Preface

To meet the requirements of future space missions, the high-precision and high- stability control problem of flight vehicles has become increasingly important. However, many uncertain factors, such as environmental and non-environmental disturbances, parameter uncertainty, and other nonlinear perturbations, widely influence the performance of flight vehicle maneuvers and operations. The present generation of flight vehicles should be capable of high-precision pointing and better robustness to external disturbances and various uncertainties. It should be noted that a distributed flight vehicle system may include multiple flight vehicles distributed in one or more orbits according to certain requirements and cooperating to perform space missions, e.g., observation, communication, reconnaissance, and navigation. It should be mentioned that formation flying and satellite clusters both belong to distributed satellite systems. Consequently, multiple complex disturbances will have a considerable influence on the stability of the flight vehicle leading to degradation in the dynamics and control performance of the system and even instability, which pose a huge challenge for control system designers, and advanced control approaches are required to improve robust performance and control accuracy in maneuver and operation to solve these problems.

In order to understand the behavior of flight vehicle maneuvers and operation properly, it is significant to investigate the advanced controller designs. To this end, Chapter 1 discusses air-breathing hypersonic vehicle, Chapter 2 discusses fast and parallel algorithms for orbit and attitude computation, Chapters 3 and 4 discuss rigid spacecraft, Chapter 5 discusses flexible spacecraft, Chapter 6 discusses vibration control using nonlinear energy sink, Chapter 7 discusses partial space elevators, and Chapters 8 and 9 discuss spacecraft formation flying and satellite cluster, respectively. In particular, Chapter 1 investigates anti- disturbance continuous fixed-time controller design for an air-breathing hypersonic vehicle, where a fast fixed-time integral sliding surface, a continuous fixed-time super-twisting-like reaching law and a uniformly convergent observer are combined. As control efficiency is very important in practice, to efficiently solve nonlinear differential equations in aerospace engineering, fast and parallel algorithms can be a good choice, and this results in the writing of Chapter 2, where a simple adaptive local variational iteration method is developed. Chapter 3 provides detailed derivations of adaptive event-triggered sliding mode controller used for attitude tracking, where the communication burden is decreased significantly. Chapter 4 investigates an adaptive finite-time controller for satellite attitude maneuver, where the singularity problem is dealt with based on the properties of Euler rotations. Chapter 5 develops an output feedback controller for attitude stabilization and vibration suppression of flexible spacecraft using negative imaginary and H∞ theories. To further investigate the vibration control and energy harvesting properties in aerospace engineering, a nonlinear energy sink approach is developed to deal with the influence of rich and complex dynamic environments in Chapter 6. Chapter 7 describes the mathematical model of partial space elevators, and a configure-keeping technology for stable cargo transportation is investigated. Furthermore, Chapters 8 and 9 discuss the distributed flight vehicle system, where adaptive fixed-time 6-DOF coordinated control for spacecraft formation flying and prescribed time control for satellite cluster reconstruction are investigated, respectively.

This book will be helpful to scientists and engineers who are interested in working on the development of flight vehicle maneuvers and operations. Researchers studying control science and engineering and advanced undergraduate and graduate students and professionals involved in the flight vehicle control field will also benefit from the information given in this book. This book covers a wide range of topics in flight vehicle maneuver and operation, e.g., hypersonic vehicle, orbit and attitude computation, single spacecraft, flexible vibration, space elevators, spacecraft formation flying, satellite cluster, et al.

The book has a broad scope and helps students and researchers in universities, industries, and national and commercial laboratories to learn the fundamentals and in-depth knowledge regarding thermal modeling and developments in solar thermal systems in the past few years. It is a research-oriented book in which different researchers have contributed in the form of different chapters. I hope that the book will provide sufficient knowledge regarding solar systems and will not discourage the readers. This book can be used as a reference tool for teaching the solar energy and thermal modeling of solar thermal systems to the students and research fellows in universities and research organizations