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 28 for “"stability margins"”.
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An Analysis of Stability Margins for Continuous Systems
When designing or reviewing control systems, it is important to understand the limitations of the system's design. Many systems today are designed using numerical methods. Although the numerical model may be controllable, stabilizable, or stable, small perturbations of the system parameters can …
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Application of Multivariable Control Theory to Improve Steering and Propulsion Control of a Containership
… Doyle and Stein is applied to provide acceptable stability margins at the plant input. Also, using robustness analysis and a numerically determined uncertainty bound, it is shown that the maximum allowable uncertainty in the ship hydrodynamic coefficients before a potential for closed loop …
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Comparative design, modeling, and control analysis of robotic transmissions
Transmission dynamics are shown to dominate the stability and performance of impedance- and torque controlled rotary electro-mechanical systems. The experimental analysis focuses on planetary, cycloidal, harmonic and cable reducers, but excludes direct-drive, pneumatic, hydraulic and friction …
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Optimal design of unmodeled linear systems using control-based continuation
… that is imposed on each of three distinct stability margins, respectively. The analysis shows that the simulation model for the DC motor may be treated analogously to an actual experiment with all information drawn from real-time measurements, rather than from the model itself. The …
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Modeling and Implementation of Controller for Switched Reluctance Motor With Ac Small Signal Model
… the controller can be designed with sufficient stability margins. The proposed PWM controller has been simulated to compare the performance against the conventional Hysteresis controller based system. It was found that through the frequency spectrum analysis, the noise spectra in audible range …
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Robust stability analysis for large-scale power systems
… to increase variability and uncertainty, making stability verification more challenging. This thesis extends the technique of robust stability analysis to large-scale electric power systems under uncertainty. In the first part of this thesis, we examine the use of the technique to solve real …
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Fractional Order Identification Method and Control: Development of Control for Non-Minimum Phase Fractional Order System
… become more prominent and thereby lead to stability concerns under variable load conditions. This dissertation presents a new method for analyzing dc-dc converters using fractional order calculus. This provides control systems designers the ability to analyze converter frequency response …
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A Hybrid Vortex Solution for Radial Equilibrium in Axial Compressors
… real boundary conditions with enhanced surge and stability margins, which is verified by CFD results.</p>
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Active control of radiated noise from a cylindrical shell using external piezoelectric panels
… the required closed-loop performance and stability margins.
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Robustness Bounds For Uncertain Sampled Data Systems With Presence of Time Delays
… induced delay play a crucial role in the system stability. Perturbation or modeling errors arise in the nominal system due to parameter variations, un-modeled dynamics, neglected non-linearities or neglected external disturbances. In the thesis, we tackle the perturbations and time delays …
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Distributed adaptive control methods for uncertain multiagent systems with coupled dynamics
… a major challenge is achieving overall system stability and performance in the presence of not only uncertainties but also coupled dynamics. Another challenge for these systems is designing distributed adaptive controllers with user-assigned positions in this case and defining the convergence …
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Spillover stabilization in the control of large flexible space structures
… modal controllers with improved spillover stability properties. It is based on the premise that the structural dynamicist will be able to predict more vibration modes than would be practical to include in the design of the controller. The proposed method calls for designing the observer so …
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Robust adaptive control in the presence of unmodeled dynamics
… quantifiable and practically meaningful robust stability margins for adaptive systems remained an open problem. Successful implementation of adaptive control theory as a viable control solution can only be achieved when global robustness properties, especially with respect to unmodeled dynamics, …
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Solving Factorable Programs with Applications to Cluster Analysis, Risk Management, and Control Systems Design
… we provide a detailed discussion on studying stability margins for control systems using polynomial programming models along with specialized solution techniques.
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Online Identification, Monitoring, and Control of A Dc/Dc Converter System Using Digital Network Analyzer Techniques
… are prone to interactions that can reduce stability and performance margins according to the so-called Middlebrook impedance criterion and its extensions. With some additional software, a converter's digital controller can also act as an online digital network analyzer capable of …
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Adaptive control design with guaranteed margins for nonlinear plants
… and a solid foundation has been laid out for stability and robustness of adaptive systems. However, a large gap between theory and practice has been an obstacle to transition theoretical results into applications and it still remains. In order to reduce the gap, this thesis presents a unified …
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Voltage Stability and Control in Autonomous Electric Power Systems with Variable Frequency
… various types of power electronic loads. The stability of these systems is a challenge due to the inherent nonlinearity of the circuits involved. Traditionally, the stability analysis in this type of power systems has been approached by means of small-signal methodology derived from the …
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Hierarchical Decentralized Control for Enhanced Stability of Large-Scale Power Systems
… in a unified manner of voltage and rotor angle stability in large-scale power systems subject to large (e.g., short circuits) and small (e.g., small load changes) disturbances. We study system robustness by calculating local stability margins. We derive decentralized control laws that guaranty …
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Modeling, Analysis, and Design of Distributed Power Electronics System Based on Building Block Concept
… the bus impedance and provides more stability margins to the distribution system. The dc bus conditioner concept and its functions are demonstrated through system simulation and preliminary hardware experiment.
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Effectiveness of a Serpentine Inlet Duct Flow Control Scheme at Design and Off-Design Simulated Flight Conditions
… (AIP) was then used to predict the resulting stability for a compression system. This study was conducted using a model of a compact, low observable, engine inlet duct developed by Lockheed Martin. A flow control technique using air injection through microjets at 1% of the inlet mass flow rate …
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