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Ballard, Michael A. "Impacts of electric propulsion systems on submarine design." Thesis, Springfield, Va. : Available from the National Technical Information Service, 1989. http://handle.dtic.mil/100.2/ADA213542.
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Thesis (Degree of Naval Engineer and M.S. in Electrical Engineering and Computer Science) Massachusetts Institute of Technology, June 1989.Includes bibliographical references. Also available online.
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Leonessa, Alexander. "Hierarchical robust nonlinear switching control design for propulsion systems." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/11997.
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Björk, Daniel. "Automated Propulsion Kit Selection for MAV : A Design Process Tool." Thesis, Linköping University, Department of Mechanical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-4164.
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This thesis project has been carried out at Linköpings universitet at the Department of Mechanical Engineering. The emphasis of the project lies in the exploration of automatic selection of components for a propulsion kit. Specifically for this project, propulsion based on electric power and meeting the requirements for use in a Micro Aerial Vehicle (MAV). The key features include a systematic selection method based on user criterias and a model for evaluating propeller performance. These are implemented in a program written as a part of the project. The conclusion is that it is possible to make a program capable of a component selection and that the programs usability is mainly reliant on three factors: model for propeller evaluation, method of selection and the quality of the component database.
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Hall, Philip D. "Design of a coaxial split flow pulse detonation engine." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Jun%5FHall.pdf.
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Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2006.Thesis Advisor(s): Jose O. Sinibaldi, Christopher M. Brophy. "June 2006." Includes bibliographical references (p. 41-42). Also available in print.
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Bradford, John Edward. "A technique for rapid prediction of aftbody nozzle performance for hypersonic launch vehicle design." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/12896.
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Kwon, Kybeom. "A novel numerical analysis of Hall Effect Thruster and its application in simultaneous design of thruster and optimal low-thrust trajectory." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34777.
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Hall Effect Thrusters (HETs) are a form of electric propulsion device which uses external electrical energy to produce thrust. When compared to various other electric propulsion devices, HETs are excellent candidates for future orbit transfer and interplanetary missions due to their relatively simple configuration, moderate thrust capability, higher thrust to power ratio, and lower thruster mass to power ratio. Due to the short history of HETs, the current design process of a new HET is a largely empirical and experimental science, and this has resulted in previous designs being developed in a narrow design space based on experimental data without systematic investigations of parameter correlations. In addition, current preliminary low-thrust trajectory optimizations, due to inherent difficulties in solution procedure, often assume constant or linear performances with available power in their applications of electric thrusters. The main obstacles come from the complex physics involved in HET technology and relatively small amounts of experimental data. Although physical theories and numerical simulations can provide a valuable tool for design space exploration at the inception of a new HET design and preliminary low-thrust trajectory optimization, the complex physics makes theoretical and numerical solutions difficult to obtain. Numerical implementations have been quite extensively conducted in the last two decades. An investigation of current methodologies reveals that to date, none provide a proper methodology for a new HET design at the conceptual design stage and the coupled low-thrust trajectory optimization. Thus, in the first half of this work, an efficient, robust, and self-consistent numerical method for the analysis of HETs is developed with a new approach. The key idea is to divide the analysis region into two regions in terms of electron dynamics based on physical intuition. Intensive validations are conducted for existing HETs from 1 kW to 50 kW classes. The second half of this work aims to construct a simultaneous design optimization environment though collaboration with experts in low-thrust trajectory optimization where a new HET and associated optimal low-thrust trajectory can be designed simultaneously. A demonstration for an orbit raising mission shows that the constructed simultaneous design optimization environment can be used effectively and synergistically for space missions involving HETs. It is expected that the present work will aid and ease the current expensive experimental HET design process and reduce preliminary space mission design cycles involving HETs.
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Cheney, Liam Jon. "Development of Safety Standards for CubeSat Propulsion Systems." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1180.
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The CubeSat community has begun to develop and implement propulsion systems. This movement represents a new capability which may satisfy mission needs such as orbital and constellation maintenance, formation flight, de-orbit, and even interplanetary travel. With the freedom and capability granted by propulsion systems, CubeSat providers must accept new responsibilities in proportion to the potential hazards that propulsion systems may present.
The Cal Poly CubeSat program publishes and maintains the CubeSat Design Specification (CDS). They wish to help the CubeSat community to safety and responsibly expand its capabilities to include propulsive designs. For this reason, the author embarked on the task of developing a draft of safety standards CubeSat propulsion systems.
Wherever possible, the standards are based on existing documents. The author provides an overview of certain concepts in systems safety with respect to the classification of hazards, determination of required fault tolerances, and the use of inhibits to satisfy fault tolerance requirements. The author discusses hazards that could exist during ground operations and through launch with respect to hazardous materials and pressure systems. Most of the standards related to Range Safety are drawn from AFSPCMAN 91-710. Having reviewed a range of hypothetical propulsion system architectures with an engineer from Range Safety at Vandenberg Air Force Base, the author compiled a case study. The author discusses many aspects of orbital safety. The author discusses the risk of collision with the host vehicle and with third party satellites along with the trackability of CubeSats using propulsion systems. Some recommendations are given for working with the Joint Functional Component Command for Space (JFCC SPACE), thanks to the input of two engineers who work with the Joint Space Operations Center (JSpOC). Command Security is discussed as an important aspect of a mission which implements a propulsion system. The author also discusses End-of-Life procedures such as safing and de-orbit operations. The orbital safety standards are intended to promote “good citizenship.”
The author steps through each proposed standard and offers justification. The author is confident that these standards will set the stage for a dialogue in the CubeSat community which will lead to the formulation of a reasonable and comprehensive set of standards. The author hopes that the discussions given throughout this document will help CubeSat developers to visualize the path to flight readiness so that they can get started on the right foot.
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Rajkumar, Vishnu Ganesh. "Design Optimization of a Regional Transport Aircraft with Hybrid Electric Distributed Propulsion Systems." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/84494.
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In recent years, there has been a growing shift in the world towards sustainability. For civil aviation, this is reflected in the goals of several organizations including NASA and ACARE as significantly increased fuel efficiency along with reduced harmful emissions in the atmosphere. Achieving the goals necessitates the advent of novel and radical aircraft technologies, NASA's X-57, is one such concept using distributed electric propulsion (DEP) technology.
Although practical implementation of DEP is achievable due to the scale invariance of highly efficient electric motors, the current battery technology restricts its adoption for commercial transport aircraft. A Hybrid Electric Distributed Propulsion (HEDiP) system offers a promising alternative to the all-electric system. It leverages the benefits of DEP when coupled with a hybrid electric system. One of the areas needing improvement in HEDiP aircraft design is the fast and accurate estimation of wing aerodynamic characteristics in the presence of multiple propellers. A VLM based estimation technique was developed to address this requirement.
This research is primarily motivated by the need to have mature conceptual design methods for HEDiP aircraft. Therefore, the overall research objective is to develop an effective conceptual design capability based on a proven multidisciplinary design optimization (MDO) framework, and to demonstrate the resulting capability by applying it to the conceptual design of a regional transport aircraft (RTA) with HEDiP systems.Master of Science
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Roth, Bryce Alexander. "A theoretical treatment of technical risk in modern propulsion system design." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/12221.
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Harper, James M. "Pocket Rocket: A 1U+ Propulsion System Design To Enhance CubeSat Capabilities." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2218.
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The research presented provides an overview of a 1U+ form factor propulsion system design developed for the Cal Poly CubeSat Laboratory (CPCL). This design utilizes a Radiofrequency Electrothermal Thruster (RFET) called Pocket Rocket that can generate 9.30 m/s of delta-V with argon, and 20.2 ± 3 m/s of delta-V with xenon. Due to the demand for advanced mission capabilities in the CubeSat form factor, a need for micro-propulsion systems that can generate between 1 – 1500 m/s of delta-V are necessary.
