Effective Friction Control for Optimization of High Speed Rail Operations

2010 ◽  
Author(s):  
Donald T. Eadie ◽  
Kevin Oldknow ◽  
Yasushi Oka ◽  
Ron Hui ◽  
Peter Klauser ◽  
...  
Keyword(s):  
High Speed ◽  
High Performance ◽  
High Reliability ◽  
Ride Quality ◽  
Oil And Grease ◽  
High Speed Rail ◽  
Wear Rates ◽  
Friction Control ◽  
Very High ◽  
Effective Friction

Expected growth of High Speed Rail (HSR) in North America will in many instances involve operation on existing infrastructure, shared with other traffic. This will pose many challenges, not least of which will be wheel and rail wear, and ride quality. This paper addresses how effective friction control can be employed to mitigate these factors and provide an important tool to the designers of new systems. Case studies describe successful use of train mounted solid stick LCF flange lubrication on high speed trains in East Asia and Japan. In each case, higher speed train operation has involved operation on areas of track with greater curvature than usual on dedicated high speed track. Appropriately designed LCF systems provide an inherently very high level of reliability and very low flange wear rates. Use of dry thin film lubricant technology has advantages over use of liquid lubricants (oil and grease) which can experience splash and fling off at high train speeds. Train mounted solid sticks provide greater consistency / reliability and ease of maintenance compared with wayside gauge face lubrication. Complementing practical field experience, modeling studies are presented which show the potential of high performance flange lubrication to allow for additional flexibility in designing wheel profiles for high speed rail. The ideal profile will balance vehicle stability (benefiting from lower conicity) and curving performance (benefiting from higher conicity). In a high speed train with long wheel base and high suspension stiffness operating in areas with significant curvature, finding an appropriate compromise becomes even more challenging than usual. Controlling flange wear at low rates with highly effective solid stick lubrication offers the opportunity to use wheel profiles providing lower effective conicity and therefore better ride quality, without compromising wheel life. This approach will be practical only in a scenario where a very high reliability wheel / rail lubrication system is employed.

Multiple CMOS Intersection Measuring System Modeling and Analysis

2012 ◽  
Vol 614-615 ◽  
pp. 1299-1302
Author(s):  
Ming Jing Li ◽  
Yu Bing Dong ◽  
Guang Liang Cheng
Keyword(s):  
High Speed ◽  
High Performance ◽  
High Reliability ◽  
System Modeling ◽  
Position Effect ◽  
Field Of View ◽  
Measuring System ◽  
Price Ratio ◽  
Matlab Simulation ◽  
Modeling And Analysis

Multiple high speed CMOS cameras composing intersection system to splice large effect field of view(EFV). The key problem of system is how to locate multiple CMOS cameras in suitable position. Effect field of view was determined according to size, quantity and dispersion area of objects, so to determine camera position located on below, both sides and ahead to moving targets. This paper analyzes effect splicing field of view, operating range etc through establishing mathematical model and MATLAB simulation. Location method of system has advantage of flexibility splicing, convenient adjustment, high reliability and high performance-price ratio.

New Generation of Brake Callipers to Improve Competitiveness and Energy Savings in Very High Performance Cars

2014 ◽  
Vol 217-218 ◽  
pp. 471-480
Author(s):  
Ivano Gattelli ◽  
Gian Luigi Chiarmetta ◽  
Marcello Boschini ◽  
Renzo Moschini ◽  
Mario Rosso ◽  
...  
Keyword(s):  
High Pressure ◽  
High Performance ◽  
Energy Savings ◽  
High Reliability ◽  
A357 Alloy ◽  
Bench Tests ◽  
Heat Treated ◽  
New Generation ◽  
Non Destructive ◽  
Very High

This paper concerns with the optimisation of the innovative rheocasting process to produce a new generation of brake callipers, characterised by very high reliability and strength. The attained very promising properties favoured their use on a very high performance car and the presented technique can be further extended for other important challenging applications. The prototype components are produced using T6 heat treated A357 alloy. Results on the samples machined directly from the produced callipers are in detail described and analysed. Pieces exhibiting some small defects, individuated by non-destructive tests, as well as defectless pieces have been underlined to severe industrial tests, e.g. high pressure tight, as well as severe bench tests, and it has been observed that the proposed technological process assure the fulfilment of the requirements contained in standards.

scholarly journals Impact of fractional order methods on optimized tilt control for rail vehicles

2017 ◽  
Vol 20 (3) ◽  
Author(s):  
Fazilah Hassan ◽  
Argyrios Zolotas
Keyword(s):  
Fractional Order ◽  
High Speed ◽  
Control Design ◽  
Ride Quality ◽  
Dynamic Interactions ◽  
High Speed Rail ◽  
Control Applications ◽  
Railway Systems ◽  
Methods Analytical ◽  
The Impact

