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  • 1.
    Andersson, E.
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Orvnäs, Anneli
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Persson, R.
    Passenger Trains Division, Bombardier Transportation, Västerås, Sweden.
    How to find a compromise between track friendliness and the ability to run at high speed2012In: Civil-Comp Proceedings, ISSN 1759-3433, Vol. 98Article in journal (Refereed)
    Abstract [en]

    When designing and optimizing a rail vehicle there is a contradiction between, on the one hand, stability on straight track at high speed and, on the other hand, reasonable wheel and rail wear in small- and medium-radius curves. This paper describes the process of developing and optimizing a track-friendly bogie. A simulation model has been used to investigate dynamic stability on straight track at high speeds along with the wheel and rail wear in sharper curves. The result is a bogie with relatively soft wheelset guidance allowing passive radial self-steering, which in combination with appropriate yaw damping ensures stability on straight track at higher speeds. This bogie has been tested according to EN 14363 at speeds up to about 300 km/h and in curves with radii ranging from 250 m and up. 

  • 2.
    Andersson, Evert
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Orvnäs, Anneli
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Persson, Rickard
    On the Optimization of a Track-Friendly Bogie for High Speed2009In: 21st International Symposium on Dynamics of Vehicles on Roads and Tracks, IAVSD'09, Stockholm, August 17-21, 2009., 2009Conference paper (Other academic)
    Abstract [en]

    When designing and optimizing a rail vehicle there is a contradiction between, on the one hand, stability on straight track at high speed and, on the other hand, reasonable wheel and rail wear in small- and medium radius curves. Higher speeds require to some extent stiffer wheelset guidance to avoid hunting and ensure stability. However, with stiffer wheelset guidance the risk of increased wheel and rail wear in curves is imminent. In this paper, the process of developing and optimizing a track-friendly bogie is described. A multi-body system (MBS) simulation model was used, taking due consideration to nonlinearities in suspension and wheel-rail contact, as well as realistic flexibilities in the track. Adequate and systematic consideration is taken to a wide range of possible non-linear wheel-rail combinations. Dynamic stability is investigated both on straight track and in wide curves at high speeds. The balance between flange wear and tread wear is studied in order to maximize wheel life between re-profiling operations in the intended average operation. The result is a bogie with relatively soft wheelset guidance allowing passive radial self-steering, which in combination with appropriate yaw damping ensures stability on straight track at higher speeds. The bogie has been subject to both certification testing and long-term service testing in the Gröna Tåget (the Green Train) research and development programme.

  • 3.
    Andersson, Evert
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Orvnäs, Anneli
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Persson, Rickard
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Radial self-steering bogies - Development, advantages and limitations2007In: ZE Vrail - Glasers Annalen: Zeitschrift fuer das gesamte System Bahn, ISSN 1618-8330, Vol. 131, no Suppl., p. 248-259Article in journal (Refereed)
    Abstract [en]

    Considering the total cost of railway operations, It is important to reduce the deterioration caused to the track by rail vehicles and vice versa. Radial steering running gear, where the wheelsets take up approximate radial positions in curves, is an important mean of reducing rail and wheel wear. They also allow curves to be negotiated at higher lateral acceleration on non-perfect track, without exceeding stipulated limits for lateral track shift forces. In order to run dynamically stable at high speed, the damping of the bogie must be appropriate, in particular the yaw damping between bogies and car body. Since the mid-1970's radial self-steering bogles have been developed and used in about 1 200 passenger rail vehicles in Scandinavia. This development continues and during 2006 a test train with radial self-steering bogies is run in speeds up till 281 km/h as part of the Swedish R&D program "GrönaTå get" (GreenTrain). Although there are limitations in the performance of passively self-steering bogles they are a simple and proven solution. Ultimately, In the future actively controlled radial steering may be considered asan appropriate mean to achieve higher performance and track-friendliness.

