Dissertations / Theses on the topic 'Vehicle range'
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Papadopoulos, Geōrgios. "Underwater vehicle localization using range measurements." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62531.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 79-83).
This thesis investigates the problem of cooperative navigation of autonomous marine vehicles using range-only acoustic measurements. We consider the use of a single maneuvering autonomous surface vehicle (ASV) to aid the navigation of one or more submerged autonomous underwater vehicles (AUVs), using acoustic range measurements combined with position measurements for the ASV when data packets are transmitted. The AUV combines the data from the surface vehicle with its proprioceptive sensor measurements to compute its trajectory. We present an experimental demonstration of this approach, using an extended Kalman filter (EKF) for state estimation. We analyze the observability properties of the cooperative ASV/AUV localization problem and present experimental results comparing several different state estimators. Using the weak observability theorem for nonlinear systems, we demonstrate that this cooperative localization problem is best attacked using nonlinear least squares (NLS) optimization. We investigate the convergence of NLS applied to the cooperative ASV/AUV localization problem. Though we show that the localization problem is non-convex, we propose an algorithm that under certain assumptions (the accumulative dead reckoning variance is much bigger than the variance of the range measurements, and that range measurement errors are bounded) achieves convergence by choosing initial conditions that lie in convex areas. We present experimental results for this approach and compare it to alternative state estimators, demonstrating superior performance.
by Georgios Papadopoulos.
S.M.
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Hui, Corinna. "Laser Range Finder Mapping of Floating Vehicle." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54476.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 48).
Using laser range finders as a method of navigation is popular with mobile land robots; however, there has been little research using it with water vehicles. Therefore, this thesis explores the usage and data flow of a laser range finder on a water raft. A unique algorithm for localization and mapping for the sensor is developed and tested both in simulation and in realtime with a vehicle. Both the localization of the vehicle and mapping of its environment are able to achieve precise locations, deviating only a few millimeters of their expected values. With this algorithm, a closed-loop control system is also developed and implemented on the vehicle. The vehicle is able to move to a predefined location and be within a very small range of acceptable values. The control loop is further explored with damping, gain variations, and different trajectories..
by Corinna Hui.
S.B.
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Kersop, Stefanus Jacobus. "Short range reconnaissance unmanned aerial vehicle / S.J. Kersop." Thesis, North-West University, 2009. http://hdl.handle.net/10394/9171.
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Unmanned aerial vehicles (UAVs) have been used increasingly over the past few years. Special Forces of various countries utilise these systems successfully in war zones such as Afghanistan. The biggest advantage is rapid information gathering without endangering human lives.
The South African National Defence Force (SANDF) also identified the need for local short range aerial reconnaissance and information gathering. A detailed literature survey identified various international players involved in the development of small hand-launch UAV systems. Unfortunately, these overseas systems are too expensive for the SANDF. A new system had to be developed locally to comply with the unique requirements, and budget, of the SANDF.
The survey of existing systems provided valuable input to the detailed user requirement statement (URS) for the new South African development. The next step was to build a prototype using off-the-shelf components. Although this aircraft flew and produced good video images, it turned out to be unreliable.
The prototype UAV was then replaced with a standard type model aircraft, purchased from Micropilot. Some modifications were needed to ensure better compliance with the URS. Laboratory and field tests proved that the aircraft can be applied for aerial images, within range of 10 km from the ground control station (GCS). The major limitation is that it can only fly for 40 minutes. Furthermore, the airframe is not robust, needing repairs after only 15 flights.
Although the system has shortcomings, it has already been used successfully. It is expected that improved battery technologies and sturdier light-weight materials will further help to improve the system beyond user specifications.Thesis (MIng (Electrical Engineering))--North-West University, Potchefstroom Campus, 2010.
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Westrick, Michael A. "Compact Wire Antenna Array for Dedicated Short-Range Communications: Vehicle to Vehicle and Vehicle to Infrastructure Communications." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1345081406.
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Jabari, Rami Steve. "Range-Based Autonomous Underwater Vehicle Navigation Expressed in Geodetic Coordinates." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71426.
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Unlike many terrestrial applications, GPS is unavailable to autonomous underwater vehicles (AUVs) while submerged due to the rapid attenuation of radio frequency signals in seawater. Underwater vehicles often use other navigation technologies. This thesis describes a range-based acoustic navigation system that utilizes range measurements from a single moving transponder with a known location to estimate the position of an AUV in geodetic coordinates. Additionally, the navigation system simultaneously estimates the currents acting on the AUV. Thus the navigation system can be used in locations where currents are unknown.
The main contribution of this work is the implementation of a range-based navigation system in geodetic coordinates for an AUV. This range-based navigation system is implemented in the World Geodetic System 1984 (WGS 84) coordinate reference system. The navigation system is not restricted to the WGS 84 ellipsoid and can be applied to any reference ellipsoid. This thesis documents the formulation of the navigation system in geodetic coordinates. Experimental data gathered in Claytor Lake, VA, and the Chesapeake Bay is presented.Master of Science
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Gantt, Lynn Rupert. "Energy Losses for Propelling and Braking Conditions of an Electric Vehicle." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/32879.
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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 Agencyâ s (EPA) Dynamometer â targetâ 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
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Devarakota, Pandu Ranga Rao. "Classification and Localization of Vehicle Occupants Using 3D Range Images." Doctoral thesis, Stockholm : Elektrotekniska system, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4603.
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Knutsen, Daniel, and Oscar Willén. "A study of electric vehicle charging patterns and range anxiety." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-201099.
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Range anxiety is a relatively new concept which is defined as the fear of running out of power when driving an electric vehicle. To decrease range anxiety you can increase the battery size or decrease the minimum state of charge, the least amount of power that can be left in the battery, or to expand the available fast charging infrastructure. But is that economical feasible or even technically possible in today’s society? In this project we have used a theoretical model for estimating range anxiety and have simulated the average electricity consumption using two different kinds of electric vehicles, to see how often they reach range anxiety according to a specific definition of range anxiety implemented in this model. The simulations were performed for different scenarios in order to evaluate the effect of different parameters on range anxiety. The result that we got were that range anxiety can be decreased with bigger batteries but to get range anxiety just a few times a year you have to use battery sizes which aren’t economical feasible today. Despite the shortcomings of todays electric vehicles there are promising new and future technologies such as better batteries which might help alleviate range anxiety for electric vehicle owner. The conclusion from this study is that in the present fleet of electric vehicles is in need of more charging stations and faster charging to get by the problem with range anxiety and having a chance to compete with gasoline and diesel vehicles.
