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Kim, Ho-Sik. "Conceptual design optimization for military helicopter maneuverability and agility." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/11969.
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Tai, Jimmy C. M. "A multidisciplinary design approach to size stopped rotor/wing configurations using reaction drive and circulation control." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/13460.
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Tatossian, Charles A. "Aerodynamic shape optimization via control theory of helicopter rotor blades using a non-linear frequency domain approach." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112586.
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This study presents a discrete adjoint-based aerodynamic optimization algorithm for helicopter rotor blades in hover and forward flight using a Non-Linear Frequency Domain approach. The goal is to introduce a Mach number variation into the Non-Linear Frequency Domain (NLFD) method and implement a novel approach to present a time-varying cost function through a multi-objective adjoint boundary condition. The research presents the complete formulation of the time dependent optimal design problem. The approach is firstly demonstrated for the redesign of a NACA 0007 and a NACA 23012 helicopter rotor blade section in forward flight. A three-dimensional inviscid Aerodynamic Shape Optimization (ASO) algorithm is then employed to validate and redesign the Caradonna and Tung experimental blade. The results in determining the optimum aerodynamic configurations require an objective function which minimizes the inviscid torque coefficient and maintains the desired thrust level at transonic conditions.
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Baker, Andrew Paul. "The role of mission requirements, vehicle attributes, technologies and uncertainty in rotorcraft system design." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/12476.
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Yue, Andrew. "H∞-design and the improvement of helicopter handling qualities." Thesis, University of Oxford, 1988. http://ora.ox.ac.uk/objects/uuid:4468a3ab-7297-4363-b605-b3e1f301d11b.
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This thesis presents the results of a study into the use of Hꝏ-optimization for the design of feedback control laws for improving the handling qualities of a Lynx helicopter. An important improvement to the Hꝏ-optimization procedure is the reduction in the number of iterative steps in the γ-iteration before convergence to the optimal γ. Some new algorithms are derived which significantly reduce the computation time for the γ-iteration. Both 2-block and 4-block cases are considered. Control laws are designed for precise control of pitch and roll attitude, yaw rate and heave velocity. Analysis of the raw helicopter showed the need for a stability augmentation system as the dynamic characteristics of the unaugmented helicopter do not comply with military helicopter handling qualities requirements. Results from current research on helicopter handling qualities were used as guidelines in order to define the required dynamic characteristics. A six-degree of freedom nonlinear simulation was used to analyse the helicopter dynamic time histories. A possible solution to the problem of incorporating helicopter handling qualities in the design of robust controllers is to use a two-degree of freedom controller structure. This is illustrated using both H2 and Hꝏ-optimization. A piloted simulation study to assess the effectiveness of advanced control laws was initiated at RAE, Bedford. The trials were carried out in the single seat cockpit flight simulator, at the Flight Research Division and represent the first ever real-time piloted simulation using a Hꝏ-controller.
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Visagie, Jonathan Gerhardus. "Stability and control characteristics of model helicopters." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50102.
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Thesis (MScEng)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: A need exists for the development of an unmanned rotorcraft capable of autonomous flight, as would be required for the survey of high voltage electricity supply lines. A program was initiated at the University of Stellenbosch in December 2002 in order to develop such an aircraft. The first goal of this thesis was the development of software that could calculate the stability and control derivatives of a model helicopter. These derivatives could then be used in the formulation of an appropriate helicopter control strategy. The second goal of the thesis was an investigation of the stability and control characteristics of model helicopters. The trim settings of the helicopter were required in the calculation of the stability and control derivatives. A computer program was developed to determine the trim settings of a helicopter in forward flight. Another program was developed to calculate the stability and control derivatives, using the results of the trim analysis. The trim analysis was based on the assumption of negligible coupling between the longitudinal and lateral modes of motion. The method proposed by Bramwell (1976) was used to perform the trim analysis. The stability and control derivatives were calculated by obtaining the trim settings from the trim analysis. These derivatives were then used to solve the roots of the characteristic equations of the longitudinal and lateral modes of motion. The stability of the helicopters were investigated firstly by examining the stability derivatives and secondly through root-loci analyses. The most important results were the following: • The root-loci analyses indicated that a helicopter without a horizontal stabiliser suffered from instability of the phugoid mode. It was also found that the short-period motion of these helicopters was heavily damped. Fitting a horizontal stabiliser to these helicopters caused the phugoid motion to become stable even at low speeds. This was achieved at the cost of a reduction in short-period motion damping. • The periods of the lateral and longitudinal motions were smaller than those found on full-scale helicopters. This was attributed to the small mass and inertia properties of the model helicopters. An increase in speed is generally accompanied by an increase in the stability of the helicopters. This could be attributed to the effective operation of the tail surfaces at higher speeds. • The axial climbing speed of a helicopter is influenced by the rotor speed. A low rotor speed allows higher climbing velocities at a given power setting. This was due to lower induced power losses at low rotor speed, assuming that no blade stall occurs. • The rotor speed does not influence the incremental amount of power (M:,) required to achieve a certain climbing velocity, due to the fact that the profile power losses are constant for a certain rotor speed. • The simplified horseshoe-vortex theory can be used to analyse the downwash angle at the horizontal stabiliser if the helicopter is in high-speed forward flight.