  • 4.
    Andersson, Evert
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Orvnäs, Anneli
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Persson, Rickard
    Radial Self-Steering Bogies: Recent Developments for High Speed2009In: 7th International Conference on Railway Bogies and Running Gears / [ed] István Zobory, 2009, p. 63-72Conference paper (Other academic)
    Abstract [en]

    Considering the total cost of railway operations, it is important to reduce the deterioration caused to the track by rail vehicles and vice versa. Radial steering running gear, where the wheelsets take up approximate radial positions in curves, is an important mean of reducing rail and wheel wear. They also allow curves to be negotiated at higher lateral acceleration on non-perfect track, without exceeding stipulated limits for lateral track shift forces. In order to run dynamically stable at high speed, the damping of the bogie must be appropriate, in particular the yaw damping between bogies and carbody. Radial self-steering bogies are used on more than 1200 rail passenger vehicles in Scandinavia since the early 1980’s. The maximum service speed of these vehicles ranges up to 210 km/h. Ongoing development seems to confirm that the use of such bogies can be extended into the very high-speed area of at least 250 km/h. There has previously been some scepticism on the feasibility of soft wheelset guidance for higher speeds, in particular with respect to running stability. Although there are some limitations in the performance of radial self-steering bogies, this solution is robust and well-proven since about 25 years. The ultimate future may be a mechatronic bogie, where the wheelsets are guided in the most optimal way through controlled and forced radial steering. Such bogies may be justified if performance is out of the possible range of passive self-steering solutions.

  • 5.
    Orvnäs, Anneli
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Active Lateral Secondary Suspension in a High-Speed Train to Improve Ride Comfort2009Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Active secondary suspension in trains has been studied for a number of years, showing promising improvements in ride comfort. However, due to relatively high implementation and maintenance costs, active technology is not being used in service operation to a large extent. The objective of this study is to develop an active lateral secondary suspension concept that offers good ride comfort improvements and enables centring of the carbody above the bogies when negotiating curves at unbalanced speed. Simultaneously, the active suspension concept should be a cost-effective solution for future series production. The thesis consists of an introductory part and three appended papers.

    The introductory part describes the concept of active secondary suspension together with different actuator types and control methods. Further, the present simulation model and applied comfort evaluation methods are presented. The introductory part also comprises a summary of the appended papers, an evaluation of track forces and suggestions for further work.

    Paper A presents the initial development of an active lateral secondary suspension concept based on sky-hook damping in order to improve vehicle dynamic performance, particularly on straight tracks. Furthermore, a Hold-Off-Device (HOD) function has been included in the suspension concept in order to centre the carbody above the bogies in curves and hence avoid bumpstop contact. Preparatory simulations as well as the subsequent on-track tests in the summer of 2007 showed that the active suspension provides improved passenger ride comfort and has significant potential to be a cost-effective solution for future implementation.

    In Paper B, measurement results from on-track tests performed in 2008 are presented. The active secondary suspension concept was slightly modified compared to the one presented in the first paper. One modification was the implementation of a gyroscope in order to enable detection of transition curves and to switch off the dynamic damping in these sections. Ride comfort in the actively suspended carbody was significantly improved compared to that in the passively suspended car. The satisfactory results led to implementation of the active suspension system in long-term tests in service operation in the beginning of 2009.

    In Paper C, a quarter-car model in MATLAB has been used to investigate a more advanced control algorithm: H instead of sky-hook. H control provides more flexibility in the design process due to the possibility to control several parameters. In particular, this is done by applying weight functions to selected signals in the system. When comparing the two control strategies through simulations, the results show that H control generates similar carbody accelerations at the same control force as sky-hook; however, the relative displacement displacement is somewhat lower.

