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Full-Text Articles in Controls and Control Theory
Nonlinear Controller Design For Uavs With Time-Varying Aerodynamic Uncertainties, Michail G. Michailidis
Nonlinear Controller Design For Uavs With Time-Varying Aerodynamic Uncertainties, Michail G. Michailidis
Electronic Theses and Dissertations
Unmanned Aerial Vehicles (UAVs) are here and they are here to stay. Unmanned Aviation has expanded significantly in recent years and research and development in the field of navigation and control have advanced beyond expectations. UAVs are currently being used for defense programs around the world but the range of applications is expected to grow in the near future, with civilian applications such as environmental and aerial monitoring, aerial surveillance and homeland security being some representative examples. Conventional and commercially available small-scale UAVs have limited utilization and applicability to executing specific short-duration missions because of limitations in size, payload, power …
Nonlinear Regression Methods For Estimation, Eric B. Nelson
Nonlinear Regression Methods For Estimation, Eric B. Nelson
Theses and Dissertations
Regression techniques are developed for batch estimation and applied to three specific areas, namely, ballistic trajectory launch point estimation, adaptive flight control, and radio-frequency target triangulation. Specifically, linear regression with an intercept is considered in detail. An augmentation formulation is developed. Extensions of theory are applied to nonlinear regression as well. The intercept parameter estimate within the linear regression is used to identify the effects of trim change that are associated with the occurrence of a control surface failure. These estimates are used to adjust the inner loop control gains via a feed-forward command, hence providing an automatic reconfigurable retrim …
Manual Tracking Flight Control With Amplitude And Rate Constrained Dynamic Actuators, Russel B. Miller
Manual Tracking Flight Control With Amplitude And Rate Constrained Dynamic Actuators, Russel B. Miller
Theses and Dissertations
A new control methodology for manual flight control, viz., real-time tracking control, is developed. Amplitude and rate constrained dynamic actuators are considered. Optimal tracking control is made possible by the use of unique reference signal prediction strategies which extrapolate the reference signal over the optimization horizon. A receding horizon, linear-quadratic inner-loop controller is employed in conjunction with an outer-loop nonlinear element. The constraint effects mitigation strategy is to optimally track a modified reference signal which yields feasible actuator commands over the optimization horizon when the pilot demanded reference is too aggressive to be tracked by the inner-loop optimal control law. …
Design Of Flight Control Laws For Aircraft With Flexible Wings Using Quantitative Feedback Theory, Christina L. Osmon
Design Of Flight Control Laws For Aircraft With Flexible Wings Using Quantitative Feedback Theory, Christina L. Osmon
Theses and Dissertations
Aircraft composed of lightweight composite materials are extremely enticing since their structural weight is greatly reduced. However, the control of these aircraft is complicated by the resultant flexibility of the wings. Two avenues of approach are possible; stiffen the wings thus losing some of the weight reduction benefits, or design the lateral/directional flight control system cognizant of the wing's flexibility. In this thesis the second approach is taken. The design of three lateral/directional flight control systems for the sub-sonic flight envelope of the F-18 is presented. The Quantitative Feedback Theory (QFT) robust control design technique is used. These designs incorporate …
Flight Control Design Using Mixed H2/Μ Optimization, Douglas D. Decker
Flight Control Design Using Mixed H2/Μ Optimization, Douglas D. Decker
Theses and Dissertations
This thesis examines the use of the mixed H2-Microns optimal control synthesis method in the design of a flight control system for the lateral-directional axes of the F-16 Variable Stability In-Flight Simulator Test Aircraft (VISTA). The method is designed to minimize the H2 norm (two-norm) for a given value of microns. This should provide adequate noise and disturbance rejection while maintaining robustness against several types of uncertainties in the system. This thesis finds that, for this problem, the two-norm is not an accurate representation of the outputs of interest. When the two-norm is broken up into its constituent parts an …
Applications Of ℓ1 And Mixed H2/ℓ1 Optimization, Mark S. Spillman
Applications Of ℓ1 And Mixed H2/ℓ1 Optimization, Mark S. Spillman
Theses and Dissertations
This thesis explores the use of ℓ1 and mixed H2/ℓ1 optimization methods to design flight control systems. ℓ1 optimization is used to handle tracking issues in the design of digital compensators. Control deflection and rate limitations, overshoot and undershoot limitations and steady-state error requirements are discussed. Model-matching techniques which produce acceptable tracking results with lower order controllers are also examined. New numerical methods for continuous H2/L1 and discrete H2/ℓ1 optimization are presented. These methods are used to design an aircraft controller in continuous and discrete time and the results are compared.