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Burke, William Churchill Taliaferro. "Large Force Range Mechanically Adjustable Dampers for Heavy Vehicle Applications." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/33386.
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Semi-active dampers utilizing various working principles have been developed for a variety of vehicles. These semi-active dampers have been designed to resolve the ride and handling compromise associated with conventional passive dampers, and increase vehicle stability. This thesis briefly reviews existing semi-active damper designs, including but not limited to MR dampers, before presenting two new prototype semi-active hydraulic dampers. Both prototype dampers are designed to provide a large force range while maintaining easily controllable valve characteristics.
The first of these dampers served primarily as a proof of concept and a means of understanding the dynamics of a disc valve housed inside the main piston. The valve design is presented, along with other information concerning the fabrication of the Initial Prototype damper. Test results are presented and analyzed, and a second iteration of the valve is designed. The Final Prototype damper is a scaled up version of the initial design, with refinements made in piston geometry, internal disc profile, and dynamic seals. This large force range damper is tested and results are compared with existing MR dampers. The Final Prototype damper provides a significantly larger force range when compared with typical MR dampers. Finally, to conclude this research, the vehicle dynamics implications of the Final Prototype damper are discussed and recommendations for further study are made.
Master of Science
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König, Daniel Hermann. "Optimization of the Control Strategy for a Range Extender Vehicle." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/78057.
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The Subject of this work is the optimization of the control stratgy for a Plug-In Range Extender in order to decrease CO2 emissions with respect to the regulations. Therefore, the vehicle is equipped with a gasoline combustion engine, a high voltage battery and two electric motors. One electric motor propells the front axle and the other one is connected to the combustion engine to generate electric power. The control is restricted by customer requirements due to the concept of the vehicle.
A Model-in-the-Loop is created to simulate the control strategy with support of a battery model. Therefore, the control strategy is optimized in a Matlab/Simulink environment. The simulation results are compared to tests on the dynamometer rig. The optimization highly depends on the specific goal function, which can be a global optimization or a local minimum to balance the State of Charge. Furthermore, customer related drive cycles are taken into account to analyze the control strategy.Master of Science
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Ambaripeta, Hari Prasad. "Range Extender Development for Electric Vehicle Using Engine Generator Set." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1424202532.
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Yung, Victor Ying Ben. "Energy use and emissions of a range-extending hybrid electric vehicle." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq21230.pdf.
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Eldeeb, Yasser M. "An adaptive system for enhancing vehicle bodies assembly using range sensing." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0011/NQ52420.pdf.
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Roebuck, C. A. "Testing and frequency response analysis of an electric vehicle traction drive." Thesis, Coventry University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384599.
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Björnsson, Lars-Henrik, Sten Karlsson, and Frances Sprei. "Objective functions for plug-in hybrid electric vehicle battery range optimization and possible effects on the vehicle fleet." Elsevier, 2017. https://publish.fid-move.qucosa.de/id/qucosa%3A72804.
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This study analyzes how, in a possible electrification of the car fleet through plug-in hybrid electric vehicles (PHEV), the choice of objective function, which potentially reflects different stakeholders’ interests, may influence the resulting optimal PHEV battery range, the PHEV share in the vehicle fleet, the fleet total cost of ownership (TCO) savings, and the fleet electric drive fraction under various economic conditions and policy options.
The optimal battery range can differ considerably among objective functions, especially between the objectives of maximizing the number of PHEVs and maximizing driving on electricity. Increased viability of the PHEV, for instance, through lower battery costs, higher running cost savings, or PHEV-promoting subsidies, will strengthen this effect. Therefore, a high share of viable PHEVs in the vehicle fleet does not necessarily result in a high share of electric driving. When designing policies to promote PHEVs, both the short- and long-term policy objectives and their potential effects need to be considered explicitly.
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Natali, Francis D., and Gerard G. Socci. "DIGITAL RECEIVER PROCESSING TECHNIQUES FOR SPACE VEHICLE DOWNLINK SIGNALS." International Foundation for Telemetering, 1985. http://hdl.handle.net/10150/615711.
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International Telemetering Conference Proceedings / October 28-31, 1985 / Riviera Hotel, Las Vegas, NevadaDigital processing techniques and related algorithms for receiving and processing space vehicle downlink signals are discussed. The combination of low minimum signal to noise density (C/No), large signal dynamic range, unknown time of arrival, and high space vehicle dynamics that is characteristic of some of these downlink signals results in a difficult acquisition problem. A method for rapid acquisition is described which employs a Fast Fourier Transform (FFT). Also discussed are digital techniques for precise measurement of space vehicle range and range rate using a digitally synthesized number controlled oscillator (NCO).
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Quek, Chin Khoon. "Vision based control and target range estimation for small unmanned aerial vehicle." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Dec%5FQuek.pdf.
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Thesis (M.S. in Engineering Science (Mechanical Engineering))--Naval Postgraduate School, December 2005.Thesis Advisor(s): Isaac I. Kaminer. Includes bibliographical references (p.39). Also available online.
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Lazúen, Ramírez Álvaro, and Jiménez Adriano Linero. "SIMULATION OF AN EXTENDED RANGE ELECTRIC VEHICLE USAGE IN A REAL ENVIRONMENT." Thesis, Högskolan i Skövde, Institutionen för teknik och samhälle, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-6317.
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In this paper the performance of an extended range electric vehicle (EREV) already available on the market is analysed through a simulation using MATLAB. A real route has been modelled. The route, 140 km, is longer than the majority of the daily travelling distance of the population in order to show how this vehicle is capable to cover the requirements of the drivers. The importance of an adequate recharge net for electric cars has been showed through the simulation of two different scenarios; the current scenario and a hypothetical future scenario where recharge points were available in all public parking. In this second scenario, the Opel Ampera has been capable to work fully in electric mode, reducing the CO 2 emissions 38%. An optimal management of the extender range of the car has been presented which reduce emissions 20%, reduce cost of the route 33%, and operating time of the range extender 30%, in the current scenario compared with the management made by the existed conduction modes of the car.
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Nwizege, Kenneth Sorle. "Adaptive data transfer for dedicated short range communications (DSRC)-based vehicle networks." Thesis, Swansea University, 2014. https://cronfa.swan.ac.uk/Record/cronfa42849.
