Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 84 for “"center of gravity"”.
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Control of Longitudinal Pitch Rate As Aircraft Center of Gravity Changes
… for an aircraft to remain in stable flight, the center of gravity (CG) of an aircraft must be located in front of the center of lift (CL). As the center of gravity moves rearward, pitch stability decreases and the sensitivity to control input increases. This increase in sensitivity is known as …
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Estimation of Uncertain Vehicle Center of Gravity using Polynomial Chaos Expansions
The main goal of this study is the use of polynomial chaos expansion (PCE) to analyze the uncertainty in calculating the lateral and longitudinal center of gravity for a vehicle from static load cell measurements. A secondary goal is to use experimental testing as a source of uncertainty and as a …
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Biologically inspired attitude control of robotic systems using center of gravity reallocation
Natural species often rely on inertial forces for their orientation control. Lizards, geckos and arboreal animals effectively use their inertial appendages to control their attitude dynamics. On the other hand, flying species such as biological bats employ their relatively heavier wings to produce …
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Linear and Angular Head Accelerations in Daily Life
The purpose of this study was to determine the linear accelerations, angular rates, and angular accelerations of the center of gravity of the head during daily activities and to determine the effect of angular terms on the linear accelerations. A total of 700 experiments were conducted with 18 …
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Adaptive Control Allocation for Unmanned Aerial Vehicles with Model Uncertainties
… carry risks to weaken the performance of any aerial system and endanger operation during flight. To this end, over-actuated aerial systems are used in flight operations to take precautions for possible incidents, which may result in improper control or a fall of the aerial vehicle. …
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An investigation of the dynamic lateral stability and control of a parawing vehicle
Parawing vehicles may have unusual values of many of the mass and aerodynamic factors affecting dynamic lateral stability and control. These unusual characteristics are due in large part to the fact that the center of gravity of parawing vehicles is located far below the parawing, whereas …
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Articulation of whispered alveolar consonants
This thesis explores the articulation of whispered and normally-spoken alveolar consonants through the use of electropalatography (EPG). While whisper is a well-researched topic, most prior studies have been limited to glottal and acoustic examinations. This study aims to directly measure the …
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Soft Surface Roll Mechanics Parameters for Light Vehicle Rollover Accident Reconstruction
Light vehicle rollover accidents on soft surfaces can be modeled assuming constant drag with linear motion equations and other engineering principles. The concept of using segment average results to evaluate roll mechanics parameters throughout a roll sequence, and specifically, segment duration to …
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Multi-fidelity data fusion for the design of multidisciplinary systems under uncertainty
… methodology to enable the incorporation of high-fidelity data into a conceptual design process. The methodology is based upon a fidelity weighted combination of Gaussian Process surrogate models that takes into account both the quality of the Gaussian Process approximation and the …
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Agile load transportation systems using aerial robots
… small scale quadrotors. First, detailed models of such transportation system are derived. These models include nonlinear models of a quadrotor, a model of a quadrotor carrying a fixed load and a model of a quadrotor carrying a suspended load. Second, the problem of quadrotor stabilization and …
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Adaptive control of a generic hypersonic vehicle
… controller applied to the Road Runner six-degree-of-freedom generic hypersonic vehicle model. Uncertainty in control effectiveness, longitudinal center of gravity location, and aerodynamic coefficients are introduced in the model, as well as sensor bias and noise, and input time delays. The …
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Static and Dynamic Response of Helically Curved Thin-Walled Girders
… dissertation presents a finite element method of analysis for the static and dynamic response of helically curved thin-walled girders. The girder is assumed to possess a doubly symmetric, open cross-section with principal axes oriented in the directions of the normal and binormal vectors to the …
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Dehumanization and irregular warfare
In the current global environment the practice of dehumanizationthe stripping away of common attributes among people that call for respect and constrain violenceand the misperception it creates have resulted in misguided attempts by militaries to influence the center of gravity in irregular …
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AEROMECHANICS OF A DOUBLE ANHEDRAL TIP COMPOSITE ROTOR: EXPERIMENT AND MODELING
… systematically. Double anhedral blades of 5.6-ft diameter were designed and fabricated. The blades had a uniform VR-7 airfoil profile, a D-spar, $-16^\circ$ twist, a $5^{\circ}$ dihedral from $80\%$R to $95\%$R and a $15^{\circ}$ anhedral from $95\%$R to the tip. The blades were built …
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The benefits of 4WD drive for a high-performance FSAE electric racecar
This thesis explores the performance of Rear-Wheel Drive (RWD) and Four-Wheel Drive (4WD) FSAE Electric racecars with regards to acceleration and regenerative braking. The benefits of a 4WD architecture are presented along with the tools for further optimization and understanding. The goal is to …
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Aerodynamic stability analysis of a CubeSat in high-speed rarefied flow
… is important to design these spacecraft, which often have modest control authority, such that the resultant aerodynamic forces and moments do not cause unstable motion, which may lead to premature loss of mission. Building from free molecular pressure and shear equations for flat plates, an …
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Approximation algorithms for multi-facility location
… deals with the development and implementation of efficient algorithms to obtain acceptable solutions for the location of several facilities to serve customer sites. The general version of facility location problem is known to be NP-hard; For locating multiple facilities we use Voronoi diagram …
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Six degree of freedom optimal trajectories for satellite rendezvous
… positions and orientations using a sequence of impulsive burns. The method makes use of the linear Clohessy-Wiltshire equations to describe translational motions, Euler's equations of rigid body motion for describing the attitude motions, and a sequential quadratic programming optimization …
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Space Control: Securing America's Future in Space
… States has come to rely extensively on the use of space for both military and commercial purposes, and this is a reliance that will only increase in the future as space becomes even more integrated into our national life. As such, space will become an important strategic center of gravity, and …
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