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On Active Secondary Suspension in Rail Vehicles to Improve Ride Comfort
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

One way to make rail vehicles a competitive means of transportation is to increase running speed. However, higher speeds usually generate increased forces and accelerations on the vehicle, which have a negative effect on ride comfort. With conventional passive suspension, it may be difficult to maintain acceptable passenger comfort. Therefore, active technology in the secondary suspension can be implemented to improve, or at least maintain, ride comfort at increased vehicle speeds or when track conditions are unfavourable.

This thesis describes the development of an active secondary suspension concept to improve ride comfort in a high-speed train. Firstly, an active lateral secondary suspension system (ALS) was developed, including dynamic control of the lateral and yaw modes of the carbody. Furthermore, quasi-static lateral carbody control was included in the suspension system in order to laterally centre the carbody above the bogies in curves at high track plane acceleration and hence to avoid bumpstop contact. By means of simulations and on-track tests, it is shown that the ALS system can offer significant lateral ride comfort improvements compared to a passive system.

Two different control strategies have been studied—the relatively simple sky-hook damping and the multi-variable H∞ control—using first a quarter-car and then a full-scale vehicle model. Simulation results show that significant ride comfort improvements can be achieved with both strategies compared to a passive system. Moreover, H∞ control in combination with the carbody centring device is better at reducing the relative lateral displacement in transition curves compared to sky-hook damping.

Secondly, an active vertical secondary suspension system (AVS) was developed, using simulations. Dynamic control of the vertical and roll modes of the carbody, together with quasi-static roll control of the carbody, show significant vertical ride comfort improvements and allow higher speeds in curves. Further, the AVS system compensates for negative ride comfort effects if the structural stiffness of the carbody is reduced and if the vertical air spring stiffness is increased.

Finally, the two active suspension systems (ALS and AVS) were combined in simulations. The results show that both lateral and vertical ride comfort is improved with the active suspension concept at a vehicle speed of 250 km/h, compared to the passive system at 200 km/h. Further, active suspension in one direction does not affect the other direction. The ALS system has been included in two recent orders comprising more than 800 cars.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2011. , 36 p.
Series
Trita-AVE, ISSN 1651-7660 ; 2011:79
Keyword [en]
rail vehicle, active secondary suspension, ride comfort, sky-hook damping, H∞ control, multi-body simulations, on-track tests
National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Gröna tåget; Järnvägsgruppen - Fordonsteknik
Identifiers
URN: urn:nbn:se:kth:diva-49880ISBN: 978-91-7501-155-4 (print)OAI: oai:DiVA.org:kth-49880DiVA: diva2:460526
Public defence
2011-12-16, E2, Lindstedtsvägen 3, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Projects
Gröna Tåget
Note
QC 20111205Available from: 2011-12-05 Created: 2011-11-30 Last updated: 2012-03-21Bibliographically approved
List of papers
1. On-track tests with active lateral secondary suspension: a measure to improve ride comfort
Open this publication in new window or tab >>On-track tests with active lateral secondary suspension: a measure to improve ride comfort
2008 (English)In: ZEV Rail Glasers Annalen, ISSN 1618-8330, Vol. 132, no 11-12, 469-477 p.Article in journal (Refereed) Published
Abstract [en]

At increased rail vehicle speed it may be difficult to maintain acceptable passenger ride comfort with conventional passive secondary suspension. This paper presents the development of an active secondary suspension that provides good ride comfort improvements, but still at an acceptable cost level to enable future implementation. On-track tests have been performed with a two-car Regina train, using electro-hydraulic actuators together with sky-hook damping control and a Hold-Off-Device function to actively control the secondary suspension. The evaluated measurement results show that the active suspension system significantly reduces the lateral dynamic carbody motions and the lateral quasi-static displacements between carbody and bogies in curves, which improves the ride comfort and allows higher speeds, particularly in curves.

Keyword
Suspensions (components), Vehicle suspensions
National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Gröna tåget
Identifiers
urn:nbn:se:kth:diva-10442 (URN)2-s2.0-58049159501 (Scopus ID)
Note
QC 20101027Available from: 2009-05-14 Created: 2009-05-14 Last updated: 2011-12-05Bibliographically approved
2. Ride comfort improvements in a high-speed train with active secondary suspension
Open this publication in new window or tab >>Ride comfort improvements in a high-speed train with active secondary suspension
2010 (English)In: Journal of Mechanical Systems for Transportation and Logistics, ISSN 1882-1782, Vol. 3, no 1, 206-215 p.Article in journal (Refereed) Published
Abstract [en]

A combination of increased vehicle speeds and non-improved railway tracks may have a negative impact on passenger comfort. Active technology can replace the conventional passive solution of the secondary suspension of a rail vehicle in order to maintain good passenger comfort even when vehicle speed is increased and track conditions are inferior. This paper focuses on the benefits of using a so-called Hold-Off-Device (HOD) function in the lateral secondary suspension. On-track tests have been performed with the active secondary suspension concept implemented in a two-car Regina train during the summers of 2007 and 2008. The evaluated measurement results have been very satisfactory and the device will be implemented in long-term tests in service operation. These tests were carried out in the beginning of 2009.