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Vehicular communications occur when two or more vehicles come into range with one another, to share data over wireless media. Its applications are far-reaching, from toll collection to collision avoidance. Rate Adaptation Algorithms (RAAs) in IEEE 802.11 wireless networks maximize throughput by selecting their t ransmission rates among the multiple available' transmission rates based on the time-varying and location-dependent wireless channel conditions. In this thesis, a detailed study is made' on Adaptive Context-Aware Rate Selection (ACARS) algorithm that is efficient for data transfers, improving energy utilization, and also suitable for road safety applications. The goal of ACARS is to implement a RAA th a t can reliably estimate Signal-t-o-Noise-Ratio (SNR) to the Physical (PHY) layer by the integration transmission power, and Access Point (AP) coordination into its design. One of the major challenges of deploying mobile nodes in wireless networks is the power management. ACARS is able to minimize the total transmission power in the presence of propagation phenomena and mobility of vehicles, by rapid estimation of SNR to the PHY layer. Regarding safety applications in vehicular communications, RAAs need to minimize delay. ACARS minimizes the delay by using optimum data rates which reduces tin' network load in order to meet the application requirements. Simulation results confirm that the airtime (delay) as one of the key factors for safety applications is within the range of 100 ms recommended by the Institute of Electrical and Electronic Engineers (IEEE) standard for vehicle safety applications.
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Cooley, Robert Bradley. "Engine Selection, Modeling, and Control Development for an Extended Range Electric Vehicle." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281546071.
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Prodduturi, Sharath Chandra. "A six-degree-of-freedom launch vehicle simulator for range safety analysis." [Gainesville, Fla.] : University of Florida, 2007. http://purl.fcla.edu/fcla/etd/UFE0020782.
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Gong, Xiaojin. "Omnidirectional Vision for an Autonomous Surface Vehicle." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/30175.
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Due to the wide field of view, omnidirectional cameras have been extensively used in many applications, including surveillance and autonomous navigation. In order to implement a fully autonomous system, one of the essential problems is construction of an accurate, dynamic environment model. In Computer Vision this
is called structure from stereo or motion (SFSM). The work in this dissertation addresses omnidirectional vision based SFSM for the navigation of an autonomous surface vehicle (ASV), and implements a vision system capable of locating stationary obstacles and detecting moving objects in real time.
The environments where the ASV navigates are complex and fully of noise, system performance hence is a primary concern. In this dissertation, we thoroughly investigate the performance of range estimation for our omnidirectional vision system, regarding to different omnidirectional stereo configurations and considering
kinds of noise, for instance, disturbances in calibration, stereo configuration, and
image processing. The result of performance analysis is very important for our
applications, which not only impacts the ASVâ s navigation, also guides the development of our omnidirectional stereo vision system.
Another big challenge is to deal with noisy image data attained from riverine environments. In our vision system, a four-step image processing procedure is designed: feature detection, feature tracking, motion detection, and outlier rejection. The choice of point-wise features and outlier rejection based method makes
motion detection and stationary obstacle detection efficient. Long run outdoor
experiments are conducted in real time and show the effectiveness of the system.Ph. D.
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Pérez-Falcón, Tony, and Ray Kolar. "Flight Safety System for Unmanned Air Vehicle." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/605594.
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International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, NevadaA Flight Safety System (RAFS) for multiple, reliable Unmanned Air Vehicles (UAV’s) capable of flying Over-the-Horizon (OTH) and outside test range airspace. In addition to the flight safety application, the described full-duplex data link is suitable as a backup command and control link for UAV’s, and for sensor control & data exfiltration. The IRIDIUM satellite system was selected to provide the communications link and because of its global coverage and requisite data throughputs. A Risk Reduction activity ensued to quantify IRIDIUM performance. Hardware and software was developed to demonstrate the feasibility of using IRIDIUM in a flight safety scenario.
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Aspnes, Richard K., and Russell J. Yuma. "MMTS: Multi-Vehicle Metric & Telemetry System." International Foundation for Telemetering, 1988. http://hdl.handle.net/10150/615244.
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International Telemetering Conference Proceedings / October 17-20, 1988 / Riviera Hotel, Las Vegas, NevadaThe Multi-Vehicle Metric & Telemetry System (MMTS) is a complete range system which performs real-time tracking, command destruct, and telemetry processing functions for support of range safety and the test and evaluation of airborne vehicles. As currently configured, the MMTS consists of five hardware and software subsystems with the capability to receive, process, and display tracking data from up to ten range sensors and telemetry data from two instrumented vehicles. During a range operation, the MMTS is employed to collect, process, and display tracking and telemetry data. The instrumentation sites designated for operational support acquire tracking and telemetered data and transmit these data to the MMTS. The raw data is then identified, formatted, time tagged, recorded, processed, and routed for display to mission control and telemetry display areas. Additionally, processed tracking data is transmitted back to instrumentation sites as an aid to acquire or maintain vehicle track. The mission control area consists of a control and status console, high resolution color graphics stations, and large screen displays. As the mission controller observes mission progress on the graphics stations operational decisions can be made and invoked by activation of the appropriate console controls. Visual alarms provided my MMTS will alert mission control personnel of hazardous conditions posed by any tracked vehicle. Manual action can then be taken to activate transmission of the MMTS vehicle destruct signal. The telemetry display area consists of ten fully-functional, PC compatible computers which are switchable to either of two telemetry front end processors. Each PC can be independently set up by telemetry analysts to display data of interest. A total of thirty data pages per PC can be defined and any defined data page can be activated during a mission. A unique feature of the MMTS is that telemetry data can be combined with tracking data for use by the range safety functions.
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Chhean, Rithy-Newton Mao. "VEHICLE-TO-GRID (V2G) BIDIRECTIONAL POWER CONVERTER DESIGN AND INTEGRATION FOR 2011 CHEVROLET VOLT - EXTENDED RANGE ELECTRIC VEHICLE (EREV) DRIVETRAIN." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/893.
