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Holmberg, Ulf
Publications (10 of 23) Show all publications
Lidström, K., Sjöberg, K., Holmberg, U., Andersson, J., Bergh, F., Bjäde, M. & Mak, S. (2012). A modular CACC system integration and design. IEEE transactions on intelligent transportation systems (Print), 13(3), 1050-1061
Open this publication in new window or tab >>A modular CACC system integration and design
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2012 (English)In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 13, no 3, p. 1050-1061Article in journal (Refereed) Published
Abstract [en]

This paper describes the Halmstad University entry in the Grand Cooperative Driving Challenge, which is a competition in vehicle platooning. Cooperative platooning has the potential to improve traffic flow by mitigating shock wave effects, which otherwise may occur in dense traffic. A longitudinal controller that uses information exchanged via wireless communication with other cooperative vehicles to achieve string-stable platooning is developed. The controller is integrated into a production vehicle, together with a positioning system, communication system, and human–machine interface (HMI). A highly modular system architecture enabled rapid development and testing of the various subsystems. In the competition, which took place in May 2011 on a closed-off highway in The Netherlands, the Halmstad University team finished second among nine competing teams.

Place, publisher, year, edition, pages
Piscataway: IEEE Press, 2012
Keywords
Cooperative adaptive cruise control, grand cooperative driving challenge, platooning
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:hh:diva-19506 (URN)10.1109/TITS.2012.2204877 (DOI)000312805000007 ()2-s2.0-84863773935 (Scopus ID)
Available from: 2012-09-07 Created: 2012-09-07 Last updated: 2018-03-22Bibliographically approved
Svensson, W. & Holmberg, U. (2010). Estimating Ground Inclination Using Strain Sensors with Fourier Series Representation. Journal of Robotics, 2010, 1-8
Open this publication in new window or tab >>Estimating Ground Inclination Using Strain Sensors with Fourier Series Representation
2010 (English)In: Journal of Robotics, ISSN 1687-9600, Vol. 2010, p. 1-8Article in journal (Refereed) Published
Abstract [en]

An embedded measurement system for foot orthosis during gait is proposed. Strain gauge sensors were mounted on a foot orthosis to give information about strain in the sagittal plane. The ankle angle of the orthosis was fixed and strain characteristics were therefore changed when walking on slopes. With a Fourier series representation of the strain during a gait cycle, ground angle at different walking speeds and inclinations could be estimated with similar accuracy as previous studies using kinematically based estimators. Furthermore, if the angle of the mechanical foot ankle was changed, the sensing technique still could estimate ground angle without need for recalibration as opposed to kinematical sensors. This indicates that embedded strain sensors can be used for online control of future orthoses with inclination adaptation. Also, there would be no need to recalibrate the sensing system when changing shoes with different heel heights.

Place, publisher, year, edition, pages
New York: Hindawi Publishing Corporation, 2010
Keywords
Estimation, Strain sensors, Fourier series, Ground inclination, Orthorsis
National Category
Signal Processing
Identifiers
urn:nbn:se:hh:diva-4295 (URN)10.1155/2010/465618 (DOI)
Note

Article ID: 465618

Available from: 2010-04-20 Created: 2010-04-19 Last updated: 2018-03-23Bibliographically approved
Svensson, W. & Holmberg, U. (2008). Ankle-Foot-Orthosis Control in Inclinations and Stairs. In: 2008 IEEE Conference on Robotics, Automation and Mechatronics. Paper presented at Robotics, Automation and Mechatronics, 2008 IEEE Conference on, Chengdu, PEOPLES Rep. CHINA, 21-24 Sept. 2008 (pp. 301-306). Piscataway, N.J.: IEEE Press
Open this publication in new window or tab >>Ankle-Foot-Orthosis Control in Inclinations and Stairs
2008 (English)In: 2008 IEEE Conference on Robotics, Automation and Mechatronics, Piscataway, N.J.: IEEE Press, 2008, p. 301-306Conference paper, Published paper (Refereed)
Abstract [en]

A control procedure is proposed for an ankle-footorthosis (AFO) for different gait situations, such as inclinations and stairs. This paper presents a novel AFO control of the ankle angle. A magneto-rheological damper was used to achieve ankle damping during foot down and locking at swing, thereby avoiding foot slap as well as foot drop.

