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You searched for +publisher:"Texas A&M University" +contributor:("Sweetman, Bert"). Showing records 1 – 3 of 3 total matches.

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Texas A&M University

1. Jackson, Justin Patrick. Modelling and control of a symmetric flapping wing vehicle: an optimal control approach.

Degree: 2009, Texas A&M University

This thesis presents a method for designing a flapping wing stroke for a flapping wing vehicle. A flapping wing vehicle is a vehicle such as a bird or an insect that uses its wings for propulsion instead of a conventional propeller or a jet engine. The intent of this research is to design a wing stroke that the wings can follow which will maintain the vehicle at a desired longitudinal flight path angle and velocity. The cost function is primarily a function of the flight path angle error, velocity error and control rate. The objective maneuver is to achieve a flight condition similar to the trim of a conventional fixed wing aircraft. Gliding configurations of the vehicle are analyzed to better understand flight in minimal energy configurations as well as the modes of the vehicle. A control law is also designed using Lyapunov?s direct method that achieves stable tracking of the wing stroke. Results are presented that demonstrate the ability of the method to design wing strokes that can maintain the vehicle at various flight path angles and velocities. The results of this research show that an optimal control problem can be posed such that the solution of the problem results in a wing stroke that a flapping wing vehicle can use to achieve a desired maneuver. The vehicle velocity is shown to be stable in controlled gliding flight and flapping flight. Advisors/Committee Members: Strganac, Thomas (advisor), Bhattacharya, Raktim (committee member), Hurtado, John (committee member), Sweetman, Bert (committee member).

Subjects/Keywords: flapping wing; control; optimal

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Jackson, J. P. (2009). Modelling and control of a symmetric flapping wing vehicle: an optimal control approach. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2854

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Jackson, Justin Patrick. “Modelling and control of a symmetric flapping wing vehicle: an optimal control approach.” 2009. Thesis, Texas A&M University. Accessed September 19, 2019. http://hdl.handle.net/1969.1/ETD-TAMU-2854.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Jackson, Justin Patrick. “Modelling and control of a symmetric flapping wing vehicle: an optimal control approach.” 2009. Web. 19 Sep 2019.

Vancouver:

Jackson JP. Modelling and control of a symmetric flapping wing vehicle: an optimal control approach. [Internet] [Thesis]. Texas A&M University; 2009. [cited 2019 Sep 19]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2854.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Jackson JP. Modelling and control of a symmetric flapping wing vehicle: an optimal control approach. [Thesis]. Texas A&M University; 2009. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2854

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Texas A&M University

2. Wang, Lei. Multibody Dynamics Using Conservation of Momentum with Application to Compliant Offshore Floating Wind Turbines.

Degree: 2012, Texas A&M University

Environmental, aesthetic and political pressures continue to push for siting off-shore wind turbines beyond sight of land, where waters tend to be deeper, and use of floating structures is likely to be considered. Savings could potentially be realized by reducing hull size, which would allow more compliance with the wind thrust force in the pitch direction. On the other hand, these structures with large-amplitude motions will make dynamic analysis both more challenging and more critical. Prior to the present work, there were no existing dynamic simulation tools specifically intended for compliant wind turbine design. Development and application of a new computational method underlying a new time-domain simulation tool is presented in this dissertation. The compliant floating wind turbine system is considered as a multibody system including tower, nacelle, rotor and other moving parts. Euler's equations of motion are first applied to the compliant design to investigate the large-amplitude motions. Then, a new formulation of multibody dynamics is developed through application of the conservation of both linear momentum and angular momentum to the entire system directly. A base body is prescribed within the compliant wind turbine system, and the equations of motion (EOMs) of the system are projected into the coordinate system associated with this body. Only six basic EOMs of the system are required to capture 6 unknown degrees of freedom (DOFs) of the base body when mechanical DOFs between contiguous bodies are prescribed. The 6 x 6 mass matrix is actually composed of two decoupled 3 x 3 mass matrices for translation and rotation, respectively. Each element within the matrix includes the inertial effects of all bodies. This condensation decreases the coupling between elements in the mass matrix, and so minimizes the computational demand. The simulation results are verified by critical comparison with those of the popular wind turbine dynamics software FAST. The new formulation is generalized to form the momentum cloud method (M- CM), which is particularly well suited to the serial mechanical N-body systems connected by revolute joints with prescribed relative rotation. The MCM is then expanded to multibody systems with more complicated joints and connection types. Advisors/Committee Members: Sweetman, Bert (advisor), Mercier, Richard (committee member), Falzarano, Jeffrey (committee member), Anis, Ayal (committee member).

