Ground Transportation Systems Research Articles

Specification and Analysis of Discrete Behavior of Hybrid Systems in the Workbench ISMA

Hybrid systems are important in applications in CAD, real-time software, robotics and automation, mechatronics, aeronautics, air and ground transportation systems, process control, and have recently been at the center of intense research activity in the control theory, computer-aided verification, and artificial intelligence communities. In the past several years, methodologies have been developed to model hybrid systems, to analyze their behavior, and to synthesize controllers that guarantee closed-loop safety and performance specifications. These advances have been complemented by computational tools for the automatic verification and simulation of hybrid systems. Modern technologies of computer simulation tools include preparing, debugging, analysis and calculation of effective program models, meaningful interpretation of research results.

PALS-Based Analysis of an Airplane Multirate Control System in Real-Time Maude

Distributed cyber-physical systems (DCPS) are pervasive in areas such as aeronautics and ground transportation systems, including the case of distributed hybrid systems. DCPS design and verification is quite challenging because of asynchronous communication, network delays, and clock skews. Furthermore, their model checking verification typically becomes unfeasible due to the huge state space explosion caused by the system's concurrency. The PALS ("physically asynchronous, logically synchronous") methodology has been proposed to reduce the design and verification of a DCPS to the much simpler task of designing and verifying its underlying synchronous version. The original PALS methodology assumes a single logical period, but Multirate PALS extends it to deal with multirate DCPS in which components may operate with different logical periods. This paper shows how Multirate PALS can be applied to formally verify a nontrivial multirate DCPS. We use Real-Time Maude to formally specify a multirate distributed hybrid system consisting of an airplane maneuvered by a pilot who turns the airplane according to a specified angle through a distributed control system. Our formal analysis revealed that the original design was ineffective in achieving a smooth turning maneuver, and led to a redesign of the system that satisfies the desired correctness properties. This shows that the Multirate PALS methodology is not only effective for formal DCPS verification, but can also be used effectively in the DCPS design process, even before properties are verified.

Magnesium-Based Sacrificial Anode Cathodic Protection Coatings (Mg-Rich Primers) for Aluminum Alloys

Magnesium is electrochemically the most active metal employed in common structural alloys of iron and aluminum. Mg is widely used as a sacrificial anode to provide cathodic protection of underground and undersea metallic structures, ships, submarines, bridges, decks, aircraft and ground transportation systems. Following the same principle of utilizing Mg characteristics in engineering advantages in a decade-long successful R&D effort, Mg powder is now employed in organic coatings (termed as Mg-rich primers) as a sacrificial anode pigment to protect aerospace grade aluminum alloys against corrosion. Mg-rich primers have performed very well on aluminum alloys when compared against the current chromate standard, but the carcinogenic chromate-based coatings/pretreatments are being widely used by the Department of Defense (DoD) to protect its infrastructure and fleets against corrosion damage. Factors such as reactivity of Mg particles in the coating matrix during exposure to aggressive corrosion environments, interaction of atmospheric gases with Mg particles and the impact of Mg dissolution, increases in pH and hydrogen gas liberation at coating-metal interface, and primer adhesion need to be considered for further development of Mg-rich primer technology.

Hierarchical Regression Model for Analyzing Truck Freight Demand

Trucks play a significant role in transporting freight through the ground transportation systems, and it is important to be able to estimate and predict the amount of freight in a highway network. In this study, truck weight and volume data, obtained from Weigh-in-Motion stations in California, are analyzed to examine temporal and seasonal patterns. Then coupled with socio- economic variables, a hierarchical regression model is established for estimating freight demand. The model reveals that truck freight demand can be estimated by the truck annual average daily traffic along with the population, number of firms and median income at that county level. What is more, it has a predicting capability of freight weight where no truck weight data is measured. Therefore it can be served for practitioners to predict the growth of freight demand in a freeway network, and is useful to achieve the optimal flows design of cargo at all segments, regardless of whether or not weight data is available.