The controller used feedback from the ankle angle only. Still it was capable of not only adjusting damping within a gait step but also changing control behavior depending on level walking, ascending and descending stairs. As a consequence, toe strike was possible in stair gait as opposed to heel strike in level walking.

Tests verified the expected behavior in stair gait and in level walking where gait speed and ground inclinations varied. The self-adjusted AFO is believed to improve gait comfort in slopes and stairs.

Place, publisher, year, edition, pages
Piscataway, N.J.: IEEE Press, 2008
Keywords
gait control, orthosis, stair walking, magneto-rheological damper
National Category
Control Engineering
Identifiers
urn:nbn:se:hh:diva-2128 (URN)10.1109/RAMECH.2008.4681479 (DOI)000269060400158 ()2-s2.0-58049120348 (Scopus ID)2082/2523 (Local ID)978-1-4244-1676-9 (ISBN)2082/2523 (Archive number)2082/2523 (OAI)
Conference
Robotics, Automation and Mechatronics, 2008 IEEE Conference on, Chengdu, PEOPLES Rep. CHINA, 21-24 Sept. 2008
Note

©2008 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

Available from: 2008-11-12 Created: 2008-11-12 Last updated: 2018-03-23Bibliographically approved
Byttner, S. & Holmberg, U. (2008). Closed-loop control of EGR using ion currents. In: L. Bruzzone (Ed.), Proceedings of the 27th IASTED International Conference on Modelling, Identification, and Control, MIC. Paper presented at 27th IASTED International Conference on Modelling, Identification, and Control, 11-13 February, 2008, Innsbruck, Austria (pp. 7). Anaheim: ACTA Press
Open this publication in new window or tab >>Closed-loop control of EGR using ion currents
2008 (English)In: Proceedings of the 27th IASTED International Conference on Modelling, Identification, and Control, MIC / [ed] L. Bruzzone, Anaheim: ACTA Press, 2008, p. 7-Conference paper, Published paper (Refereed)
Abstract [en]

Two virtual sensors are proposed that use the spark-plug based ion current sensor for combustion engine control. The first sensor estimates combustion variability for the purpose of controlling exhaust gas recirculation (EGR) and the second sensor estimates the pressure peak position for control of ignition timing. Use of EGR in engines is important because the technique can reduce fuel consumption and NOx emissions, but recirculating too much can have the adverse effect with e.g. increased fuel consumption and poor driveability of the vehicle. Since EGR also affects the phasing of the combustion (because of the diluted gas mixture with slower combustion) it is also necessary to control ignition timing otherwise efficiency will be lost. The combustion variability sensor is demonstrated in a closed-loop control experiment of EGR on the highway and the pressure peak sensor is shown to handle both normal and an EGR condition.

Place, publisher, year, edition, pages
Anaheim: ACTA Press, 2008
Keywords
ion currents, virtual sensing, electronic engine control, exhaust gas recirculation, ignition timing, combustion variability
National Category
Control Engineering
Identifiers
urn:nbn:se:hh:diva-1861 (URN)2-s2.0-77955173650 (Scopus ID)2082/2256 (Local ID)978-0-88986-711-6 (ISBN)978-0-88986-712-3 (ISBN)2082/2256 (Archive number)2082/2256 (OAI)
Conference
27th IASTED International Conference on Modelling, Identification, and Control, 11-13 February, 2008, Innsbruck, Austria
Note

Sponsors, the International Association of Science and Technology for Development (IASTED), Technical Committee on Modelling and Simulation, Technical Committee on Control, World Modelling and Simulation Forum (WMSF)

Available from: 2008-09-09 Created: 2008-09-09 Last updated: 2018-03-23Bibliographically approved
Svensson, W. & Holmberg, U. (2008). Ground angle estimator from an ankle foot orthosis based on strain sensing and Fourier series. In: IEEE International Conference on Mechatronics and Automation, 2008. ICMA 2008. Paper presented at IEEE International Conference on Mechatronics and Automation Location, Takamatsu, JAPAN, 5-8 August, 2008 (pp. 203-206). Piscataway, N.J.: IEEE Press
Open this publication in new window or tab >>Ground angle estimator from an ankle foot orthosis based on strain sensing and Fourier series
2008 (English)In: IEEE International Conference on Mechatronics and Automation, 2008. ICMA 2008, Piscataway, N.J.: IEEE Press, 2008, p. 203-206Conference paper, Published paper (Refereed)
Abstract [en]