A Quantitative Feedback Theory Fcs Design For The Subsonic Envelope Of The Vista F-16 Including Configuration Variation, Scott N. Phillips
A Quantitative Feedback Theory Fcs Design For The Subsonic Envelope Of The Vista F-16 Including Configuration Variation, Scott N. Phillips
Theses and Dissertations
An aircraft's response to control inputs varies widely throughout its flight envelope. The aircraft configuration also impacts control response through variations in center of gravity and moments of inertia. Designing a flight control system (FCS) to accommodate the full flight envelope and configuration set of an aircraft is clearly a complex undertaking. Quantitative feedback theory (QFT) is a design tool which enables the engineer to attack this task in an efficient way. Although QFT is a robust control design technique, it is an interactive algorithm allowing the engineer full control over compensator order and gain. In this research effort, a …
A Gain Scheduling Optimization Method Using Genetic Algorithms, Robert C. Martin Iv
A Gain Scheduling Optimization Method Using Genetic Algorithms, Robert C. Martin Iv
Theses and Dissertations
Gain scheduling. the traditional method of providing adaptive control to a nonlinear system, has long been an ad hoc design process. Until recently; little theoretical guidance directed this practitioners' art. For this reason a systematic study of this design process and its potential for optimization has never been accomplished. Additionally, the nonlinearities and the large search space involved in gain scheduling also precluded such an optimization study. Traditionally, the gain scheduling process has been some variation of a linear interpolation between discrete design points. By using powerful non-traditional optimization tools such as genetic algorithms there are ways of improving this …
Direct Reduced Order Mixed H2/H∞ Control For The Short Take-Off And Landing-Maneuver Technology Demonstrator (Stol-Mtd), William C. Reigelsperger Jr.
Direct Reduced Order Mixed H2/H∞ Control For The Short Take-Off And Landing-Maneuver Technology Demonstrator (Stol-Mtd), William C. Reigelsperger Jr.
Theses and Dissertations
One of the conclusions from the STOL/MTD program was the need for a multivariable method of designing controllers of low order. This research investigated that problem by studying reduced order mixed H2/H∞ control theory applied to the STOL Landing configuration which employs both thrust vectoring and the use of a canard. Model matching techniques were used to obtain responses that met handling qualities criteria and reduced pilot workload by decoupling pitch rate and velocity commands. The time responses were found through nonlinear simulation and showed that the full order designs did match the ideal models very well …
A Handling Qualities Investigation Of Conventional, Rate Command- Attitude Hold, And Attitude Command-Attitude Hold Response-Types In The Probe And Drogue Air Refueling Task, Michael J. Taschner
A Handling Qualities Investigation Of Conventional, Rate Command- Attitude Hold, And Attitude Command-Attitude Hold Response-Types In The Probe And Drogue Air Refueling Task, Michael J. Taschner
Theses and Dissertations
This investigation examines the suitability of conventional, rate command/attitude hold (RCAH), and attitude command attitude hold (ACAH) response-types for the probe and drogue air refueling task. Data from a 1974 Calspan handling qualities investigation involving conventional response-types in the probe and drogue air refueling task were analyzed using the Bandwidth and STI Dropback criterions. Flight control laws were developed to achieve twelve superaugmented and two conventional configurations. The NT-33A analog variable stability system was used to simulate a relaxed static stability fighter and the NT-33A programmable digital flight control computer simulated the desired response-types. The handling qualities of the fourteen …
Automation Of Formation Flight Control, Vincent P. Reyna
Automation Of Formation Flight Control, Vincent P. Reyna
Theses and Dissertations
The research contained in this thesis explores the concepts of Automated Formation Flight Control documented in three previous AFIT theses. The generic formation analyzed consists of a Leader and Wingman, with the Wingman referencing its maneuvers off of Leader maneuvers. Specifically, planar formation flight control concerning only heading and velocity changes is considered. Next, the vertical separation constraint is relaxed to allow wing maneuvers outside of the flight plane of the lead in order to minimize the energy expended by the wing in a maneuver. Analysis of the two forms of formation flight control investigated in this thesis reveals the …