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This thesis proposes of an integrated two-stage V2G bidirectional power converter for the 2011 Chevy Volt’s EREV drivetrain. The power converter consists of a four switch bidirectional buck-boost DC-DC converter, 2-legged HB bidirectional DC-AC converter, and LCL grid filter. Designs in literature have integrated DC-AC converter via traction inverter, but this design also integrates DC-DC converter via modified secondary traction inverter. The proposed structure allows battery charging and V2G functionality to be integrated into existing electronics of the 2011 Chevy Volt; only the following additional components are needed: GFI, a few passive components, diodes, and relays. The converter structure is advantageous as cost, volume, and weight are minimized. Those factors are automakers main concerns. The proposed structure shows the feasibility of bringing V2G functionality to the mass market. Matlab Simulink was used to verify the design. Simulations were performed for high and low battery SOC to show voltage versatility, stiff and weak grid conditions to show filter robustness, and generator powering V2G to show topology DG capabilities. Results of simulations prove the topology to be promising as grid current has low distortion, almost meeting all IEEE 1547 current harmonic limit requirements.
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Mackall, Dale A., Robert Sakahara, and Steven E. Kremer. "THE X-33 EXTENDED FLIGHT TEST RANGE." International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/609678.
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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, CaliforniaDevelopment of an extended test range, with range instrumentation providing continuous vehicle communications, is required to flight-test the X-33, a scaled version of a reusable launch vehicle. The extended test range provides vehicle communications coverage from California to landing at Montana or Utah. This paper provides an overview of the approaches used to meet X-33 program requirements, including using multiple ground stations, and methods to reduce problems caused by reentry plasma radio frequency blackout. The advances used to develop the extended test range show other hypersonic and access-to-space programs can benefit from the development of the extended test range.
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MODI, SACHIN BRISMOHAN. "COMPARISON OF THREE OBSTACLE AVOIDANCE METHODS FOR AN AUTONOMOUS GUIDED VEHICLE." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1029343700.
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Kress, Gregory A. "Preliminary development of a VTOL unmanned air vehicle for the close-range mission." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23752.
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Pallotti, Daniel. "Electric Range Estimation algorithm for a high performance Plug-in Hybrid Electric Vehicle application." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
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The main purpose of this activity is the creation of a function able to estimate the residual electric range, for a high-performance Plug-In Hybrid Electric Vehicle in electric and hybrid mode. A function that is able to report the same information that a normal on-board computer provides to the driver in real time. The model within which this function was built deals with the management of the strategies for determining the torque required in each situation within the imposed driving cycle, in order to determine the right electric / hybrid split depending on the circumstances.
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Nguyen, Matthew P. "Investigation of the Under-Body Flow Field of a Prototype Long-Range Electric Vehicle." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2060.
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This thesis presents changes to the design of the Prototype Vehicles Laboratory (PROVE Lab) Endurance Car, an electric car intended to break the Guinness World Record for the single-charge range of an electric vehicle. The design range is 1609.34 km, however at the design velocity of 104.6 kph, the drag is 196 N; which requires more battery capacity than the 100 kWh maximum of the baseline model. With a fixed frontal area, drag reduction can come from lowered velocity or reduced CD. CD reduction is attempted in four ways: side skirts between the fenders, a raised ride height, an elongated diffuser, and a widened rear. Side skirts were added to move pressure recovery from the front ducts to the diffuser by lowering the pressure between the side skirts; this had the intended effect but increased the tendency of the flow to separation in the already-separated areas. There was no significant change in pressure drag, but the shear drag and downforce increased. The ride height was increased to reduce drag and downforce; this change did not have a significant effect on the resultant forces and the separation on the underbody was largely unchanged. The diffuser was extended by 12.7 cm without modifying the aspect ratio, to lower the divergence angle. The pressure and shear drag reduced by 8 N and 1.1 N, respectively, and downforce decreased by 80 N, but separation in the diffuser was not eliminated. Finally, the fourth strategy reduced the divergence angle to approximately zero degrees by widening the center of the vehicle. This decreased pressure drag by 13 N and downforce by 188 N. Additionally, this strategy allows a larger 180 kWh battery, which permits 1609.34 km of range at 104.6 kph.
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Hemmelgarn, Ronald J. "Development of a long-range gliding unmanned underwater vehicle utilizing Java Sun SPOT technology." Monterey, Calif. : Naval Postgraduate School, 2008. http://edocs.nps.edu/npspubs/scholarly/theses/2008/Sept/08Sep%5FHemmelgarn.pdf.
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Thesis (M.S. in Modeling, Virtual Environments and Simulation (MOVES))--Naval Postgraduate School, September 2008.Thesis Advisor(s): Brutzman, Don. "September 2008." Description based on title screen as viewed on November 10, 2008. Includes bibliographical references (p. 95-96). Also available in print.
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Chin, Yung-Kang. "A permanent magnet synchronous motor for an electric vehicle - design analysis." Licentiate thesis, KTH, Electrical Systems, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1763.
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This thesis presents the study and the design analysis of apermanent magnet synchronous motor (PMSM) for the tractionapplication of an electric vehicle. An existing inductiontraction motor for an electric forklift benchmarks the expectedperformances of the proposed PMSM design. Further, thepossibility of using the identical stator as the one used inthe induction motor is explored for the fast prototyping. Theprototype motor is expected to be field-weakened and to have aconstant power speed range (CPSR) of 2.5 to 3.
A design approach based on the CPSR contour plot in aninterior permanent magnet (IPM) parameter plane is derived toobtain the possible designs that meet all the designspecifications and the targeted CPSR. This study provides thepossible alternative designs for the subsequent futureprototype motors.
An analytical approach to estimate the iron loss in PMsynchronous machines is developed and included in the designprocedure. The proposed technique is based on predicting theflux density waveforms in the various regions of the machine.The model can be applied at any specified load condition,including the field-weakening operation region. This model canbe ultimately embedded in the design process for a routine usein loss estimations.
The first prototype motor with an inset permanent magnetrotor has been built and the available measurements are used tovalidate the design performance. In particular, the thermalanalyses based both on the lumped-circuit approach and thenumerical method are compared with the measured results. Asecond and possibly a third prototype motor targeting a widerand higher performance will be carried out in the continuingphase of the project.
Keywords:Constant Power Speed Range, Electric Vehicles,Field-weakening, Reference Flux Linkage, Iron Loss, PermanentMagnet Synchronous Motor, Thermal Analysis
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Cameron, Alan, Tony Cirineo, and Karl Eggertsen. "The Family of Interoperable Range System Transceivers (First)." International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/611408.