A ground angle estimation technique for use on ankle-foot-orthosis AFO, during gait is proposed. Strain gauge sensors were mounted on a foot orthosis in order to give information about strain in the sagittal plane. The ankle angle of the orthosis was fixed. Strain characteristics were therefore changed when walking on slopes. It was investigated if strain information could be used for detection of inclination and estimation of inclination angle. With a Fourier series representation of the strain during a gait cycle, ground angle at different walking speeds and inclinations could be estimated with similar accuracy as previous studies using kinematically based estimators. This indicates that embedded strain sensors can be used for online control of future orthoses with inclination adaptation.

Place, publisher, year, edition, pages
Piscataway, N.J.: IEEE Press, 2008
Keywords
Fourier series, ankle foot orthosis, gait cycle, ground angle estimation, strain gauge sensors
National Category
Control Engineering
Identifiers
urn:nbn:se:hh:diva-1789 (URN)10.1109/ICMA.2008.4798752 (DOI)000267671500037 ()2-s2.0-65349119316 (Scopus ID)2082/2184 (Local ID)978-1-4244-2632-4 (ISBN)2082/2184 (Archive number)2082/2184 (OAI)
Conference
IEEE International Conference on Mechatronics and Automation Location, Takamatsu, JAPAN, 5-8 August, 2008
Note

©2008 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

Available from: 2008-08-21 Created: 2008-08-21 Last updated: 2018-03-23Bibliographically approved
Svensson, W., Salomonsson, T. & Holmberg, U. (2007). Foot orthosis strain sensing in hill walking. In: ICORR '07: 2007 IEEE 10th International Conference on Rehabilitation Robotics : June 12-15, Noordwijk, The Netherlands. Paper presented at 10th International Conference on Rehabilitation Robotics, June 12-15, Noordwijk, The Netherlands (pp. 700-703). Piscataway, N.J.: IEEE Press
Open this publication in new window or tab >>Foot orthosis strain sensing in hill walking
2007 (English)In: ICORR '07: 2007 IEEE 10th International Conference on Rehabilitation Robotics : June 12-15, Noordwijk, The Netherlands, Piscataway, N.J.: IEEE Press, 2007, p. 700-703Conference paper, Published paper (Refereed)
Abstract [en]

An embedded measurement system for foot orthosis during gait is proposed. In this paper strain gauge sensors are mounted on a foot orthosis in order to give information about strain in the sagital plane. The ankle angle of the orthosis is fixed. Strain characteristics are therefore changed when walking on slopes. It is investigated if strain information can be used for detection of inclination and estimation of inclination angle. Also walking speed influence is studied. It is shown that strain sensing only gives significant information about up hill walking. At a known walking speed ground angle can be estimated for up hill walking.

Place, publisher, year, edition, pages
Piscataway, N.J.: IEEE Press, 2007
Series
International Conference on Rehabilitation Robotics ICORR, ISSN 1945-7898
Keywords
strain sensing, orthosis, embedded measurement system, hill walking, foot orthosis, strain gauge sensors
National Category
Control Engineering
Identifiers
urn:nbn:se:hh:diva-1800 (URN)10.1109/ICORR.2007.4428502 (DOI)000255389600105 ()2-s2.0-48349108993 (Scopus ID)2082/2195 (Local ID)978-1-4244-1320-1 (ISBN)2082/2195 (Archive number)2082/2195 (OAI)
Conference
10th International Conference on Rehabilitation Robotics, June 12-15, Noordwijk, The Netherlands
Note

©2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

Available from: 2008-08-27 Created: 2008-08-27 Last updated: 2018-03-23Bibliographically approved
Svensson, W. & Holmberg, U. (2007). Stair Gait Classification from Kinematic Sensors. In: Sashi S. Kommu (Ed.), Rehabilitation Robotics (pp. 523-534). Wien: I-Tech Education and Publishing KG
Open this publication in new window or tab >>Stair Gait Classification from Kinematic Sensors
2007 (English)In: Rehabilitation Robotics / [ed] Sashi S. Kommu, Wien: I-Tech Education and Publishing KG, 2007, p. 523-534Chapter in book (Other academic)
Abstract [en]

Gait measurement is of interest for both orthopedists and biomechanical engineers. It is useful for analysis of gait disorders and in design of orthotic and prosthetic devices.

