Wolfgang Rulka

ADVANCES IN COMBINED STRUCTURAL DYNAMICS AND SYSTEM DYNAMICS ANALYSES OF RAIL VEHICLES

SUMMARY The use of a virtual product development (VPD) system allows a computer-based description of a product throughout the complete development process. An accurate description of the complex motion of a rail vehicle is possible using the methods of multibody simulation embedded in the VPD system. The VPD system represents the geometry data generated using computer aided design (CAD) methods. The relevant theories applied for the dynamic simulation are described. Numerical results achieved from the virtual models are compared with hardware measurements gained from a physical prototype.

Sliding mode control for comfort improvement in railway vehicles

There already exist various investigations in the field of comfort improvement with the help of actuators in the secondary suspension. They are often based on the assumption that only track set irregularities but not trace are chosen as a disturbance variable of the system. The first part of this contribution describes how to ensure a comfortable journey along a track with inclination changes and no track set irregularities, using information on the trace and current vehicle position. If this technique is combined with comfort optimisation methods to control short-wave irregularities, the nonlinear parts of the characteristic curves of the spring and damper elements are used. The application of successful comfort optimisation methods, notwithstanding these nonlinearities, with the aid of Sliding Mode Control is given in the second part of the paper.

Model Based Measurement of Railway Track Irregularities

Abstract Knowledge of track irregularities is highly important for the railway system. The established measuring methods need special measuring vehicles or other complex and expensive measuring tools. According to the measuring method presented in this paper track irregularities are calculated with the help of the car body acceleration measured on the rail vehicle. The calculation proceeds on the basis of the well-known and verified multibody model of a rail vehicle. The range of measurement devices is reduced to two acceleration measurement points in the drivers cab of a vehicle. The initial part of the present article elucidates the idea of the measuring method. Then, the example of a single-mass oscillator with, first, two independent and, finally, two correlated excitations shows how the measuring method can be applied to rail vehicles. Results are illustrated with a two-dimensional total vehicle model.

Analysis of the braking performance of a rail vehicle emphasizing mechatronic components

For the development of mechatronic components for railway vehicles, suitable methods, processes and tools have to be applied. As an example, the use of these methods and tools for the design of a wheelslide protection system will be addressed in this article. Modern simulation techniques for mechatronic systems enable more unique versions of the implemented algorithm on the controller hardware and in the design and simulation test environment. To simulate the braking behaviour of a railway vehicle, creep force characteristics at different friction conditions have been shaped out from measurements and implemented in the multi-body simulation program SIMPACK. As statements from pure off-line simulations of the braking performance of a rail vehicle are limited, a roller rig has been designed that enables tests and improvements of a wheelslide protection controller. Finally, only practical field tests can prove the function of a new developed system. Following the V-model for the design process of mechatronic systems, results from integrated off-line simulations, tests on a single-wheel roller rig and field tests will be explained. †This article includes words that are asserted to be a proprietary term or trade mark. Its inclusion does not imply it has acquired for legal purposes a non-proprietary or general significance, nor is any other judgement implied concerning its legal status.

Creepage control for use in wheelslide protection systems

Abstract In order to achieve acceptable braking distances, the wheelslide protection controller of a railway vehicle should hold an operating point in the macro-slip range on the decreasing branch of the creep force curve. Based on mathematical models of the railway vehicle, the creep force characteristics and the brake system, a stability analysis is performed for the open-loop system during braking in the macro-slip range. In addition, a creepage controller that stabilises the closed loop over the entire vehicle velocity range is presented and its performance is discussed with the help of simulation results.

Adaptiver Gleitschutz für Schienenfahrzeuge (Adaptive Wheelslide Protection System for Railway Vehicles)

Abstract Dieser Beitrag beschäftigt sich mit der Auslegung und dem Test einer Gleitschutzregelung für Schienenfahrzeuge. Als Grundlage für die Reglerentwicklung werden zunächst einfache Modelle des Schienenfahrzeugs, der Kraftschlussbeanspruchung und des Bremssystems vorgestellt. An Hand einer Analyse des Gesamtmodells kann der Wertebereich eines bestimmten Modellparameters berechnet werden, der bei der Auslegung des linearen, robusten Schlupfreglers berücksichtigt werden muss. Daneben wird die Adaption der Reglerverstärkung an einen leicht zu identifizierenden Fahrzeugparameter (Bremszustandsfaktor) beschrieben. Schließlich werden Versuchsergebnisse von Testfahrten mit einer Regelung im Mikroschlupfbereich vorgestellt und diskutiert.