Robust Nonlinear Aircraft Flight Control


Book Description

This project addresses the development of both control synthesis and analysis methods for affordable, highly integrated nonlinear aircraft control systems through basic research and development of control science and dynamical systems theory. The technical approach is to explore the following three primary research areas: (1) stability analysis, (2) robust nonlinear control, and (3) robust reconfigurable control. The stability analysis task assesses robustness of a baseline flight control system. The analysis results are used to develop on-board model and control allocation requirements for the other two tasks. The robust nonlinear control task includes development of compact on-board model and dynamic control allocation synthesis methods. The reconfigurable control design task includes development of an on-board model update synthesis method. The main accomplishment for the stability analysis task is using structured singular value analysis to formalize control allocation stability implications and to specify stability and control derivative accuracy requirements for on-board model synthesis. The main accomplishments for the robust nonlinear control design task are development of a dynamic control allocation formulation and development of a compact on-board model synthesis method. The main accomplishment for the robust reconfigurable control design task is the development of an on-line learning method for on-board model updates to enhance the robustness of indirect adaptive flight control systems.




Robust Multivariable Flight Control


Book Description

Manual flight control system design for fighter aircraft is one of the most demanding problems in automatic control. Fighter aircraft dynamics generally have highly coupled uncertain and nonlinear dynamics. Multivariable control design techniques offer a solution to this problem. Robust Multivariable Flight Control provides the background, theory and examples for full envelope manual flight control system design. It gives a versatile framework for the application of advanced multivariable control theory to aircraft control problems. Two design case studies are presented for the manual flight control of lateral/directional axes of the VISTA-F-16 test vehicle and an F-18 trust vectoring system. They demonstrate the interplay between theory and the physical features of the systems.




Robust Flight Control


Book Description

In October 1994, 22 organisations throughout Europe accepted a challenge to solve a specific robust flight control design problem. The results of that design challenge, presented at the GARTEUR Specialists' Workshop in Toulouse, France in April 1997, are reported here. Two flight control benchmarks are considered, based on the automatic landing phase of a large cargo aircraft and on the control of a military aircraft. Methods applied include: classical control; multi-objective optimisation; eigenstructure assignment; modal multi-model approach; LQ, Lyapunov and H¿-techniques; ¿-synthesis; nonlinear dynamic inversion; robust inverse dynamics estimation; model predictive control and following; and fuzzy control. Involved in the definition of the benchmarks and the evaluation process have been representatives from the European aeronautical industry, bringing a strong link with flight control law design practice.




Advanced Nonlinear Control: Robustness and Stability with Applications to Aircraft Flight Control Systems


Book Description

An example of a large-scale system is a group of autonomous airships performing the function of a temporary mobile cell phone network. An airship mobile cell phone network is a novel solution to the problem of maintaining communication during the advent of extensive damage to the communication infrastructure; be it from a flood, earthquake, hurricane, or terrorist attack. A first principle force-based dynamic model for the Tri-Turbofan Airship was developed and will be discussed in detail. The mathematical model was based on actual flight test data that has been collected at the Gait Analysis and Innovative Technologies Laboratory. This model was developed to research autonomous airship operations using decentralized control techniques for large-scale systems.




Robust Nonlinear Control of Vectored Thrust Aircraft


Book Description

An interdisciplinary program in robust control for nonlinear systems with applications to a variety of engineering problems is outlined. Major emphasis will be placed on flight control, with both experimental and analytical studies. This program builds on recent new results in control theory for stability, stabilization, robust stability, robust performance, synthesis, and model reduction in a unified framework using Linear Fractional Transformations (LFT's), Linear Matrix Inequalities (LMI's), and the structured singular value micron. Most of these new advances have been accomplished by the Caltech controls group independently or in collaboration with researchers in other institutions. These recent results offer a new and remarkably unified framework for all aspects of robust control, but what is particularly important for this program is that they also have important implications for system identification and control of nonlinear systems. This combines well with Caltech's expertise in nonlinear control theory, both in geometric methods and methods for systems with constraints and saturations. Doyle, John C. and Murray, Richard and Morris, John Unspecified Center NAG2-792...