In this chapter an algorithm is presented to suit estimation of one foot angle in the sagital plane, independent on gait conditions. Only one gyro is used during swing and two accelerometers are needed for calibration during stance. Also, the sensor placement at the front foot avoids the need for heel strike for stance transition. Stair walking can therefore be studied. From the estimated swing trajectory three different gait conditions: up stair, horizontal and down stair are classified.

Place, publisher, year, edition, pages
Wien: I-Tech Education and Publishing KG, 2007
Keywords
Stair gait classification, kinematic sensors
National Category
Control Engineering
Identifiers
urn:nbn:se:hh:diva-1797 (URN)2082/2192 (Local ID)978-3-902613-01-1 (ISBN)2082/2192 (Archive number)2082/2192 (OAI)
Note

Abstracting and non-profit use of the material is permitted with the credit to the source. After this work has been published by the I-Tech Education and Publishing, authors have the right to republish it, in whole or part, in any publication of which they are an author or editor, and the make other personal use of the work. (www.ars-journal.com)

Available from: 2008-08-27 Created: 2008-08-27 Last updated: 2018-03-23Bibliographically approved
Petersson, D., Johansson, J., Holmberg, U. & Åstrand, B. (2007). Torque Sensor Free Power Assisted Wheelchair. In: ICORR '07: 2007 IEEE 10th International Conference on Rehabilitation Robotics : June 12-15, Noordwijk, The Netherlands. Paper presented at 10th International Conference on Rehabilitation Robotics, June 12-15, Noordwijk, The Netherlands (pp. 151-157). Piscataway, N.J.: IEEE Press
Open this publication in new window or tab >>Torque Sensor Free Power Assisted Wheelchair
2007 (English)In: ICORR '07: 2007 IEEE 10th International Conference on Rehabilitation Robotics : June 12-15, Noordwijk, The Netherlands, Piscataway, N.J.: IEEE Press, 2007, p. 151-157Conference paper, Published paper (Refereed)
Abstract [en]

A power assisted wheelchair combines human power, which is delivered by the arms through the pushrims, with electrical motors, which are powered by a battery. Todays electric power assisted wheelchairs use force sensors to measure the torque exerted on the pushrims by the user. This leads to rather expensive and clumsy constructions. A new design, which only relies on velocity feedback, thus avoiding the use of expensive force sensors in the pushrims, is proposed in this paper. The control design is based on a simple PD-structure with only two design parameters easily tuned to fit a certain user; one parameter is used to adjust the amplification of the user’s force and the other one is used to change the lasting time of the propulsion influence. Since the new assisting control system only relies on the velocity, the torque sensor free power assisted wheelchair will besides giving the user assisting power also give an assistant, which pushes the wheelchair, additional power. This is a big advantage compared to the pushrim activated one, where this benefit for the assistant is not possible.

Place, publisher, year, edition, pages
Piscataway, N.J.: IEEE Press, 2007
Series
International Conference on Rehabilitation Robotics ICORR, ISSN 1945-7898
Keywords
wheelchair, power assist, electric power assisted wheelchairs, velocity feedback, torque sensor, force sensors
National Category
Control Engineering
Identifiers
urn:nbn:se:hh:diva-1799 (URN)10.1109/ICORR.2007.4428421 (DOI)000255389600024 ()2-s2.0-48349125718 (Scopus ID)2082/2194 (Local ID)978-1-4244-1320-1 (ISBN)2082/2194 (Archive number)2082/2194 (OAI)
Conference
10th International Conference on Rehabilitation Robotics, June 12-15, Noordwijk, The Netherlands
Note