Keyword
Active Suspension, Hold-Off-Device, Ride Comfort, On-Track Tests
National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Gröna tåget
Identifiers
urn:nbn:se:kth:diva-10443 (URN)10.1299/jmtl.3.206 (DOI)
Note
QC 20101027Available from: 2009-05-14 Created: 2009-05-14 Last updated: 2011-12-05Bibliographically approved
3. Development and test of active secondary suspension in a rail vehicle
Open this publication in new window or tab >>Development and test of active secondary suspension in a rail vehicle
2009 (English)In: Proceedings of the 21st International Symposium: Dynamics of Vehicles on Roads and Tracks, 2009Conference paper, Published paper (Other academic)
Abstract [en]

This paper deals with a quarter-car rail vehicle model using active lateral secondary suspension. H control theory is applied to the active suspension with the purpose of improving the dynamic performance of the vehicle. In H control, weight functions are applied to certain signals in order to design the controller. Different combinations of signal weighting have been evaluated through simulations. The main goal is to minimise the carbody acceleration and hence improve ride comfort. Furthermore, the H control theory is compared to sky-hook damping, which has been used in previous studies by the authors. Simulation results show that both control methods significantly improve the ride comfort as compared to a passive case. Compared to sky-hook damping, H control provides more flexibility in the design process due to the possibility to control several parameters. Furthermore, H control generates similar carbody accelerations at the same control force as sky-hook damping; however, the relative displacement is somewhat lower with H control.

National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Gröna tåget
Identifiers
urn:nbn:se:kth:diva-10444 (URN)
Conference
21st International Symposium on Dynamics of Vehicles on Roads and Tracks. Stockholm, Sweden, 17-21 August 2009
Note
QC 20101027Available from: 2009-05-14 Created: 2009-05-14 Last updated: 2011-12-05Bibliographically approved
4. Active Lateral Secondary Suspension with H∞ Control to Improve Ride Comfort: Simulations on a Full-Scale Model
Open this publication in new window or tab >>Active Lateral Secondary Suspension with H∞ Control to Improve Ride Comfort: Simulations on a Full-Scale Model
2011 (English)In: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 49, no 9, 1409-1422 p.Article in journal (Refereed) Published
Abstract [en]

In this study, a full-scale rail vehicle model is used to investigate how lateral ride comfort is influenced by implementing the H and sky-hook damping control strategies. Simulations show that significant ride comfort improvements can be achieved on straight track with both control strategies compared with a passive system. In curves, it is beneficial to add a carbody centring Hold-Off Device (HOD) to reduce large spring deflections and hence to minimise the risk of bumpstop contact. In curve transitions, the relative lateral displacement between carbody and bogie is reduced by the concept of H control in combination with the HOD. However, the corresponding concept with sky-hook damping degrades the effect of the carbody centring function. Moreover, it is shown that lateral and yaw mode separation is a way to further improve the performance of the studied control strategies.

Keyword
rail vehicle, active secondary suspension, ride comfort, simulations, full-scale model
National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Gröna tåget; Järnvägsgruppen - Fordonsteknik
Identifiers
urn:nbn:se:kth:diva-39472 (URN)10.1080/00423114.2010.527011 (DOI)000299561600003 ()2-s2.0-79960832886 (Scopus ID)
Funder
TrenOp, Transport Research Environment with Novel Perspectives
Note
QC 20110921Available from: 2011-09-09 Created: 2011-09-09 Last updated: 2017-12-08Bibliographically approved
5. Aspects of Using Active Vertical Secondary Suspension to Improve Ride Comfort
Open this publication in new window or tab >>Aspects of Using Active Vertical Secondary Suspension to Improve Ride Comfort
(English)In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017Article in journal (Other academic) Submitted
Abstract [en]

This paper presents various aspects of using active vertical secondary suspension in arail vehicle to improve ride comfort. Dynamic control of the vertical and roll modes ofthe carbody is achieved by means of actuators replacing the conventional vertical dampersin the secondary suspension. Active damping improves vertical ride comfort, compared toa passive system. Besides dynamic control, the actuators are able to generate quasi-staticroll control between the carbody and bogies in curves. This allows for higher speeds incurves, without negatively affecting ride comfort. Furthermore, the anti-roll bar is removedto reduce the number of components.

National Category
Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-48821 (URN)
Funder
TrenOp, Transport Research Environment with Novel Perspectives
Note

QCR 20161212

Available from: 2011-11-23 Created: 2011-11-23 Last updated: 2017-12-08Bibliographically approved
6. An Active Secondary Suspension Concept to Improve Lateral and Vertical Ride Comfort
Open this publication in new window or tab >>An Active Secondary Suspension Concept to Improve Lateral and Vertical Ride Comfort
(English)In: Journal of Computational and Nonlinear Dynamics, ISSN 1555-1415, E-ISSN 1555-1423Article in journal (Other academic) Submitted
Abstract [en]

This paper presents an active secondary suspension conceptfor lateral and vertical ride comfort improvement in arail vehicle. Dynamic control of the lateral, yaw and verticalcarbody modes is achieved by means of actuators replacingthe conventional lateral and vertical dampers in the secondarysuspension. Active damping significantly improveslateral and vertical ride comfort compared to a passive system.Besides dynamic control, the actuators can generatequasi-static lateral and roll control of the carbody. This allowsfor higher speeds in curves, without negatively affectingride comfort. Furthermore, the active suspension concept reducesthe influence on ride comfort caused by the air springstiffness. This means that the total air spring volume can bereduced.

National Category
Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-48823 (URN)
Note

QS 2011

Available from: 2011-11-30 Created: 2011-11-23 Last updated: 2017-12-08Bibliographically approved

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