  • 6.
    Orvnäs, Anneli
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Active Secondary Suspension in Trains: A Literature Survey of Concepts and Previous Work2008Report (Other academic)
  • 7.
    Orvnäs, Anneli
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Methods for Reducing Vertical Carbody Vibrations of a Rail Vehicle: A Literature Survey2010Report (Other academic)
    Abstract [en]

    The trend towards higher rail vehicle speeds generally results in increased vibrations in the carbody, which has a negative impact on ride comfort. Carbody vibrations can be reduced either by focusing on the structural stiffness of the system or by optimizing the damping components. When a conventional passive damping system cannot be further optimized, active components can be a solution to achieve improvements.

    Previous research concerning active control in rail vehicles to improve ride comfort show that significant benefits may be gained compared to a passive system. The overall goals are normally to improve, or at least maintain, ride comfort at increased vehicle speed or when running on tracks of inferior quality. Therefore, active suspension can be regarded as a cost-efficient solution if vehicle speed can be increased or track maintenance costs can be minimised. However, despite satisfactory results throughout the years, active suspension in rail vehicles has not yet made a convincing breakthrough in operational use. The main reason for the lack of success is most likely that the solutions offered so far have been too expensive in relation to the benefits gained.

    The purpose of this literature survey is to give an overview of previous studies regarding methods to passively or actively achieve vertical vibration reduction in a rail vehicle. The main focus is on active components.

  • 8.
    Orvnäs, Anneli
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    On Active Secondary Suspension in Rail Vehicles to Improve Ride Comfort2011Doctoral 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.

  • 9.
    Orvnäs, Anneli
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Simulation of Rail Wear on the Swedish Light Rail Line Tvärbanan2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Rail wear can result in extensive costs for the track owner if it is not predicted and preventedin an efficient way. To limit these costs, one measure is to predict rail wear through wear simulations. The purpose with this work is to perform simulations of successive rail wear on the Swedish light rail line Tvärbanan in Stockholm, by means of the track-vehicle dynamics software GENSYS in combination with a wear calculation program developed in MATLAB.

    The simulation procedure is based on a methodology with a simulation set design, where the simulations to be performed are selected through a parametric study. The simulations include track-vehicle simulations, where the wheel-rail contact is modelled according to the Hertzian contact theory together with Kalker’s simplified theory (including the numerical algorithm FASTSIM). The results from the track-vehicle simulations serve as input to the wear calculations. When modelling rail wear Archard’s wear model has been used, including wear coefficients based on laboratory measurements. The measurements have been performed under dry conditions, so the wear coefficients under lubricated conditions (both natural and deliberate lubrication) are reduced by factors estimated by field observations. After the wear depth calculations the wear distribution is smoothed and the rail profile is updated. The simulation procedure continues with a new wear step as long as the desired tonnage is not attained.

    Four curves of Tvärbanan with different curve radii, ranging from 85 to 410 m, have beenstudied in this work. On three of the curves the high rail is deliberately lubricated, whereas no lubrication has been applied in the widest curve. The vehicle operating the light rail line is an articulated tram with two motor end bogies and one intermediate trailer bogie. The line was opened in August 1999 and extended in one direction one year later. Rail profile measurements have been carried out by SL since March 2002. The traffic tonnage at the selected sites from the opening of the line to the last measurement occasion (September2004) is at most 8.9 mega gross ton per track.

    The results of the rail wear prediction tool are evaluated by comparing worn-off area of the simulated rail profiles with that of the measured rail profiles. Simulated and measured resultsdo not agree too well, since the simulated rail wear is more extensive than the measured one, especially on the outer rail. However, the shapes of the simulated worn rail profiles are comparable to those of the measured rail profiles.

  • 10.
    Orvnäs, Anneli
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Andersson, Evert
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Persson, Rickard
    Development of Track-Friendly Bogies for High Speed: A Simulation Study2007Report (Other academic)
  • 11.
    Orvnäs, Anneli
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Persson, Rickard
    Active Lateral Secondary Suspension with H∞ Control to Improve Ride Comfort: Simulations on a Full-Scale Model2011In: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 49, no 9, p. 1409-1422Article in journal (Refereed)
    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.