AFRIKAANSE OPSOMMING: Daar is tans 'n vraag na die ontwikkeling van onbemande rotor-vlerk vliegtuie wat die vermoë beskik om hulself te beheer. Hierdie tipe vliegtuie sal gebruik word om byvoorbeeld hoë-spannings elektrisiteitverskaffingsdrade na te gaan. 'n Program is in Desember 2002 by die Universiteit van Stellenbosch begin om sulke vliegtuie te ontwikkel. Die eerste doel van hierdie tesis was om sagteware te ontwikkel wat die stabiliteit- en beheerafgeleides van 'n model helikopter kon bereken. Hierdie afgeleides kan dan gebruik word om 'n gepaste helikopter beheerstrategie saam te stel. Die tweede doel van die tesis was om die stabiliteit- en beheerseienskappe van model helikopters te ondersoek. Die berekening van die stabiliteit- en beheerafgeleides van die helikopter berus op die beheerinsette benodig om die helikopter in ewewig te hou (trim). 'n Rekenaarprogram is ontwikkelom hierdie beheerinsette vir 'n helikopter in voorwaartse vlug te bereken. 'n Ander program is ontwikkelom die stabiliteit- en beheerafgeleides te bereken met behulp van die ewewig beheerinsette. Die analise van die helikopter in ewewig berus op die aanname dat die grootte van die koppeling tussen die longitudinale en laterale beweginsmodusse weglaatbaar klein is. Die beheerinsette van die helikopter in ewewig tydens voorwaartse vlug is bereken deur van Bramwell (1976) se metode te gebruik. Die stabiliteit- en beheerafgeleides is bereken deur van hierdie beheerinsette gebruik te maak. Die afgeleides is gebruik om die wortels van die karakteristieke vergelykings van die longitudinale en laterale bewegingsmodusse te bereken. Die stabiliteit van die helikopters is eerstens beoordeel deur die stabiliteitsafgeleides te ondersoek en tweedens deur middel van 'n wortel-lokus analise. Die belangrikste resultate is as volg: • Die wortel-lokus analise toon dat 'n helikopter sonder 'n horisontale stabiliseerder phugoid-onstabiliteit (Iangperiode onstabiliteit) het. Die kort-periode beweging van hierdie helikopters het verder groot hoveelhede demping aangetoon. Die phugoid-beweging kon selfs teen lae snelhede gestabiliseer word deur 'n horisontale stabiliseerder aan te heg. Hierdie stabiliteit is egter bereik ten koste van die demping van die kort-periode beweging wat verminder is. • Die periodes van die longitudinale en laterale bewegings is kleiner gewees as vir volskaal helikopters. Dit kan toegeskryf word aan die klein massa en inersie van die model helikopters. • Die stabiliteit van die helikopter is in die algemeen verbeter soos die snelheid verhoog. Dit kan toegeskryf word aan die beter werking van die stert teen die verhoogde snelhede. • Die klimtempo van die helikopter word beïnvloed deur die hoofrotor snelheid. 'n Lae hoofrotor snelheid laat 'n hoër klimptempo toe teen 'n spesifieke drywinginset. Dit is as gevolg van die laer geïndusseerde drywingsverliese teen die laer hoofrotor snelheid. Daar word aanvaar dat die lugvloei oor die lem nie staak nie. • Die hoofrotor snelheid beïnvloed nie die inkrimentele drywing (M,,) wat benodig word om 'n sekere klimtempo te bereik nie. Dit is as gevolg van die konstante drywings verliese teen 'n sekere hoofrotor snelheid. • Die vereenvoudigde perdeskoenwerwel teorie kan gebruik word om die afspoel hoek by die horisontale stabiliseerder te bereken indien die helikopter in hoë-spoed voorwaartse vlug is.
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Davis, Joseph Hutson. "Design Methodology for Developing Concept Independent Rotorcraft Analysis and Design Software." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19721.
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Throughout the evolution of rotorcraft design, great advancements have been made in developing performance analysis and sizing tools to assist designers during the preliminary and detailed design phases. However, very few tools exist to assist designers during the conceptual design phase. Most performance analysis tools are very discipline or concept specific, and many are far too cumbersome to use for comparing vastly different concepts in a timely manner. Consequently, many conceptual decisions must be made qualitatively. A need exists to develop a single software tool which is capable of modeling any type of feasible rotorcraft concept using different levels of detail and accuracy in order to assist in the decision making throughout the conceptual and preliminary design phases. This software should have a very intuitive and configurable user interface which allows users of different backgrounds and experience levels to use it, while providing a broad capability of modeling traditional, innovative, and highly complex design concepts.
As an illustration, a newly developed Concept Independent Rotorcraft Analysis and Design Software (CIRADS) will be presented to prove the applicability of such software tools. CIRADS is an object oriented application with a Graphical User Interface (GUI) for specifying mission requirements, aircraft configurations, weight component breakdowns, engine performance, and airfoil characteristics. Input files from the GUI are assembled to form analysis and design project files which are processed using algorithms developed in MATLAB but compiled as a stand alone executable and imbedded in the GUI. The performance calculations are based primarily upon a modified momentum theory with empirical correction factors and simplified blade stall models. The ratio of fuel (RF) sizing methodology is used to size the aircraft based on the mission requirements specified by the user. The results of the analysis/design simulations are then displayed in tables and Text Fields in the GUI. The intent for CIRADS is to become a primary conceptual sizing and performance estimation tool for the Georgia Institute of Technology rotorcraft design teams for use in the annual American Helicopter Society Rotorcraft Design Competition.
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Thériault, France. "Optimized design of a composite helicopter structure by resin transfer moulding." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99795.
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This research project is partnership project involving industrial, university and government collaborators. The overall objective is to develop and enhance tools for use in Resin Transfer Moulding (RTM) design technology in order to re-design existing metallic parts using composite materials.The specific objective of this work is to present preliminary research findings of the development of an optimized design of a leading edge slat (horizontal stabilizer component) from the Bell Model 407 Helicopter. The results presented here focus on the static stress analysis and the structure design aspects. The findings will serve as a basis for future design optimization as well as further developments in the use of RTM technology in re-designing metallic aeronautic components and can be considered to be "semi-optimized".
This research is based on extensive finite element analysis (FEA) of several composite material configurations, with a comparison made with the original metallic design. Different key criteria of the part design such as ply lay-up, bracket geometry, angle and configuration are tested using FEA technology with the objective of selecting the design which is minimizing stress concentrations. The influence of the modification of model-related parameters was also studied.
Preliminary comparative studies show that the slat configuration with half brackets opened towards the inside with an angle of 70 degrees (angle between the top of the airfoil and the side of the bracket) is the best option according to minimum stress concentration and structural flexibility. This choice is confirmed by other factors such as material savings and ease of processing.
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Johnson, Kevin Lee. "Prediction of operational envelope maneuverability effects on rotorcraft design." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47601.
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Military helicopter operations require precise maneuverability characteristics for performance to be determined for the entire helicopter flight envelope. Historically, these maneuverability analyses are combinatorial in nature and involve human-interaction, which hinders their integration into conceptual design. A model formulation that includes the necessary quantitative measures and captures the impact of changing requirements real-time is presented. The formulation is shown to offer a more conservative estimate of maneuverability than traditional energy-based formulations through quantitative analysis of a typical pop-up maneuver. Although the control system design is not directly integrated, two control constraint measures are deemed essential in this work: control deflection rate and trajectory divergence rate. Both of these measures are general enough to be applied to any control architecture, while at the same time enable quantitative trades that relate overall vehicle maneuverability to control system requirements. The dimensionality issues stemming from the immense maneuver space are mitigated through systematic development of a maneuver taxonomy that enables the operational envelope to be decomposed into a minimal set of fundamental maneuvers. The taxonomy approach is applied to a helicopter canonical example that requires maneuverability and design to be assessed simultaneously. The end result is a methodology that enables the impact of design choices on maneuverability to be assessed for the entire helicopter operational envelope, while enabling constraints from control system design to be assessed real-time.
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Suhr, Stephen Andrew. "Preliminary Turboshaft Engine Design Methodology for Rotorcraft Applications." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14128.
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In the development of modern rotorcraft vehicles, many unique challenges emerge due to the highly coupled nature of individual rotorcraft design disciplines therefore, the use of an integrated product and process development (IPPD) methodology is necessary to drive the design solution. Through the use of parallel design and analysis, this approach achieves the design synthesis of numerous product and process requirements that is essential in ultimately satisfying the customers demands. Over the past twenty years, Georgia Techs Center for Excellence in Rotorcraft Technology (CERT) has continuously focused on refining this IPPD approach within its rotorcraft design course by using the annual American Helicopter Society (AHS) Student Design Competition as the design requirement catalyst. Despite this extensive experience, however, the documentation of this preliminary rotorcraft design approach has become out of date or insufficient in addressing a modern IPPD methodology.