By 2019, Pocket Rocket had been developed to a Technology Readiness Level (TRL) of 5 and ground tested in a 1U CubeSat form factor that incorporated propellant storage, pressure regulation, RF power and thruster control, as well as two Pocket Rocket thrusters under vacuum, and showcased a thrust of 2.4 mN at a required 10 Wdc of power with Argon propellant. The design focused on ground testing of the thruster and did not incorporate all necessary components for operation of the thruster. Therefore in 2020, a 1U+ Propulsion Module that incorporates Pocket Rocket, the RF amplification PCB, a propellant tank, propellant regulation and delivery, as well as a DC-RF conversion with a PIB, that are all attached to a 2U customer CubeSat for a 3U+ overall form factor. This design was created to increase the TRL level of Pocket Rocket from 5 to 8 by demonstrating drag compensation in a 400 km orbit with a delta-V of 20 ± 3 m/s in the flight configuration. The 1U+ Propulsion Module design included interface and requirements definition, assembly instructions, Concept of Operations (ConOps), as well as structural and thermal analysis of the system. The 1U+ design enhances the capabilities of Pocket Rocket in a 1U+ form factor propulsion system and increases future mission capabilities as well as propulsion system heritage for the CPCL.
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Davis, Thomas L. Davis. "Development and Characterization of a UAS Propulsion Test Bench." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent152573490048759.
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Bauer, Christian Anton [Verfasser]. "Design and Test of Resonance Ignition Systems for Methane/Oxygen In-Space Propulsion Systems / Christian Anton Bauer." München : Verlag Dr. Hut, 2021. http://d-nb.info/1232847976/34.
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Kroll, Douglas M. (Douglas Michael). "Using polymer electrolyte membrane fuel cells in a hybrid surface ship propulsion plant to increase fuel efficiency." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61909.
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Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 59).
An increasingly mobile US Navy surface fleet and oil price uncertainty contrast with the Navy's desire to lower the amount of money spent purchasing fuel. Operational restrictions limiting fuel use are temporary and cannot be dependably relied upon. Long term technical research toward improving fuel efficiency is ongoing and includes advanced gas turbines and integrated electric propulsion plants, but these will not be implemented fleet wide in the near future. The focus of this research is to determine if a hybrid fuel cell and gas turbine propulsion plant outweigh the potential ship design disadvantages of physically implementing the system. Based on the potential fuel savings available, the impact on surface ship architecture will be determined by modeling the hybrid fuel cell powered ship and conducting a side by side comparison to one traditionally powered. Another concern that this solution addresses is the trend in the commercial shipping industry of designing more cleanly running propulsion plants.
Douglas M. Kroll.
S.M.in Engineering and Management
Nav.E.
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McClure, Erin Kathleen. "An evolving-requirements technology assessment process for advanced propulsion concepts." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-07062006-101749/.
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Thesis (Ph. D.)--Aerospace Engineering, Georgia Institute of Technology, 2007.Danielle Soban, Committee Member ; Dimitri Mavris, Committee Chair ; Alan Porter, Committee Member ; Gary Seng, Committee Member ; Daniel Schrage, Committee Member.
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Maser, Adam Charles. "Optimal allocation of thermodynamic irreversibility for the integrated design of propulsion and thermal management systems." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45913.
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More electric aircraft systems, high power avionics, and a reduction in heat sink capacity have placed a larger emphasis on correctly satisfying aircraft thermal management requirements during conceptual design. Thermal management systems must be capable of dealing with these rising heat loads, while simultaneously meeting mission performance. Since all subsystem power and cooling requirements are ultimately traced back to the engine, the growing interactions between the propulsion and thermal management systems are becoming more significant. As a result, it is necessary to consider their integrated performance during the conceptual design of the aircraft gas turbine engine cycle to ensure that thermal requirements are met. This can be accomplished by using thermodynamic modeling and simulation to investigate the subsystem interactions while conducting the necessary design trades to establish the engine cycle. As the foundation for this research, a parsimonious, transparent thermodynamic model of propulsion and thermal management systems performance was created with a focus on capturing the physics that have the largest impact on propulsion design choices. A key aspect of this approach is the incorporation of physics-based formulations involving the concurrent usage of the first and second laws of thermodynamics to achieve a clearer view of the component-level losses. This is facilitated by the direct prediction of the exergy destruction distribution throughout the integrated system and the resulting quantification of available work losses over the time history of the mission. The characterization of the thermodynamic irreversibility distribution helps give the designer an absolute and consistent view of the tradeoffs associated with the design of the system. Consequently, this leads directly to the question of the optimal allocation of irreversibility across each of the components. An irreversibility allocation approach based on the economic concept of resource allocation is demonstrated for a canonical propulsion and thermal management systems architecture. By posing the problem in economic terms, exergy destruction is treated as a true common currency to barter for improved efficiency, cost, and performance. This then enables the propulsion systems designer to better fulfill system-level requirements and to create a system more robust to future requirements.
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Smith, Bryan K. (Bryan Karl) 1961. "Definition, expansion and screening of architectures for planetary exploration class nuclear electric propulsion and power systems." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/91776.
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Lunde, Dominic Charles. "A Homegrown DSMC-PIC Model for Electric Propulsion." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2066.
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Powering spacecraft with electric propulsion is becoming more common, especially in CubeSat-class satellites. On account of the risk of spacecraft interactions, it is important to have robust analysis and modeling tools of electric propulsion engines, particularly of the plasma plume. The Navier-Stokes equations used in classic continuum computational fluid dynamics do not apply to the rarefied plasma, and therefore another method must be used to model the flow. A good solution is to use the DSMC method, which uses a combination of particle modeling and statistical methods for modeling the simulated molecules. A DSMC simulation known as SINATRA has been developed with the goal to model electric propulsion plumes. SINATRA uses an octree mesh, is written in C++, and is designed to be expanded by further research. SINATRA has been initially validated through several tests and comparisons to theoretical data and other DSMC models. This thesis examines expanding the functionality of SINATRA to simulate charged particles and make SINATRA a DSMC-PIC hybrid. The electric potential is calculated through a 7-point 3D stencil on the mesh nodes and solved with a Gauss-Seidel solver. It is validated through test cases of charged particles to demonstrate the accuracy and capabilities of the model. An ambipolar diffusion test case is compared to a neutral diffusion case and the electric field is shown to stabilize the diffusion rate. A steady state flow test case shows the simulation is able to stabilize and solve the electric potential for a plume-like scenario. It includes additional features to simplify further research including a comprehensive user manual, industry-standard version control, text file inputs, GUI control, and simple parallelism of the simulation. Compilation and execution are standardized to be simple and platform independent to allow longevity of the code base. Finally, the execution bottlenecks of linking particles to cells and particle moving were removed to reduce the simulation time by 95%.
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Kinkaid, Timothy J. "Study of micro-sized technology, micro air vehicles, and design of a payload carrying flapping wing micro air vehicle." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Mar%5FKinkaid.pdf.
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Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, March 2006.Thesis Advisor(s): Isaac Kaminer, Kevin Jones. "March 2006." Includes bibliographical references (p.49-50). Also available online.
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de, Tenorio Cyril. "Methods for collaborative conceptual design of aircraft power architectures." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34818.
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This thesis proposes an advanced architecting methodology. This methodology allows for the sizing and optimization of aircraft system architecture concepts and the establishment of subsystem development strategies. The process is implemented by an architecting team composed of subsystem experts and architects. The methodology organizes the architecture definition using the SysML language. Using meta-modeling techniques, this definition is translated into an analysis model which automatically integrates subsystem analyses in a fashion that represents the specific architecture concept described by the team. The resulting analysis automatically sizes the subsystems composing it, synthesizes their information to derive architecture-level performance and explores the architecture internal trade-offs. This process is facilitated using the Coordinated Optimization method proposed in this dissertation. This method proposes a multi-level optimization setup. An architecture-level optimizer orchestrates the subsystem sizing optimizations in order to optimize the aircraft as whole. The methodologies proposed in this thesis are tested and demonstrated on a proof of concept based on the exploration of turbo-electric propulsion aircraft concepts.
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Marchetti, Paul J. "Electric propulsion and controller design for drag-free spacecraft operation in low earth orbit." Link to electronic thesis, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-122006-144358/.
