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 24 for “"roll motion"”.
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Analysis and Modeling of Hydrodynamic Components for Ship Roll Motion in Heavy Weather
Ship roll motion has been the subject of many studies, because of the complexities associated with this mode of ship motion, and its impact on operability, safety, and survivability. Estimation and prediction of the energy transfer and dissipation of the hydrodynamic components, added inertia and …
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Rudder roll reduction for small ships
Roll motion on a ship can be very uncomfortable, and in the extreme, dangerous. It is possible to use the rudder to reduce roll motion as has been demonstrated by others on naval and coastguard vessels. For this study, five controllers were chosen and designed to implement a rudder roll reduction …
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Estudo do movimento de balanço de um sistema com perturbação interna
The roll motion of a system with internal perturbation is investigated. The system consists of a rigid box with a pendulum fixed on the top and supported by an elastic dissipative suspension. The mathematical model is obtained by the Newtonian Mechanics. One establishes the rtability chart with …
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Non-linear rolling of ships in large sea waves
… model tests show a ship that is prone to extreme roll transients. This thesis examines a simple method of producing a non-linear simulation of roll motion using a tumblehome hull provided by the Office of Naval Research. This research demonstrates the significant difference that a variable …
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Analysis of the dynamic stability derivatives for high angle of attack aircraft
… are required to be able to fly and be controlled over a wide variety of flight conditions. In order to predict the aircraft behavior and control requirements over the entire flight regime it is necessary to have a proper aerodynamic model. Flight conditions at high angles of attack lead to …
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Estudo das características estocásticas do roll paramétrico
… three mathematical models for simulation of motions of floating systems have been developed. The developed models are capable of simulating the heave, roll and pitch motions under regular and irregular longitudinal waves. Especial effort has been made in capturing in an accurate and efficient …
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Robust Yaw/roll Control of High-Speed Containerships
This thesis proposes a controller design for high-speed containerships with aggravated yaw/roll characteristics. With the trend of higher superstructures, low density cargo, and the deck loading of containerships, major problems have arisen in regard to roll motion stabilization. To minimize the …
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Force and hydrodynamic efficiency measurements of a three-dimensional flapping foil
… foils, varying both the kinematics of the motion and the flexibility of the foil. However, no thorough investigation into the hydrodynamic efficiency of three-dimensional flapping foils has been made. In this thesis, experimental hydrodynamic efficiency measurements and force measurements …
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AeroDima: a cheetah-inspired aerodynamic tail for rapid manoeuvrability
… of the tail on high-speed manoeuvres through a roll motion swing of the tail. The system was tested both in simulation and physical experiments. The simulation, developed with MATLAB's Simscape Multibody toolbox, was designed to be a comprehensive model of AeroDima.
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Design study of flapping foil propulsion for an Odyssey Class autonomous underwater vehicle
… on MIT's RoboTuna research on the swimming motions of fish, the proposed design hopes to achieve a speed of 1.5 m/s. Oscillating two tail links independently at a tail flapping frequency of about 1 Hz should provide this performance. The links are driven with DC brushless motor systems …
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Modeling and performance analysis of ABS systems with nonlinear control
… Four-wheel steering vehicle model with Limited Roll motion (YFLR) incorporating the nonlinear Magic Formula tire model (MF). Similar maneuvers are applied to the same vehicle model that is equipped with the conventional PID controller. Braking and vehicle stability performances are compared for …
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Roll stabilization for fast monohulls by using passive and active lifting appendages
Roll stabilization for monohulls is an important issue in naval architecture. Several methods including roll stabilization tanks, active control fins, rudder roll stabilization systems, and bilge keels are commonly used for roll stabilization purposes and each one of them has its own advantages and …
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The effects of motion experience on reflexive eye movements and dynamic tilt perception
… from disparate experiences with psychophysical motion stimuli. To test this hypothesis, horizontal and torsional eye movements, as well as roll tilt perception, were measured in both "naive" and "experienced" human subjects during 0.5 Hz sinusoidal roll motion. Between these measurement …
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Quantifying Extreme Event Statistics for Ship Motions and Loads Using Low-Fidelity Models and Recurrent Neural Networks
Ship operators and designers alike use ship motion simulation software to predict ship responses in irregular ocean waves, along with the statistics of extreme events. Ship operators rely on precalculated polar plots during heavy seas to select speeds and headings that will protect the ship and …
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Simplified Analysis of IMU Sensor Corruptions on Existing Pendulation Control System For Ship-Mounted Crane
… directly correlates to the ship's pitch and roll motion that in turn relates to the current particular sea-state. In this study, we analyze an existing Pendulation Control System (PCS) developed by Sandia National Laboratories that reduces the payload's pendulation movement during transport. …
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Improved Guidance, Navigation, and Control for Autonomous Underwater Vehicles: Theory and Experiment
… has not been performed for the pitch-axis motion of underwater vehicles. In this dissertation, we study the utility and the limitations of second-order approximate models for AUVs. We seek to improve the flight performance and shorten the time required to re-design a control algorithm when …
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Parametric Excitation of a DWSC
… when one of the coefficients in the equation of motion (EOM) modeling the system varies with time. Parametric instability might be triggered for certain values of the parameters describing the time-varying coefficient. The DWSC, basically a stepped classic spar with a catamaran as its deck, …
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Analytical and experimental investigations of ships impact interaction with one-sided barrier
… of ships with one-sided ice barrier during roll dynamics. An analytical model of ship roll motion interacting with ice is developed based on Zhuravlev and Ivanov non-smooth coordinate transformations. These transformations have the advantage of converting the vibro-impact oscillator into an …
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Effects of Frame Design and Cab Suspension on the Ride Quality of Heavy Trucks
… mounted vertically to control the vertical motion. The first suspension used two horizontally mounted dampers to control the lateral motion, while the second used a panhard rod connected to a torsion spring. In addition, two different sets of airsprings and two sets of vertical shocks were …
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Integrated vehicle dynamics control using active steering, driveline and braking
… that include longitudinal, lateral and yaw motions of the vehicle and body roll motion relative to the chassis about the roll axis as well as the rotational dynamics of four wheels. The lateral vehicle dynamics are analysed for the entire handling region and two distinct control objectives …
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