In no design discipline is this need for updated documentation more prevalent than in propulsion system design, specifically in the area of gas turbine technology. From an academic perspective, the vast majority of current propulsion system design resources are focused on fixed-wing applications with very limited reference to the use of turboshaft engines. Additionally, most rotorcraft design resources are centered on aerodynamic considerations and largely overlook propulsion system integration. This research effort is aimed at bridging this information gap by developing a preliminary turboshaft engine design methodology that is applicable to a wide range of potential rotorcraft propulsion system design problems. The preliminary engine design process begins by defining the design space through analysis of the initial performance and mission requirements dictated in a given request for proposal (RFP). Engine cycle selection is then completed using tools such as GasTurb and the NASA Engine Performance Program (NEPP) to conduct thorough parametric and engine performance analysis. Basic engine component design considerations are highlighted to facilitate configuration trade studies and to generate more detailed engine performance and geometric data. Throughout this approach, a comprehensive engine design case study is incorporated based on a two-place, turbine training helicopter known as the Georgia Tech Generic Helicopter (GTGH). This example serves as a consistent propulsion system design reference highlighting the level of integration and detail required for each step of the preliminary turboshaft engine design methodology.
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Bruce, Scott Alan. "Human-powered helicopter : a program for design and construction." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28266.
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Jeram, Geoffrey James Joseph. "Open Platform for Limit Protection with Carefree Maneuver Applications." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4933.
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This Open Platform for Limit Protection guides the open design of maneuver limit protection systems in general, and manned, rotorcraft, aerospace applications in particular. The platform uses three stages of limit protection modules: limit cue creation, limit cue arbitration, and control system interface. A common set of limit cue modules provides commands that can include constraints, alerts, transfer functions, and friction. An arbitration module selects the best limit protection cues and distributes them to the most appropriate control path interface. This platform adopts a holistic approach to limit protection whereby it considers all potential interface points, including the pilots visual, aural, and tactile displays; and automatic command restraint shaping for autonomous limit protection.
For each functional module, this thesis guides the control system designer through the design choices and information interfaces among the modules. Limit cue module design choices include type of prediction, prediction mechanism, method of critical control calculation, and type of limit cue. Special consideration is given to the nature of the limit, particularly the level of knowledge about it, and the ramifications for limit protection design, especially with respect to intelligent control methods such as fuzzy inference systems and neural networks.
The Open Platform for Limit Protection reduces the effort required for initial limit protection design by defining a practical structure that still allows considerable design freedom. The platform reduces lifecycle effort through its open engineering systems approach of decoupled, modular design and standardized information interfaces.
Using the Open Platform for Limit Protection, a carefree maneuver system is designed that addresses: main rotor blade stall as a steady-state limit; hub moment as a transient structural limit; and pilot induced oscillation as a controllability limit. The limit cue modules in this system make use of static neural networks, adaptive neural networks, and fuzzy inference systems to predict these limits. Visual (heads up display) and tactile (force-feedback) limit cues are employed. The carefree maneuver system is demonstrated in manned simulation using a General Helicopter (GENHEL) math model of the UH-60 Black Hawk, a projected, 53 degree field of view for the pilot, and a two-axis, active sidestick for cyclic control.
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Riviello, Luca. "Rotorcraft trim by a neural model-predictive auto-pilot." Thesis, Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-04142005-203616/unrestricted/riviello%5Fluca%5F200505%5Fmast.pdf.
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Thesis (M. S.)--Aerospace Engineering, Georgia Institute of Technology, 2005.Bottasso, Carlo, Committee Chair ; Hodges, Dewey, Committee Member ; Bauchau, Olivier, Committee Member. Includes bibliographical references.
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Agarwal, Sandeep. "Aeromechanical Stability Augmentation Using Semi-Active Friction-Based Lead-Lag Damper." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7547.
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Lead-lag dampers are present in most rotors to provide the required level of damping in all flight conditions. These dampers are a critical component of the rotor system, but they also represent a major source of maintenance cost. In present rotor systems, both hydraulic and elastomeric lead-lag dampers have been used. Hydraulic dampers are complex mechanical components that require hydraulic fluids and have high associated maintenance costs. Elastomeric
dampers are conceptually simpler and provide a ``dry" rotor, but are rather costly. Furthermore, their damping characteristics can degrade with time without showing external signs of failure. Hence, the dampers must be replaced on a regular basis. A semi-active friction based lead-lag damper is proposed as a replacement for hydraulic and elastomeric dampers. Damping is provided by optimized energy dissipation due to frictional forces in semi-active joints. An actuator in the joint modulates the normal force that controls
energy dissipation at the frictional interfaces, resulting in large hysteretic loops.
Various selective damping strategies are developed and tested for a simple system containing two different frequency modes in its
response, one of which needs to be damped out. The system reflects the situation encountered in rotor response where 1P excitation is present along with the potentially unstable regressive lag motion. Simulation of the system response is obtained to compare their effectiveness. Next, a control law governing the actuation in the
lag damper is designed to generate the desired level of damping for performing adaptive selective damping of individual blade lag
motion. Further, conceptual design of a piezoelectric friction based lag damper for a full-scale rotor is presented and various factors
affecting size, design and maintenance cost, damping capacity, and power requirements of the damper are discussed. The selective semi-active damping strategy is then studied in the context of
classical ground resonance problem. In view of the inherent nonlinearity in the system due to friction phenomena, multiblade transformation from rotating frame to nonrotating frame is not
useful. Stability analysis of the system is performed in the rotating frame to gain an understanding of the dynamic characteristics of rotor system with attached semi-active friction
based lag dampers. This investigation is extended to the ground resonance stability analysis of a comprehensive UH-60 model within the framework of finite element based multibody dynamics
formulations. Simulations are conducted to study the performance of several integrated lag dampers ranging from passive to semi-active ones with varying levels of selectivity. Stability analysis is performed for a nominal range of rotor speeds using Prony's method.
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Unnikrishnan, Suraj. "Adaptive Envelope Protection Methods for Aircraft." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11478.