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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, CaliforniaThe objective of the FIRST project is to define a modern DoD Standard Datalink capability. This defined capability or standard is to provide a solution to wide variety of test and training range digital data radio communications problems with a common set of components, flexible to fit a broad range of applications, yet be affordable in all of them. This capability is to be specially designed to meet the expanding range distances and data transmissions rates needed to test modern weapon systems. Presently, the primary focus of the project is more on software, protocols, design techniques and standards, than on hardware development. Existing capabilities, on going developments and emerging technologies are being investigated and will be utilized as appropriate. Modern processingintensive communications technology can perform many complex range data communications tasks effectively, but a large-scale development effort is usually necessary to exploit it to its full potential. Yet, range communications problems are generally of limited scope, so different from one another that a communication system applicable to all of them is not likely to solve any of them well. FIRST will resolve that dilemma by capitalizing on another feature of modern communications technology: its high degree of programmability. This can enable custom-tailoring of datalink operation to particular applications, just as a PC can be tailored to perform a multitude of diverse tasks, through appropriate selection of software and hardware components.
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Luusua, Emil. "Vehicle Detection, at a Distance : Done Efficiently via Fusion of Short- and Long-Range Images." Thesis, Linköpings universitet, Datorseende, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-167073.
Full textAbstract:
Object detection is a classical computer vision task, encountered in many practical applications such as robotics and autonomous driving. The latter involves serious consequences of failure and a multitude of challenging demands, including high computational efficiency and detection accuracy. Distant objects are notably difficult to detect accurately due to their small scale in the image, consisting of only a few pixels. This is especially problematic in autonomous driving, as objects should be detected at the earliest possible stage to facilitate handling of hazardous situations. Previous work has addressed small objects via use of feature pyramids and super-resolution techniques, but the efficiency of such methods is limited as computational cost increases with image resolution. Therefore, a trade-off must be made between accuracy and cost. Opportunely though, a common characteristic of driving scenarios is the predominance of distant objects in the centre of the image. Thus, the full-frame image can be downsampled to reduce computational cost, and a crop can be extracted from the image centre to preserve resolution for distant vehicles. In this way, short- and long-range images are generated. This thesis investigates the fusion of such images in a convolutional neural network, particularly the fusion level, fusion operation, and spatial alignment. A novel framework — DetSLR — is proposed for the task and examined via the aforementioned aspects. Through adoption of the framework for the well-established SSD detector and MobileNetV2 feature extractor, it is shown that the framework significantly improves upon the original detector without incurring additional cost. The fusion level is shown to have great impact on the performance of the framework, favouring high-level fusion, while only insignificant differences exist between investigated fusion operations. Finally, spatial alignment of features is demonstrated to be a crucial component of the framework.
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Kouns, Heath. "Analysis of Performance Characteristics of Electric Vehicle Traction Drive in Low Speed/Low Torque Range." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/36287.
Full textAbstract:
In a world with a growing population there is a trend toward higher and higher energy usage. Because of the cost involved in producing extra energy, there is a need for more efficient usage of the energy that is already available. The issue of efficiency rings home especially clear with electric motors. Although induction motors are used in many different applications, the motors used in electric vehicles must be able to generate a large starting torque as well as operate over a wide speed range. This work analyzes the restrictions placed on the motor and inverter drive system. It also looks at the best method for controlling the drive in order to achieve the highest efficiency out of the drive. While other works have shown methods of achieve high efficiency out of the motor, it is the assertion of this work that the efficiency of the total drive is more important. It is to that end that this work analyzes the performance of an induction motor under low torque and speed where a traction drive utilizes the most energy.Master of Science
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Zetts, Andrew Wyatt. "The Impact of a Microturbine Power Plant on an Off Road Range Extended Electric Vehicle." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/72974.
Full textAbstract:
The purpose of this thesis is to examine the feasibility of using a microturbine to power an off-road Series Hybrid Autonomous Vehicle (SHEV), and evaluate the benefits and drawbacks inherent in using a microturbine rather than an Internal Combustion Engine (ICE). The specific power plant requirements for a low speed hybrid vehicle that must operate extensively as an Electric Vehicle (EV) and run on JP-8 (a diesel equivalent) are unusual; few options can adequately address all of these needs. Most development of Hybrid Electric Vehicles (HEVs) has focused on gasoline ICE power plants, but Diesel ICEs are heavier, which has an adverse effect on EV range.
While mechanically-linked turbine vehicles failed to have the same performance abilities of their ICE counterparts, a microturbine generator-powered SHEV can take advantage of its battery pack to avoid the issues inherent in its mechanical predecessors. A microturbine generator is mechanically decoupled from the powertrain, allowing for an incredibly power dense power plant that lightens the weight of the vehicle. This weight reduction directly correlates to an increased EV operational range, enhancing mobility, stealth, and the tactical effectiveness of the squad that the vehicle is intended to support.
To determine the full impact that a microturbine might have on this specific SHEV, modeling of the vehicle was conducted to directly compare a microturbine and an ICE power plant using two drive cycles that were designed to simulate the typical operation specific to the vehicle. Drive cycle analysis revealed that the improved EV performance and design flexibility offered by the microturbine's weight justifies the selection of a microturbine over an ICE for this specific case. This decision is dependent upon several factors: a microturbine with fuel efficiency comparable to an ICE, the selection of a large battery pack, and an emphasis on EV operations.Master of Science
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Sandberg, Staffan. "How do battery electric vehicle drivers behave in a range critical situation in VR when using a "guess-o-meter" vs a novel range management tool?" Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-281696.
