Robust Multivariable Control Design For Hover Aircraft Control Using Lqg Ltr

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.

Linear multiple-input multiple-output (multivariable) control systems are considered. The intent of this report is to familiarize the working engineers with some of the developments in the area of robust multivariable control theory that have occurred in the past 10 years. The concepts of singular values are used to systematically develop robust control systems analysis and design techniques. The advantages and limitations of these techniques are discussed. Examples are used to illustrate the methods. Keywords: Roll attitude control; LQG/LTR(Linear Quadratic Gaussian with Loop Transfer Recovery); and Drone aircraft. (Author).

Classical design and analysis techniques, many of which date back to the 1950's, are still predominantly used in the aerospace industry for the design and analysis of automatic flight control and aero-engine control systems. The continued success and popularity of these techniques is particularly impressive considering the radical advances in aircraft and spacecraft design and avionics technology made over this period. Clearly, an understanding of both the advantages and limitations of these methods is essential in order to properly evaluate the likely usefulness of more modern techniques for the design and analysis of aerospace control systems. One of the themes of this book is that the multivariable robust control methods it describes are logical and natural extensions of the more classical methods, and not replacements for them. It is assumed that readers of this publication are already familiar with classical flight control techniques. Emphasis is on the philosophy, advantages and limitations of the classical approach to flight control system design and analysis. Abstracted in Inspec

A robust controller for the approach and landing phase of the Short Take-off and Landing (STOL) F-15 is developed via LQG/LTR (Linear System model, Quadratic cost, Gaussian models of uncertainty, used for controller synthesis, with Loop Transmission Recovery techniques of tuning the filter in the loop for control robustness enhancement) methods. Reduced-order full-state feedback controllers are synthesized using CGT/PT (Command Generator Tracking feedforward compensator to incorporate handling qualities, with Proportional plus Integral feedback) synthesis, specifically using implicit model following to provide good robustness characteristics in the full-state feedback case. The robustness is fully assessed using realistic simulations of the real-world system with meaningful deviations from design conditions. Once a Kalman filter is embedded into the loop to estimate states rather than assuming artificial access to all states, LTR methodology is used to preserve as much robustness as possible. A full assessment of performance and robustness of these final implementable designs is provided. Keywords: LQG/LTR, Multivariable Control, STOL, Kalman Filter, and Model Following Controller.

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.

The workshop was organized and conducted by the Control Techniques Group, Flight Control Division, Flight Dynamics Laboratory, as part of an ongoing effort in flight control specification/criteria development. The workshop focused on the results of applying multivariable control techniques to the development of flight control systems for present day aircraft. This report contains condensed versions of the five papers presented at the workshop: (1) Multivariable Control Laws for the AFTI/F-16, (2) Design of a Complete Multivariable Digital Flight Control System, (3)Digital Multivariable Tracker Control Laws for the C-141-A Starlifter Aircraft; (4) High-Gain Error Actuated Flight Control Systems for Continuous Linear Multivariable Plants, and (5) Reconfigurable Digital Control Laws for the A-7D DIGITAC II Aircraft With Failed Primary Control Surfaces.

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.