AbstractAdvances in the use of fractional order calculus in control theory increasingly make their way into control applications such as in the process industry, electrical machines, mechatronics/robotics, albeit at a slower rate into control applications in automotive and railway systems. We present work on advances in high-speed rail vehicle tilt control design enabled by use of fractional order methods. Analytical problems in rail tilt control still exist especially on simplified tilt using non-precedent sensor information (rather than use of the more complex precedence (or preview) schemes). Challenges arise due to suspension dynamic interactions (due to strong coupling between roll and lateral dynamic modes) and the sensor measurement. We explore optimized PID-based non-precedent tilt control via both direct fractional-order PID design and via fractional-order based loop shaping that reduces effect of lags in the design model. The impact of fractional order design methods on tilt performance (track curve following vs ride quality) trade off is particularly emphasized. Simulation results illustrate superior benefit by utilizing fractional order-based tilt control design.

4H-SIC Dmosfets for High Frequency Power Switching Applications

2003 ◽  
Vol 764 ◽  
Author(s):  
Sei-Hyung Ryu ◽  
Anant K. Agarwal ◽  
James Richmond ◽  
John W. Palmour
Keyword(s):  
High Voltage ◽  
High Speed ◽  
High Performance ◽  
High Frequency Power ◽  
Power Devices ◽  
Power Switching ◽  
High Speed Switching ◽  
Unipolar Devices ◽  
Very High ◽  
Frequency Power

AbstractVery high critical field, reasonable bulk electron mobility, and high thermal conductivity make 4H-Silicon carbide very attractive for high voltage power devices. These advantages make high performance unipolar switching devices with blocking voltages greater than 1 kV possible in 4H-SiC. Several exploratory devices, such as vertical MOSFETs and JFETs, have been reported in SiC. However, most of the previous works were focused on high voltage aspects of the devices, and the high speed switching aspects of the SiC unipolar devices were largely neglected. In this paper, we report on the static and dynamic characteristics of our 4H-SiC DMOSFETs. A simple model of the on-state characteristics of 4H-SiC DMOSFETs is also presented.

III-V HETEROJUNCTION BIPOLAR TRANSISTORS FOR HIGH-SPEED APPLICATIONS

1990 ◽  
Vol 01 (03n04) ◽  
pp. 245-301 ◽  
Author(s):  
M.F. CHANG ◽  
P.M. ASBECK
Keyword(s):  
Integrated Circuits ◽  
Heterojunction Bipolar Transistors ◽  
High Speed ◽  
High Performance ◽  
Growth Parameters ◽  
Bipolar Transistors ◽  
System Requirements ◽  
Potential Impact ◽  
Computational Systems ◽  
Very High

Recent advances in communication, radar and computational systems demand very high performance electronic circuits. Heterojunction bipolar transistors (HBTs) have the potential of providing a more efficient solution to many key system requirements through intrinsic device advantages than competing technologies. This paper reviews the present status of GaAs and InP-based HBT technologies and their applications to digital, analog, microwave and multifunction circuits. It begins with a brief review of HBT device concepts and critical epitaxial growth parameters. Issues important for device modeling and fabrication technologies are discussed. The paper then highlights the performance and the potential impact of HBT devices and integrated circuits in various application areas. Key prospects for future HBT development are also addressed.

Design Considerations in the Development of a North American High Speed Turnout

2010 ◽  
Author(s):  
Brian C. Abbott ◽  
Tom Lee ◽  
Gary Click ◽  
Steve Mattson ◽  
Ken W. Ouelette
Keyword(s):  
North American ◽  
High Speed ◽  
Support Systems ◽  
Ride Quality ◽  
Lateral Loads ◽  
High Speed Rail ◽  
Design Elements ◽  
Entire Vehicle ◽  
Axle Loads ◽  
New Generation

North American turnout and special trackwork design has evolved in an operating environment in which axle loads have increased significantly but operating speeds have remained modest. Consequently, while trackwork components have become much more robust, turnout geometries and overall system design has remained essentially static for many decades. Implementation of high speed rail (“HSR”) in North America will necessitate a radically different approach to turnout engineering. While there is much to be learned from European and Asian experience with high speed, it is anticipated that vehicle designs and mixed freight access will result in much greater axle loads. The combination of operating speed and loading will present unique challenges. Critical design elements for North America’s new generation of HSR turnouts will include: a) Compound geometries to optimize ride quality and safety while keeping overall lengths within manageable limits. b) Fastening and horizontal support systems to withstand high dynamic lateral loads. c) Dampening systems to attenuate high frequency vibration. d) Detailing such as rail seat canting and kinematic gauge optimization to enhance ride quality and increase component life. e) High modulus vertical support systems. f) Drive and locking systems specifically tailored to long HSR layouts. Regulations governing the layout and maintenance tolerances of North American turnouts will also have to be re-examined with the advent of high speed rail. Complex geometries and rapid transient loading will render the conventional approach of limiting speeds based on calculated imbalance ineffective. Accurate and rational assessment of operating safety will demand the application of dynamic numeric modeling to the entire vehicle / turnout system.