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Battery electric vehicles are becoming more common but still fall behind combustion engine cars in terms of driving range and charging time. The displayed driving range in electric vehicles' dashboard can be a volatile parameter suddenly dropping by 10-20\%, for instance when speed is increased. Which can result in a condition referred to as range anxiety . Hence it is interesting to observe more in detail how drivers behave and think in scenarios where range is important and the cars' available range can change drastically depending on the drivers driving style. Such scenarios are problematic to test in real traffic for practical and ethical reasons. In this article, without putting anyone at risk, we present a study using a VR driving simulator in a critical scenario with a substantial risk of running out of battery. Two separate groups (N=10) each drove on the same test track using two different range displays. One group had a typical range display showing the distance left to empty (out of battery) and the other group a novel and more transparent display. The novel display shows how speed is affecting the range. Both displays allow the driver to set a target driving range. The results indicate that the novel display allows for a more agile and adaptive driving style by changing between specific speeds rather than searching and "guessing" which speed is the most optimal as with typical range displays. Although, it can hide other affecting factors, such as acceleration and road height. Which was more prevalent amongst drivers who had to search and guess.Batterielbilar blir allt vanligare men når inte riktigt upp till samma nivå som bilar med förbränningsmotorer när det handlar om räckvidd och laddtid. Den kvarstående körsträckan som visas i elbilars instrumentpanel kan vara en instabil variabel och plötsligt sjunka med 10-20%, när man till exempel ökar hastigheten. Vilket kan leda till ett tillstånd som kallas räckviddsångest . Därav intresset för att undersöka i detalj hur förare agerar och tänker i scenarier där räckvidd är extra viktigt och bilens kvarstående körsträcka kan ändras drastiskt beroende på körstil. Sådana scenarier är problematiska att testa ute i trafiken av både praktiska och etiska skäl. I denna artikel, utan att placera någon i en verklig riskfylld situation, presenterar vi en studie där en bilsimulator i VR används för att testa ett kritiskt scenario där risken för att strömmen tar slut är stor. Två separata grupper (N=10) körde samma sträcka fast med olika instrumentpaneler. Där den ena är mer konventionell och endast visar kvarstående körsträcka. Medan den andra är mer originell och visar hur hastighet påverkar kvarstående körsträcka. Båda instrumentpanelerna tillåter föraren att ställa in hur långt man vill köra. Resultaten indikerar på att den originella instrumentpanelen tillåter en mer agil och adaptiv körstil, genom att byta mellan specifika hastigheter istället för att leta och gissa vilken hastighet som är optimal, vilket skedde med den konventionella instrumentpanelen. Men den kan även dölja andra faktorer som påverkar körsträckan, såsom acceleration och höjdskillnader. Vilket användare av den originella instrumentbrädan noterade i större utsträckning.
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Gadre, Aditya Shrikant. "Observability Analysis in Navigation Systems with an Underwater Vehicle Application." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/26154.
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Precise navigation of autonomous underwater vehicles (AUV) is one of the most important challenges in the realization of distributed and cooperative algorithms for marine applications. We investigate an underwater navigation technology that enables an AUV to compute its trajectory in the presence of unknown currents in real time and simultaneously estimate the currents, using range or distance measurements from a single known location. This approach is potentially useful for small AUVs which have severe volume and power constraints.
The main contribution of this work is observability analysis of the proposed navigation system using novel approaches towards uniform observability of linear time-varying (LTV) systems. We utilize the notion of limiting systems in order to address uniform observability of LTV systems. Uniform observability of an LTV system can be studied by assessing finite time observability of its limiting systems. A new definition of uniform observability over a finite interval is introduced in order to address existence of an observer whose estimation error is bounded by an exponentially decaying function on the finite interval. We also show that for a class of LTV systems, uniform observability of a lower dimensional subsystem derived from an LTV system is sufficient for uniform observability of the LTV system.Ph. D.
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Hinton, Thomas Glyn. "A thesis regarding the vehicle routing problem including a range of novel techniques for its solution." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.535180.
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Bernacki, Mark. "Design and development of an extended range electric bywire/wireless hybrid vehicle with a near wheel motor drivetrain." Thesis, UOIT, 2009. http://hdl.handle.net/10155/42.
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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.
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Bardanis, Florios. "Kill Vehicle Effectiveness for Boost Phase Interception of Ballistic Missiles /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FBardanis.pdf.
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Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, June 2004.Thesis advisor(s): Phillip E. Pace, Murali Tummala. Includes bibliographical references (p. 49-50). Also available online.
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Walker, Jonathan Bearnarr. "An Empirical Method of Ascertaining the Null Points from a Dedicated Short-Range Communication (DSRC) Roadside Unit (RSU) at a Highway On/Off-Ramp." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/85151.
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The deployment of dedicated short-range communications (DSRC) roadside units (RSUs) allows a connected or automated vehicle to acquire information from the surrounding environment using vehicle-to-infrastructure (V2I) communication. However, wireless communication using DSRC has shown to exhibit null points, at repeatable distances. The null points are significant and there was unexpected loss in the wireless signal strength along the pathway of the V2I communication. If the wireless connection is poor or non-existent, the V2I safety application will not obtain sufficient data to perform the operation services. In other words, a poor wireless connection between a vehicle and infrastructure (e.g., RSU) could hamper the performance of a safety application.
For example, a designer of a V2I safety application may require a minimum rate of data (or packet count) over 1,000 meters to effectively implement a Reduced Speed/Work Zone Warning (RSZW) application. The RSZW safety application is aimed to alert or warn drivers, in a Cooperative Adaptive Cruise Control (CACC) platoon, who are approaching a work zone. Therefore, the packet counts and/or signal strength threshold criterion must be determined by the developer of the V2I safety application. Thus, we selected an arbitrary criterion to develop an empirical method of ascertaining the null points from a DSRC RSU.
The research motivation focuses on developing an empirical method of calculating the null points of a DSRC RSU for V2I communication at a highway on/off-ramp. The intent is to improve safety, mobility, and environmental applications since a map of the null points can be plotted against the distance between the DSRC RSU and a vehicle's onboard unit (OBU). The main research question asks: 'What is a more robust empirical method, compared to the horizontal and vertical laws of reflection formula, in determining the null points from a DSRC RSU on a highway on/off ramp?'
The research objectives are as follows:
1. Explain where and why null points occur from a DSRC RSU (Chapter 2)
2. Apply the existing horizontal and vertical polarization model and discuss the limitations of the model in a real-world scenario for a DSRC RSU on a highway on/off ramp (Chapter 3 and Appendix A)
3. Introduce an extended horizontal and vertical polarization null point model using empirical data (Chapter 4)
4. Discuss the conclusion, limitations of work, and future research (Chapter 5).
The simplest manner to understand where and why null points occur is depicted as two sinusoidal waves: direct and reflective waves (i.e., also known as a two-ray model). The null points for a DSRC RSU occurs because the direct and reflective waves produce a destructive interference (i.e., decrease in signal strength) when they collide. Moreover, the null points can be located using Pythagorean theorem for the direct and reflective waves.
Two existing models were leveraged to analyze null points: 1) signal strength loss (i.e., a free space path loss model, or FSPL, in Appendix A) and 2) the existing horizontal and vertical polarization null points from a DSRC RSU. Using empirical data from two different field tests, the existing horizontal and vertical polarization null point model was shown to contain limitations in short distances from the DSRC RSU. Moreover, the existing horizontal and vertical polarization model for null points was extremely challenging to replicate with over 15 DSRC RSU data sets. After calculating the null point for several DSRC RSU heights, the paper noticed a limitation of the existing horizontal and vertical polarization null point model with over 15 DSRC RSU data sets (i.e., the model does not account for null points along the full length of the FSPL model).