Computational methods for the optimisation and design of electromechanical vehicle systems

The development of advanced electromechanical vehicle systems requires the consideration of multiple physical processes including electromagnetics, fluid flow, heat transfer, and structural mechanics. Accordingly, this paper presents a suite of simulation, optimisation, and design strategies that may be applied to the research and development of modern electric and hybrid-electric vehicles. These computational methods are illustrated through three examples that involve electric motors and electronic systems. Two and three-dimensional topology optimisation studies, parametric geometry sweeps, and multi-scale models are shown to inform unique designs prior to the fabrication and testing of advanced prototypes. It is expected that such computational techniques will have a significant impact on the development of highly efficient future ground transportation systems.

Dynamic response analysis of single-span guideway caused by high speed maglev train

High speed maglev is one of the most important reformations in the ground transportation systems because of its no physical contact nature. This paper intends to study the dynamic response of the single-span guideway induced by moving maglev train. The dynamic model of the maglev train-guideway system is established. In this model, a maglev train consists of three vehicles and each vehicle is regarded as a multibody system with 34 degrees-of-freedom. The guideway is modeled as a simply supported beam. Considering the motion-dependent nature of electromagnetic forces in the maglev system, an iterative approach is presented to compute the dynamic response of a maglev train-guideway system. The histories of the train traversing the guideways are simulated and the dynamic responses of the guideway and the train vehicles are calculated. A field experiment is carried out to verify the results of the analysis. The resonant conditions of single-span guideway are analyzed. The results show that all the dynamic indexes of train-guideway system are far less than permissive values of railway and maglev system, the vertical resonant of guideways caused by periodical excitations of the train will not happen.

Ice protection of offshore platforms

Climate change-induced reduction in the extent and duration of sea ice cover, as well as an increase in energy demands, has caused renewed interest in exploring and drilling for oil in Arctic waters. Superstructure icing from sea spray and atmospheric icing in the Arctic may impact offshore platform operations. Though icing has not caused the loss of an offshore platform, it can reduce safety, operational tempo, and productivity. Historically, many ice protection technologies were tested on offshore platforms with little success. However, new technologies and modern versions of old technologies used successfully in aviation, the electric power industry, and ground transportation systems, may be adapted to an offshore environment. This paper provides a framework for assessing the relative threat of ice accumulation types, such as superstructure ice, glaze, rime, frost, and snow, to the safety of platform functions. A review of ice protection strategies for functional platform areas is also provided.

CICLoPE—a response to the need for high Reynolds number experiments

Although the equations governing turbulent flow of fluids are well known, understanding the overwhelming richness of flow phenomena, especially in high Reynolds number turbulent flows, remains one of the grand challenges in physics and engineering. High Reynolds number turbulence is ubiquitous in aerospace engineering, ground transportation systems, flow machinery, energy production (from gas turbines to wind and water turbines), as well as in nature, e.g. various processes occurring in the planetary boundary layer. High Reynolds number turbulence is not easily obtained in the laboratory, since in order to have good spatial resolution for measurements, the size of the facility itself has to be large. In this paper, we discuss limitations of various existing facilities and propose a new facility that will allow good spatial resolution even at high Reynolds number. The work is carried out in the framework of the Center for International Cooperation in Long Pipe Experiments (CICLoPE), an international collaboration that many in the turbulence community have shown an interest to participate in.

A Vision for a Secure Transportation System Without Hydrogen or Oil

A Vision for a Secure Transportation System Without Hydrogen or Oil

Shear Lag in Bolted Single Aluminum Angle Tension Members

Aluminum angles are widely used in engineering structures, examples of which include bracing in railcars, secondary members in ground transportation systems, scaffolding, and cooling towers. Often, aluminum angles are used as tension members with bolted end connections. Applicable design limit states include (a) yielding on the gross cross section, (b) tensile rupture through the net area, (c) progressive bearing failure, (d) bolt shear, and (e) block shear. As geometric considerations often preclude the connection of both legs of an angle, joint efficiency and tensile strength are reduced. The objectives of the experimental investigation include determination of the net section strength by physical tests of single aluminum angle tension members, examination of shear lag effects for several geometric parameters, and development of a more rational design approach.

