Performance Evaluation and Design of Flight Vehicle Control Systems E-Book

Eric T. Falangas

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 589

Veröffentlichungsjahr: 2015

Beschreibung

The purpose of this book is to assist analysts, engineers, and students toward developing dynamic models, and analyzing the control of flight vehicles with various blended features comprising aircraft, launch vehicles, reentry vehicles, missiles and aircraft. * Graphical methods for analysing vehicle performance * Methods for trimming deflections of a vehicle that has multiple types of effectors * Presents a parameters used for speedily evaluating the performance, stability, and controllability of a new flight vehicle concept along a trajectory or with fixed flight conditions

Leseprobe

IEEE Press445 Hoes Lane Piscataway, NJ 08854

IEEE Press Editorial BoardTariq Samad, Editor in Chief

George W. Arnold

Vladimir Lumelsky

Linda Shafer

Dmitry Goldgof

Pui-In Mak

Zidong Wang

Ekram Hossain

Jeffrey Nanzer

MengChu Zhou

Mary Lanzerotti

Ray Perez

George Zobrist

Kenneth Moore, Director of IEEE Book and Information Services (BIS)

Technical Reviewer

Don Edberg, California State Polytechnic University

Performance Evaluation and Design of Flight Vehicle Control Systems

ERIC T. FALANGAS

Copyright © 2016 by Eric T. Falangas.

Published by John Wiley & Sons, Inc., Hoboken, New Jersey. All rights reserved.

Published simultaneously in Canada.

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Library of Congress Cataloging-in-Publication Data is available.

ISBN: 978-1-119-00976-4

CONTENTS

Preface

Acknowledgments

Introduction

1: Description of the Dynamic Models

1.1 Aerodynamic Models

1.2 Structural Flexibility

1.3 Propellant Sloshing

1.4 Dynamic Coupling Between Vehicle, Actuators, and Control Effectors

1.5 Control Issues

1.6 Coordinate Axes

1.7 Nomenclature

2: Nonlinear Rigid-Body Equations Used in 6-DOF Simulations

2.1 Force and Acceleration Equations

2.2 Moment and Angular Acceleration Equations

2.3 Gravitational Forces

2.4 Engine TVC Forces

2.5 Aerodynamic Forces and Moments

2.6 Propellant Sloshing Using the Pendulum Model

2.7 Euler Angles

2.8 Vehicle Altitude and Cross-Range Velocity Calculation

2.9 Rates with Respect to the Stability Axes

2.10 Turn Coordination

2.11 Acceleration Sensed by an Accelerometer

2.12 Vehicle Controlled with a System of Momentum Exchange Devices

2.13 Spacecraft Controlled with Reaction Wheels Array

2.14 Spacecraft Controlled with an Array of Single-Gimbal CMGs

3: Linear Perturbation Equations Used in Control Analysis

3.1 Force and Acceleration Equations

3.2 Linear Accelerations

3.3 Moment and Angular Acceleration Equations

3.4 Gravitational Forces

3.5 Forces and Moments due to an Engine Pivoting and Throttling

3.6 Aerodynamic Forces and Moments

3.7 Modeling a Wind-Gust Disturbance

3.8 Propellant Sloshing (Spring–Mass Analogy)

3.9 Structural Flexibility

3.10 Load Torques

3.11 Output Sensors

3.12 Angle of Attack and Sideslip Estimators

3.13 Linearized Equations of a Spacecraft with CMGs in LVLH Orbit

3.14 Linearized Equations of an Orbiting Spacecraft with RWA and Momentum Bias

3.15 Linearized Equations of Spacecraft with SGCMG

4: Actuators for Engine Nozzles and Aerosurfaces Control

4.1 Actuator Models

4.2 Combining a Flexible Vehicle Model with Actuators

4.3 Electromechanical Actuator Example

5: Effector Combination Logic

5.1 Derivation of an Effector Combination Matrix

5.2 Mixing-Logic Example

5.3 Space Shuttle Ascent Analysis Example

6: Trimming the Vehicle Effectors

6.1 Classical Aircraft Trimming

6.2 Trimming Along a Trajectory

7: Static Performance Analysis Along a Flight Trajectory

7.1 Transforming the Aeromoment Coefficients

7.2 Control Demands Partial Matrix (

C

T

)