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Carefree handling refers to the ability of a pilot to operate an aircraft without the need to continuously monitor aircraft operating limits. At the heart of all carefree handling or maneuvering systems, also referred to as envelope protection systems, are algorithms and methods for predicting future limit violations. Recently, envelope protection methods that have gained more acceptance, translate limit proximity information to its equivalent in the control channel. Envelope protection algorithms either use very small prediction horizon or are static methods with no capability to adapt to changes in system configurations. Adaptive approaches maximizing prediction horizon such as dynamic trim, are only applicable to steady-state-response critical limit parameters. In this thesis, a new adaptive envelope protection method is developed that is applicable to steady-state and transient response critical limit parameters. The approach is based upon devising the most aggressive optimal control profile to the limit boundary and using it to compute control limits. Pilot-in-the-loop evaluations of the proposed approach are conducted at the Georgia Tech Carefree Maneuver lab for transient longitudinal hub moment limit protection. Carefree maneuvering is the dual of carefree handling in the realm of autonomous Uninhabited Aerial Vehicles (UAVs). Designing a flight control system to fully and effectively utilize the operational flight envelope is very difficult. With the increasing role and demands for extreme maneuverability there is a need for developing envelope protection methods for autonomous UAVs. In this thesis, a full-authority automatic envelope protection method is proposed for limit protection in UAVs. The approach uses adaptive estimate of limit parameter dynamics and finite-time horizon predictions to detect impending limit boundary violations. Limit violations are prevented by treating the limit boundary as an obstacle and by correcting nominal control/command inputs to track a limit parameter safe-response profile near the limit boundary. The method is evaluated using software-in-the-loop and flight evaluations on the Georgia Tech unmanned rotorcraft platform- GTMax. The thesis also develops and evaluates an extension for calculating control margins based on restricting limit parameter response aggressiveness near the limit boundary.
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Riddell, Kevin Donald Alexander. "Design, testing and demonstration of a small unmanned aircraft system (SUAS) and payload for measuring wind speed and particulate matter in the atmospheric boundary layer." Thesis, Arts and Science, 2014. http://hdl.handle.net/10133/3416.
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The atmospheric boundary layer (ABL) is the layer of air directly influenced by the Earth’s surface and is the layer of the atmosphere most important to humans as this is the air we live in. Methods for measuring the properties of the ABL include three general approaches: satellite-based, ground- based and airborne. A major research challenge is that many contemporary methods provide a restricted spatial resolution or coverage of variations of ABL properties such as how wind speed varies across a landscape with complex topography. To enhance our capacity to measure the properties of the ABL, this thesis presents a new technique that involves a small unmanned aircraft system (sUAS) equipped with a customized payload for measuring wind speed and particulate matter. The research presented herein outlines two key phases in establishing the proof-of-concept of the payload and its integration on the sUAS: (1) design and testing and (2) field demonstration. The first project focuses on measuring wind speed, which has been measured with fixed wing sUASs in previous research, but not with a helicopter sUAS. The second project focuses on the measurement of particulate matter, which is a major air pollutant typically measured with ground- based sensors. Results from both proof-of-concept projects suggest that ABL research could benefit from the proposed techniques.
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Fitzsimons, Philip Matthew. "Design of a helicopter automatic flight control system using adaptive control." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/16641.
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Heiges, Michael W. "A helicopter flight path controller design via a nonlinear transformation technique." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/12482.
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Holmes, Christopher Edward 1963. "Effective platform designs for medium lift helicopters." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/29148.
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Thesis (S.M.)--Massachusetts Institute of Technology, System Design & Management Program, February 1999.Includes bibliographical references (leaves 91-95).
This thesis demonstrates that the use of platform design for medium lift helicopters can provide opportunities for reduced time to market and faster return to service of helicopters through faster design generation and reduced planning requirements. Through historical review of the S70 helicopter and the derivatives oft he basic model this thesis demonstrates that platform design methodologies address and minimize many of the difficulties associated with both the manufacture and post-deployment modification of the basic vehicle. Platform designing is used in a large number of industries with the rotorcraft industry being an exception. Point designs to specific customer requirements have been the historical norm. Given the high non-recurring costs associated with the development and certification of new aircraft systems, there remains a tendency in the rotorcraft industry to prolong the timeframe in which a specific aircraft continues to be manufactured by a particular supplier. Furthermore, after these aircraft are fielded they tend to have useful lives that could exceed thirty years and in many cases long after the circumstances for the original requirement have been removed. Also, the embedded technologies within the aircraft continue to evolve after the aircraft is fielded. Changing requirements and roles sometime require that these newer technologies be incorporated into the aircraft. Due to the high value of these already fielded aircraft there is a tendency of the operators to modify the fielded aircraft to adapt to the new mission and role as opposed to procuring newer a aircraft with the newer technologies already installed. This thesis concludes that through an understanding of the architecture of the air vehicle coupled with an assessment of the likely sections of that architecture that will change the enterprise is better positioned to respond to customer requirements with lower development investment. This thesis provides a review of the architecture of the S70A with particular attention to the instrument panel and allows for demonstration of protocols of platform designing. Various perspectives for assessing the architecture and maintaining the flexibility of the architecture are provided in the platform design context using the S70A helicopter as the central figure with the goal of providing a case study for reference during development of the next medium lift helicopter.
by Christopher Edward Holmes.
S.M.
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Liu, Cunjia. "Advanced control for miniature helicopters : modelling, design and flight test." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8969.
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Unmanned aerial vehicles (UAV) have been receiving unprecedented development during the past two decades. Among different types of UAVs, unmanned helicopters exhibit promising features gained from vertical-takeoff-and-landing, which make them as a versatile platform for both military and civil applications. The work reported in this thesis aims to apply advanced control techniques, in particular model predictive control (MPC), to an autonomous helicopter in order to enhance its performance and capability. First, a rapid prototyping testbed is developed to enable indoor flight testing for miniature helicopters. This testbed is able to simultaneously observe the flight state, carry out complicated algorithms and realtime control of helicopters all in a Matlab/Simulink environment, which provides a streamline process from algorithm development, simulation to flight tests. Next, the modelling and system identification for small-scale helicopters are studied. A parametric model is developed and the unknown parameters are estimated through the designed identification process. After a mathematical model of the selected helicopter is available, three MPC based control algorithms are developed focusing on different aspects in the operation of autonomous helicopters. The first algorithm is a nonlinear MPC framework. A piecewise constant scheme is used in the MPC formulation to reduce the intensive computation load. A two-level framework is suggested where the nonlinear MPC is combined with a low-level linear controller to allow its application on the systems with fast dynamics. The second algorithm solves the local path planning and the successive tracking control by using nonlinear and linear MPC, respectively. The kinematics and obstacle information are incorporated in the path planning, and the linear dynamics are used to design a flight controller. A guidance compensator dynamically links the path planner and flight controller. The third algorithm focuses on the further reduction of computational load in a MPC scheme and the trajectory tracking control in the presence of uncertainties and disturbances. An explicit nonlinear MPC is developed for helicopters to avoid online optimisation, which is then integrated with a nonlinear disturbance observer to significantly improve its robustness and disturbance attenuation. All these algorithms have been verified by flight tests for autonomous helicopters in the dedicated rapid prototyping testbed developed in this thesis.
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Tombs, Michael Stanley. "Robust control system design with application to high performance helicopters." Thesis, University of Oxford, 1987. https://ora.ox.ac.uk/objects/uuid:21939746-c2ee-47c6-9507-e953f139303e.