Subjects/Keywords: Floating wind turbines; Large-amplitude motion; Conservation of momentum; Multibody Dynamics; Multibody system; Simulation; Euler angles

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Wang, L. (2012). Multibody Dynamics Using Conservation of Momentum with Application to Compliant Offshore Floating Wind Turbines. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11740

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Wang, Lei. “Multibody Dynamics Using Conservation of Momentum with Application to Compliant Offshore Floating Wind Turbines.” 2012. Thesis, Texas A&M University. Accessed September 19, 2019. http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11740.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Wang, Lei. “Multibody Dynamics Using Conservation of Momentum with Application to Compliant Offshore Floating Wind Turbines.” 2012. Web. 19 Sep 2019.

Vancouver:

Wang L. Multibody Dynamics Using Conservation of Momentum with Application to Compliant Offshore Floating Wind Turbines. [Internet] [Thesis]. Texas A&M University; 2012. [cited 2019 Sep 19]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11740.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Wang L. Multibody Dynamics Using Conservation of Momentum with Application to Compliant Offshore Floating Wind Turbines. [Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11740

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

3. Choi, Myoung. THE MODAL DISTRIBUTION METHOD: A NEW STATISTICAL ALGORITHM FOR ANALYZING MEASURED RESPONSE.

Degree: 2010, Texas A&M University

A new statistical algorithm, the "modal distribution method", is proposed to statistically quantify the significance of changes in mean frequencies of individual modal vibrations of measured structural response data. In this new method, a power spectrum of measured structural response is interpreted as being a series of independent modal responses, each of which is isolated over a frequency range and treated as a statistical distribution. Pairs of corresponding individual modal distributions from different segments are compared statistically. The first version is the parametric MDM. This method is applicable to well- separated modes having Gaussian shape. For application to situations in which the signal is corrupted by noise, a new noise reduction methodology is developed and implemented. Finally, a non-parametric version of the MDM based on the Central Limit Theorem is proposed for application of MDM to general cases including closely spaced peaks and high noise. Results from all three MDMs are compared through application to simulated clean signals and the two extended MDMs are compared through application to simulated noisy signals. As expected, the original parametric MDM is found to have the best performance if underlying requirements are met: signals that are clean and have well-separated Gaussian mode shapes. In application of nonparametric methods to Gaussian modes with high noise corruption, the noise reduction MDM is found to have lower probability of false alarms than the nonparametric MDM, though the nonparametric is more efficient at detecting changes. In closely related work, the Hermite moment model is extended to highly skewed data. The aim is to enable transformation from non-Gaussian modes to Gaussian modes, which would provide the possibility of applying parametric MDM to well- separated non-Gaussian modes. A new methodology to combine statistical moments using a histogram is also developed for reliable continuous monitoring by means of MDM. The MDM is a general statistical method. Because of its general nature, it may find a broad variety of applications, but it seems particularly well suited to structural health monitoring applications because only very limited knowledge of the excitation is required, and significant changes in computed power spectra may indicate changes, such as structural damage. Advisors/Committee Members: Sweetman, Bert (advisor), Mercier, Richard (committee member), Barroso, Luciana (committee member), Anis, Ayal (committee member).

Subjects/Keywords: Structural Health Monitoring; Modal Analysis; Spectral Density Function; Statistical Analysis; Random Vibration; Data Processing

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Choi, M. (2010). THE MODAL DISTRIBUTION METHOD: A NEW STATISTICAL ALGORITHM FOR ANALYZING MEASURED RESPONSE. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-580

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Choi, Myoung. “THE MODAL DISTRIBUTION METHOD: A NEW STATISTICAL ALGORITHM FOR ANALYZING MEASURED RESPONSE.” 2010. Thesis, Texas A&M University. Accessed September 19, 2019. http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-580.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Choi, Myoung. “THE MODAL DISTRIBUTION METHOD: A NEW STATISTICAL ALGORITHM FOR ANALYZING MEASURED RESPONSE.” 2010. Web. 19 Sep 2019.

Vancouver:

Choi M. THE MODAL DISTRIBUTION METHOD: A NEW STATISTICAL ALGORITHM FOR ANALYZING MEASURED RESPONSE. [Internet] [Thesis]. Texas A&M University; 2010. [cited 2019 Sep 19]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-580.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Choi M. THE MODAL DISTRIBUTION METHOD: A NEW STATISTICAL ALGORITHM FOR ANALYZING MEASURED RESPONSE. [Thesis]. Texas A&M University; 2010. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-580

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.