Neural Networks For Dynamic Flight Control, Ronald E. Setzer
Neural Networks For Dynamic Flight Control, Ronald E. Setzer
Theses and Dissertations
This thesis examines the application of artificial neural networks (NNs) to the problem of dynamic flight control. The specific application is the control of a flying model helicopter. The control interface is provided through a hardware and software test bed called the Fast Adaptive Maneuvering Experiment (FAME). The NN design approach uses two NNs: one trained as an emulator of the plant and the other trained to control the emulator. The emulator neural network is designed to reproduce the flight dynamics of the experimental plant. The controller is then designed to produce the appropriate control inputs to drive the emulator …
Exploring Qdes As A Tool For Determining Limits Of Achievable Performance In Aircraft Design, Mark F. Reidinger
Exploring Qdes As A Tool For Determining Limits Of Achievable Performance In Aircraft Design, Mark F. Reidinger
Theses and Dissertations
This thesis explores the usefulness of a computer aided control design software package called QDES in determining the limits of achievable aircraft performance as it relates to controller capability. Modern aircraft, particularly fighters, are being designed to be statically unstable to enhance their maneuverability and performance. It is possible that the aircraft, although physically capable of a certain level of performance due to its engine/ airframe combination, may be uncontrollable up to this level. This study sought to develop a methodology to use QDES to make a preliminary analysis of an aircraft design to determine if there exists a controller …
Design Of A Subsonic Envelope Flight Control System For The Vista F-16 Using Quantitative Feedback Theory, Odell R. Reynolds
Design Of A Subsonic Envelope Flight Control System For The Vista F-16 Using Quantitative Feedback Theory, Odell R. Reynolds
Theses and Dissertations
A controlled plant's characteristics can vary widely throughout its operational envelope. This is a major problem in nominal plant-based control system design. Hence, gain scheduling is often used for full envelop design. In this paper, it is proposed to address the plant's variability using robust control design concepts. In particular, the frequency domain based Quantitative Feedback Theory Multiple-Input Multiple-Output robust control design method is employed for the synthesis of a full envelop flight control system for an F-16 derivative. Compensators for the aircraft's pitch and lateral directional channels are designed, and the designs are validated using linear simulations.
Evaluation Of Moderate Angle Of Attack Roll Of A Dual Engine, Thrust Vectoring Aircraft Using Quantitative Feedback Theory, Kevin E. Boyum
Evaluation Of Moderate Angle Of Attack Roll Of A Dual Engine, Thrust Vectoring Aircraft Using Quantitative Feedback Theory, Kevin E. Boyum
Theses and Dissertations
This thesis develops an innovative approach to the design of a flight control system for performing the large-amplitude velocity vector roll maneuver at high angles of attack AOAs. A six degree of freedom aircraft model is developed from the fundamental nine-state equations of motion using a modified linearization technique. The MIMO multiple-input multiple-output Quantitative Feedback Theory QFT robust control design technique is then used to jointly address the system nonlinearities present in this maneuver and the changes in the system parameters due to changes in flight condition, treating them as structured uncertainty in the design of a three-axis rate-commanded control …
Design Of A Flight Controller For An Unmanned Research Vehicle With Control Surface Failures Using Quantitative Feedback Theory, Mark S. Keating
Design Of A Flight Controller For An Unmanned Research Vehicle With Control Surface Failures Using Quantitative Feedback Theory, Mark S. Keating
Theses and Dissertations
This thesis describes the application of the multiple-input multiple- output (MIMO) Quantitative Feedback Theory (QFT) design technique to the design of a digital flight control system for the Lambda Unmanned Research Vehicle (URV). The QFT technique allows the synthesis of a control system which is robust in the presence of structured plant uncertainties. Uncertainties considered in this design are the aircraft's plant variation within the flight envelope and the effects of damage to aircraft control surfaces. Mathematical models of control surface failure effects on aircraft dynamics are derived and used to modify an existing small perturbation model of the Lambda. …