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This thesis presents one of the first applications of H∞-optimization to the design of controllers for industrial problems. The system considered was an unstable helicopter model, obtained from a large nonlinear simulation (provided by the Royal Aircraft Establishment, Bedford) configured to represent future high performance helicopters. The problem was to design a full authority flight control system, to stabilize the aircraft and decouple the controlled inputs, thus reducing pilot workload. Robustness was a primary issue because of model uncertainty, particularly due to the omission from the design model of higher order rotor dynamics. The optimization problem was based on the minimization of sensitivity (for performance) and control output (for robustness) transfer functions. Simple weighting functions were found to be useful for examining the fundamental performance-versus-robustness trade-off, and to be more effective at shaping the closed loop transfer functions than LQG/LTR techniques. A controller designed for a 4-input, 6-output, 8-state linearized plant model was successfully implemented in a non-linear simulation with rotor dynamics. This stabilized the system and enabled good control for small variations about the design operating point. The 'standard problem', consisting of the plant augmented with weights, had 20 states; the controller had 18, which was much smaller than researchers had been predicting, and it is conjectured that all H∞-optimal controllers will have at most the same number of states as the defining 'standard problem'. An important improvement to the H∞-optimization solution process was the development of a numerically reliable algorithm to perform minimal realization. This algorithm solves for a truncated balanced realization of stable state-space systems that are arbitrarily close to being either uncontrollable and/or unobservable. Depending on the choice of partitioning of the Hankel singular values, it can be used to perform minimal realization, or model reduction, with a guaranteed L∞ error bound.
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Stevens, David John. "Review of Alternative Construction Methods for Transmission Towers." Thesis, University of Canterbury. Management, Marketing, and Entrepreneurship, 2014. http://hdl.handle.net/10092/8937.
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It is important to ensure that Transpower is prepared to deliver upcoming transmission tower refurbishment projects that are located on sites with difficult access. This project reviews the availability, capability and cost of utilising alternative construction methods and any associated wider issues. The focus of this report is on how Transpower can more effectively utilise helicopters and gin poles for transmission tower erection and material delivery on remote sites.
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Tapia, Fidencio. "Inverse methodology for multi-point aerodynamic rotor blade design." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/13335.
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Nygren, Kip P. "An investigation of helicopter higher harmonic control using a dynamic system coupler simulation." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/12082.
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Westerhoff, Kevin M. (Kevin Matthew) 1978. "Construction based design." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/84827.
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Gündüz, Mustafa Emre. "Software integration for automated stability analysis and design optimization of a bearingless rotor blade." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33916.
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The concept of applying several disciplines to the design and optimization processes may not be new, but it does not currently seem to be widely accepted in industry. The reason for this might be the lack of well-known tools for realizing a complete multidisciplinary design and analysis of a product. This study aims to propose a method that enables engineers in some design disciplines to perform a fairly detailed analysis and optimization of a design using commercially available software as well as codes developed at Georgia Tech. The ultimate goal is when the system is set up properly, the CAD model of the design, including all subsystems, will be automatically updated as soon as a new part or assembly is added to the design; or it will be updated when an analysis and/or an optimization is performed and the geometry needs to be modified. Such a design process takes dramatically less time to complete; therefore, it should reduce development time and costs. The optimization method is demonstrated on an existing helicopter rotor originally designed in the 1960's. The rotor is already an effective design with novel features. However, application of the optimization principles together with high-speed computing resulted in an even better design. The objective function to be minimized is related to the vibrations of the rotor system under gusty wind conditions. The design parameters are all continuous variables. Optimization is performed in a number of steps. First, the most crucial design variables of the objective function are identified. With these variables, Latin Hypercube Sampling method is used to probe the design space of several local minima and maxima. After analysis of numerous samples, an optimum configuration of the design that is more stable than that of the initial design is reached. The process requires several software tools: CATIA as the CAD tool, ANSYS as the FEA tool, VABS for obtaining the cross-sectional structural properties, and DYMORE for the frequency and dynamic analysis of the rotor. MATLAB codes are also employed to generate input files and read output files of DYMORE. All these tools are connected using ModelCenter.
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Xie, Xiaoling. "Communications in construction design." Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/7571.
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Construction design has become an increasingly complex synthesis activity for which effective solutions depend upon co-operative participation by a number of people. Thus communication, including the integration of specialised knowledge and negotiation of differences between team members, is a vital process for collaborative design. A questionnaire survey was initially conducted to investigate communication issues and problems, which had been highlighted from a review of the literature, in current construction design. The results confirmed that communication among the different construction team members is often difficult although of paramount important to design outcomes. Based on these results, case studies have been carried out to gain further insights into communication issues and problems, and explore why and how they are caused. Through the application of multiple approaches, a model has been developed, which suggests strategies that may help participants communicate more effectively and ultimately improve the quality of construction design outcomes.
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Soto, Leticia S. M. Massachusetts Institute of Technology. "Construction design as a process for flow : applying lean principles to construction design." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42995.
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Thesis (S.M.)--Massachusetts Institute of Technology, System Design and Management Program, 2007.Includes bibliographical references (p. 108-111).
Delays and cost overruns are the rule rather than the exception in the construction industry. Design changes due to lack of constructability late in the construction phase generating costly ripple effect which create delay and disruption throughout the entire organization, are the largest contributors to the stated rule. In the building construction industry, of increased competitiveness, demand from many companies continued effort to develop new methods and tools, in which the design for quality, cost, construability and reliability play an important role. The planning and management of building design has historically focused upon traditional methods of planning such as Critical Path Method (CPM). Little effort is made to understand the complexities of the design process; instead design managers focus on allocating work packages where the planned output is a set of deliverables. This current design method forces design teams to manage their work on a discipline basis, each working on achieving their deliverable as dictated by the design program with little regard of the relationship with other disciplines and organizations. In addition, because Architect and Engineering firms view design and construction as two separate independent phases of work in project it makes it difficult to verify constructability in a design and create flow in the overall process. The goal of this study is to look at how aligning interests, objectives and practices based on lean fundamentals, during the earliest stages of a project, as a method of improving construction performance.
by Leticia Soto.
S.M.
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De, Jager Andries Matthys. "The design and implementation of vision-based autonomous rotorcraft landing." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6523.
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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011.ENGLISH ABSTRACT: This thesis presents the design and implementation of all the subsystems required to perform precision autonomous helicopter landings within a low-cost framework. To obtain high-accuracy state estimates during the landing phase a vision-based approach, with a downwards facing camera on the helicopter and a known landing target, was used. An e cient monocular-view pose estimation algorithm was developed to determine the helicopter's relative position and attitude during the landing phase. This algorithm was analysed and compared to existing algorithms in terms of sensitivity, robustness and runtime. An augmented kinematic state estimator was developed to combine measurements from low-cost GPS and inertial measurement units with the high accuracy measurements from the camera system. High-level guidance algorithms, capable of performing waypoint navigation and autonomous landings, were developed. A visual position and attitude measurement (VPAM) node was designed and built to perform the pose estimation and execute the associated algorithms. To increase the node's throughput, a compression scheme is used between the image sensor and the processor to reduce the amount of data that needs to be processed. This reduces processing requirements and allows the entire system to remain on-board with no reliance on radio links. The functionality of the VPAM node was con rmed through a number of practical tests. The node is able to provide measurements of su cient accuracy for the subsequent systems in the autonomous landing system. The functionality of the full system was con rmed in a software environment, as well as through testing using a visually augmented hardware-in-the-loop environment.
