International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / Communications support for the X-33 requires addressing several unique challenges to meet program and range safety requirements. As an avenue to minimize costs, the program has reduced requirements to the communications system, which lowered the cost of networking the extended range. Cost trade-offs showed that by lowering the telemetry data rate from 2 Megabits per second to 1.440 Megabits per second that significant cost avoidance could be realized. Also, by adopting standard telecommunications data rate for the uplink data stream, an efficient and integrated solution for the extended range communications could be supported. Meeting the program requirements as well as range safety requirements for this effort are critical to the success of the program. This paper describes some of the important requirements driving the design of the extended range communications support and the design of the system to meet those requirements.

Large area high throughput metrology plays an important role in several technologies like MEMS. In current metrology systems the parallel operation of multiple metrology probes in a tool has been hindered by their bulky sizes. This study approaches this problem by developing a metrology technique based on miniaturized scanning grating interferometers (μSGIs). Miniaturization of the interferometer is realized by novel micromachined tunable gratings fabricated using SOI substrates. These stress free flat gratings show sufficient motion (~500nm), bandwidth (~50 kHz) and low damping ratio (~0.05). Optical setups have been developed for testing the performance of μSGIs and preliminary results show 6.6 μm lateral resolution and sub-angstrom vertical resolution. To achieve high resolution and to reduce the effect of ambient vibrations, the study has developed a novel control algorithm, implemented on FPGA. It has shown significant reduction of vibration noise in 6.5 kHz bandwidth achieving 6x10-5 nmrms/√Hz noise resolution. Modifications of this control scheme enable long range displacement measurements, parallel operation and scanning samples for their dynamic profile. To analyze and simulate similar optical metrology system with active micro-components, separate tools are developed for mechanical, control and optical sub-systems. The results of these programs enable better design optimization for different applications.

The x-ray atomic form-factor determines the x-ray optical properties of materials and is a fundamental parameter for critical x-ray investigations. However, despite uncertainty estimates of order 1%, differences of 2-10% between x-ray mass attenuation measurements render comparison with the various theoretical tabulations meaningless. Moreover, such uncertainties impose limits on the accuracy of various quantitative investigations. We determine the imaginary component of the atomic form-factor from measurements of the x-ray mass attenuation coefficient. With the exception of the measurements of Tran et.al. [Phys. Rev. A 64, (062506); 67, (042716); J. Phys. B 38, (89)] with a 0.3% accuracy, previous work has been unable to achieve accuracies below 1%, and differences between results claiming this accuracy often exceed 6%.We have developed a full-foil mapping technique which has improved the measurement accuracy by an order of magnitude. This technique overcomes limitations arising from absorber thickness variations, using the average integrated column density and attenuation measurements across the entire surface of the absorber. We have examined measurements obtained over a wide range of parameter space for systematic deviations indicative of experimental error. Among others, this has led to the identification and correction of a 1% discrepancy arising from the x-ray bandwidth. Resulting measurement accuracies for molybdenum are 0.02-0.15%. Preliminary results for tin suggest a final accuracy of 0.1-1%. We compare these measurements with several commonly-used tabulations and identify a number of systematic discrepancies whose causes are discussed.