7.3 Performance Parameters

7.4 Notes on Spin Departure

7.5 Appendix

References

8: Graphical Performance Analysis

8.1 Contour Plots of Performance Parameters Versus (Mach and Alpha)

8.2 Vector Diagram Analysis

8.3 Converting the Aero Uncertainties from Individual Surfaces to Vehicle Axes

9: Flight Control Design

9.1 Lqr State-Feedback Control

9.2

H

-Infinity State-Feedback Control

9.3

H

-Infinity Control Using Full-Order Output Feedback

9.4 Control Design Examples

9.5 Control Design for a Reentry Vehicle

9.6 Rocket Plane with a Throttling Engine

9.7 Shuttle Ascent Control System Redesign Using

H

-Infinity

9.8 Creating Uncertainty Models

10: Vehicle Design Examples

10.1 Lifting-Body Space-Plane Reentry Design Example

10.2 Launch Vehicle with Wings

10.3 Space Station Design Example

Bibliography

Index

EULA

List of Tables

Chapter 2

Table 2.1

Table 2.2

Chapter 7

Table 7.1

Table 7.2

Chapter 10

Table 10.1

Guide

Cover

Table of Contents

Preface

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PREFACE

The purpose of this book is to assist analysts and students toward developing dynamic models, analyzing and controlling flight vehicles of various blended features comprising aircraft, launch vehicles, re-entry vehicles, missiles, and spacecraft. The vehicle models are for simulations, control design, and stability analysis purposes. The vehicles are controlled by different types of effectors, such as aerosurfaces, thrust vector control, throttling engines, reaction control jets, control moment gyros, and reaction wheels. It is intended for flight control designers, dynamic analysts, and in general, for engineers and students who design and analyze atmospheric vehicles with asymmetric blended features using different types of actuators. It presents a unified approach in modeling, effector trimming, and in combining multiple types of flight vehicle control effectors.

The book begins with the rigid-body nonlinear equations of motion used in generic flight vehicle 6-DOF simulations and it gradually includes additional dynamic effects and details, such as propellant sloshing, structural flexibility, aeroelasticity, actuators, and tail-wags-dog dynamics. It presents some commonly used actuator models and describes in detail the dynamic coupling between actuators and flexibility of the supporting structure that often causes flexure oscillations. It also presents a method for augmenting the dynamic model to include structured parameter uncertainties used for analyzing the control system robustness using μ-analysis. It describes the design of a mixing-logic matrix that combines various types of effectors together, maximizes control efficiency, and reduces dynamic coupling between the control axes. It highlights two of the most commonly used flight control design methods, the LQR and H-infinity, and includes numerous design examples in detail. It describes methods of effector trimming and presents interactive trimming methods for balancing the vehicle moments and forces along a trajectory by adjusting the positions of the effectors. It develops criteria for analyzing the static performance of a generic flight vehicle and presents simple graphical methods for evaluating static stability, performance, and control authority prior to detailed modeling, analysis, and simulations. It concludes with design examples of two flight vehicles and a space station that demonstrate the methodology described in detail.

ERIC T. FALANGAS

ACKNOWLEDGMENTS

I would like to acknowledge Dr. Aditya Paranjape for his contribution on spin susceptibility, my colleagues John Harduvel for the derivation of conditions on slosh stability, Viet Nguyen for educating me on reentry dynamics and static performance analysis, Dale Jensen for his inputs on flexibility and launch vehicle dynamics, and Don Edberg for reviewing this book. I would also like to thank NASA for allowing me to download illustrative pictures from their website, and also my family.

INTRODUCTION

The stability and performance of a flight vehicle can be analyzed from two distinct perspectives: static and dynamic. The static analysis is described in the second half of this book and it deals with the capability of the vehicle controls to balance the steady-state aerodynamic moments and forces and also having sufficient control authority to counteract the expected wind shear along a trajectory. Dynamic analysis evaluates the behavior of the closed-loop vehicle and control system together by using linear control analysis and requires dynamic models of the vehicle consisting of differential equations. In aerospace vehicle development, one of the central features is the simulation model of the vehicle dynamics. This model is a mathematical representation of its expected behavior and dynamic response to the control commands and to wind disturbances. This math model is used by the stability and control engineer to develop control laws that allow a human pilot or an autopilot to maneuver the vehicle and to perform its mission. It is necessary to understand the physics of how forces cause objects to move in order to be able to predict the resulting motion of a flight vehicle to excitations. This field of study is called “dynamics” and it examines the behavior of structures under the effects of external forces and torques. Equations of motion describe how the vehicle will move in response to applied forces. For example, simple equations describe how a rocket will accelerate when a constant thrust is provided by the rocket's engine. More difficult equations describe how the sloshing of propellant in a rocket's tank will cause the rocket's structure to vibrate or throw the rocket off course. Another type of modeling would be to predict, in a mathematical equation, how an aircraft will respond to hitting an updraft in the atmosphere, or how the aircraft will respond to the deflection of the control surfaces at different airspeeds. These equations are differential equations, in which the rate of change of some variables, called states, is described as being dependent upon inputs and other states. The set of mathematical equations that describe these motions are collectively called a math model or simulation model of the vehicle, and they can range in complexity from a single equation to a complex set of equations. Complex vehicle models are, for convenience, broken down into subsystems that deal with different sets of dynamics, such as vehicle, sensor, and actuator subsystems.