AFRIKAANSE OPSOMMING: Hierdie tesis beskryf die ontwikkeling van die substelsels wat vir akkurate outonome helikopter landings benodig word. 'n Onderliggende doel was om al die ontwikkeling binne 'n lae-koste raamwerk te voltooi. Hoe-akkuraatheid toestande word benodig om akkurate landings te verseker. Hierdie metings is verkry deur middel van 'n optiese stelsel, bestaande uit 'n kamera gemonteer op die helikopter en 'n bekende landingsteiken, te ontwikkel. 'n Doeltreffende mono-visie posisie-en-orientasie algoritme is ontwikkel om die helikopter se posisie en orientasie, relatief tot die landingsteiken, te bepaal. Hierdie algoritme is deeglik ondersoek en vergelyk met bestaande algoritmes in terme van sensitiwiteit, robuustheid en uitvoertyd. 'n Optimale kinematiese toestandswaarnemer, wat metings van GPS en inersiele sensore kombineer met die metings van die optiese stelsel, is ontwikkel en deur simulasie bevestig. Hoe-vlak leidingsalgoritmes is ontwikkel wat die helikopter in staat stel om punt-tot-punt navigasie en die landingsprosedure uit te voer. 'n Visuele posisie-en-orientasie meetnodus is ontwikkel om die mono-visie posisie-en orientasie algoritmes uit te voer. Om die deurset te verhoog is 'n saampersingsalgoritme gebruik wat die hoeveelheid data wat verwerk moet word, te verminder. Dit het die benodigde verwerkingskrag verminder, wat verseker het dat alle verwerking op aanboord stelsels kan geskied. Die meetnodus en mono-visie algoritmes is deur middel van praktiese toetse bevestig en is in staat om metings van voldoende akkuraatheid aan die outonome landingstelsel te verskaf. Die werking van die volledige stelsel is, deur simulasies in 'n sagteware en hardeware-indie- lus omgewing, bevestig.
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Bayar, Fatih Mehmet. "Desig And Analysis Of Fixturing In Assembly Of Sheet Metal Components Of Helicopters." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608193/index.pdf.
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Assembling of the compliant parts used in aviation industry is a challenging process. Assembly fixtures are quite important tools in this effort and widely used in industry. In fixturing of easily deformable sheet metal parts, besides restraining the rigid body motion of the parts, the possible deformations that
may occur during the assembly process and the spring-back effect on the final product need to be taken in to consideration. In order to guarantee a successful assembling, in other words, to obtain the final product within specified tolerances, a systematic approach to the fixture design problem is required. The designer should predict the correlation between the input variations and the final assembly variation, especially, for the complex assemblies.
This study proposes a design and analysis approach in fixturing of sheet metal assemblies for helicopter components. The design of an assembly fixture for a particular tail cone has been completed convenient to the existing locating principles. Finite Element Analysis (FEA) has been realized
in simulating the assembling process in order to predict the possible variation of the interested feature on a complex assembly due to deformations.
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Chew, En Phin. "Superconducting Transformer Design and Construction." Thesis, University of Canterbury. Electrical and Computer Engineering, 2010. http://hdl.handle.net/10092/4977.
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This thesis first outlines the testing undertaken on a partial core superconducting
transformer under open circuit, short circuit, full load and endurance test conditions.
During the endurance test, a failure occurred after 1 minute and 35 seconds. During the
failure, voltage dipping and rapid liquid nitrogen boil off was observed. This prompted
a failure investigation which concluded that the lack of cooling in the windings was the
most probable cause to the failure.
Full core transformer and superconductor theories are then introduced. A copper
winding transformer model, based on a Steinmetz equivalent circuit and a reverse
design method, is described. A superconductor loss model which outlines the different
types of losses experienced under AC conditions is used to determine the resistance
of the windings in the Steinmetz equivalent circuit. This resistance changes with the
magnitude of current and the strength of the magnetic field that is present in the gaps
between each layer of the windings. An alternative leakage flux model is then presented,
where the flux is modelled based on the combination of the reluctance of the core and
the air surrounding the windings. Based on these theories, an iterative algorithm to
calculate the resistance of the superconductor is developed.
A new design of a 15kVA single phase full core superconducting transformer, operating
in liquid nitrogen, is presented. The issues with building the superconducting
transformer are outlined. First, a copper mockup of the superconducting transformer
was designed where the mockup would have the same tape and winding dimensions
as the superconducting transformer, which means the same core can be used for two
different sets of windings. This led to designing a core that could be easily taken apart
as well as reassembled. Construction of the core, the copper windings and the superconductor
windings ensued. The process of cutting the core laminations, insulating the
copper and superconductor tapes, and making the steel fasteners and terminations are
described.
The copper mockup and superconducting transformers was then tested under open
circuit, short circuit, different load and endurance conditions at both liquid nitrogen
and room temperatures. These test results were then compared with the those from
two models. The comparison showed a significant inaccuracy in the reactances in
the models. This introduced a correction factor into the superconductor model which
ii
made it more accurate. However, further work is required to explain and quantify the
correction factors for the copper transformer model under different load conditions.
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Sebille, Michel. "Design :construction, automorphisms and colourings." Doctoral thesis, Universite Libre de Bruxelles, 2002. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211428.
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Leung, Chi-ming. "Design consultancy vs design and build consultancy : present trends in the construction industry /." Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B14038869.
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Steyn, J. (Johannes). "Design, manufacture and test of a bearingless rotor hub for the 24% scale model of the Rooivalk attack helicopter." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51676.
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Thesis (MEng) -- Stellenbosch University, 2000.Some digitised pages may appear illegible due to the condition of the original hard copy.
ENGLISH ABSTRACT: This document contains the work done on the bearingless rotor hub for the 24% scale model of the Rooivalk Attack Helicopter situated at the CSIR in Pretoria. This work forms part of the MSc Ing degree of Johannes Steyn. This work was deemed necessary because of a movement away from the fully articulated rotor to one of hingeless and more recently bearingless rotors. The main emphasis of this thesis is to be a technology demonstrator more than the design of a fully working bearingless rotor hub. With this in mind the final design in this report is not an optimal one, but the procedures and methodology in getting to a design are laid out in this document. To verify the design, tests were identified and created. The procedures for these tests are also included in this document. For the fatigue test a test bench had to be designed and built. This document also includes the design of this test bench
AFRIKAANSE OPSOMMING: Die dokument lewer verslag van die aktiwiteite vir die ontwerp van ‘n laerlose rotor van die 24% skaal model van die Rooivalk Helikopter, gelee by die WNNR in Pretoria. Die werk gedoen vorm deel van die MSc Ing graad van Johannes Steyn. Die werk is nodig geag omdat daar ‘n tendens is om weg te beweeg van die volledig geartikuleerde rotor na die van ‘n skanierlose en meer huidig ‘n laerlose rotor. Die hoof klem van die tesis is om as tegnologie demonstrator op te tree, eerder as die daarstel van ‘n werkende laerlose rotor. Na aanleiding van bogenoemde stelling kan die finale ontwerp nie as optimaal beskou word nie. Die prosedures en metodiek wat gevolg is om die ontwerp te kry word uitgele in die dokument. Om die ontwerp te verifieer is toetse gei'dentifiseer. Die prosedures vir elk van die toetse word ook in die dokument ingesluit. Vir die uitputtingstoetse moes ‘n spesiale toetsbank ontwerp en gebou word. Die ontwerp van hierdie toetsbank is ook in die dokument.