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White, Daniel B. Jr. "Technology survey and performance scaling for the design of high power nuclear electric power and propulsion systems." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67559.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 239-252).
High power nuclear electric propulsion systems have the capability to enable many next-generation space exploration applications. To date, use of electric primary propulsion in flight systems has been limited to low-power, solar electric missions. There is a need for a large-scale research and development effort to field systems capable of meeting the demands of future high-power electric propulsion missions, especially missions utilizing nuclear power plants to power electric propulsion systems. In formulating such an effort, it is first important to identify the likely requirements around which such a system might be designed. These requirements can be effectively cast in terms of required thruster lifetime, thrust, specific impulse, output power, and power plant specific power. Projected requirements can be derived based on the mass characteristics of space-borne nuclear power plants, and the optimized trajectories of spacecraft missions enabled by the use of megawatt-level nuclear electric power systems. Detailed mass modeling of space-based Rankine cycle nuclear power plants is conducted to evaluate the achievable specific power of these systems. Based on the figures for specific power so obtained, mission modeling is next conducted using the Mission Analysis Low-Thrust Optimization software package. Optimized thrust, specific impulse and lifetime figures are derived for several missions of interest. A survey of available electric propulsion thrusters is conducted and thruster configurations presenting the lowest developmental risks in migrating to high thruster output power are identified. Design evolutions are presented for three thrusters that would enhance or enable operation at the megawatt level. First, evaluation of projected lifetime for dual-stage gridded ion thrusters is conducted using the CEX2D simulation tool to evaluate the utility of multi-stage gridded ion engines in obtaining the required thruster lifetime for operation at high specific impulse. Next, to evaluate the utility of Hall thrusters operating at high propellant mass flow rate, a numerical thruster model is developed that incorporates the effects of the neutral fluid in predicting thruster performance. Using this code, numerical simulations are conducted to investigate the effects of variations in propellant mass flow rate, magnetic field topology, and thruster channel geometry on achievable performance. Finally, the effects of variations in the channel contour of magnetoplasmadynamic thrusters on performance and efficiency are evaluated using the MACH2 software package. Incremental variations in thruster channel contour are implemented, and the effects of these variations on the performance onset condition, and electrode current distributions are observed. Conclusions regarding the utility of each of these three design evolutions in developing thrusters for multi-megawatt electric propulsion systems are discussed. Contributions stemming from this research include, first, the establishment of an appropriate requirements space for the design of advanced highpower electric power and propulsion systems. This design space is comprised of projected requirements for power plant specific power, derived from power plant mass modeling, and thruster output power, specific impulse and lifetime derived from mission modeling. Additionally, this work provides evaluation, using state-of-the-art simulation suites, of several electric thruster design evolutions of potential utility in developing electric propulsion systems designed to operate at the megawatt level.
by Daniel B. White.
Ph.D.
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Lindahl, Peter Allan. "Simulation, design and validation of a solid oxide fuel cell powered propulsion system for an unmanned aerial vehicle." Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/lindahl/LindahlP0509.pdf.
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This thesis presents a physically-based model for design and optimization of a fuel cell powered electric propulsion system for an Unmanned Aerial Vehicle (UAV). Components of the system include a Solid Oxide Fuel Cell (SOFC) providing power, motor controller, Brushless DC (BLDC) motor, and a propeller. Steady-state models for these components are integrated into a simulation program and solved numerically. This allows an operator to select constraints and explore design trade-offs between components, including fuel cell, controller, motor and propeller options. We also presents a graphical procedure using the model that allows rapid assessment and selection of design choices, including fuel cell characteristics and hybridization with multiple sources. To validate this simulation program, a series of experiments conducted on an instrumented propulsion system in a low-speed wind tunnel is provided for comparison. These experimental results are consistent with model predictions.
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Nam, Taewoo. "A Generalized Sizing Method for Revolutionary Concepts under Probabilistic Design Constraints." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14575.
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Internal combustion (IC) engines that consume hydrocarbon fuels have dominated the propulsion systems of air-vehicles for the first century of aviation. In recent years, however, growing concern over rapid climate changes and national energy security has galvanized the aerospace community into delving into new alternatives that could challenge the dominance of the IC engine. Nevertheless, traditional aircraft sizing methods have significant shortcomings for the design of such unconventionally powered aircraft. First, the methods are specialized for aircraft powered by IC engines, and thus are not flexible enough to assess revolutionary propulsion concepts that produce propulsive thrust through a completely different energy conversion process. Another deficiency associated with the traditional methods is that a user of these methods must rely heavily on experts experience and advice for determining appropriate design margins. However, the introduction of revolutionary propulsion systems and energy sources is very likely to entail an unconventional aircraft configuration, which inexorably disqualifies the conjecture of such connoisseurs as a means of risk management.
Motivated by such deficiencies, this dissertation aims at advancing two aspects of aircraft sizing: 1) to develop a generalized aircraft sizing formulation applicable to a wide range of unconventionally powered aircraft concepts and 2) to formulate a probabilistic optimization technique that is able to quantify appropriate design margins that are tailored towards the level of risk deemed acceptable to a decision maker.
A more generalized aircraft sizing formulation, named the Architecture Independent Aircraft Sizing Method (AIASM), was developed for sizing revolutionary aircraft powered by alternative energy sources by modifying several assumptions of the traditional aircraft sizing method. Along with advances in deterministic aircraft sizing, a non-deterministic sizing technique, named the Probabilistic Aircraft Sizing Method (PASM), was developed. The method allows one to quantify adequate design margins to account for the various sources of uncertainty via the application of the chance-constrained programming (CCP) strategy to AIASM. In this way, PASM can also provide insights into a good compromise between cost and safety.
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D'Anniballe, Alessandro. "Development of a sizing tool for preliminary mission analysis and design of propulsion systems for orbit control of small satellites in LEO -VLEO." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14719/.
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The ever-growing necessity for faster and cheaper access to space, makes the building of artificial satellites to shift more and more towards small measures. The most exemplar case of small satellites is given by the so called CubeSats, i.e. modular satellites practically ‘built in blocks’ of approximately the same size and weight. Such an approach allows to fasten the design and decrease the overall project complexity, but at the same time has many limitations. The main one is equipping the satellites with a propulsion system for the control of their operative orbit. Such a task normally requires a consistent amount of propellant, and so a specific dedicated propulsion system, that weighs consistently (in terms of both mass and volume) on the budget of these small spacecrafts.
The present thesis studies the feasibility of providing small satellites with a propulsion system that would enable them to perform orbit control maneuvers all along the mission duration. The concept is to create a computer tool able to carry out a rapid analysis of the satellite mission, for the determination of the needed Δv, and then a preliminary design of the main components of the required propulsion system. Different propulsion technologies can in this way be considered, being then able to do a trade-off to choose the best solution, in terms of mass and performances.
Satellite models ranging from nano to mini-sat standard in LEO-VLEO missions of different durations (2, 5 and 7 years) have been used for feasibility simulations, and re-sults show that the use of some propulsion technology is possible to reach the fixed mission goals.
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Flath, Allen III. "Mathematical Programming Approach for the Design of Satellite Power Systems." UKnowledge, 2019. https://uknowledge.uky.edu/ece_etds/136.
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Satellite power systems can be understood as islanded dc microgrids supplied by specialized and coordinated solar cell arrays augmented by electrochemical battery systems to handle high-power loads and periods of eclipse. The periodic availability of power, the limited capacity of batteries, and the dependence of all mission service on power consumption create a unique situation in which temporal power and energy scarcity exist. A multi-period model of an orbital satellite power system’s performance over a mission’s duration can be constructed. A modular power system architecture is used to characterize the system’s constraints. Using mathematical programming, an optimization problem can be posed such that the optimal power and energy ratings for the power system are determined for any load schedule imposed by a given mission’s requirements. The optimal energy trajectory of the electrical power system over a mission’s duration is also determined when the mathematical programming problem is solved. A generic set of mission requirements is identified to test this approach, but the objective function of the resulting optimization problem can be modified to return different results. These results can provide a clear illustration of the trade-offs that designers of such power systems consider in the design process.