Comparing Operating Characteristics of High-Speed Rail and Maglev Systems: Case Study of Beijing-Shanghai Corridor

The need for high-speed ground transportation systems (HSGT) has become more urgent than ever, evidenced by congestion in both urban and intercity travel. Congestion problems are no longer confined to densely developed urban areas or industrialized countries but also spread into suburban regions and developing countries. Characterized by high speed, operating reliability, passenger riding comfort, and an excellent safety record, HSGT presents a vital solution for our congestion problems, intercity or urban. There are two distinguished technologies under the general HSGT umbrella: high-speed rail (HSR) and magnetic levitation (Maglev). Sharing some common characteristics of HSGT, such as very high speed and riding comfort, these two technologies are dramatically different in guideway requirements, propulsion sources, operating characteristics, environmental impacts, and costs. Ongoing debates among the academic community have not presented any strong evidence to favor one over another in lieu of specific corridor alignment. A focus is on the engineering comparison of HSR and Maglev systems and their potential implementation in the Beijing and Shanghai corridor. It is undeniable that cost, political will, and social and cultural acceptance play vital roles in the eventual realization of any technology. An emphasis is on the overview of technology, comparison of operating characteristics of HSR and Maglev, and the implications of their potential application in a 1,300-km-long corridor from Beijing to Shanghai—the top economic, population, and culture engine in China.

Tomorrow's transportation: changing cities, economies, and lives

The Car and Traffic. Introduction The Car That Can Drive Itself. Congestion: The Devil We Know. What Are We Doing About It? A Better Strategy. Some New Kinds of Cars. The City and Transportation. Transportation and the Evolution of the City. The Modern Dilemma - What to Do? A New Kind of Mini-City. The Second-Story City. The Variegated City. Achieving Variegated Transportation for Variegated Cities. Energy and Emissions. Between Cities: Rail and Other Ground Transportation Systems. The Innovation That Changed the World: How Did it Happen? America and the Two-Step Dance. Where Are We Today? Where Would We Like to Go? Serendipity. Beyond Railroading: A New System. A Superspeed Highway. Big and Slow -- But Cheap! The Air Transportation System. To Grandmother's House We Fly. The Los Angeles Airport System - 2020 - 2040 - 2060. The New Millennium. Communication and Transportation. Optimism.

Operational stability enhancement analysis of a transverse flux linear switched-reluctance motor

This paper aims to analyze the electromagnetic force characteristics of a transverse flux linear switched-reluctance motor (TFLSRM) that is applicable for track-guided ground transportation and industrial automation systems. Stability enhancements on the three-dimensional (3-D) operational behaviors and application validity of this machine will be illustrated by both the finite element analysis (FEA) and the eigenvalue analysis. Besides, a supplemental comparison for flux guidance and force augmentation of a linear motor with and without permanent magnet implementation is investigated for practical consideration.

空力浮上形輸送システムの空力特性とその安定性に関する研究

New ground transport system, Ground Effect Transport System (GETS), which has potential for solving the green house problem of the earth by saving fuel to transport because the system is expected to have high lift-to-drag ratio, had been newly proposed, and fundamental investigations needed to develop such transport system has been conducted in university laboratory level. In the present study, some of the essential aerodynamic characteristics of an wing-in-ground effect of the GETS is investigated experimentally. Namely, effect of the tandem wing height from the ground and the wing interference are investigated. The results are compared with the numerical simulation results. It was shown that the effect of the interference of the wings could be ignored when the distance became more than 2.5 times the chord length of the wings. It was also found to be important that the boundary layer of the ground plate should be eliminated in the experimental study of such system that required very small gap between the wing and the ground plate.