©2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

Available from: 2008-08-27 Created: 2008-08-27 Last updated: 2018-03-23Bibliographically approved
Svensson, W. & Holmberg, U. (2006). An Autonomous Control System for a Prosthetic Foot Ankle. In: 4th IFAC Symposium on Mechatronic Systems (2006). Paper presented at 4th IFAC Symposium on Mechatronic Systems, 12 - 14 september, 2006, Ruprecht-Karls-University, Germany (pp. 856-861). International Federation of Automatic Control (IFAC)
Open this publication in new window or tab >>An Autonomous Control System for a Prosthetic Foot Ankle
2006 (English)In: 4th IFAC Symposium on Mechatronic Systems (2006), International Federation of Automatic Control (IFAC) , 2006, p. 856-861Conference paper, Published paper (Refereed)
Abstract [en]

When walking on inclined ground the biological foot adjusts the ankle angle accordingly. Prosthetic foot users have often a limited range of motion in their ankle which makes walking on hills uncomfortable. This paper describes a system which can autonomously correct the ankle angle to the inclination. The ground angle is estimated using an accelerometer. The angle foot blade to heel is then adjusted with a DC-motor. Since the controller only activates the motor when the foot is lifted and thus not loaded, a small powered system can be used.

Place, publisher, year, edition, pages
International Federation of Automatic Control (IFAC), 2006
Series
Mechatronic Systems ; vol. 4, part 1
Keywords
accelerometers, hill climbing, walking, actuator, adaptive system
National Category
Control Engineering
Identifiers
urn:nbn:se:hh:diva-1798 (URN)2082/2193 (Local ID)978-3-902661-17-3 (ISBN)2082/2193 (Archive number)2082/2193 (OAI)
Conference
4th IFAC Symposium on Mechatronic Systems, 12 - 14 september, 2006, Ruprecht-Karls-University, Germany
Note

Preprints of the 4th IFAC-Symposium on Mechatronics Systems. Copyright © 2006 International Federation of Automatic Control (IFAC). All rights reserved. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional pruposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from IFAC. For technical support please contact Transfer GmbH.

Available from: 2008-08-27 Created: 2008-08-27 Last updated: 2018-03-23Bibliographically approved
Svensson, W. & Holmberg, U. (2005). Foot and ground measurement using portable sensors. In: 2005 IEEE 9th International Conference on Rehabilitation Robotics: Chicago, IL, 28 June - 1 July 2005. Paper presented at IEEE 9th International Conference on Rehabilitation Robotics, June 28-July 01, 2005, Chicago, IL (pp. 448-451). Piscataway, N.J.: IEEE Press
Open this publication in new window or tab >>Foot and ground measurement using portable sensors
2005 (English)In: 2005 IEEE 9th International Conference on Rehabilitation Robotics: Chicago, IL, 28 June - 1 July 2005, Piscataway, N.J.: IEEE Press, 2005, p. 448-451Conference paper, Published paper (Refereed)
Abstract [en]

A portable gait measurement system for foot dynamic analysis is proposed. Portable cheap sensors are suitable in active control rehabilitation equipments such as prostheses and orthoses. A system of one gyroscope and two accelerometers was used to measure the foot movement in the sagital plane. Both ground inclination during stance and foot angle relative to ground during swing are estimated. This enables fast detection of changing environments such as hills and stairs.

Place, publisher, year, edition, pages
Piscataway, N.J.: IEEE Press, 2005
Series
International Conference on Rehabilitation Robotics ICORR, ISSN 1945-7898
Keywords
Computer simulation, Image sensors, Object recognition, Orthopedics, Portable equipment, Prosthetics, Sensory feedback
National Category
Engineering and Technology
Identifiers
urn:nbn:se:hh:diva-18727 (URN)000233375400102 ()2-s2.0-33745790480 (Scopus ID)0-7803-9003-2 (ISBN)
Conference
IEEE 9th International Conference on Rehabilitation Robotics, June 28-July 01, 2005, Chicago, IL
Note

Article number 1501139

Category number EX1028

Code 67638

Available from: 2012-10-16 Created: 2012-06-25 Last updated: 2018-03-22Bibliographically approved
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