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Gates, Nathaniel Spencer. "Combined Trajectory, Propulsion and Battery Mass Optimization for Solar-Regenerative High-Altitude Long-Endurance Aircraft." BYU ScholarsArchive, 2021. https://scholarsarchive.byu.edu/etd/8980.
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This thesis presents the work of two significant projects. In the first project, a suite of benchmark problems for grid energy management are presented which demonstrate several issues characteristic to the dynamic optimization of these systems. These benchmark problems include load following, cogeneration, tri-generation, and energy storage, and each one assumes perfect foresight of the entire time horizon. The Gekko Python package for dynamic optimization is introduced and two different solution methods are discussed and applied to solving these benchmarks. The simultaneous solve mode out-performs the sequential solve mode in each benchmark problem across a wide range of time horizons with increasing resolution, demonstrating the ability of the simultaneous mode to handle many degrees of freedom across a range of problems of increasing difficulty. In the second project, combined optimization of propulsion system design, flight trajectory planning and battery mass optimization is applied to solar-regenerative high-altitude long-endurance (SR-HALE) aircraft through a sequential iterative approach. This combined optimization approach yields an increase of 20.2% in the end-of-day energy available on the winter solstice at 35°N latitude, resulting in an increase in flight time of 2.36 hours. The optimized flight path is obtained by using nonlinear model predictive control to solve flight and energy system dynamics over a 24 hour period with a 15 second time resolution. The optimization objective is to maximize the total energy in the system while flying a station-keeping mission, staying within a 3 km radius and above 60,000 ft. The propulsion system design optimization minimizes the total energy required to fly the optimal path. It uses a combination of blade element momentum theory, blade composite structures, empirical motor and motor controller mass data, as well as a first order motor performance model. The battery optimization seeks to optimally size the battery for a circular orbit. Fixed point iteration between these optimization frameworks yields a flight path and propulsion system that slightly decreases solar capture, but significantly decreases power expended. Fully coupling the trajectory and design optimizations with this level of accuracy is infeasible with current computing resources. These efforts show the benefits of combining design and trajectory optimization to enable the feasibility of SR-HALE flight.
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Ali, Ahmed Mohammed [Verfasser], and Dirk [Akademischer Betreuer] Söffker. "Design of Hybrid Propulsion Systems for Vehicles Considering Optimal Power Management and Control in Real-Time / Ahmed M. Ali ; Betreuer: Dirk Söffker." Duisburg, 2019. http://d-nb.info/1196008132/34.
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McCrink, Matthew H. "Development of Flight-Test Performance Estimation Techniques for Small Unmanned Aerial Systems." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1449142886.
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Retho, Fabien. "Méthodologie collaborative d'aide à la construction de produits virtuels pour la conception d'aéronefs à propulsion électrique." Thesis, CentraleSupélec, 2015. http://www.theses.fr/2015SUPL0010/document.
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La recherche de moyens alternatifs pour la propulsion d'un aéronef est primordiale tant la dépendance au pétrole est forte. Le travail proposé dans cette thèse s'inscrit dans le besoin de soutenir les concepteurs de systèmes de propulsion innovants utilisant l'électricité. En partant du constat qu'il est primordial de s'appuyer sur l'analyse de l'aéronef dans sa globalité, nous proposons une approche basée sur les modèles, faisant appel aux modèles d’ingénierie système, aux modèles comportementaux basés sur la physique et à la simulation numérique, et collaborative, car la conception implique de nombreux métiers.L'objectif de cette approche est la création d'un produit virtuel qui est un modèle global multidisciplinaire exécutable du produit pour en faciliter la conception. Une méthodologie est alors construite pour se concentrer sur la relation entre le produit virtuel, ses modèles constitutifs et leur obtention. Le fil directeur de la méthodologie correspond à une recherche d'informations, au moyen de l'analyse des interactions et impacts multidisciplinaires qui apparaissent dans le système, puis l'application de cette information pour la construction d'un modèle d'intention qui permet la requête de modèles comportementaux auprès d'experts. C'est finalement le lien manquant entre la conception globale conduite par l'ingénierie système et la conception basée sur la physique du monde réel qui est implicitement traité dans ces travaux. Pour réaliser l'ensemble de la méthodologie, un nouveau rôle a été défini, le rôle d'architecte de simulation. Cette thèse présente la méthodologie de manière théorique, incluant ses rôles et concepts, puis cette dernière est démontrée sur un cas d'étude correspondant à l'hybridation d'un drone de type hélicoptèreThe research of alternative aircraft propulsion system is mandatory because oil dependence is too strong. The work proposed in this thesis is oriented to support electric based innovative propulsion system designers. Considering that it is important to consider entire aircraft analysis, we propose a model based, with systems engineering models, physics-based behavioral models and numerical simulation, and collaborative, because design require numerous business expertise. The objective of this approach is to build a virtual product, which means a global multidisciplinary executable model of the product under design in order to facilitate its design. A methodology is then developed, focused on the relation between the virtual product, its constitutive models and their acquisition. The methodology director wire corresponds to information research, with multidisciplinary interactions and impacts in the system, and then the application of those pieces of information to build a model of intention which allows requesting a behavioral model from experts. Finally, it is the missing link between global design driven with systems engineering and real physics based design which is implicitly at stake. To perform the methodology, a new role has been defined, the simulation architect. This thesis presents theoretically the methodology, including roles and concepts, and then this methodology is demonstrated on a helicopter based drone study-case
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Sands, Jonathan Stephen. "Robust design methodology for common core gas turbine engines." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53520.
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A gas turbine engine design process was developed for the design of a common core engine family. The process considers initial and projected variant engine applications, likely technology maturation, and various sources of uncertainty when making initial core design considerations. A physics based modeling and simulation environment was developed to enforce geometric core commonality between the core defining design engine and a common core variant engine. The environment also allows for upgrade options and technology to be infused into the variant engine design. The relationships established in the model enable commonality to be implicitly enforced when performing simultaneous design space explorations of the common core design and all corresponding variant engine designs. A robust design simulation process was also developed, enabling probabilistic surrogate model representations of the common core engine family design space to be produced. The probabilistic models provide confidence interval performance estimates with a single function call for an inputted set of core and variant design settings and the uncertainty distribution shape parameter settings representative of an uncertainty scenario of interest. The unique form of the probabilistic surrogate models enables large numbers of common core engine family applications to be considered simultaneously, each being simulated under a unique uncertainty scenario. Implications of core design options can be instantaneously predicted for all engine applications considered, allowing for favorable common core design regions to be identified in a highly efficient manner.
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Retaureau, Ghislain J. "On recessed cavity flame-holders in supersonic cross-flows." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43703.
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Flame-holding in a recessed cavity is investigated experimentally in a Mach 2.5 preheated cross-flow for both stable and unstable combustion, with a relatively low preheating. Self-sustained combustion is investigated for stagnation pressures and temperatures reaching 1.4 MPa and 750 K. In particular, cavity blowout is characterized with respect to cavity aspect ratio (L/D =2.84 - 3.84), injection strategy (floor - ramp), aft ramp angle (90 deg - 22.5 deg) and multi-fuel mixture (CH₄-H₂ or CH₄-C₂H₄ blends). The results show that small hydrogen addition to methane leads to significant increase in flame stability, whereas ethylene addition has a more gradual effect. Since the multi-fuels used here are composed of a slow and a fast chemistry fuel, the resulting blowout region has a slow (methane dominant) and a fast (hydrogen or ethylene dominant) branch. Regardless of the fuel composition, the pressure at blowout is close to the non-reacting pressure imposed by the cross-flow, suggesting that combustion becomes potentially unsustainable in the cavity at the sub-atmospheric pressures encountered in these supersonic studies. The effect of preheating is also investigated and results show that the stability domain broadens with increasing stagnation temperature. However, smaller cavities appear less sensitive to the cross-flow preheating, and stable combustion is achieved over a smaller range of fuel flow rate, which may be the result of limited residence and mixing time. The blowout data point obtained at lower fuel flow rate fairly matches the empirical model developed by Rasmussen et al. for floor injection phi = 0.0028 Da^-.8, where phi is the equivalence ratio and Da the Damkohler number. An alternate model is proposed here that takes into account the ignition to scale the blowout data. Since the mass of air entrained into the cavity cannot be accurately estimated and the cavity temperature is only approximated from the wall temperature, the proposed scaling has some uncertainty. Nevertheless the new phi-Da scaling is shown to preserve the subtleties of the blowout trends as seen in the current experimental data.