Decentralized Robust Nonlinear Model Predictive Control for UAS


Book Description

The nonlinear and unsteady nature of aircraft aerodynamics and limited range of controls and states make the use of linear control theory inadequate. For unmanned aerial systems in particular, control technology must evolve to a point where autonomy is extended to the entire mission flight envelope. This requires advanced controllers that have sufficient robustness, track complex trajectories, and use all the vehicle's control capabilities at higher levels of accuracy. In this work, a robust nonlinear model predictive controller is designed to command and control an unmanned aerial system to track complex tight trajectories in the presence of perturbances. The flight control system developed achieves the above performance by using a nonlinear guidance algorithm that enables the vehicle to follow an arbitrary trajectory; a formulation that embeds the guidance logic and trajectory information in the aircraft model, avoiding cross coupling; an artificial neural network, designed to adaptively estimate aerodynamic and propulsive forces; a mixed sensitivity approach that enhances the robustness for an adaptive nonlinear model predictive controller.




Robust Multivariable Flight Control


Book Description

Manual flight control system design for fighter aircraft is one of the most demanding problems in automatic control. Fighter aircraft dynamics generally have highly coupled uncertain and nonlinear dynamics. Multivariable control design techniques offer a solution to this problem. Robust Multivariable Flight Control provides the background, theory and examples for full envelope manual flight control system design. It gives a versatile framework for the application of advanced multivariable control theory to aircraft control problems. Two design case studies are presented for the manual flight control of lateral/directional axes of the VISTA-F-16 test vehicle and an F-18 trust vectoring system. They demonstrate the interplay between theory and the physical features of the systems.




Robust and Adaptive Control


Book Description

Robust and Adaptive Control shows the reader how to produce consistent and accurate controllers that operate in the presence of uncertainties and unforeseen events. Driven by aerospace applications the focus of the book is primarily on continuous-dynamical systems. The text is a three-part treatment, beginning with robust and optimal linear control methods and moving on to a self-contained presentation of the design and analysis of model reference adaptive control (MRAC) for nonlinear uncertain dynamical systems. Recent extensions and modifications to MRAC design are included, as are guidelines for combining robust optimal and MRAC controllers. Features of the text include: · case studies that demonstrate the benefits of robust and adaptive control for piloted, autonomous and experimental aerial platforms; · detailed background material for each chapter to motivate theoretical developments; · realistic examples and simulation data illustrating key features of the methods described; and · problem solutions for instructors and MATLAB® code provided electronically. The theoretical content and practical applications reported address real-life aerospace problems, being based on numerous transitions of control-theoretic results into operational systems and airborne vehicles that are drawn from the authors’ extensive professional experience with The Boeing Company. The systems covered are challenging, often open-loop unstable, with uncertainties in their dynamics, and thus requiring both persistently reliable control and the ability to track commands either from a pilot or a guidance computer. Readers are assumed to have a basic understanding of root locus, Bode diagrams, and Nyquist plots, as well as linear algebra, ordinary differential equations, and the use of state-space methods in analysis and modeling of dynamical systems. Robust and Adaptive Control is intended to methodically teach senior undergraduate and graduate students how to construct stable and predictable control algorithms for realistic industrial applications. Practicing engineers and academic researchers will also find the book of great instructional value.




Advanced Robust Nonlinear Control Approaches for Quadrotor Unmanned Aerial Vehicle


Book Description

This book studies selected advanced flight control schemes for an uncertain quadrotor unmanned aerial vehicle (UAV) systems in the presence of constant external disturbances, parametric uncertainties, measurement noise, time-varying external disturbances, and random external disturbances. Furthermore, in all the control techniques proposed in this book, it includes the simulation results with comparison to other nonlinear control schemes recently developed for the tracking control of a quadrotor UAV. The main contributions of the present book for quadrotor UAV systems are as follows: (i) the proposed control methods are based on the high-order sliding mode controller (SMC) and hybrid control algorithm with an optimization method. (ii) the finite-time control schemes are developed by using fast terminal SMC (FTSMC), nonsingular FTSMC (NFTSMC), global time-varying SMC, and adaptive laws. (iii) the fractional-order flight control schemes are developed by using the fractional-order calculus theory, super twisting algorithm, NFTSMC, and the SMC. This book covers the research history and importance of quadrotor system subject to system uncertainties, external wind disturbances, and noise measurements, as well as the research status of advanced flight control methods, adaptive flight control methods, and flight control based on fractional-order theory. The book would be interesting to most academic undergraduate, postgraduates, researchers on flight control for drones and applications of advanced controllers in engineering field. This book presents a must-survey for advanced finite-time control for quadrotor system. Some parts of this book have the potential of becoming the courses for the modelling and control of autonomous flying machines. Readers (academic researcher, undergraduate student, postgraduate student, MBA/executive, and education practitioner) interested in nonlinear control methods find this book an investigation. This book can be used as a good reference for the academic research on the control theory, drones, terminal sliding mode control, and related to this or used in Ph.D. study of control theory and their application in field engineering.