Ride comfort improvements in switches using active secondary suspension with preview

Trains often have to change their track when entering or leaving a station. This represents a challenging scenario related to passenger ride comfort due to small curve radii in switches. The abrupt change of curvature usually results in a bumpstop contact in the secondary suspension. The paper presents a control strategy with preview information based on stored track data. For this purpose, a calculation method is introduced to determine forces and torques acting on the carbody, e.g. when passing switches in advance. This data can be used by an active lateral secondary suspension in order to prevent bumpstop contact. Corresponding multibody simulations showed promising results. Peak values of lateral acceleration acting on the passengers can be reduced significantly resulting in better ride comfor

Sensitivity analysis for operating loads in fatigue design of railway vehicles

For the reliable simulation-based fatigue design of railway vehicles, the operation conditions and resulting loads over the lifespan of the vehicle have to be considered. After introducing the relevant fatigue loads on the vehicle and the methods for modelling the fatigue damage, this work aims at analysing the influence of the operating conditions and loads on the damage using sensitivity analysis. Two approaches are studied: the variance-based sensitivity analysis of the loads acting on the car body and the influence of different operating conditions using statistical values per track section. The loads are obtained from multi-body simulations and the damage is estimated using both physical FE-models and meta-models. The performances of linear regression models and polynomial chaos models are evaluated. The proposed sensitivity analysis is applied to the highspeed train being developed in the Next Generation Train (NGT) project at DLR and will serve as a basis for the virtual design and reliability analysis

Ride Comfort Improvements on Disturbed Railroads Using Model Predictive Control

This paper proposes a control strategy for active lateral secondary suspension that uses preview data. Based on a derived analytical model, a model predictive controller (MPC) is implemented. The influence of the track irregularities upon carbody lateral dynamics is considered explicitly. The controller developed is applied to a full-scale rail vehicle model. Ride comfort is evaluated according to EN 12299. Multibody simulations show that there is a significant increase in continuous ride comfort on poor-quality tracks

Development of the DLR Next Generation Train running gear research facility (NGT-FuN)

A full-scale prototype of the Next Generation Train (NGT) running gear with a roller rig installation bench will be built as proof of concept of the running gear and its suitability for high-speed traffic. It will be available as the research platform “Forschungsinfrastruktur NGT-Fahrwerk” (FuN) for the German Aerospace Center (DLR) internal and external research activities. This work presents an innovative method and tool chain to develop application software for the automation of a mechatronic running gear (prototype). The methodology, development, and simulation tools that offer a consistent tool chain from model creation to real-time software and measurement data processing are presented. The model and software structures that are necessary for the software environment are described. The software-in-the-loop environment couples the existing multi-body simulations for the development process with signal-based simulation software using a co-simulation interface. The resulting software-in-theloop simulation environment contains a novel interface layer that translates the mechanical states of the multi-body simulation to pseudo-electrical signals that are read or written by the application software. This makes it possible to develop real-time applications and software structures in software-in-the-loop architectures. The real-time software contains a dedicated model structure of input, processing and output submodels, which is based on signal flow and distinct assignment of tasks. On the rapid-control-prototyping hardware, the real-time software is investigated with a virtual installation bench simulation

DLR Forschungsinfrastruktur NGT-Fahrwerk (NGT-FuN)

Das Deutsche Zentrum für Luft- und Raumfahrt baut im Rahmen des Projektes Next Generation Train einen ersten Prototyp des für den Hochgeschwindigkeitsverkehr entwickelten, mechatronischen Einzelradfahrwerkes. Bis Ende 2022 wird das Fahrwerk mit einem Integrationsprüfstand in Betrieb genommen und anschließend auf Rollprüfständen und in Versuchsfahrzeugen weiter getestet

Schritte zum generischen IT Security Architekturmodell von Schienenfahrzeugen

Dieser Bericht erarbeitet ein generisches IT Security Architekturmodell von Schienenfahrzeugen in dem er die Schritte des Arbeitsablaufdiagramms zur Festlegung der Zonen und Zonenübergänge sowie zur Beurteilung des Risi-kos aus der DIN EN 62443-3-2 [23] auf einen typischen Triebzug anwendet. Als Ergebnis entstand eine Tabelle mit der Zuordnung der typischen Funktionen des Triebfahrzeuges auf Funktionsgruppen und Zonen unter Berücksichtigung der Zonenübergänge (Conduits). Diese Tabelle ist als Handreichung für die praktische Analyse von Schienenfahrzeugen gedacht. Um deren Anwendung zu erleichtern wird im Bericht die Herleitung der Tabelle beginnend mit der gesetzlichen und normativen Einbettung über das Vorgehen bei der Ermittlung der Zonen und Zonenübergänge im Detail dargestellt. Bei der Erarbeitung der genannten Tabelle wurde deutlich, dass eines der größten Risiken für eine Gefährdung der IT-Sicherheit in den Wartungszugängen liegt. Hier bietet sich eine Vertiefung im Rahmen einer weiterführenden Untersuchung an – speziell im Hinblick auf eine Standardisierung

The Ganymede Laser Altimeter (GALA) for the Jupiter Icy Moons Explorer (JUICE): Mission, science, and instrumentation of its receiver modules

The Jupiter Icy Moons Explorer (JUICE) is a science mission led by the European Space Agency, being developed for launch in 2023. The Ganymede Laser Altimeter (GALA) is an instrument onboard JUICE, whose main scientific goals are to understand ice tectonics based on topographic data, the subsurface structure by measuring tidal response, and small-scale roughness and albedo of the surface. In addition, from the perspective of astrobiology, it is imperative to study the subsurface ocean scientifically. The development of GALA has proceeded through an international collaboration between Germany (the lead), Japan, Switzerland, and Spain. Within this framework, the Japanese team (GALA-J) is responsible for developing three receiver modules: the Backend Optics (BEO), the Focal Plane Assembly (FPA), and the Analog Electronics Module (AEM). Like the German team, GALA-J also developed software to simulate the performance of the entire GALA system (performance model). In July 2020, the Proto-Flight Models of BEO, FPA, and AEM were delivered from Japan to Germany. This paper presents an overview of JUICE/GALA and its scientific objectives and describes the instrumentation, mainly focusing on Japan’s contribution

From Scaled Experiments of Mechatronic Guidance to Multibody Simulations of DLR’s Next Generation Train Set

The paper presents the progress of control development for mechatronic guidance within the DLR-internal project Next Generation Train. It reports on the implementation of the control on the experimental running gear hardware operated at the scale 1:5 roller rig at DLR. The state feedback control synthesis utilizes the parameter space approach in order to explicitly consider varying conicities. A feed-forward controller is introduced by model inversion. The resulting control performance is demonstrated by measurements. Then, the approach is transferred and applied to a full scale multibody model of the NGT train set. Specific measures are required to account for gyroscopic effects in transition curves, where the superelevation of the track is in- or decreasing. Simulation results document the achievements of the control design and validate the underlying considerations

Train Communication Networks and Prospects

This article presents an overview of communication systems in mainline railways and in particular the train communication network (TCN) defined in IEC 61375. Current systems and ongoing developments are systematized by traffic, technological, and organizational topics. TCN is displayed in detail with a prospect of possible future wireless extensions

Train Communication Networks - Status and Prospect

This paper presents an overview of communication systems in mainline railways and in particular the Train Communication Network TCN defined in IEC 61375. Current systems and ongoing developments are systematized by traffic, technological and organizational topics. TCN is displayed in detail with a prospect to possible future wireless extensions