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Stückl, Stefan [Verfasser], Mirko [Akademischer Betreuer] [Gutachter] Hornung, and Rudolf [Gutachter] Voit-Nitschmann. "Methods for the Design and Evaluation of Future Aircraft Concepts Utilizing Electric Propulsion Systems / Stefan Stückl. Betreuer: Mirko Hornung. Gutachter: Mirko Hornung ; Rudolf Voit-Nitschmann." München : Universitätsbibliothek der TU München, 2016. http://d-nb.info/1107543258/34.
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Aktosun, Erdem. "Identification of hydrodynamic forces developed by flapping fins in a watercraft propulsion flow field." ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1900.
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In this work, the data analysis of oscillating flapping fins is conducted for mathematical model. Data points of heave and surge force obtained by the CFD (Computational Fluid Dynamics) for different geometrical kinds of flapping fins. The fin undergoes a combination of vertical and angular oscillatory motion, while travelling at constant forward speed. The surge thrust and heave lift are generated by the combined motion of the flapping fins, especially due to the carrier vehicle’s heave and pitch motion will be investigated to acquire system identification with CFD data available while the fin pitching motion is selected as a function of fin vertical motion and it is imposed by an external mechanism. The data series applied to model unsteady lifting flow around the system will be employed to develop an optimization algorithm to establish an approximation transfer function model for heave force and obtain a predicting black box system with nonlinear theory for surge force with fin motion control synthesis.
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Bartlett, Brandon. "Simulation of a Configurable Hybrid Aircraft." DigitalCommons@CalPoly, 2021. https://digitalcommons.calpoly.edu/theses/2318.
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As the demand for air transportation is projected to increase, the environmental impacts produced by air travel will also increase. In order to counter the environmental impacts while also meeting the demand for air travel, there are goals and research initiatives that aim to develop more efficient aircraft. An emerging technology that supports these goals is the application of hybrid propulsion to aircraft, but there is a challenge in effectively exploring the performance of hybrid aircraft due to the time and money required for safe flight testing and due to the diverse design space of hybrid architectures and components. Therefore, computational tools that are capable of simulating the performance of a hybrid aircraft are incredibly useful in the design process and research space.
Existing work on the simulation of hybrid aircraft focuses on modelling a specific hybrid propulsion system in a particular airframe, but it would be desirable to have a simulation tool that is not specific to one design. In this thesis, a simulation framework that can be easily configured for different types of hybrid structures and components is presented, and the simulator is validated using flight test data which demonstrates that the performance of the simulated aircraft is representative of a real aircraft. A design for a hybrid aircraft is also modelled and simulated over different flight profiles in order to study the performance of the hybrid propulsion system. Results indicate that the hybrid aircraft can be successfully simulated and demonstrate how the simulator can be used as a tool to study the best way to fly and operate a hybrid aircraft.
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Bodnar, Maxwell J. "The Creation, Analysis, and Verification of a Comprehensive Model of a Micro Ion Thruster." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1565.
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A computational model of the micro-ion thruster MiXI has been developed, analyzed, and partially verified. This model includes submodels that govern the physical, magnetic, electrostatic, plasma physics, and power deposition of the thruster. Over the past few years, theses have been conducted with the goal of running tests and analyzing the results; this model is used to understand how the thruster components interact so as to make predictions about, and allow for optimization of, the thruster operation. Testing is then performed on the thruster and the results are compared to the output of the code. The magnetic structure of the thruster was analyzed and numerous different configurations generated which were also evaluated by the optimizer and tested. Using the different configurations, models, and optimization tools, the total efficiency of the thruster is theoretically able to reach 69.4%. Operational testing of the thruster at many different throttle settings demonstrated a maximum total efficiency of 45.9 ±24.6%, discharge loss values as low as 109 ±25 eV/ion, and total power required as low as 50.5 ±0.1W to maintain thruster operation with beam extraction. Measurements of the plasma were taken using a Langmuir probe and the interpretation of the tests are used to verify the plasma physics submodel. Power draw measurements and analysis of the throttle inputs during testing are compared to the performance model outputs but were not accurate or consistent enough to fully verify the power deposition and plasma physics models. Analysis of the models and operational testing in this study have led to an increased understanding of the performance and operation of the MiXI-CP-V3 thruster, furthering the effort to create an efficient, flight capable micro-ion thruster.
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Morrisey, Bryan J. "Multidisciplinary Design Optimization of an Extreme Aspect Ratio HALE UAV." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/113.
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ABSTRACT
Multidisciplinary Design Optimization of an Extreme Aspect Ratio HALE UAV
Bryan J. Morrisey
Development of High Altitude Long Endurance (HALE) aircraft systems is part of a vision for a low cost communications/surveillance capability. Applications of a multi payload aircraft operating for extended periods at stratospheric altitudes span military and civil genres and support battlefield operations, communications, atmospheric or agricultural monitoring, surveillance, and other disciplines that may currently require satellite-based infrastructure. Presently, several development efforts are underway in this field, including a project sponsored by DARPA that aims at producing an aircraft that can sustain flight for multiple years and act as a pseudo-satellite. Design of this type of air vehicle represents a substantial challenge because of the vast number of engineering disciplines required for analysis, and its residence at the frontier of energy technology.
The central goal of this research was the development of a multidisciplinary tool for analysis, design, and optimization of HALE UAVs, facilitating the study of a novel configuration concept. Applying design ideas stemming from a unique WWII-era project, a “pinned wing” HALE aircraft would employ self-supporting wing segments assembled into one overall flying wing. The research effort began with the creation of a multidisciplinary analysis environment comprised of analysis modules, each providing information about a specific discipline. As the modules were created, attempts were made to validate and calibrate the processes against known data, culminating in a validation study of the fully integrated MDA environment. Using the NASA / AeroVironment Helios aircraft as a basis for comparison, the included MDA environment sized a vehicle to within 5% of the actual maximum gross weight for generalized Helios payload and mission data. When wrapped in an optimization routine, the same integrated design environment shows potential for a 17.3% reduction in weight when wing thickness to chord ratio, aspect ratio, wing loading, and power to weight ratio are included as optimizer-controlled design variables.
Investigation of applying the sustained day/night mission requirement and improved technology factors to the design shows that there are potential benefits associated with a segmented or pinned wing. As expected, wing structural weight is reduced, but benefits diminish as higher numbers of wing segments are considered. For an aircraft consisting of six wing segments, a maximum of 14.2% reduction in gross weight over an advanced technology optimal baseline is predicted.
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Conrad, Michael Curt. "COMET: CONSTRAINED OPTIMIZATION OF MULTIPLE-DIMENSIONS FOR EFFICIENT TRAJECTORIES." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/666.
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The paper describes the background and concepts behind a master’s thesis platform known as COMET (Constrained Optimization of Multiple-dimensions for Efficient Trajectories) created for mission designers to determine and evaluate suitable interplanetary trajectories. This includes an examination of the improvements to the global optimization algorithm, Differential Evolution, through a cascading search space pruning method and decomposition of optimization parameters. Results are compared to those produced by the European Space Agency’s Advanced Concept Team’s Multiple Gravity Assist Program. It was found that while discrepancies in the calculation of ΔV’s for flyby maneuvers exist between the two programs, COMET showed a noticeable improvement in its ability to avoid premature convergence and find highly isolated solutions.
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Green, Clayton R. "MODELING AND TEST OF THE EFFICIENCY OF ELECTRONIC SPEED CONTROLLERS FOR BRUSHLESS DC MOTORS." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1459.