New noise impact criteria for high-speed ground transportation systems in the United States

New noise impact criteria have been developed by the U. S. Department of Transportation for the assessment of environmental impacts of high-speed rail projects. The environmental impacts of new high-speed rail projects in the United States are the responsibility of the Federal Railroad Administration (FRA). Adoption of these criteria will assure a uniform treatment of noise impacts of new high-speed rail systems throughout the country. The noise impact levels were developed based on well-documented criteria, and on comprehensive social survey data concerning annoyance due to transportation noise. Impact levels are based on the Schultz response curve and include consideration of the combination of project and ambient noise levels. Correction terms are included in the case of high-speed rail (and maglev) to account for startle effects from fast rise times. This presentation discusses the basis for the curves used as thresholds of impact—where noise mitigation is to be considered—and severe impact—where noise mitigation must be implemented. These criteria are included in a new guidance manual published by the FRA on ‘‘High Speed Ground Transportation Noise and Vibration Impact Assessment’’ and will be used throughout the USA.

Mechatronics in ground transportation-current trends and future possibilities

The paper provides a review of the current and future impact of mechatronic technologies upon ground transportation systems. The basic idea of mechatronics is explained first, followed by an appraisal of social and environmental factors which dictate the fundamental requirements for ground transport. The way in which mechatronics has already affected the design of road and rail systems is described, and various indications are given regarding future mechatronic developments. Some concluding remarks bring together the various ideas in order to predict the long term possibilities from a full exploitation of mechatronics.

Dynamic Characteristics of Magnetically-Levitated Vehicle Systems

The dynamic response of magnetically-levitated (maglev) ground transportation systems has important consequences for safety and ride quality, guideway design, and system costs. This article, which reviews various aspects of the dynamic characteristics, experiments and analysis, and design guidelines for maglev systems, discusses electrodynamic system (EDS) maglev 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. This review article includes 157 references.

Mechatronics in Ground Transportation - Current Trends and Future Possibilities

The paper provides a review of the current and future impact of mechatronic technologies upon ground transportation systems. The basic idea of mechatronice is explained first, followed by an appraisal of social and environmental factors which dictate the fundamental requirements for ground transport The way in which mechatronics has already affected the design of road and rail systems is described, and some indications are given regarding future mechatronic developments. Some concluding remarks bring together the various ideas in order to predict the long term possibilities from a full exploitation of mechatronics.

Ultra-low-frequency ride motions and kinetosis

Proposed ultra-high-speed ground transportation systems, such as Maglev, may have motion characteristics affecting passenger comfort different from anything previously experienced in ground transportation. These motions not only include isolated vertical maneuvers but also repeated motions. For these repeated motions the power spectra is as important as the magnitude in predicting kinetosis. Segments of the New York State Thruway were simulated by flying an airliner through a series of several dozen roll maneuvers based on nine combinations of speed and curvature. The combinations were also simulated using a moving base simulator which provided a geometrically accurate ‘‘out of the window view.’’ Analysis of the data lead to the following conclusions: (1) More than 95% of the public would accept isolated maneuvers involving bank angles up to 37° and roll rates up to 7°/s. (2) The majority found the plane simulation comfortable and felt no motion sickness. Differences between subjects’ appear to have been greater than the physical effects of the differences in bank angle. (3) Cumulative dosage and duration of exposure showed significant correlation with the motion-sickness ratings procedure developed based on the work of M. J. Griffin and British Standard 6841:1987.

HSGT Corridor Planning: Land-Use and Other Considerations

This paper explores land-use and other considerations in planning for high-speed ground transportation (HSGT) systems in the United States. Beyond the critical issue of project financing, upon which all HSGT projects proposed to date in the United States have foundered, effective corridor planning (including route alignment and station siting decisions) will be key to the successful implementation of future HSGT project proposals in this country. The corridor planning process must consider many variable factors in deciding issues such as station locations, track/guideway routing and construction type, and overall route alignments. Additionally, there are many institutional factors, including community and environmental considerations as well as political and economic issues, which influence route selection and station location decisions. The general planning framework used throughout the United States (shaped, in large part, by federal regulations) is discussed, and comparisons are made with high-speed rail development in other countries, particularly the larger transportation policy issues that have enabled HSGT development elsewhere.