A Variable Free Control Characteristic Vehicle

A variable characteristic car (VCC) has been developed at Melbourne University for driverlvehicle handling research. The vehicle is unusual in that it has facilities for varying both its fixed control and free control dynamic characteristics over wide ranges. In this paper the servo systems used to effect these changes are described. The calibration methods used to relate the vehicle response characteristics to the variable servo settings are detailed. Sample calibration results are given for the fixed control parameters steering ratio, yaw response time and stability factor. Calibration of the free control parameters is also described and results are given for the steering torque gradient, and the time-to-peak and percentage overshoot of the steering wheel motion in response to a step input of torque.     

为英国市场提供的改进型电动车组Desiro UK

Siemens公司为英国铁路区间交通开发了能适应当地各种不同需要的动车组家族Desiro UK.动车组设计考虑了两种不同的电流制、不同的车辆和列车长度以及端车的两种不同车头形式.主要影响牵引设备和车辆控制设计的准入程序是一特殊的挑战.     

Modeling and Dynamics of Friction Wedge Dampers in Railroad Freight Trucks

A mechanical model for the vertical response of the bolster and friction-wedge suspension elements in a railroad freight truck is developed. The model incorporates linear stiffnesses and dry friction contact between rigid elements. Numerical bifurcation diagrams for sticking events, obtained for parameterizations of the amplitude and frequency of a harmonic track excitation, and for various friction laws, reveal distinct parameter-dependent dynamic responses: strongly nonlinear stick-slip oscillations, observed away from period-1 resonance; and weakly nonlinear, nearly harmonic responses, observed near the period-one resonance. The analytical method of harmonic balance is applied to develop a first order approximation for the period-1 response, and, as should be expected, is found to correspond well with the numerical results in the large amplitude limit and near the resonance location. Given that such weakly nonlinear, large amplitude, period-1 responses are not common for the speeds and system parameters of most freight vehicles, we conclude that friction-wedge models based on some form of equivalent linearization may be inadequate for simulating freight car dynamics in many cases of practical importance.     

Theoretical Analysis of a Semi Active Suspension Fitted to an Off-Road Vehicle

A theoretical analysis is presented to model a hydromechanical, semi-active suspension system, first as a single wheel station and then as fitted to each wheel of an off-road vehicle. Predicted results show that two benefits are obtained by comparison with the equivalent passive system. First, vehicle attitude is controlled for changes in body forces arising from static loads or braking/cornering inputs. Second, a significant improvement in ride comfort is obtained because low suspension stiffnesses can be used.     

Shorter sea routes as a result of increasing cargo flows

This paper examines the apparent paradox involved in shipping lines responding to increasing cargo flows from Britain to mainland Europe by moving to shorter routes. Analysis shows, however, this move to be a logical and valuable defensive response by shipping lines but at a cost to the transport consumer.     

Contributors to this issue

Contributors to this issue     

INTERFERON γ－INDEPENDENT EFFECTS OF INTERLEUKIN 12 ADMINISTERED DURING ACUTE OR ESTABLISHED INFECTION DUE TO LEISHMANIAMAJOR

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Trip characteristics of selected israeli cities

Over the last 15 years travel patterns were investigated in 15 urban settlements in Israel. The results indicate an unusual combination of high trip generation by dwelling unit and low motorization rates.The diversity of socio-economic characteristics of population groups, as well as that of city size distribution, are reflected both in motorization rates and in trip generation.     

Pedestrianisation: London's Oxford Street experiment

Oxford Street in London, is the capital's principal shopping street and famous throughout the Western World; it is also the most obvious route from the city of London to the West, the Midlands and the North of England.The conflict between its twin roles of shopping centre and major traffic route was demonstrated in its accident record which put Oxford Street top of the list of accident blackspots in London, whilst its location in the most fashionable area of London make the costs of new road construction prohibitive.A comprehensive accident analysis defined the pedestrian/vehicle conflict by time and place and facilitated the detail design of a limited traffic ban with associated rerouting.Considerable uncertainties in prediction of the resulting traffic conditions, in the absence of data on demand elasticity, dominated the design of the experiment and led to the inclusion of an avert chaos policy. Traffic predictions which included details of the probable manner in which congestion would spread were assisted by a new network simulation model developed by one of the authors and described here.The report outlines the history of the experiment from conception to implementation (in record time) and reports some early and generally encouraging results. On the strength of which the Greater London Council has confirmed the scheme (August 1973) and has announced plans for its extension to the remaining half of Oxford Street — from Oxford Circus to St. Giles' Circus — which still carries the full weight of traffic.Previously undertaking doctoral research at Imperial College, London.