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Small electric uninhabited aerial vehicles (UAV) represent a rapidly expanding market requiring optimization in both efficiency and weight; efficiency is critical during cruise or loiter where the vehicle operates at part power for up to 99% of the mission time. Of the four components (battery, motor, propeller, and electronic speed controller (ESC)) of the electric propulsion system used in small UAVs, the ESC has no accepted performance model and almost no published performance data. To collect performance data, instrumentation was developed to measure electrical power in and out of the ESC using the two wattmeter method and current sense resistors; data was collected with a differential simultaneous data acquisition system. Performance of the ESC was measured under different load, commanded throttle, bus voltage, and switching frequency, and it was found that ESC efficiency decreases with increasing torque and decreasing bus voltage and does not vary much with speed and switching frequency. The final instrumentation was limited to low-voltage systems and error propagation calculations indicate a great deal of error at low power measurements; despite these limitations, an understanding of ESC performance appropriate for conceptual design of these systems was obtained.
MODELING AND TEST OF THE EFFICIENCY OF ELECTRONIC SPEED CONTROLLERS FOR BRUSHLESS DC MOTORS
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Josselyn, Scott B. "Optimization of low thrust trajectories with terminal aerocapture." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FJosselyn.pdf.
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Thesis (Aeronautical and Astronautical Engineer)--Naval Postgraduate School, June 2003.Thesis advisor(s): I. Michael Ross, Steve Matousek. Includes bibliographical references (p. 149-150). Also available online.
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Dlima, Kendrick M. "Conceptual Design of a South Pole Carrier Pigeon UAV." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2145.
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Currently, the South Pole has a large data problem. It is estimated that 1.2 TB of data is being produced every day, but less than 500 GB of that data is being uploaded via aging satellites to researchers in other parts of the world. This requires those at the South Pole to analyze the data and carefully select the parts to send, possibly missing out on vital scientific information. The South Pole Carrier Pigeon will look to bridge this data gap.
The Carrier Pigeon will be a small unmanned aerial vehicle that will carry a 30 TB solid-state hard drive from the South Pole to various destinations in the Southern Hemisphere, but it has been designed to y to Christchurch, New Zealand. This 87 lb. UAV will be able to y 3,650 nmi. up to 25,000 ft., using a 5.7 hp. engine. It will feature an de-icing system on the leading edge of its 8 ft. span wing to allow it to y through cold, moist climates. It will have a 39 in. long fuselage with a tail boom of 33 in.
The aircraft has been designed to be made out of composites, thus reducing both the weight of the aircraft as well as its drag. It has been designed to come apart in order to be shipped successfully to the South Pole. There, it will be assembled and launched via a custom pneumatic launcher. It will y autonomously to 15,000 ft. and cruise climb throughout the flight to 25,000 ft., before descending to its destination. There, it will be caught by a net restraint system, where the hard drive will be extracted. The Carrier Pigeon is truly a unique vehicle for its size, range, and robustness.
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Stevens, John Wesley. "A design of a low-cost propulsion system for an electric scooter." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/17885.
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Dhand, Aditya. "Design of electric vehicle propulsion system incorporating flywheel energy storage." Thesis, City University London, 2015. http://openaccess.city.ac.uk/13699/.
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Battery electric vehicles are crucial for moving towards a zero emission transport system. Though battery electric vehicle technology has been rapidly improving, it is still not competitive to the conventional vehicles in terms of both cost and performance. The limited driving range and high cost are significant impediments to the popularity of battery electric vehicles. The battery is the main element which affects the range and cost of the vehicle. The battery has to meet the requirements of sufficient power and energy, quick recharge, safety, low cost and sufficient life. However the battery can either provide high power or high energy but not both. Hybridisation of the energy source is one of the methods to improve the energy efficiency of the vehicle, which would involve combining a high energy battery with a high power source. High power batteries, ultracapacitors and high speed flywheels are the potential high power sources that could be used. Out of these, the high speed flywheel in combination with a mechanical transmission is an attractive high power source for the battery electric vehicle due to its favourable characteristics of high specific power, sufficient high specific energy, high energy efficiency, long cycle life, quick recharge and low cost . This thesis presents and critically assesses a concept of a mechanically connected flywheel assisted battery electric vehicle propulsion system for a modern passenger car application. The main contribution of this thesis is the analysis of the effect of utilizing a mechanically connected flywheel in a hybrid energy storage with Li-ion batteries on the energy efficiency of the electric vehicle. The starting point of the research was to create a base electric vehicle model based on current technology. An analysis of the battery electric vehicle, its various components and control strategy and various approaches to model it was discussed which led to the creation of the baseline model. Simulations using the baseline model on three real world driving cycles representing urban, extra urban and motorway conditions, showed the potential for improving the energy efficiency of the vehicle by utilizing a power handling device that could transmit power directly to the driveline such as a mechanically connected flywheel. Hybridisation of the energy storage with the incorporation of the mechanically connected flywheel was presented. The flywheel was sized and a road data analysis was performed to support the sizing analysis. To accomplish the integration of the flywheel with the driveline, a fundamental analysis of the mechanical power split continuously variable transmission was conducted which showed various ways of obtaining the desired ratio range for the flywheel operation according to vehicle requirements. The speed ratio, power flow and efficiency were derived for three different types of transmissions. This analysis produced a simple methodology that can be applied to design a transmission for flywheel energy storage to provide any required speed ratio coverage and predict its efficiency in both directions of power flow, which is an important contribution of the thesis. The hybrid vehicle layout was presented and all its components were discussed. Further to obtain the maximum potential for improvement in energy consumption with the hybrid vehicle, optimisation of the energy management strategy was conducted. The optimisation problem was complex because of factors such as the small storage capacity of the flywheel, the kinematic constraints and the slipping of clutches. Dynamic programming was used to find optimal energy management strategy on the three real world driving cycles, which was the first instance of its implementation for such a powertrain; another important contribution of the thesis. The results were compared with baseline using a quasi static backward model. There was significant reduction in energy consumption for the more aggressive motorway cycle, less for the extra urban cycle, while there was a small increase in energy consumption for the relatively less aggressive urban cycle. However significant reduction in battery stress was observed for all the cycles which is expected to lead to improvements in battery life and lower operating costs. To provide a further step in implementation, a predictive energy management strategy was applied in the backward model for the hybrid vehicle based on dynamic programming with short computation time and utilizing limited future journey information which showed good performance in comparison to the benchmark simulation results. Finally the control was tested in a forward dynamic simulation to verify its suitability for real life implementation, and showed small deviation in performance compared to the backward simulation.
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Kaloun, Adham. "Conception de chaînes de traction hybrides et électriques par optimisation sur cycles routiers." Thesis, Ecole centrale de Lille, 2020. http://www.theses.fr/2020ECLI0019.