An extended horizontal and vertical polarization model is proposed that calculates the null point from a DSRC RSU. There are 18 model comparisons of the packet counts and signal strengths at various thresholds as perspective extended horizontal and vertical polarization models. This paper compares the predictive ability of 18 models and measures the fit. Finally, a predication graph is depicted with the neural network's probability profile for packet counts =1 when greater than or equal to 377. Likewise, a python script is provided of the extended horizontal and vertical polarization model in Appendix C.
Consequently, the neural network model was applied to 10 different DSRC RSU data sets at 10 unique locations around a circular test track with packet counts ranging from 0 to 11. Neural network models were generated for 10 DSRC RSUs using three thresholds with an objective to compare the predictive ability of each model and measure the fit. Based on 30 models at 10 unique locations, the highest misclassification was 0.1248, while the lowest misclassification was 0.000. There were six RSUs mounted at 3.048 (or 10 feet) from the ground with a misclassification rate that ranged from 0.1248 to 0.0553. Out of 18 models, seven had a misclassification rate greater than 0.110, while the remaining misclassification rates were less than 0.0993. There were four RSUs mounted at 6.096 meters (or 20 feet) from the ground with a misclassification rate that ranged from 0.919 to 0.000. Out of 12 models, four had a misclassification rate greater than 0.0590, while the remaining misclassification rates were less than 0.0412.
Finally, there are two major limitations in the research: 1) the most effective key parameter is packet counts, which often require expensive data acquisition equipment to obtain the information and 2) the categorical type (i.e., decision tree, logistic regression, and neural network) will vary based on the packet counts or signal strength threshold that is dictated by the threshold criterion. There are at least two future research areas that correspond to this body of work: 1) there is a need to leverage the extended horizontal and vertical polarization null point model on multiple DSRC RSUs along a highway on/off ramp, and 2) there is a need to apply and validate different electric and magnetic (or propagation) models.Ph. D.
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Rowe, Christopher D. "Channel Propagation Model for Train to Vehicle Alert System at 5.9 GHz using Dedicated Short Range Communication." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/73178.
Full textAbstract:
The most common railroad accidents today involve collisions between trains and passenger vehicles at railroad grade crossings [1][2]. Due to the size and speed of a train, these collisions generally result in significant damage and serious injury. Despite recent efforts by projects such as Operation Lifesaver to install safety features at grade crossings, up to 80% of the United States railroad grade crossings are classified as 'unprotected' with no lights, warnings, or crossing gates [2]. Further, from January to September 2012, nearly 10% of all reported vehicle accidents were a result of train-to-vehicle collisions. These collisions also accounted for nearly 95% of all reported fatalities from vehicular accidents [2].
To help provide a more rapidly deployable safety system, advanced dedicated short range communication (DSRC) systems are being developed. DSRC is an emerging technology that is currently being explored by the automotive safety industry for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications to provide intelligent transportation services (ITS). DSRC uses WAVE protocols and the IEEE 1609 standards. Among the many features of DSRC systems is the ability to sense and then provide an early warning of a potential collision [6]. One potential adaption for this technology is for use as a train-to-vehicle collision warning system for unprotected grade crossings. These new protocols pose an interesting opportunity for enhancing cybersecurity since terrorists will undoubtedly eventually identify these types of mass disasters as targets of opportunity.
To provide a thorough channel model of the train to vehicle communication environment that is proposed above, large-scale path loss and small scale fading will both be analyzed to characterize the propagation environment. Measurements were collected at TTCI in Pueblo Colorado to measure the received signal strength in a train to vehicle communication environment. From the received signal strength, different channel models can be developed to characterize the communication environment.
Documented metrics include large scale path loss, Rician small scale fading, Delay spread, and Doppler spread. An analysis of the DSRC performance based on Packet Error Rate is also included.Master of Science
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Cordell, Christopher E. "Computational fluid dynamics and analytical modeling of supersonic retropropulsion flowfield structures across a wide range of potential vehicle configurations." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50355.
Full textAbstract:
For the past four decades, Mars missions have relied on Viking heritage technology for supersonic descent. Extending the use of propulsion, which is required for Mars subsonic deceleration, into the supersonic regime allows the ability to land larger payload masses. Wind tunnel and computational experiments on subscale supersonic retropropulsion models have shown a complex aerodynamic flow field characterized by the interaction of underexpanded jet plumes exhausting from nozzles on the vehicle with the supersonic freestream. Understanding the impact of vehicle and nozzle configuration on this interaction is critical for analyzing the performance of a supersonic retropropulsion system, as deceleration will have components provided by both the aerodynamic drag of the vehicle and thrust from the nozzles.
This investigation focuses on the validity of steady state computational approaches to analyze supersonic retropropulsion flowfield structures and their effect on vehicle aerodynamics. Wind tunnel data for a single nozzle and a multiple nozzle configuration are used to validate a steady state, turbulent computational fluid dynamics approach to modeling supersonic retropropulsion. An analytic approximation to determine plume and bow shock structure in the flow field is also developed, enabling rapid assessment of flowfield structure for use in improved grid generation and as a configuration screening tool. Results for both the computational fluid dynamics and analytic approaches show good agreement with the experimental datasets. Potential limitations of the two methods are identified based on the comparisons with available data.
Six additional geometries are defined to investigate the extensibility of the analytical model and determine the variation of supersonic retropropulsion performance with configuration. These validation geometries are split into two categories: three geometries with nozzles located on the vehicle forebody at varying nozzle cant angles, and three geometries with nozzles located on the vehicle aftbody at varying nozzle cant angles and number of nozzles.
The forebody nozzle configurations show that nozzle cant angle is a significant driver in performance of a vehicle employing supersonic retropropulsion. Aerodynamic drag preservation for a given thrust level increases with increasing cant angle. However, increasing the cant angle reduces the contribution of thrust to deceleration. The tradeoff between these two contributions to the deceleration force is examined, noting that performance improvements are possible with modest nozzle cant angles. Static pitch stability characteristics are investigated for the lowest and highest cant angle configurations.
