Anton Stribersky

Comfort Enhancement By an Active Vibration Reduction System for a Flexible Railway Car Body

In order to improve the ride comfort of lightweight railway vehicles, an active vibration reduction system using piezo-stack actuators is proposed and studied in simulations. The system consists of actuators and sensors mounted on the vehicle car body. Via a feedback control loop, the output signals of the sensors which are measuring the flexible deformation of the car body generate a bending moment, which is directly applied to the car body by the actuators. This bending moment reduces the structural vibration of the vehicle car body. Simulations have shown that a significant reduction in the vibration level is achieved.

Vibration Damping of a Flexible Car Body Structure Using Piezo-Stack Actuators

In this work piezo-stack actuators mounted in consoles are utilized to actively dampen vibrations of a flexible car body structure by introducing bending moments. Using an example of a heavy metro vehicle the complete design for the active vibration damping system is presented. Both analytical modeling and a system identification of the vehicle are described, issues of modal representation and model reduction are covered, and a robust controller design is motivated and explained. The excellent performance of the proposed method is documented by both experimental results from a scaled model and an extensive co-simulation of the overall system.

Design and Evaluation of a Semi-Active Damping System for Rail Vehicles

Abstract The paper describes the development of a semi-active damping system used on rail vehicles. Applying a skyhook control strategy, improvement of the ride comfort can be achieved for the passengers. The system design and the hydraulic damper are explained. Computer simulations of complex three-dimensional rail vehicles served for the design process and the results are described. Measured force responses of a prototype semi-active damper are shown and compared to simulation results. First measurements from field tests with the prototype semi-active damping system show, that up to 15% improvement of the ride quality can be achieved with the real vehicle.

Structural dynamics and ride comfort of a rail vehicle system

The paper describes the development of a virtual vehicle system using virtual prototyping computer tools. The virtual vehicle is used for the prediction of the structural dynamics. Since the modelling process for complete rail vehicle systems becomes increasingly more complex, time and cost can be saved by the use of a database concept and an automated assembling process for the vehicle of interest.Supported by a modular design concept, vehicle components for a metro train have been modelled and stored as substructures in a specific vehicle component database. Using this database, train configurations up to a three-car train can be assembled very quickly to perform structural dynamics analyses and to predict the ride comfort.Experimental results have been compared with simulation results of the rail vehicle to improve the modelling technique and the accuracy of the developed virtual vehicle system.The mathematical modelling of the rail vehicle system featuring elastic components, the structure of the database as well as numerical and experimental results are presented in this paper.

On Dynamic Analyses of Rail Vehicles With Electronically Controlled Suspensions

SUMMARY This paper presents the results of dynamic analyses conducted to investigate the performance of a rail vehicle system consisting of a passenger car, an inertial measurement unit for measuring accelerations related to the dynamic movement of the vehicle and for measuring the tilting angle of the car body, a digital control unit, and actuators to reduce the accelerations felt by the passengers. The control strategies are described. The method of multibody systems has been used to design the control systems. The nonlinear dynamics of a virtual vehicle system has been analyzed on the computer synchronously to the hardware realization of the vehicle system. The paper focuses on how advanced software tools can be applied by the rail vehicle engineer for designing advnnced rail vehicle suspensions and performing vehicle system dynamic analyses.

MODELING AND SIMULATION OF ADVANCED RAIL VEHICLES

The growing importance of automatic control for the design of new bogies for rail vehicles is becoming increasingly visible. Since the development process of novel designs also needs new development tools, software to extend the multibody program SIMPACK has been written recently to serve for the simulation of advanced rail vehicles. In this paper the mathematical modeling for a railway vehicle with active car body tilting is described and simulation results, applying the developed software, are shown and compared with experimental results from a prototype vehicle.

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.

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.

APPLICATIONS OF SYMBOLIC MANIPULATION FOR INVESTIGATING THE NONLINEAR DYNAMICS OF GROUND VEHICLES

SUMMARY Symbol manipulation tools can aid in the analysis of the nonlinear dynamics of ground vehicles in several ways. The equations of motion, derived automatically in symbolic form, can be numerically integrated to obtain a single simulated test. Alternatively, the nature of the overall nonlinear stability can be determined if the equations are derived in a certain form. Formulating equations for the stability analysis involves considerable algebraic manipulation, such that the analysis is practical only with computer aid. Recent improvements of computer hardware and recently developed computer algebra software now allow a level of automation that makes these analyses practical for general use by engineers. Applications from both rail and road vehicles are given in this paper as examples.