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La conception des chaînes de traction hybrides est une tâche complexe, qui fait appel à des experts de différents domaines s'appuyant sur des compétences et des outils distincts. En plus de cela, la recherche d'une solution optimale nécessite un retour système. Cela peut être, selon la granularité des modèles de composants, très coûteux en temps de calcul. Ceci est d'autant plus vrai lorsque la performance du système est déterminée par sa commande, comme c'est le cas du véhicule hybride. En fait, différentes possibilités peuvent être sélectionnées pour fournir le couple requis aux roues pendant le cycle de conduite. Ainsi, le principal obstacle est d'atteindre l'optimalité tout en conservant une méthodologie rapide et robuste. Dans ces travaux de thèse, de nouvelles approches visant à exploiter le potentiel complet de l'hybridation sont proposées et comparées. La première stratégie est une approche bi-niveaux composée de deux blocs d'optimisation imbriqués: un processus d'optimisation des paramètres de design externe qui calcule la meilleure valeur de consommation de carburant à chaque itération en se basant sur une version améliorée de la programmation dynamique pour l'optimisation de la commande. Deux stratégies de conception systémique différentes basées sur le schéma itératif sont également proposées. La première approche est basée sur la réduction de modèle tandis que la seconde se repose sur des techniques précises de réduction de cycle. Cette dernière permet l'utilisation de modèles de haute précision sans pénaliser le temps de calcul. Une approche simultanée est ensuite mise en œuvre, qui optimise à la fois les variables de conception et les paramètres d'une nouvelle stratégie efficace à base de règles. Cette dernière permettra une optimisation plus rapide par rapport à l'optimisation directe de toutes les variables de décision. Enfin, une technique basée sur l'utilisation des méta-modèles est exploréeDesigning hybrid powertrains is a complex task, which calls for experts from various fields. In addition to this, finding the optimal solution requires a system overview. This can be, depending on the granularity of the models at the component level, highly time-consuming. This is even more true when the system’s performance is determined by its control, as it is the case of the hybrid powertrain. In fact, various possibilities can be selected to deliver the required torque to the wheels during the driving cycle. Hence, the main obstacle is to achieve optimality while keeping the methodology fast and robust. In this work, novel approaches to exploit the full potential of hybridization are proposed and compared. The first strategy is a bi-level approach consisting of two nested optimization blocks: an external design optimization process that calculates the best fuel consumption value at each iteration, found through control optimization using an improved version of dynamic programming. Two different systemic design strategies based on the iterative scheme are proposed as well. The first approach is based on model reduction while the second approach relies on precise cycle reduction techniques. The latter enables the use of high precision models without penalizing the calculation time. A co-optimization approach is implemented afterwards which adjusts both the design variables and parameters of a new efficient rule-based strategy. This allows for faster optimization as opposed to an all-at-once approach. Finally, a meta-model based technique is explored
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Nakka, Sai Krishna Sumanth. "Co-design of Hybrid-Electric Propulsion System for Aircraft using Simultaneous Multidisciplinary Dynamic System Design Optimization." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1602153187738909.
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Sato, Sho Ph D. Massachusetts Institute of Technology. "Design and characterization of Hover Nano Aerial Vehicle (HNAV) propulsion system." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44925.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 321).
On October 4th 2005, DARPA released a request for proposals for a Nano-Air Vehicle (NAV) program. The program sought to develop an advanced urban reconnaissance vehicle. According the requirement imposed by DARPA, the NAV was to have dimensions smaller than 7.5 cm in diameter, and a weight of approximately 10 grams, to allow indoor operation. On top of these requirements, this vehicle was to operate for about 20 minutes, and have a low noise signature to avoid risk of detection. This thesis addresses the propulsion system required to enable the DARPA NAV. In particular, a rotary-wing vehicle is favored because of its high efficiency and simplicity. One large challenge faced for this design is the torque canceling mechanism to counter the torque produced by the rotating rotor. To provide a reasonable torque canceling, the solution proposed here is to use a rotating motor inside the vehicle. One rotor will be attached to the shaft of the motor and the other to a motor body that is left free to rotate inside the vehicle. By letting the motor rotate freely inside the body, the torque is cancelled automatically without a gearbox. In addition to this passive torque canceling mechanism, a novel approach is used in the fabrication approach of the motor in order to maximize the power density of this propulsion system. This new fabrication method involves the use of flexible printed circuit for the stator of the motor, which allows for the motor to achieve high power density, while simplifying its manufacturing process. The main goal of this project is to combine these two novel approaches in order to design, fabricate and assess the performance of the proposed propulsion system design. In this thesis, a prototype propulsion system for this vehicle, featuring the new motor fabrication approach, is designed, fabricated and tested.
(cont.) Firstly, the design model required to design the main components of the propulsion system (the motor model, the propeller model, and the design optimization program) is developed. The fabrication process of the propulsion system is then established, and an operational propulsion system prototype is fabricated using the established design tools and fabrication procedure. Finally, series of experiments are conducted in order to characterize the performance of the propulsion system and to validate the model used in the design of the propulsion system. Based on the results obtained from the experiment, it is found that the motor model used in the design of the motor for the propulsion system is accurate, with an error of 5% in the prediction of output shaft power of the motor. Among various configuration tested for the propulsion system, a combination of 5-bladed propeller and 3-bladed propeller, designed around the motor operating speed of 9,000 rpm is found to be most optimal for this propulsion system, featuring the following performance:for maximum achievable thrust of 17.28 g, well beyond hover thrust required for the vehicle;for capable of providing hover thrust at a power consumption of 1.26W, which translates to an hovering endurance of approximately 20 minutes using a lithyum polymer battery chosen for the vehicle;for torque cancelling mechanism capable of cancelling up to 99% of torque generated in the motor; and for noise footprint lower than 45 dBA, a typical indoor background noise during the day, 1 m away from the propulsion system. Based on these results, it is concluded that the propulsion system developed here is capable of meeting all the requirement imposed by DARPA. Since this research does not focus on the control aspect of the vehicle, further research should be conducted in the field of control and navigation in order to achieve a fully autonomous NAV.
by Sho Sato.
S.M.
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Espinosa, Orozco Jesus. "Intake Design, and Optimization for an Atmosphere- Breathing Electric Propulsion System." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-292688.
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Over the last two decades, Very Low Earth Orbit (VLEO) has gained researchers attention as it provides a significant amount of benefits in the field of earth observation and telecommunications. VLEO provides increased payload performance, improved geospatial accuracy, lower launch mass, simplified end of life disposal, and they reduce space-debris collision risk. However, the utilization of orbits with such low altitudes presents its own set of challenges, denser atmosphere will significantly increase aerodynamic drag, decaying the orbit in a short period of time. Besides increased drag VLEO environment will produce high levels of spacecraft (SC) charging and the presence of atomic oxygen will generate a constant erosion on the surfaces of the SC. An Atmosphere-Breathing Electric Propulsion (ABEP) ingests the residual atmosphere through an intake and uses it as propellant for an electric thruster. Theoretically applicable to any planet with an atmosphere, the system might allow drag compensation for an unlimited time without carrying propellant. In this thesis, different approaches for an intake are introduced, while the modeling, and numerical testing by Direct Simulation Monte Carlo (DSMC) is also presented. The intake is optimized for the RF Helicon-based Plasma Thruster (IPT) developed at IRS and a new concept design takes advantage of new materials properties, for specular surface interactions. Simulation results over different altitudes and conditions used for the verification of the design have been performed achieving a maximum collection efficiency of 94%.Under de senaste två decennierna har “Very Low Earth Orbit“ VLEO fått stor uppmärksamhet inom forskningsvärlden då det leder till en mängd fördelar inom jordobservation och telekommunikation. VLEO ger ökad nyttolastprestanda, förbättrad geospatial noggrannhet, lägre startmassa, förenklat bortförskaffande och minskning kollisionsrisken för rymdskräp. Användningen av omloppsbanor på så låg höjd medför dessvärre också utmaningar. Den lägre höjden innebär tätare atmosfär och ökar därav det aerodynamiska luftmotståndet avsevärt. Förutom ökad luftmotstånd kommer miljön i VLEO att producera höga nivåer av rymdfarkostladdning och närvaron av atomärt syre leder till en konstant erosion av farkosters ytor. En ABEP leder in den återstående atmosfären genom ett intag och använder den som drivmedel för en elektrisk drivraket. Teoretiskt tillämpbart på alla planeter med en atmosfär, kan systemet tillåta luftmotståndskompensation under obegränsad tid utan något annat drivmedel än den redan befintliga atmosfären. I denna avhandling presenteras olika modeller för ett intag samtidigt som modellering och numerisk testning av DSMC också presenteras. Intaget optimeras för den IPT som utvecklats vid IRS och en ny konceptdesign utnyttjar nya materialegenskaper för speciella ytinteraktioner. Simuleringsresultat över olika höjder och förhållanden som används för verifiering av designen har utförts och resulterat i en maximal insamlingseffektivitet på 94%.