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Stettner, Martin. "Tiltrotor multidisciplinary optimization." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/12996.
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Ajayi, Saheed O. "Design, procurement and construction strategies for minimizing waste in construction projects." Thesis, University of the West of England, Bristol, 2017. http://eprints.uwe.ac.uk/30123/.
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The construction industry contributes the largest portion of waste to landfill, and it consumes a significant proportion of mineral resources excavated from nature. Due to adverse environmental impacts of waste generation, as well as financial gains associated with its minimization, waste intensiveness of the industry has remained a major concern across nations. This study investigates the design, procurement and construction strategies for waste minimization, using a dynamic approach. Apart from an investigation of the key and underlying measures for construction waste mitigation, the study considers the interrelationship between stages of projects' lifecycle. This is as activities carried out at an earlier stage are capable of engendering occurrences at later stages of the dynamic project delivery processes. Following the tenets of critical realism philosophy and exploratory sequential mixed method, the study combined qualitative and quantitative approaches at intensive and extensive stages respectively. At the early stage of the study, data were collected through literature review and focus group discussions with industry experts. Results of the qualitative study were used to develop a questionnaire, which was analysed using statistical approach and structural equation modelling. As a means of investigating the key drivers of waste minimization at a holistic level, a system dynamic model was developed to simulate the interplay and effects of different strategies that were confirmed through the previous process. The study suggests that design stage has the most decisive impacts on construction waste minimization. At this stage, the key dimensions for designing out waste include design for modern methods of construction, collaborative design process, design for standardisation and waste-efficient design documentation. Error-free design and involvement of contractors at early design stage are part of the critical success factors for designing out waste. With design being much important for waste minimization, competencies of design in terms of waste behavioural competency, design task proficiency, construction-related knowledge and inter-professional collaborative competency are essential for designing out waste. Materials procurement process could enhance waste minimization by considering its key dimensions for driving waste-efficient projects, which includes waste-efficient materials purchase management, suppliers' alliance and waste-efficient bill of quantity. Efficient materials take-off and take back scheme are confirmed as critical success factors for driving waste minimization through materials procurement processes. During construction activities, waste could be reduced through prefabrication and offsite technology, contractual requirements, maximisation of materials reuse and improved collaboration, among others. Prefabrication, supply chain alliance and collaborative procurement routes are confirmed as the critical success factors for reducing waste during construction process. Dynamic interplay among these sets of strategies suggests that notwithstanding the significance of the different measures during design, procurement and construction processes, prefabrication technology and collaborative procurement route are the holistic drivers of construction waste minimisation. The study implies that designers could effectively drive waste minimization through dimensional coordination and standardisation of design in line with standard materials supplies. In addition to the need for prefabrication and offsite technologies, increasing collaboration among project team is requisite to reducing waste generated by construction activities. By implementing the strategies suggested in the study, substantial proportion of construction waste would be diverted from landfill.
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Ferguson, A. J. L. "Dilution refrigerator : Design, construction and performance." Thesis, University of Ulster, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378638.
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Jeffries, James R. "Construction implications of photolithography equipment design /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Batzer, Rachel E. (Rachel Elizabeth). "Design and construction of a dynamometer." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68827.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011."June 2011." Cataloged from PDF version of thesis.
Includes bibliographical references (p. 20).
Access to a dynamometer is a useful tool for any electrical system where the motors must be selected from various suppliers and fully characterized. Motor suppliers usually provide a torque, speed, efficiency curve, but it frequently lacks complete motor characterization and includes motor controller losses in the total system loss. The dynamometer presented in this thesis is primarily designed for testing of high efficiency motors and motor controllers in the power and speed range requires for competition in the World Solar Challenge, a transcontinental race for solar electric vehicles. The testing specifications of a solar electric vehicles are uncommon among motor testing needs because it requires high torque, low power, high efficiency, and the only a small operating range. This thesis covers the design and construction of the dynamometer.
by Rachel E. Batzer.
S.B.
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Bibby, Lee. "Improving design management techniques in construction." Thesis, Loughborough University, 2003. https://dspace.lboro.ac.uk/2134/793.
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Recent years has seen a significant drive away from traditional procurement routes with contractors finding themselves with an increasing responsibility for control of design - a process they have had little experience in managing. They now have to adapt accordingly. The learning curve is steep, not least because many projects must now be delivered fast track while co-ordinating increasingly complex fabric and content of buildings without a platform of accepted good practice to manage the design process. This is a major factor preventing the UK construction industry from delivering projects on time, to budget and to the specified quality. There is a need to educate an increasing number of people in design management techniques to equip them to manage today's fast moving and demanding projects. However, many current design management tools are insufficiently developed for industry application. Therefore, to improve design management in the industry, current techniques must be modified to align them with the needs of the modern design manager. This research has developed and tested a training initiative aimed at improving design management practice within a major UK Design and Construct Contractor. It comprises a Design Management Handbook, Design Management Training, Team Support and Project Monitoring. The Design Management Handbook is the core of the training initiative. It addresses critical aspects of design management practice and provides design management tools. Training provides guidance to project teams on the tools and practices. In Team Support project teams are supported in the implementation of the new practices and tools to help embed new ways of working in company practice. Project Monitoring establishes the impact of the new practices on project performance to demonstrate that they are working and thus reinforce change. To establish the training initiative's effectiveness and key findings, the impact of the initiative on design management performance has been explored. The research has established which practices and tools were used, which were not, as well as an understanding the applicability and performance of each Handbook practice and tool. From this, barriers to implementing new design management tools in industry were identified and strategies developed in order to overcome such barriers.
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Collins, Kyle Brian. "A multi-fidelity framework for physics based rotor blade simulation and optimization." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26481.
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Thesis (Ph.D)--Aerospace Engineering, Georgia Institute of Technology, 2009.Committee Co-Chair: Dr. Dimitri Mavris; Committee Co-Chair: Dr. Lakshmi N. Sankar; Committee Member: Dr. Daniel P. Schrage; Committee Member: Dr. Kenneth S. Brentner; Committee Member: Dr. Mark Costello. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Petras, James P. "Prefabrication and the Construction Industry: An Examination of Design, Construction, and Efficiency." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1277120331.