  • 12.
    Orvnäs, Anneli
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Persson, Rickard
    An Active Secondary Suspension Concept to Improve Lateral and Vertical Ride ComfortIn: Journal of Computational and Nonlinear Dynamics, ISSN 1555-1415, E-ISSN 1555-1423Article in journal (Other academic)
    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.

  • 13.
    Orvnäs, Anneli
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Persson, Rickard
    Aspects of Using Active Vertical Secondary Suspension to Improve Ride Comfort2011In: 22nd International Symposium on Dynamics of Vehicles on Roads and Tracks, IAVSD'11, 2011Conference paper (Other academic)
    Abstract [en]

    This paper presents various aspects of using active vertical secondary suspension in a rail vehicle to improve ridecomfort. Dynamic control of the vertical and roll modes of the carbody is achieved by means of actuators replacingthe conventional vertical dampers in the secondary suspension. Active damping improves vertical ride comfort,compared to a passive system. Besides dynamic control, the actuators are able to generate quasi-static roll controlbetween the carbody and bogies in curves. This allows for higher speeds in curves, without negatively affecting ridecomfort.

  • 14.
    Orvnäs, Anneli
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Persson, Rickard
    Development and test of active secondary suspension in a rail vehicle2009In: Proceedings of the 21st International Symposium: Dynamics of Vehicles on Roads and Tracks, 2009Conference 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.

  • 15.
    Orvnäs, Anneli
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Persson, Rickard
    On-track tests with active lateral secondary suspension: a measure to improve ride comfort2008In: ZEV Rail Glasers Annalen, ISSN 1618-8330, Vol. 132, no 11-12, p. 469-477Article in journal (Refereed)
    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.

  • 16.
    Orvnäs, Anneli
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Persson, Rickard
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Ride Comfort Improvements in a High-Speed Train with Active Secondary Suspension2009In: Proceedings of the International Symposium on Speed-Up, Safety and Service Technology for Railway and Maglev Systems, STECH'09, Niigata, Japan, June 16-19, 2009, 2009Conference paper (Refereed)
  • 17.
    Orvnäs, Anneli
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Persson, Rickard
    Ride comfort improvements in a high-speed train with active secondary suspension2010In: Journal of Mechanical Systems for Transportation and Logistics, ISSN 1882-1782, Vol. 3, no 1, p. 206-215Article in journal (Refereed)
    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.

  • 18.
    Orvnäs, Anneli
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Persson, Rickard
    Ride Comfort Improvements of a REGINA Train with Active Lateral Secondary Suspension2010In: 8th International Conference on Railway Bogies and Running Gears, BOGIE '10, Budapest, Hungary, September 13-16, 2010., 2010Conference paper (Other academic)
    Abstract [en]

    This study describes the development of a system of active lateral secondary suspension (ALS) for commercial use. Simulations and on-track tests have been performed with a two-car REGINA train-set since 2007, using electro-hydraulic actuators together with sky-hook damping and a carbody centring Hold-Off Device to actively control the secondary suspension. Measurement results show that the ALS system significantly reduces the lateral dynamic carbody accelerations. Furthermore, the lateral quasi-static displacements between carbody and bogies in curves at high track plane accelerations are significantly reduced. Hence, lateral ride comfort is improved and higher speeds, particularly in curves, may be allowed. The satisfactory results have led to long-term tests in service operation, which are being carried out since the beginning of 2009.

  • 19. Orvnäs, Anneli
    et al.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Persson, Rickard
    Qazizadeh, Alireza
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    An active secondary suspension concept to improve lateral and vertical ride comfort2013In: 9th international conference on railway bogies and running gears, Budapest, September 9-12 / [ed] Prof. Istvan Zobory, Budapest, Hungary: Department of Railway vehicles, Aircraft and Ships at the BME , 2013, p. 86-88Conference paper (Refereed)
    Abstract [en]

    When the speed of a rail vehicle is increased, ride comfort is normally negatively affected. The suspensions of the vehicle have to be modified in order to compensate for the amplified vibrations in the carbody. However, the possibilities of improvement by means of conventional passive damping will eventually reach a limit. Therefore, active suspension technology in rail vehicles is considered to be an alternative solution, since it offers better options of improving the vehicle’s dynamic performance compared to conventional passive solutions.

