Analysis and comparison of Scalextric, SCX, and Carrera Digital slot car systems: A mechatronic engineering design case study

Digital slot cars operate by transmitting both power and data over a single pair of wires much like DCC-controlled model railways and some home automation systems. In this manuscript we analyse and compare the cars, track, controllers, and electronic data transmission protocols of the three popular digital slot car systems

Design and Switching Performance Evaluation of a 10 kV SiC MOSFET Based Phase Leg for Medium Voltage Applications

10 kV SiC MOSFETs are promising to substantially boost the performance of future medium voltage (MV) converters, ranging from MV motor drives to fast charging stations for electric vehicles (EVs). Numerous factors influence the switching performance of 10 kV SiC MOSFETs with much faster switching speed than their Si counterparts. Thorough evaluation of their switching performance is necessary before applying them in MV converters. Particularly, the impact of parasitic capacitors in the MV converter and the freewheeling diode is investigated to understand the switching performance more comprehensively and guide the converter design based on 10 kV SiC MOSFETs.A 6.5 kV half bridge phase leg based on discrete 10 kV/20 A SiC MOSFETs is designed and fully validated to operate continuously at rated voltage with dv/dt up to 80 V/ns. Based on the phase leg, the impact of parasitic capacitors brought by the load inductor and the heatsink on the switching transients and performance of 10 kV SiC MOSFETs is investigated. Larger parasitic capacitors result in more oscillations, longer switching transients, as well as higher switching energy loss especially at low load current. As for the freewheeling diode, the body diode of 10 kV SiC MOSFETs is suitable to serve as the freewheeling diode, with negligible reverse recovery charge at various temperatures. The switching performance with and without the anti-parallel SiC junction barrier Schottky (JBS) diode is compared quantitatively. It is not recommended to add an anti-parallel diode for the 10 kV SiC MOSFET in the converter because it increases the switching loss

The Jet Propulsion Laboratory Electric and Hybrid Vehicle System Research and Development Project, 1977-1984: A Review

The JPL Electric and Hybrid Vehicle System Research and Development Project was established in the spring of 1977. Originally administered by the Energy Research and Development Administration (ERDA) and later by the Electric and Hybrid Vehicle Division of the U.S. Department of Energy (DOE), the overall Program objective was to decrease this nation's dependence on foreign petroleum sources by developing the technologies and incentives necessary to bring electric and hybrid vehicles successfully into the marketplace. The ERDA/DOE Program structure was divided into two major elements: (1) technology research and system development and (2) field demonstration and market development. The Jet Propulsion Laboratory (JPL) has been one of several field centers supporting the former Program element. In that capacity, the specific historical areas of responsibility have been: (1) Vehicle system developments (2) System integration and test (3) Supporting subsystem development (4) System assessments (5) Simulation tool development

Towards a human body model for prediction of vehicle occupant kinematics in omni-directional pre-crash events

As the vehicle fleet becomes more equipped with crash avoidance systems, the proportion of crashes preceded by evasive manoeuvres is expected to increase. In an evasive manoeuvre, occupant position and posture can be influenced by the induced loading. Therefore, there is a need to predict the occupant response from evasive manoeuvres. During evasive manoeuvres, the occupant kinematics can also be affected by muscle activity, and as such, taking the effect from active muscles into account in simulations of occupant response to evasive manoeuvres is important.In this thesis, a method for activation of the neck and lumbar muscles in an active human body model, based on recorded muscle activity from volunteers, was enhanced and evaluated. The active human body model successfully predicted passenger kinematics in lane change, braking, and combined manoeuvres. As a step towards a model capable of predicting driver kinematics in evasive manoeuvres, the same method was adapted to control the shoulder muscles. The model with active shoulder muscles was evaluated in a simplified test setup. The active model successfully predicted peak elbow displacement for all loading directions.Based on the results from the included studies, an active muscle controller based on directionally dependent muscle activity data can successfully predict kinematics from reflex response to loading in a finite element human body model. These findings represent an important step towards developing an active human body model able to predict occupant kinematics and muscle forces in omni-directional pre-crash events

Precision measurement of carbon isotope ratio in exhaled breath for the detection of helicobacter pylori

The utility of breath trace compounds as bio-markers for various physiological conditions has long been exploited for the diagnosis of various diseases. Urea breath tests have been adopted as the gold standard for the detection of Helicobacter pylori which is a primary cause for acute gastritis and peptic ulcers. In these tests, small changes in the ratio of stable CO2 isotopomers, 13CO2 and 12CO2, present in exhaled breath are measured precisely and this is conventionally done by using anIsotope Ratio Mass Spectrometer. However, the huge cost and complexity involved in operating these instruments has restricted their widespread use. A viable and low cost alternative is offered by instruments employing non-dispersive infrared absorption techniques. The feasibility of such an instrument has been explored in this work.The instrument presented here is a two channel isotope ratiometer that performs whole band integrated absorption measurements. Detection is based on a novel feedback mechanism whereby an imbalance in the channel absorptions causes the pathlength along one of the channels to be altered in order to bring the system back to balance. This change in ratio of pathlengths is directly related to thechange in the 13CO2/12CO2 concentration. Significant amount of work has already been done to investigate the effects of interferences from coincident absorption bands and other spectral effects that can lead to spurious results.A comprehensive description of the overall system design, development and performance evaluation of the first prototype instrument has been presented here. This involved significant computer modeling and simulations and the results were verified experimentally. These results provided sufficient evidence to suggest the feasibility of such an instrument as a diagnostic tool. It was also concluded that some design improvements were required to circumvent issues related to pathlength variation and a list of recommendations has been provided for this purpose. On the basis of the results obtained as part of this research endeavour, it was concluded that the non-dispersive instrument design presented here can form the basis for a low cost commercial alternative for performing carbon isotope ratio breath tests.</p