Superconducting Interconnections in Future High Performance Systems

1987 ◽  
Vol 108 ◽  
Author(s):  
R. C. Frye
Keyword(s):  
Critical Current ◽  
High Speed ◽  
High Performance ◽  
Electronic Systems ◽  
Maximum Current Density ◽  
Maximum Current ◽  
High Performance Systems ◽  
Current Densities ◽  
Very High ◽  
Scaling Rule

ABSTRACTNew, high temperature superconducting materials could eventually be used for interconnections in electronic systems. Such interconnections would undoubtedly cost more to implement than conventional ones, so the most likely applications would be for complex, high-speed systems that could benefit from the performance advantages of a resistance-free interconnecting medium. The problem with conventional conductors in these systems is that the resistance of wires increases quadratically as dimensions are scaled down. The most important advantage offered by superconductors is that they are not linked to this scaling rule. Their principal limitation is the maximum current density that they will support and this determines the range of applications for which they are superior to conventional conductors. An analysis will be presented which examines the relative advantages of superconductors for different critical current densities, wire dimensions and system sizes.If their critical current densities are adequate, and if they can statisfy a number of processing criteria, then superconductors could find useful applications in a number of high performance electronic systems. The most likely applications will be those demanding very high interconnection densities. Several of these systems will be discussed.

Remote Ride Quality Monitoring of Acela Train Set Performance

Joint Rail ◽  
2002 ◽  
Author(s):  
Patrick Ackroyd ◽  
Steven Angelo ◽  
Boris Nejikovsky ◽  
Jeffrey Stevens
Keyword(s):  
Wireless Communications ◽  
Remote Monitoring ◽  
High Speed ◽  
High Reliability ◽  
Real Life ◽  
Ride Quality ◽  
Monitoring Systems ◽  
Car Body ◽  
Central Processing ◽  
Remote Monitoring Systems

Federal Track Safety Standards require daily measurements of car body and truck accelerations on trains operating at speeds above 125-MPH. In compliance with this requirement, twelve high-speed Acela coaches, operating in the Northeast Corridor between Boston, MA, and Washington DC, have been equipped with remote monitoring systems. The systems provide continuous measurement of car body and truck motions, detect various acceleration events, tag them with GPS time and location information, and deliver the data to Central Processing Stations through wireless communications channels. The Central Processing Stations installed at the National Railroad Passenger Corporation (Amtrak) and ENSCO, Inc., headquarters provide email and pager notifications to designated Amtrak officers and also make the data available to them over secure Intranet and Internet connections. The overall architecture has multiple levels of protection and redundancy in order to ensure high reliability and availability of the service. The systems have been in continuous operation for over a year and provided a multitude of valuable information. Examples of system-reported acceleration events include events caused by track irregularities and train handling. The paper also describes some of the real-life operational scenarios and situations that arise when autonomous remote monitoring systems are used, including wireless communications coverage issues, GPS location pitfalls, and maintenance issues.

High Temperature Silicon Carbide Power Modules for High Performance Systems

2011 ◽  
Vol 2011 (HITEN) ◽  
pp. 000159-000166 ◽  
Author(s):  
J. Hornberger ◽  
B. McPherson ◽  
J. Bourne ◽  
R. Shaw ◽  
E. Cilio ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
High Speed ◽  
High Performance ◽  
High Reliability ◽  
Extreme Environment ◽  
High Energy ◽  
Energy Applications ◽  
Power Modules ◽  
Reliability Systems

The demands of modern high-performance power electronics systems are rapidly surpassing the power density, efficiency, and reliability limitations defined by the intrinsic properties of silicon-based semiconductors. The advantages of silicon carbide (SiC) are well known, including high temperature operation, high voltage blocking capability, high speed switching, and high energy efficiency. In this discussion, APEI, Inc. presents two newly developed high performance SiC power modules for extreme environment systems and applications. These power modules are rated to 1200V, are operational at currents greater than 100A, can perform at temperatures in excess of 250 °C, and are designed to house various SiC devices, including MOSFETs, JFETs, or BJTs. One newly developed module is designed for high performance, ultra-high reliability systems such as aircraft and spacecraft, and features a hermetically sealed package with a ring seal technology capable of sustaining temperatures in excess of 400°C. The second module is designed for high performance commercial and industrial systems such as hybrid electric vehicles or renewable energy applications, implements a novel ultra-low parasitic packaging approach that enables high switching frequencies in excess of 100 kHz, and weighs in at just over 130 grams (offering ~5× mass reduction and ~3× size reduction in comparison with industry standard power brick packaging technology). It is configurable as either a half or full bridge converter. In this discussion, APEI, Inc. introduces these products and presents practical testing of each.

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