wash. Here, a diagnostic algorithm is carefully combined with non-linear state observers to achieve fault tolerant performance estimation. The proposed approach is evaluated in an experimental case study with six months of measurement data from a gas turbine site. The investigation shows that faults in all gas path instrumentation sensors are detectable and isolable. A key result of the case study is the ability to detect and isolate a slowly varying sensor fault in the discharge temperature sensor after the compressor. The fault is detected and isolated before the wash condition of the compressor is triggered, resulting in fault tolerant estimation of compressor health parameters.charge temperature sensor after the compressor. The fault is detected and isolated before the wash condition of the compressor is triggered, resulting in fault tolerant estimation of compressor health parameters.

National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-89299 (URN)10.1115/GT2013-95727 (DOI)978-0-7918-5518-8 (ISBN)
Conference
ASME 2013 Turbo Expo: Turbine Technical Conference and Exposition (GT2013), June 3-7, 2013, San Antonio, Texas, USA.
Available from: 2013-02-25 Created: 2013-02-25 Last updated: 2018-01-30
Nickmehr, N., Eriksson, L. & Åslund, J. (2013). Methodology for modeling, parameter estimation and validation of powertrain torsional vibration. In: The 54th SIMS conference on Simulation and Modelling: . Paper presented at The 54th SIMS conference on Simulation and Modelling, Bergen, Norway, October 16-18, 2013.
Open this publication in new window or tab >>Methodology for modeling, parameter estimation and validation of powertrain torsional vibration
2013 (English)In: The 54th SIMS conference on Simulation and Modelling, 2013Conference paper, Published paper (Refereed)
Abstract [en]

A vehicular powertrain is a lightly damped dynamic system that transfers the engine torque to the driving wheels through a number of inertias and elastic elements. Therefore, it is prone to vibrate and emit noise when disturbances are applied. Providing a methodology, for powertrain vibration modeling and simulation, is one of the key steps in various research topics in the field of automobile engineering. Verification of the engine crankshaft torsion and vibration model, as a subsystem of the powertrain, is proposed in this paper. This is achieved by constructing a rotational multi-body system in MATLAB and utilizing nonlinear least squares method for estimation of the model parameters. The simulated engine angular velocity is compared to the measured data, from a car, which shows a good agreement.

National Category
Vehicle Engineering
Identifiers
urn:nbn:se:liu:diva-137728 (URN)
Conference
The 54th SIMS conference on Simulation and Modelling, Bergen, Norway, October 16-18, 2013
Available from: 2017-06-02 Created: 2017-06-02 Last updated: 2018-01-30
Lundahl, K., Berntorp, K., Olofsson, B., Åslund, J. & Nielsen, L. (2013). Studying the Influence of Roll and Pitch Dynamics in Optimal Road-Vehicle Maneuvers. In: : . Paper presented at The 23rd International Symposium on Dynamics of Vehicles on Roads and Tracks, 19-23 August, Qingdao, China.
Open this publication in new window or tab >>Studying the Influence of Roll and Pitch Dynamics in Optimal Road-Vehicle Maneuvers
Show others...
2013 (English)Conference paper, Published paper (Other academic)
Abstract [en]

A comparative analysis shows how vehicle motion models of different complexity, capturing various characteristics, influence the solution when used in time-critical optimal maneuvering problems. Vehicle models with combinations of roll and pitch dynamics as well as load transfer are considered, ranging from a single-track model to a double-track model with roll and pitch dynamics and load transfer. The optimal maneuvers in a 90◦-turn and a double lane-change scenario are formulated as minimum-time optimization problems, and are solved using numerical optimization software. The results obtained with the different models show that variables potentially important for safety systems, such as the yaw rate, slip angle, and geometric path, are qualitatively the same. Moreover, the numeric differences are mostly within a few percent. The results also indicate that although input torques differ about 50–100 % for certain parts of the maneuver between the most and least complex model considered, the resulting vehicle motions obtained are similar, irrespective of the model. Our main conclusion isthat this enables the use of low-order models when designing the onboard optimization-based safety systems of the future.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-94205 (URN)
Conference
The 23rd International Symposium on Dynamics of Vehicles on Roads and Tracks, 19-23 August, Qingdao, China
Available from: 2013-06-18 Created: 2013-06-18 Last updated: 2013-06-18Bibliographically approved
Organisations

Search in DiVA

Show all publications