Sustainable seabed mining: guidelines and a new concept for Atlantis II Deep

The feasibility of exploiting seabed resources is subject to the engineering solutions, and economic prospects. Due to rising metal prices, predicted mineral scarcities and unequal allocations of resources in the world, vast research programmes on the exploration and exploitation of seabed minerals are presented in 1970s. Very few studies have been published after the 1980s, when predictions were not fulfilled. The attention grew back in the last decade with marine mineral mining being in research and commercial focus again and the first seabed mining license for massive sulphides being granted in Papua New Guinea’s Exclusive Economic Zone.Research on seabed exploitation and seabed mining is a complex transdisciplinary field that demands for further attention and development. Since the field links engineering, economics, environmental, legal and supply chain research, it demands for research from a systems point of view. This implies the application of a holistic sustainability framework of to analyse the feasibility of engineering systems. The research at hand aims to close this gap by developing such a framework and providing a review of seabed resources. Based on this review it identifies a significant potential for massive sulphides in inactive hydrothermal vents and sediments to solve global resource scarcities. The research aims to provide background on seabed exploitation and to apply a holistic systems engineering approach to develop general guidelines for sustainable seabed mining of polymetallic sulphides and a new concept and solutions for the Atlantis II Deep deposit in the Red Sea.The research methodology will start with acquiring a broader academic and industrial view on sustainable seabed mining through an online survey and expert interviews on seabed mining. In addition, the Nautilus Minerals case is reviewed for lessons learned and identification of challenges. Thereafter, a new concept for Atlantis II Deep is developed that based on a site specific assessment.The research undertaken in this study provides a new perspective regarding sustainable seabed mining. The main contributions of this research are the development of extensive guidelines for key issues in sustainable seabed mining as well as a new concept for seabed mining involving engineering systems, environmental risk mitigation, economic feasibility, logistics and legal aspects

Powertrain modelling for engine stop-start dynamics and control of micro/mild hybrid construction machines

Engine stop-start control is considered as the key technology for micro/mild hybridisation of vehicles and machines. To utilize this concept, especially for construction machines, the engine is desired to be started in such a way that the operator discomfort can be minimized. To address this issue, this paper aims to develop a simple powertrain modelling approach for engine stop-start dynamic analysis and an advanced engine start control scheme newly applicable for micro/mild hybrid construction machines. First, a powertrain model of a generic construction machine is mathematically developed in a general form which allows to investigate the transient responses of the system during the engine cranking process. Second, a simple parameterisation procedure with a minimum set of data required to characterise the dynamic model is presented. Third, a model- based adaptive controller is designed for the starter to crank the engine quickly and smoothly without the need of fuel injection while the critical problems of machine noise, vibration and harshness can be eliminated. Finally, the advantages and effectiveness of the proposed modelling and control approaches have been validated through numerical simulations. The results imply that with the limited data set for training, the developed model works better than a high fidelity model built in AMESim while the adaptive controller can guarantee the desired cranking performance

Design, set up and commissioning of a test facility for smokeless rich diesel combustion research

Low Temperature Combustion (LTC) is a strategy that harnesses the properties of exhaust gas, through the use of large quantities of exhaust gas recirculation (EGR), to reduce the peak combustion temperatures below that favoured by the formation processes of oxides of nitrogen (Ox) and those of soot. There is interest within the fuels research community in investigating the effects of diesel fuel formulations on LTC, using a suitable engine test platform. The objective of this study was to design and set up a test apparatus capable of achieving LTC in a diesel research engine, that could subsequently be used to study LTC behaviour with different fuels. In addition, it was necessary to present test data demonstrating the engine's performance, in terms of engine-out emissions and indicated specific fuel consumption (ISFC), transitioning between conventional diesel combustion (CDC) and LTC. The mechanical, electrical and control requirements for attaining CDC and LTC conditions were investigated in the literature and through consultations with experts in the fuels research field. These requirements were distilled into a definitive System Requirement Specification

Design Analysis of a Sapce Based Chromotomographic Hyperspectral Imaging Experiment

This research develops the design of several components and/or systems for an experimental space-based chromotomographic hyperspectral imager that is being built by the Air Force Institute of Technology. The design work includes three separate topics. The first topic was the development of a structure utilizing finite element analysis and eigenanalysis for the ground-based version of the chromotomographic experiment (CTEx). The ground-based experiment was performed as a risk mitigation measure for the space-based experiment. The second topic includes a design review of a contractor\u27s proposed off-axis Mersenne telescope for the space-based chromotomographic hyperspectral imager. The work included the creation of preliminary verification requirements from the contract and sub- sequent analysis of the telescope design based on those requirements. The third topic addressed was a trade study of on-orbit focus, alignment, and calibration schemes for the space-based version of CTEx. The selected imaging focusing method entails imaging Earth-based sodium lights at night while stepping through several focus settings. The optimal focus setting shows the clearest sodium spectral features. The critical alignment concerns were identified as the alignment of the prism and of the collimated light onto the prism. The space-based CTEx utilizes three separate calibration methods involving vicarious Earth-based targets, and on-board laser diodes and spectral filters. The results of the research varied by topic. For the first topic, a structural assembly was successfully fabricated that allowed the goals of the ground-based CTEx to be met, validating the design approach. The design review for the second topic was successful with the contractor\u27s telescope design currently undergoing fabrication with delivery in May 2010. For the third topic, applicable methods and procedures were developed for the space-based CTEx