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On the Unsteady-Motion Theory of Magnetic Forces for Maglev

Description: Motion-dependent magnetic forces are the key elements in the study of magnetically levitated vehicle (maglev) system dynamics. In the past, most maglevsystem designs were based on a quasisteady-motion theory of magnetic forces. This report presents an experimental and analytical study that will enhance our understanding of the role of unsteady-motion-dependent magnetic forces and demonstrate an experimental technique that can be used to measure those unsteady magnetic forces directly. The experimental technique provides a useful tool to measure motion-dependent magnetic forces for the prediction and control of maglev systems.
Date: November 1993
Creator: Chen, Shoei-Sheng; Zhu, S. & Cai, Y.
Partner: UNT Libraries Government Documents Department

Dynamic Stability of Maglev Systems

Description: Because dynamic instability is not acceptable for any commercial maglev systems, it is important to consider this phenomenon in the development of all maglev systems. This study considers the stability of maglev systems based on experimental data, scoping calculations, and simple mathematical models. Divergence and flutter are obtained for coupled vibration of a three-degree-of-freedom maglev vehicle on a guideway consisting of double L-shaped aluminum segments attached to a rotating wheel. The theory and analysis developed in this study identifies basic stability characteristics and future research needs of maglev systems.
Date: April 1992
Creator: Cai, Y.; Chen, Shoei-Sheng; Mulcahy, T. M. & Rote, D. M.
Partner: UNT Libraries Government Documents Department

Dynamics and Controls in Maglev Systems

Description: The dynamic response of magnetically levitated (maglev) ground transportation systems has important consequences for safety and ride quality, guideway design, and system costs. Ride quality is determined by vehicle response and by environmental factors such as humidity and noise. The dynamic response of the vehicles is the key element in determining ride quality, and vehicle stability is an important safety-related element. To design a proper guideway that provides acceptable ride quality in the stable region, vehicle dynamics must be understood. Furthermore the trade-off between guideway smoothness and the levitation and control systems must be considered if maglev systems are to be economically feasible. The link between the guideway and the other maglev components is vehicle dynamics. For a commercial maglev system, vehicle dynamics must be analyzed and tested in detail. In this study, the role of dynamics and controls in maglev vehicle/guideway interactions is discussed, and the literature on modeling the dynamic interactions of vehicle/guideway and suspension controls for ground vehicles is reviewed. Particular emphasis is placed on modeling vehicle/guideway interactions and response characteristics of maglev systems for a multicar, multiload vehicle traveling on a single- or doublespan flexible guideway, including coupling effects of vehicle/guideway, comparison of concentrated and distributed loads, and ride comfort. Different control-law designs are introduced into vehicle suspensions when a simple two-degree-of-freedom vehicle model is applied. Active and semiactive control designs for primary and secondary suspensions do improve the response of vehicle and provide acceptable ride comfort. Finally, future research associated with dynamics and controls of vehicle/guideway systems is identified.
Date: September 1992
Creator: Cai, Y.; Chen, Shoei-Sheng & Rote, D. M.
Partner: UNT Libraries Government Documents Department

A Review of Dynamic Characteristics of Magnetically Levitated Vehicle Systems

Description: The dynamic response of magnetically levitated (maglev) ground transportation systems has important consequences for safety and ride quality, guideway design, and system costs. Ride quality is determined by vehicle response and by environmental factors such as humidity and noise. The dynamic response of the vehicles is the key element in determining ride quality, while vehicle stability is an important safety-related element. To design a guideway that provides acceptable ride quality in the stable region, vehicle dynamics must be understood. Furthermore, the trade-off between guideway smoothness and levitation and control systems must be considered if maglev systems are to be economically feasible. The link between the guideway and the other maglev components is vehicle dynamics. For a commercial maglev system, vehicle dynamics must be analyzed and tested in detail. This report, which reviews various aspects of the dynamic characteristics, experiments and analysis, and design guidelines for maglev systems, discusses vehicle stability, motion dependent magnetic force components, guideway characteristics, vehicle/ guideway interaction, ride quality, suspension control laws, aerodynamic loads and other excitations, and research needs.
Date: November 1995
Creator: Cai, Y. & Chen, Shoei-Sheng
Partner: UNT Libraries Government Documents Department

Dynamic Stability Experiment of Maglev Systems

Description: This report summarizes the research performed on Maglev vehicle dynamic stability at Argonne National Laboratory during the past few years. It also documents magnetic-force data obtained from both measurements and calculations. Because dynamic instability is not acceptable for any commercial Maglev system, it is important to consider this phenomenon in the development of all Maglev systems. This report presents dynamic stability experiments on Maglev systems and compares their numerical simulation with predictions calculated by a nonlinear dynamic computer code. Instabilities of an electrodynamic system (EDS)-type vehicle model were obtained from both experimental observations and computer simulations for a five-degree-of-freedom Maglev vehicle moving on a guideway consisting of double L-shaped aluminum segments attached to a rotating wheel. The experimental and theoretical analyses developed in this study identify basic stability characteristics and future research needs of Maglev systems.
Date: April 1995
Creator: Cai, Y.; Rote, D. M.; Mulcahy, T. M.; Wang, Z.; Chen, Shoei-Sheng & Zhu, S.
Partner: UNT Libraries Government Documents Department

Vehicle/Guideway Interaction in Maglev Systems

Description: Dynamic interactions between the vehicle and guideway in a high-speed ground transportation system based on magnetically levitated (maglev) vehicles were studied, with an emphasis on the effects of vehicle and guideway parameters. Two dynamic models for the vehicle are presented. In one model, the vehicle is considered to be a moving force traveling at various speeds on a simply supported single- or two-span beam. In the second model, the vehicle is considered to be one-dimensional and has two degrees of freedom; this model consists of the primary and secondary suspensions of the vehicle, with lumped masses, linear springs, and dampings. The Bernoulli-Euler beam equation is used to model the characteristics of a flexible guideway, and the guideway synthesis is based on modal analysis. Analyses were performed to gain an understanding of response characteristics under various loading conditions and to provide benchmark data for verification of existing comprehensive computer programs and some basic design guidelines for maglev systems. Finally, the German Transrapid maglev system was evaluated.
Date: March 1992
Creator: Cai, Y.; Chen, Shoei-Sheng & Rote, D. M.
Partner: UNT Libraries Government Documents Department

New Ways: Tiltrotor Aircraft and Magnetically Levitated Vehicles

Description: Common issues for these systems include their possible contributions to improving mobility in congested corridors, U.S. technology leadership, the Federal role in transportation research and development, and institutional and community barriers to major, new infrastructure programs. Moreover, some Federal financing is likely to be required if commercial maglev or tiltrotor technologies are to be developed by U.S. industry over the next decade. Congress will need to clarify its objectives for supporting or encouraging these technologies before it can make wise decisions on when or whether to undertake substantial, long-term Federal programs in support of either or both of them. This report identifies several funding and management options for consideration if such goals are established.
Date: September 1991
Creator: United States. Congress. Office of Technology Assessment.
Partner: UNT Libraries Government Documents Department

U.S. Passenger Rail Technologies

Description: An assessment by the Office of Technology Assessment (OTA) that examines "the prospects of magnetic levitation (maglev) technologies - ultra-high-speed ground transportation that relies on magnetic suspension instead of conventional steel wheels on rail - and the status of railcar manufacturing industries" (p. ix).
Date: December 1983
Creator: United States. Congress. Office of Technology Assessment.
Partner: UNT Libraries Government Documents Department