Electromechanical actuator for active suspension of a rail vehicle

Application of active suspension on passenger vehicles has engaged many vehicle dynamics specialists in recent years. The technology can be used for different purposes including improving comfort, stability or wear behavior. Despite these benefits, industries do not yet find these technologies attractive enough. One reason is that the achieved benefits do not pay back for itself since the vehicle will become more expensive. Therefore, more steps should be taken to make active suspension attractive. One such a step can be using active suspension for resolving classical limitations in rail vehicle dynamics. An example of this is a non-bogie rail vehicle with two axles. One of the problems associated with these vehicles is their short axle distance limiting the length of the vehicle. The short axle distance is partly for limiting wheel-rail wear. This paper describes how to reduce wheel wear through achieving better wheelset steering in curves so that longer axle distances can be allowed. Wheelset steering is performed by H∞ control strategy.

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Design and Development of Smart Semi Active Suspension for Nonlinear Rail Vehicle Vibration Reduction

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455420501205 ◽

2020 ◽

Vol 20 (11) ◽

pp. 2050120

Author(s):

Sunil Kumar Sharma ◽

Jaesun Lee

Keyword(s):

Predictive Model ◽

High Speed ◽

Mr Damper ◽

Active Suspension ◽

Creep Model ◽

Ride Quality ◽

High Speed Rail ◽

Running Safety ◽

Rail Vehicle ◽

Fluid Dampers

In this paper, the semi-active suspension in railway vehicles based on the controlled magnetorheological (MR) fluid dampers is examined, and compared with the semi-active low and semi-active high suspension systems to enhance the running safety and ride quality for a high-speed rail vehicle. Predictive model controllers are used as system controllers to determine the desired damping forces for front and rear bogie frame with force track-ability. A 28 degree of freedom (DoF) mathematical model of the rail vehicle is formulated using nonlinear vehicle suspension and nonlinear heuristic creep model. The MR model of Ali and Ramaswamy is formulated to characterize the behavior of the MR damper. The simulation result is validated using the experimental results. Four different suspension strategies are proposed with MR damper, i.e. passive, semi-active low, semi-active high and semi-active smart controller based on predictive model controller. A comparison indicates that the semi-active controller gives the optimum for comfort vibration actuation and improves the ride quality and it has little influence on derailment quotients, offload factors, as a result, it will not endanger the running safety of rail vehicle.

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Proposal for systematic studies of active suspension failures in rail vehicles

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1177/0954409716663583 ◽

2016 ◽

Vol 232 (1) ◽

pp. 199-213 ◽

Cited By ~ 3

Author(s):

Alireza Qazizadeh ◽

Sebastian Stichel ◽

Rickard Persson

Keyword(s):

High Speed ◽

Failure Modes ◽

Ride Comfort ◽

Fault Tree Analysis ◽

Active Suspension ◽

Vehicle Safety ◽

Active Suspensions ◽

Analysis Techniques ◽

Rail Vehicle ◽

Rail Vehicles

Application of active suspensions in high-speed passenger trains is gradually getting more and more common. Active suspensions are primarily aimed at improving ride comfort, wear or stability. Failure of these systems may not only just deteriorate the performance but it may also put vehicle safety at risk. There are not many studies that explain how a thorough study proving safety of active suspension should be performed. Therefore, initiating this type of study is necessary for not only preventing incidences but also for assuring acceptance of active suspension by rail vehicle operators and authorities. This study proposes a flowchart for systematic studies of active suspension failures in rail vehicles. The flowchart steps are solidified by using failure mode and effects analysis and fault tree analysis techniques and also acceptance criteria from the EN14363 standard. Furthermore, six failure modes are introduced which are very general and their use can be extended to other studies of active suspension failure. In the last section of the paper, the proposed flowchart is put into practice through four failure examples of active vertical suspension.

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