In den letzten zwei Jahrzenten gewann die tiefe Erdumlaufbahn “Very Low Earth Orbit“ (VLEO) durch die erheblichen Vorteile für Erdbeobachtung und Telekommunikation an Aufmerksamkeit in der Wissenschaft. VLEO ermöglicht eine höhere Nutzlastleistung, verbesserte räumliche Genauigkeit, eine geringere Startmasse, vereinfachte “End-of-Life“ - Entsorgung und verringert das Kollisionsrisiko von Weltraumschrott. Die Nutzung von Umlaufbahnen in diesen geringen Höhen stellt jedoch auch eine Reihe von Herausforderungen dar. Die dichtere Atmosphäre im VLEO erhöht den Luftwiderstand erheblich und verringert die Umlaufbahn in kurzer Zeit. Neben dem erhöhten Luftwiderstand tritt auch hohe Raumschiff- oder Satellitenladung auf und durch atomaren Sauerstoff entsteht konstante Erosion an den Oberflächen. Ein atmosphärenatmender elektrischer Antrieb (ABEP) nimmt die Restatmosphäre über einen Einlass auf und verwendet sie als Treibstoff für ein elektrisches Triebwerk. Theoretisch auf jeden Planeten mit Atmosphäre anwendbar, könnte das System so den Widerstand zeitlich unbefristet ohne Treibstoffverwendung kompensieren. In dieser Arbeit werden verschiedene Ansätze für einen Einlass vorgestellt, und die Modellierung und numerischen Tests durch die “Direct Simulation Monte Carlo“ (DSMC) werden präsentiert. Der Einlass ist für den am IRS entwickelten RF Helicon-basierten Plasma Thruster (IPT) optimiert. Ein neues Konzeptdesign nutzt neue Materialeigenschaften für spiegelartige Oberflächen-Reflektionseigenschaften. Simulationsergebnisse verschiedener Höhen und Konditionen wurden zu der Überprüfung des Entwurfs verwendet, wobei eine maximale Einlassammlungswirkungsgrad von 94% erreicht wurde.
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Roper, Daniel. "Energy based control system designs for underactuated robot fish propulsion." Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/1560.
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In nature, through millions of years of evolution, fish and cetaceans have developed fast efficient and highly manoeuvrable methods of marine propulsion. A recent explosion in demand for sub sea robotics, for conducting tasks such as sub sea exploration and survey has left developers desiring to capture some of the novel mechanisms evolved by fish and cetaceans to increase the efficiency of speed and manoeuvrability of sub sea robots. Research has revealed that interactions with vortices and other unsteady fluid effects play a significant role in the efficiency of fish and cetaceans. However attempts to duplicate this with robotic fish have been limited by the difficulty of predicting or sensing such uncertain fluid effects. This study aims to develop a gait generation method for a robotic fish with a degree of passivity which could allow the body to dynamically interact with and potentially synchronise with vortices within the flow without the need to actually sense them. In this study this is achieved through the development of a novel energy based gait generation tactic, where the gait of the robotic fish is determined through regulation of the state energy rather than absolute state position. Rather than treating fluid interactions as undesirable disturbances and `fighting' them to maintain a rigid geometric defined gait, energy based control allows the disturbances to the system generated by vortices in the surrounding flow to contribute to the energy of the system and hence the dynamic motion. Three different energy controllers are presented within this thesis, a deadbeat energy controller equivalent to an analytically optimised model predictive controller, a $H_\infty$ disturbance rejecting controller with a novel gradient decent optimisation and finally a error feedback controller with a novel alternative error metric. The controllers were tested on a robotic fish simulation platform developed within this project. The simulation platform consisted of the solution of a series of ordinary differential equations for solid body dynamics coupled with a finite element incompressible fluid dynamic simulation of the surrounding flow. results demonstrated the effectiveness of the energy based control approach and illustrate the importance of choice of controller in performance.
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Rößler, Christian Ottmar [Verfasser]. "Conceptual Design of Unmanned Aircraft with Fuel Cell Propulsion System / Christian Rößler." München : Verlag Dr. Hut, 2012. http://d-nb.info/102253520X/34.
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Jia-Richards, Oliver. "Design and analysis of a stage-based electrospray propulsion system for CubeSats." Thesis, Massachusetts Institute of Technology, 2019.
Find full textAbstract:
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2019
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 147-149).
The standardization of small spacecraft through CubeSats has allowed for more affordable space exploration. This progress in affordability has been limited to Earth orbit due in part to the lack of high [delta]V propulsion systems that are compatible with the small form factor. The ion Electrospray Propulsion System developed at the Space Propulsion Laboratory at the Massachusetts Institute of Technology is a promising technology foundation for a compact, high [delta]V propulsion system. However, the [delta]V output of the propulsion system is limited by the lifetime of individual electrospray thrusters. This thesis presents the design and analysis of a stage-based concept for the ion Electrospray Propulsion System where the propulsion system is composed of a stack of electrospray thruster arrays. The stage-based propulsion system bypasses the lifetime limit of individual electrospray thrusters in order to increase the lifetime of the entire propulsion system. In effect, propulsion capabilities for CubeSats can be advanced without the need for technological developments. With the current performance metrics of the ion Electrospray Propulsion System, deep-space missions with an initial spacecraft form factor of a 3U CubeSat are feasible with current propulsion technology. Mechanisms required for the stage-based system are designed and demonstrated in a vacuum environment. In addition, analytical methodologies for the analysis of stage-based propulsion systems are developed to assist in preliminary mission design as well as provide the framework for autonomous decision making. Finally, applications of a stage-based propulsion system for missions to near-Earth asteroids are explored as well as analytical guidance for the escape trajectory.
NASA Space Technology Mission Directorate through the Small Spacecraft Technology Programgrant 80NSSC18M0045
NASA Space Technology Research Fellowshipgrant 80NSSC18K1186
by Oliver Jia-Richards.
S.M.
S.M. Massachusetts Institute of Technology, Department of Aeronautics and Astronautics
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Guerra, Gabriele. "Design, assembly and commissioning of a flexible testbench for propulsion system components." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-277641.
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Since its foundation in 2011 and among other things, OHB Sweden has beenappointed to fully develop, from the design to the assembly, a yearly increasingnumber of propulsion systems, ranging from chemical propelled to fully electricalspacecraft. One of the major contributor to the cost of this process, both in termsof money and time spent, is the verication phase, a combination of processes thatsets out to demonstrate that all the applicable requirements are met and to provethat the system is capable of fullling its objective during the mission lifespan.The increasing number of projects running simultaneously led to the need for aninnovative, smart solution to reduce the overall eorts spent on verication.The thesis work described in this document addresses the development of a newtest bench that allows carrying out qualication and acceptance tests on dierentcomponents or sub-assemblies of propulsion systems while requiring minimumsetup modications. The achievement of this goal would result in great benets toOHB Sweden, decreasing both the direct and indirect costs of the testing activities.Indeed, the current baseline approach consists of developing and assembling a newsetup every time a test is scheduled. Flexibility of the bench is a major goal: it isachieved by mounting relevant components in custom design brackets that can inturn slide on aluminium rails. This ensures the possibility of adding, removing orreplacing components without the need of disassembling the entire setup.Sedan företagets begynnelse 2011 har OHB Sweden bemötts av ett ständigt ökandebehov att utveckla både kemiskt och fullständigt elektriska satelliteframdrivningssystem. En av de största kostnaderna, både i tid och i pengar, för sådana processer är projektens verifikationssteg. Detta verifikationssteg består av en kombination av processor som tillsammans visar att produktens krav specifikationer uppfylls på ett tillfredställande under hela produktens livscykel, vilket görs från minsta komponent till den färdigbyggda rymdfarkosten. Då antalet projekt hos företaget ökat explosionsartat behövdes en innovativ metod för att minska arbetsbelastning under projektens verfikationssteg.Detta examensarbete beskriver utvecklingen av en ny typ av testbänk för kvalifikation och godkännande av ett framdrivningssystems olika delar, som tillåter stor testmöjlighet med minimal testbänksmodifiering. En nyutvecklad testbänk skulle innebära stora framdrifter hos OHB Sweden då direkta och indirekta kostnader kan kapas av förenklade testuppställningar, då tidigare testbänkar krävde komplex isäroch ihopplockning av speciella testbänksvarianter. Testbänkens huvudsakliga mål är att den är flexibel för varierade testuppställningar. Målet uppnås genom att de relevanta komponenterna monteras i särskilda konsoler som i sin tur kan glida fritt längs med aluminiumräls. Detta så att användaren slipper montera av eller tuppställningar.