The market segment of hybrid-electric and full function electric vehicles is growing within the automotive transportation sector. While many papers exist concerning fuel economy or fuel consumption and the limitations of conventional powertrains, little published work is available for vehicles which use grid electricity as an energy source for propulsion. Generally, the emphasis is put solely on the average drive cycle efficiency for the vehicle with very little thought given to propelling and braking powertrain losses for individual components. The modeling section of this paper will take basic energy loss equations for vehicle speed and acceleration, along with component efficiency information to predict the grid energy consumption in AC Wh/km for a given drive cycle. This paper explains how to calculate the forces experienced by a vehicle while completing a drive cycle in three different ways: using vehicle characteristics, United States Environmental Protection Agency's (EPA) Dynamometer "target" coefficients, and an adaptation of the Sovran parameters. Once the vehicle forces are determined, power and energy demands at the wheels are determined. The vehicle power demands are split into propelling, braking, and idle to aide in the understanding of what it takes to move a vehicle and to identify possible areas for improvement. Then, using component efficiency data for various parameters of interest, the energy consumption of the vehicle as a pure EV is supplied in both DC (at the battery terminals) and AC (from the electric grid) Wh/km. The energy that flows into and out of each component while the vehicle is driving along with the losses at each step along the way of the energy path are detailed and explained. The final goal is to make the results of the model match the vehicle for any driving schedule. Validation work is performed in order to take the model estimates for efficiencies and correlate them against real world data. By using the Virginia Tech Range Extended Crossover (VTREX) and collecting data from testing, the parameters that the model is based on will be correlated with real world test data. The paper presents a propelling, braking, and net energy weighted drive cycle averaged efficiency that can be used to calculate the losses for a given cycle. In understanding the losses at each component, not just the individual efficiency, areas for future vehicle improvement can be identified to reduce petroleum energy use and greenhouse gases. The electric range of the vehicle factors heavily into the Utility Weighted fuel economy of a plug-in hybrid electric vehicle, which will also be addressed. / Master of Science

With automobile propulsion energy sources turning away from petroleum, the evolution of technology naturally lends itself to electrical hybrid vehicle architectures relying on alternatives as a primary electrical energy source. This thesis presents a design solution of a direct-drive and drive-by-wire prototype of a hybrid extended range electric vehicle (EREV) based on a dune buggy test bed. The developed setup eliminates nearly all mechanical inefficiencies in the rear wheel drive transaxle drivetrain. All controls have been purposely designed as a duplicate set to allow for full independent control of both rear wheels in a truly independent architecture. Along with the controls supporting the design, the motors have been mounted in a near wheel fashion to adequately replace a true hub motor setup. In addition, by-wire throttle and by-wireless brakes in a servomechanical fashion have been developed. The by-wireless braking system is used to control regenerative braking for the rear of the vehicle only allowing for the front brakes to be the primary means of braking as well as a mechanical safety redundancy. This design allows for developments in the areas of truly independent electronic differential systems and studies of the effect of near wheel motor setup. The efficiencies gained by the design solutions implemented in this thesis project have shown their ability to be used in a functioning motor vehicle. Direct gains in mechanical efficiency as well as the removal of a non eco-friendly gasoline powertrain have been attained. In addition, an electric architecture has been developed for further research in future studies such as vehicle stability control, traction control and all-wheel-drive architectures.

In recent decades there has been a growing global concern with regards to vehicle-generated green house gas (GHG) emissions and the resulting air pollution. Currently, gasoline and diesel are the most widely used automotive fuels and are refined from crude oil which is a nonrenewable resource. When they are combusted in an Internal Combustion Engine (ICE) they release significant amounts of air pollutants and Green House Gasses (GHG’s), such as NOx, CO2, SOx, CO, and PM10 into the atmosphere. The results of a feasibility study indicate that intermediary automotive propulsion systems are needed in order to begin a transition from fossil fuels to a clean, renewable transportation system. The Extended Range Electric Vehicle (E-REV) has been identified as an ideal intermediate vehicle technology. In this context, the objective of this thesis is to establish the scientific and engineering fundamentals for the design and development of a Dual-Fuel (hydrogen + Gasoline) Power Generation System for the E-REV sustainable mobility architecture. The devised power generation system is comprised of hydrogen and gasoline storage reservoirs, their respective fuelling systems, a Spark Ignition Internal Combustion Engine (SI ICE), an electric generator, batteries, as well as supplementary electronic systems. The batteries are used to provide power directly to the electric motors and are recharged with both the on-board electric generator and via plug-in capabilities. The developed prototype vehicle, which used a commercial Dune Buggy as a test bed, combined with the on-board rechargeable LiFePO4 battery pack, can provide the users with a daily commute range of ~ 65 [km] relying solely on the battery’s electric power, whereas for longer duration trips the use of the on-board generator would be necessary. The developed Dual-Fuel E-REV power generation system offers the following benefits when compared to the original gasoline ICE architecture: reduced emissions, improved acceleration (47% ↑), improved range (75% ↑), improved fuel economy (22% ↑) and decreased average fuel cost/km (29% ↓).