relo_vif - Control of Railway Vehicles with independently rotating Wheels

Nowadays public means of transportation with low-floor-access are essential in urban areas. Their objective is to provide easy and comfortable embarkation and disembarkation without steps and without raised platforms. The use of low-floor vehicles lead to shorter times for embarkation and disembarkation what again leads to shorter time of travel and shorter vehicle intervals. Low-floor vehicles are useful for the entire community, including disabled people. Light rail vehicles with independently rotating wheels can fulfill this demand most suitable. In contradiction to vehicles with independently rotating wheels, the wheels of a conventional wheelset are connected by a rigid axle. For vehicles with independently rotating wheels no persistent axle is necessary which is determining the height of the floor. Usually the wheelsets are coupled to the bogie by passive spring-damper elements. These passive vehicles with independently rotating wheels are dynamically stable but create a lot of wheel and rail wear, due to the reason that in the majority of cases the stable ride condition results in flange contact. The flange contact of wheel and rail leads to squeal noise as well. In this project new approaches for active guiding of railway vehicles with independently rotating wheels were pursued to eliminate the mentioned drawbacks. By developing control strategies new methods were presented to improve railway vehicles with independently rotating wheels by means of modern mechatronic systems. To estimate the existing potential of the approaches and methods further investigations are necessary. For example some physical values which are necessary inputs for the control laws are difficult or impossible to measure. Therefore estimators or observers have to be applied. The reaction of the control laws on disturbances has to be verified, i. e. robustness against track excitations and measurement noise. Parameter uncertainties as well have to be included in the considerations. This is due to the reason that values of stiffness, damping, masses, etc. are subjected to tolerances and temporal variations.