The aftbody nozzle configuration results show that removing the plume flow from the region forward of the vehicle results in less interaction with the bow shock structure. This impacts aerodynamic performance, as the surface pressure remains relatively undisturbed for all thrust values examined. Static pitch stability characteristics for each of the aftbody nozzle configurations are investigated; noting that supersonic retropropulsion for these configurations exhibits a transition point from static stability to instability as a function of this center of mass location along the axis.
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Sharifzadeh, Shayan. "Design Optimization and Analysis of Long-Range Hydrogen-Fuelled Hypersonic Cruise Vehicles." Doctoral thesis, Universite Libre de Bruxelles, 2017. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/255764.
Full textAbstract:
Aviation industry is continuously growing especially for very long distance flights due to the globalisation of local economies around the world and the explosive economic growth in Asia. Reducing the time of intercontinental flights from 16-20 hours to 4 hours or less would therefore make the, already booming, ultra-long distance aviation sector even more attractive. To accomplish this drastic travel time reduction for civil transport, hypersonic cruise aircraft are considered as a potential cost-effective solution. Such vehicles should also be fuelled by liquid hydrogen, which is identified as the only viable propellant to achieve antipodal hypersonic flight with low environmental impact. Despite considerable research on hypersonic aircraft and hydrogen fuel, several major challenges should still be addressed before such airliner becomes reality. The current thesis is therefore motivated by the potential benefit of hydrogen-fuelled hypersonic cruise vehicles associated with their limited state-of-the-art.Hypersonic cruise aircraft require innovative structural configurations and thermal management solutions due to the extremely harsh flight environment, while the uncommon physical properties of liquid hydrogen, combined with high and long-term heat fluxes, introduce complex design and technological storage issues. Achieving hypersonic cruise vehicles is also complicated by the multidisciplinary nature of their design. In the scope of the present research, appropriate methodologies are developed to assess, design and optimize the thermo-structural model and the cryogenic fuel tanks of long-range hydrogen-fuelled hypersonic civil aircraft. Two notional vehicles, cruising at Mach 5 and Mach 8, are then investigated with the implemented methodologies. The design analysis of light yet highly insulated liquid hydrogen tanks for hypersonic cruise vehicles indicates an optimal gravimetric efficiency of 70-75% depending on insulation system, tank wall material, tank diameter, and flight profile. A combination of foam and load-bearing aerogel blanket leads to the lightest cryogenic tank for both the Mach 5 and the Mach 8 aircraft. If the aerogel blanket cannot be strengthened sufficiently so that it can bear the full load, then a combination of foam and fibrous insulation materials gives the best solution for both vehicles. The aero-thermal and structural design analysis of the Mach 5 cruiser shows that the lightest hot-structure is a titanium alloy construction made of honeycomb sandwich panels. This concept leads to a wing-body weight of 143.9 t, of which 36% accounts for the wing, 32% for the fuselage, and 32% for the cryogenic tanks. As expected, hypersonic thermal loads lead to important weight penalties (of more than 35%). The design of the insulated cold structure, however, demonstrates that the long-term high-speed flight of the airliner requires a substantial thermal protection system, such that the best configuration (obtained by load-bearing aerogel blanket) leads to a titanium cold design of only 4% lighter than the hot structure. Using aluminium 7075 rather than titanium offers a further weight saving of about 2%, resulting in a 135.4 t wing-body weight (with a contribution of 23%, 25%, 18% and 34% from the TPS, the wing, the fuselage, and the cryogenic tanks respectively). Given the design hypotheses, the difference in weight is not significant enough to make a decisive choice between hot and cold concepts. This requires the current methodologies to be further elaborated by relaxing the simplifications. Investigation of the thermal protection must be extended from one single point to different regions of the vehicle, and the TPS thickness and weight should be considered in the structural sizing of the cold design. More generally, the design process should be matured by including additional (static, dynamic and transient) loads, special structural concepts, multi-material configurations and other parameters such as cost and safety aspects.Doctorat en Sciences de l'ingénieur et technologie
This thesis was conducted in co-tutelle between University of Sydney and Université Libre de Bruxelles.Professor Dries Verstraete was my supervisor at the University of Sydney (so as a member of SydneyUni), but is automatically registered here as a member of ULB because he worked at ULB almost ten years ago.Ben Thornber is also a member of the University of Sydney but the application does not save it for an unknown reason.
info:eu-repo/semantics/nonPublished
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Anil, Vijay Sankar. "Mission-based Design Space Exploration and Traffic-in-the-Loop Simulation for a Range-Extended Plug-in Hybrid Delivery Vehicle." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587663664531601.
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Shaw, Althoff Peggy S. "Indicators of disturbance and recovery of a tallgrass prairie ecosystem following military vehicle traffic." Diss., Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/460.
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Hegde, Bharatkumar. "Look-Ahead Energy Management Strategies for Hybrid Vehicles." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu153199304661774.
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Plötz, Patrick, Niklas Jakobsson, and Frances Sprei. "On the distribution of individual daily driving distances." Elsevier, 2017. https://publish.fid-move.qucosa.de/id/qucosa%3A72184.
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Plug-in electric vehicles (PEV) can reduce greenhouse gas emissions. However, the utility of PEVs, as well as reduction of emissions is highly dependent on daily vehicle kilometres travelled (VKT). Further, the daily VKT by individual passenger cars vary strongly between days. A common method to analyse individual daily VKT is to fit distribution functions and to further analyse these fits. However, several distributions for individual daily VKT have been discussed in the literature without conclusive decision on the best distribution. Here we analyse three two-parameter distribution functions for the variation in daily VKT with four sets of travel data covering a total of 190,000 driving days and 9.5 million VKT. Specifically, we look at overall performance of the distributions on the data using four goodness of fit measures, as well as the consequence of choosing one distribution over the others for two common PEV applications: the days requiring adaptation for battery electric vehicles and the utility factor for plug-in hybrid electric vehicles. We find the Weibull distribution to fit most vehicles well but not all and at the same time yielding good predictions for PEV related attributes. Furthermore, the choice of distribution impacts PEV usage factors. Here, the Weibull distribution yields reliable estimates for electric vehicle applications whereas the log-normal distribution yields more conservative estimates for PEV usage factors. Our results help to guide the choice of distribution for a specific research question utilising driving data and provide a methodological advancement in the application of distribution functions to longitudinal driving data.
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Kruckenberg, John. "Fault Diagnosis and Hardware in the Loop Simulation for the EcoCAR Project." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306180272.
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