| 1. |
- Andersson, Evert, et al.
(author)
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How to find a compromise between track friendliness and the ability to run at high speed
- 2012
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In: Civil-Comp Proceedings. - Stirlingshire, UK : Civil-Comp Press. - 1759-3433. ; 98
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Journal article (peer-reviewed)abstract
- 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.
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| 2. |
- Andersson, Evert, et al.
(author)
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On the Optimization of a Track-Friendly Bogie for High Speed
- 2009
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In: 21st International Symposium on Dynamics of Vehicles on Roads and Tracks, IAVSD'09, Stockholm, August 17-21, 2009..
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Conference paper (other academic/artistic)abstract
- 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.
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| 3. |
- Andersson, Evert, et al.
(author)
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Radial Self-Steering Bogies : Recent Developments for High Speed
- 2009
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In: 7th International Conference on Railway Bogies and Running Gears. - 9789634209775 ; , s. 63-72
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Conference paper (other academic/artistic)abstract
- 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.
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| 4. |
- Andersson, Evert, et al.
(author)
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Radial self-steering bogies - Development, advantages and limitations
- 2007
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In: ZE Vrail - Glasers Annalen: Zeitschrift fuer das gesamte System Bahn. - 1618-8330. ; 131:Suppl., s. 248-259
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Journal article (peer-reviewed)abstract
- 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.
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| 5. |
- Orvnäs, Anneli
(author)
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Active Lateral Secondary Suspension in a High-Speed Train to Improve Ride Comfort
- 2009
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Licentiate thesis (other academic/artistic)abstract
- 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.
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| 6. |
- Orvnäs, Anneli, et al.
(author)
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Active Lateral Secondary Suspension with H∞ Control to Improve Ride Comfort : Simulations on a Full-Scale Model
- 2011
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In: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 49:9, s. 1409-1422
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Journal article (peer-reviewed)abstract
- 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.
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| 7. |
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| 8. |
- Orvnäs, Anneli, et al.
(author)
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An Active Secondary Suspension Concept to Improve Lateral and Vertical Ride Comfort
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In: Journal of Computational and Nonlinear Dynamics. - 1555-1415 .- 1555-1423.
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Journal article (other academic/artistic)abstract
- 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.
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| 9. |
- Orvnäs, Anneli, et al.
(author)
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An active secondary suspension concept to improve lateral and vertical ride comfort
- 2013
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In: 9th international conference on railway bogies and running gears, Budapest, September 9-12. - Budapest, Hungary : Department of Railway vehicles, Aircraft and Ships at the BME. ; , s. 86-88
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Conference paper (peer-reviewed)abstract
- 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.
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| 10. |
- Orvnäs, Anneli, et al.
(author)
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Aspects of Using Active Vertical Secondary Suspension to Improve Ride Comfort
- 2011
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In: 22nd International Symposium on Dynamics of Vehicles on Roads and Tracks, IAVSD'11.
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Conference paper (other academic/artistic)abstract
- 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.
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