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Full-Text Articles in Engineering
Removal Of Biofilm Through Controlled Cavitation, Mathew Chackalackal Mathew
Removal Of Biofilm Through Controlled Cavitation, Mathew Chackalackal Mathew
Master's Theses - Daytona Beach
Human kind is poised to take the next "giant step" in space exploration, the manned mission to Mars, among other things. But before any plans for such long term habitation on an alien planet, there has to be consideration towards prevention and removal of bacterial contamination. Bacterial contamination or rather degradation of materials was considered of negligible importance. Bacterial degradation can be serious for long-term manned space mission, more so because there is no way to obtain quick replacements. For such conditions, a new innovative way of bacterial removal has been proposed wherein the bacteria is removed with no damage …
Control System Design And Simulation Of Spacecraft Formations Via Virtual Formation Approach, Pavan Donepudi
Control System Design And Simulation Of Spacecraft Formations Via Virtual Formation Approach, Pavan Donepudi
Master's Theses - Daytona Beach
The problem of formation control of multiple spacecraft using the virtual structure approach is studied. The thesis first summarizes the progress made in the area of spacecraft formation control and then provides an overview of the virtual structure method. Modifying earlier established control design techniques, new feedback laws are constructed to control both the rotational and translational motion of a group of spacecraft. Several computer simulations are performed to illustrate the effectiveness of the modified control laws. The ephemeris and attitude data files generated via Matlab are exported to Satellite Tool Kit (STK) to create 3D animations. Various formation scenarios …
Parameter Estimation Of Spacecraft Fuel Slosh Using Pendulum Analogs, Keith L. Schlee
Parameter Estimation Of Spacecraft Fuel Slosh Using Pendulum Analogs, Keith L. Schlee
Master's Theses - Daytona Beach
The nutation (wobble) of a spinning spacecraft in the presence of energy dissipation is a well-known problem in dynamics and is of particular concern for space missions. Its rate of growth is characterized by the Nutation Time Constant (NTC). For analytical prediction of the NTC, fuel slosh is often modeled using simple mechanical analogs such as pendulums or rigid rotors coupled to the spacecraft. Identifying model parameter values which adequately represent the sloshing dynamics is the most important step in obtaining a good NTC estimate. Currently, the identification of the model parameters is a laborious trial-and-error process in which the …
Maneuvering Control Of A Spacecraft With Propellant Sloshing, Philip A. Savella
Maneuvering Control Of A Spacecraft With Propellant Sloshing, Philip A. Savella
Master's Theses - Daytona Beach
Propellant slosh has been a problem studied in spacecraft designs since the early days of large, liquid-fuel rockets. The conventional design solution involves physical structures inside the fuel tanks that limit propellant motion. Although effective, baffles and bladders add to spacecraft mass and structural complexity. In this research, the sloshing fuel mass is treated as an unactuated degree of freedom within a rigid body. Specifically, the propellant is modeled as a pendulum mass anchored at the center of a spherical tank. After obtaining the coupled equations of motion, several linear controllers are developed to achieve planar spacecraft pitch-maneuvers while suppressing …
Modeling And Slew-Maneuver Control Of A Flexible Spacecraft, Jeremy E. Eckhart
Modeling And Slew-Maneuver Control Of A Flexible Spacecraft, Jeremy E. Eckhart
Master's Theses - Daytona Beach
Slew-maneuver control problem is studied for a flexible spacecraft consisting of a rigid main body to which a long flexible appendage is attached. Nonlinear dynamical system models are developed using both distributed parameter modeling and discrete parameter modeling; these models are shown to be equivalent for appropriately chosen system parameters. Lyapunov-based nonlinear feedback controllers are designed for the control of rigid-body motion while suppressing the lowest frequency vibrational mode. In case of large-angle maneuvers, these nonlinear controllers are shown to outperform the linearization-based controllers including the filtered proportional-derivative (PD) controllers as well as the linear quadratic regulator (LQR) controllers. Finally, …
Control System Design And Simulation Of Spacecraft Formations, Daniel Dyer
Control System Design And Simulation Of Spacecraft Formations, Daniel Dyer
Master's Theses - Daytona Beach
The objective of this thesis is to analyze an effective control scheme for a formation of spacecraft, implement that control, and provide a 3-D simulation. The thesis first summarizes the progress made in formation flight control schemes and then provides a theoretical framework for the control system design. Using established control design techniques, feedback laws are constructed to control both rotational and translational motion of a group of spacecraft. Computer simulations are carried out using Matlab to generate the ephemeris and attitude data, which are exported to Satellite Tool Kit (STK) to create animations. The process by which Matlab is …
Modeling Launch Vehicle Success Using Artificial Neural Networks, Jennifer A. Schuck
Modeling Launch Vehicle Success Using Artificial Neural Networks, Jennifer A. Schuck
Master's Theses - Daytona Beach
Expendable launch vehicles in the United States currently have a reliability of 92%. The failures that do occur cost millions of dollars in spacecraft replacement, lost revenue, and other expenses. These costs are passed on in higher insurance rates and launch vehicle price. If the launch outcome of the launch vehicles could be better predicted, the overall cost of launching payloads into space would decrease. This study used artificial neural networks to model the overall launch outcome of a launch vehicle so that the results of a launch could be predicted. Two neural network architectures--MLP and fuzzy ARTMAP--were trained on …
An Experimental Investigation Of Direct And Indirect Viewing Of A Remote Manipulation, Stephen N. Plishka
An Experimental Investigation Of Direct And Indirect Viewing Of A Remote Manipulation, Stephen N. Plishka
Master's Theses - Daytona Beach
The purpose of this study was to evaluate direct and indirect viewing of a remote manipulation. With continued exploration of inner and outer space, the ability to directly manipulate objects is lost due to the nature of operating in harsh environments. Remote viewing and operation of equipment is used in such things as the space shuttle manipulator arm, orthoscopic surgery, undersea exploration, and hazardous material management. Most of these operations do not have the luxury of direct viewing. This study will compare the effects of direct viewing vs. indirect viewing from three different viewing distances of 20cm, 60cm and 100cm.
Cooperative Power-Limited Optimal Rendezvous Between Many Spacecraft, Virginie Guerre
Cooperative Power-Limited Optimal Rendezvous Between Many Spacecraft, Virginie Guerre
Master's Theses - Daytona Beach
The minimum fuel rendezvous problem between several power-limited low-thrust spacecraft neighboring either a circular or an elliptic orbit is investigated. Both cooperative and non cooperative maneuvers are studied. The maximum principle of Pontryagin is applied to the optimal control rendezvous problem of several spacecraft. The gravitational field models investigated are the Clohessy-Wiltshire field and the inverse-square gravity field. Numerical solutions using a shooting method and the finite difference method are used in order to determine the trajectories of the spacecraft. Unlike previous investigations, this work is not restricted to a rendezvous of two spacecraft around a circular orbit, but a …