    Although previous research has been performed concerning concepts of combined active lateral and vertical secondary suspension – by replacing the lateral and vertical dampers with actuators – no such concept known to the authors has been introduced for service implementation.

    This paper presents an active secondary suspension concept used to simultaneously improve lateral and vertical ride comfort. In the first phase of the research project, focus was on an active secondary suspension concept in the lateral direction (ALS), including dynamic and quasi-static lateral control of the carbody. Simulations were validated against running tests, showing significant ride comfort improvements. The ALS system will soon be taken into service operation.

    In the next phase of the project, simulations were performed with the active suspension device in the vertical direction (AVS), including dynamic vertical and quasi-static roll control of the carbody. The simulations performed with the AVS system indicated significant ride comfort improvements compared to the passive system.

    In the final phase of the project, the ALS and AVS systems are combined. Simulation results show that the active system significantly improves lateral and vertical ride comfort compared to a passive system. Further, by means of the quasi-static roll control of the carbody, higher speeds in curves can be allowed without negatively affecting ride comfort. Moreover, the active suspension concept reduces the influence on ride comfort caused by the air spring stiffness. This means that the total air spring volume can be reduced.

  • 20. Persson, Richard
    et al.
    Andersson, Evert
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Orvnäs, Anneli
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Bogies towards higher speed on existing tracks2014In: International Journal of Rail transportation, ISSN 2324-8378, E-ISSN 2324-8386, Vol. 2, no 1, p. 40-49Article in journal (Refereed)
    Abstract [en]

    Running faster on existing tracks is a common operator’s wish that should be set in relation to the necessary infrastructure maintenance costs for track quality enhancement. Designing a track-friendly running gear that exerts moderate forces on the track is a key to relax this relation. A design providing good ride quality even on non-perfect track is preferred to avoid excessive track maintenance costs when speeds are higher. This paper describes how simulations and tests have been performed to optimise certain parts of a high-speed bogie. The result is a bogie with relatively soft wheelset guidance allowing passive radial self-steering in common curve radii, which in combination with appropriate yaw damping ensures stability at higher speeds. It also includes active secondary suspension to further ease the maintenance requirements on the track and/or to improve ride quality. This bogie has been tested and approved according to EN 14363 for a service speed of 250 km/h in combination with enhanced curving speed. Both simulations and recently performed on-track tests further showed that the ride comfort with active secondary suspension at 250 km/h can be at least as good as with passive suspensions at 200 km/h.

  • 21.
    Stichel, Sebastian
    et al.
    Bombardier Transportation, Västerås, Sweden .
    Persson, Rickard
    Bombardier Transportation, Västerås, Sweden .
    Himmelstein, Günther
    Andersson, Evert
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Orvnäs, Anneli
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Development of Next Generation High-Speed Trains for Scandinavia2009In: Proceedings of the 12th International Conference on Civil, Structural and Environmental Engineering Computing, 2009Conference paper (Refereed)
    Abstract [en]

    This paper describes the development of new running gear technology for future high-speed trains within the Swedish development programme Gröna Tåget (Green Train). Three different technologies are developed and tested: a passive radial self-steering "soft" bogie, an active lateral suspension including also a Hold-Off-Device function and a mechatronic bogie actively controlling the wheelset motions with actuators attached to the bogie frame. In contrast to other high-speed train developments, focus is here the challenge of balancing the contradictory demands of good running behaviour at high speeds on straight track on the one hand and good curving performance with low track and wheel damage and maintained good ride comfort on the other hand. Results are presented which confirm that all three technologies in almost all aspects meet the goals set up in the beginning of the project.

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