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 15 of 15 for “"Limit Cycle Oscillation"”.
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A formulation of nonlinear limit cycle oscillation problems in aircraft flutter
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1993.
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Time Spectral Adjoint Based Design for Flutter and Limit Cycle Oscillation Suppression
… does not overlap with regions of flutter or Limit Cycle Oscillation (LCO). A quick assessment of these dynamic aeroelastic for various design candidates is key to successful design. Flutter based design requires the sensitivity of flutter parameters to be known with the respect of design …
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Prediction of Limit Cycle Oscillation in an Aeroelastic System using Nonlinear Normal Modes
… flutter analysis method capable of predicting limit cycle oscillation in aeroelastic systems. A review is conducted of analysis methods and experiments that have attempted to better understand and model limit cycle oscillation (LCO). The recently developed method of nonlinear normal modes (NNM) …
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Investigation of slow oscillations in blood pressure
… short-term control of blood pressure, and soft-limiting nonlinearities inherent in this loop, are thought to give rise to a slow limit cycle oscillation in blood pressure at 0.1 Hz in the human. Measurement of the strength of this slow oscillation has been proposed as the basis for the …
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Modeling and design of digital current-mode constant on-time control
… the voltage regulator module. One issue is the limit cycle oscillation problem caused by the quantization effect from the ADC and DPWM of the digital control chip. Another issue is the delay problem coming from the sample-hold effect. In this thesis, the modeling, analysis and design methodology …
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An evaluation of the longitudinal dynamic stability of an aircraft at stall.
… stall trait. The characteristics of this limit-cycle oscillation were examined.
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Modeling of Circadian Rhythms: Robust Temperature Compensation in Drosophila melanogaster and Testable Hypotheses in Neurospora crassa
… on the dynamics of multiple steady states and limit cycle oscillation, we propose an alternative mechanism for robust temperature compensation. We start with a simple model in order to understand the core dynamics of the clock mechanism, and move to a more comprehensive model. In both cases, we …
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Robust Nonlinear Estimation and Control Applications using Synthetic Jet Actuators
<p>Limit cycle oscillations (LCO), also known as utter, cause significant challenges in flight control of small unmanned aerial vehicles (SUAVs), and could potentially lead to structural damage and catastrophic failures. LCO can be described as vibrational motions in the rocking, pitching and …
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Numerical Study in Wind Energy Extraction from Controlled Limit-Cycle Oscillations in Modified Glauert Airfoil
… Glauert (MG) airfoil experiencing aeroelastic limit cycle oscillation (LCO) from which energy may be extracted. Synthetic jet actuators (SJA)s are used along with the unique geometry of the MG airfoil to control flow separation and amplify the LCO and energy generation potential of the system. …
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Dynamic recurrent neural networks for stable adaptive control of wing rock motion
Wing rock is a self-sustaining limit cycle oscillation (LCO) which occurs as the result of nonlinear coupling between the dynamic response of the aircraft and the unsteady aerodynamic forces. In this thesis, dynamic recurrent RBF (Radial Basis Function) network control methodology is proposed to …
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Adaptive Control of an Aeroelastic System for Active Flutter Suppression and Disturbance Rejection
… effective aeroelastic control and flutter or limit-cycle oscillation suppression over a wider range of flight conditions compared to the standard LQR controller. In addition, the MRAC is shown to provide robustness to nonlinear stiffness, first-order and second-order actuator dynamics, and …
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TUNING 2-BY-2 MULTI-LOOP PI CONTROLLERS USING RELAY FEEDBACK
… multi-loop PI controllers can be tuned from the oscillations in such a system will be discussed. A multivariable system which is placed under multi-loop relay feedback control can display one of three possible modes of oscillations. The first mode consists of identical relay outputs which are …
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Buckling, Flutter, and Postbuckling Optimization of Composite Structures
… the vicinity of the flutter boundary should be limited to stable limit cycle oscillation. A parametric study is carried out to investigate the tradeoff between designs for thermal buckling and flutter. In an effort to include the postbuckling constraint into the multilevel design optimization of …
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Neuroinspired control strategies with applications to flapping flight
… of freedom and need to excite large-displacement oscillations in order to locomote. Combining these factors can make high-level control design difficult. This thesis revolves around three different levels of abstraction, providing tools for analysis and design. First, we consider central pattern …
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Small-signal Analysis and Design of Constant-on-time V2 Control for Ceramic Caps
… V2 control suffers from the sub-harmonic oscillation due to the lagging phase of the capacitor voltage ripple relative to the inductor current ripple. Two solutions to eliminate sub-harmonic oscillations are discussed in [39] and the small-signal models are also derived based on …