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Rehnberg, Adam. "Suspension design for off-road construction machines." Doctoral thesis, KTH, Fordonsdynamik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-33883.
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Construction machines, also referred to as engineering vehicles or earth movers, are used in a variety of tasks related to infrastructure development and material handling. While modern construction machines represent a high level of sophistication in several areas, their suspension systems are generally rudimentary or even nonexistent. This leads to unacceptably high vibration levels for the operator, particularly when considering front loaders and dump trucks, which regularly traverse longer distances at reasonably high velocities. To meet future demands on operator comfort and high speed capacity, more refined wheel suspensions will have to be developed. The aim of this thesis is therefore to investigate which factors need to be considered in the fundamental design of suspension systems for wheeled construction machines. The ride dynamics of wheeled construction machines are affected by a number of particular properties specific to this type of vehicle. The pitch inertia is typically high in relation to the mass and wheelbase, which leads to pronounced pitching. The axle loads differ considerably between the loaded and the unloaded condition, necessitating ride height control, and hence the suspension properties may be altered as the vehicle is loaded. Furthermore, the low vertical stiffness of off-road tyres means that changes in the tyre properties will have a large impact on the dynamics of the suspended mass. The impact of these factors has been investigated using analytical models and parameters for a typical wheel loader. Multibody dynamic simulations have also been used to study the effects of suspended axles on the vehicle ride vibrations in more detail. The simulation model has also been compared to measurements performed on a prototype wheel loader with suspended axles. For reasons of manoeuvrability and robustness, many construction machines use articulated frame steering. The dynamic behaviour of articulated vehicles has therefore been examined here, focusing on lateral instabilities in the form of “snaking” and “folding”. A multibody dynamics model has been used to investigate how suspended axles influence the snaking stability of an articulated wheel loader. A remote-controlled, articulated test vehicle in model-scale has also been developed to enable safe and inexpensive practical experiments. The test vehicle is used to study the influence of several vehicle parameters on snaking stability, including suspension, drive configuration and mass distribution. Comparisons are also made with predictions using a simplified linear model. Off-road tyres represent a further complication of construction machine dynamics, since the tyres’ behaviour is typically highly nonlinear and difficult to evaluate in testing due to the size of the tyres. A rolling test rig for large tyres has here been evaluated, showing that the test rig is capable of producing useful data for validating tyre simulation models of varying complexity. The theoretical and experimental studies presented in this thesis contribute to the deeper understanding of a number of aspects of the dynamic behaviour of construction machines. This work therefore provides a basis for the continued development of wheel suspensions for such vehicles.QC 20110531
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Brouqueyre, Laurent. "Hydro-acoustic therapy : design, construction and testing." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/18215.
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Roth, Fabian. "Explicit design, and adaptation in self-construction /." Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17005.
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Bogdanov, Anton. "Design and construction of widebeam riometer system." Thesis, Lancaster University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.588505.
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Ionospheric absorption is a controlling factor in accurate prediction of medium to high frequency signal levels that are passing through ionosphere. Particularly at high latitudes ionospheric storms are the main problem, causing unreliable communication. Sometimes these storms can lead HF radio signals to "polar blackouts" (reducing the signal in-time by 20 % or more) or they can even be completely absorbed by ionosphere. [Ware and Owren, 1958] This project report presents the design, construction and testing of a device that is used to measure ionospheric cosmic noise absorption, which is called riometer. During the project development different methods of filter design (all-pole and coupled capacitor resonator filters), impedance matching (L, pi and capacitor tapped matching) and signal attenuation calculation (impedance mismatch, pi attenuator and potential divider) are showed and described. The need for new riometer design had arisen, because some discrete components used in previous riometer designs are obsolete [LIS Riometers] and therefore the new riometers cannot be made based on the old designs, so the new design had to be invented. This new riometer design also includes the new feature of controlling the switching between antenna and calibration using the computer control inputs and mechanical override switch, thus providing higher system flexibility.
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Yung, Keung-Shing, and 翁強盛. "Piling design and construction in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B4257609X.
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Yung, Keung-Shing. "Piling design and construction in Hong Kong." Click to view the E-thesis via HKUTO, 2001. http://sunzi.lib.hku.hk/hkuto/record/B4257609X.
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Robinson, Adrian C. "ISBU modular construction and building design prototypes." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/27480.
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With the use of industrialised construction increasing, Buro Happold (BH) commissioned this research as part of on-going initiatives to address the lack of efficiency in design and construction. The research considers two major case studies where modularisation has been used to minimise complexity and increase standardisation. Referred to in this thesis as construction product prototypes and building design prototypes , the two studies examine firstly the product development of an Intermodal Steel Building Unit (ISBU) used in multi-storey construction and secondly a modular station pre-design used and repeated on four station buildings. The ISBU is based on a standard ISO dry-freight container and its use in modular construction maximises the use of factory based off-site methods (OSM); this should improve consistency of product outcome with minimised impact on site. Very little academic work has been published on ISBU modular construction. The research therefore looks in detail at the process of ISBU modular product development and its engineering performance. It also compares production and procurement of the units on supplier-driven accommodation buildings in comparison to similar but non-modular client-led projects. Using multiple stages of project team interviews and project document analysis, the research data is coded, measured and analysed to describe the processes of product and design prototyping. The research demonstrates that the ISBU product was developed and refined through several major building projects and has reasonable engineering performance characteristics but may be more suited to temporary buildings. The principle of modular pre-designs as found in stations has benefits for rationalising the design process and simplifying and internalising complexities of construction. The research considers solutions for problems that are ill defined and a design process that is difficult to assimilate. This part of the research uses models for framing and problem/solution co-evolution to solve problems of ill definition and linear/non-linear design processes by building on Gero s (1990) design prototyping theory model. Modularisation of the station designs was successful in reducing design effort and allowed a repeatable pre-design to be refined, but the design team struggled with the bespoke nature of the project designs. The comparison of case study data to models for manufacturing, procurement and design prototype development has led to a better understanding as to how these designs were achieved and how these same approaches could be applied in future.
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Dias, Jay D. "Design, Construction, and Optimization of Microprobe Beamlines." Thesis, University of Louisiana at Lafayette, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10812789.
Full textAbstract:
A new external microprobe beamline for irradiation experiments has been commissioned and constructed at the Louisiana Accelerator Center. This microprobe was designed to use the Oxford Triplet lens con?guration with no scanning system. The beamline was designed to allow for the post focus expansion of the ion beam to create an even ?led of current distribution at a sample. The samples are irradiated in air in a glove box so that a Biosaftey-Level 2 (BSL-2) environment is created, reducing risk of contamination for biological sample irradiation. The nature of a microprobe allows the ?ux, and therefore the dose, to be su?ciently low for space radiation studies. The beamline was designed using WinTRAX [18] and constriction has been completed. This thesis is an overview of what a microprobe is, how the new microprobe was designed, and how the beamline was constricted.