Advances in Aerospace Guidance, Navigation and Control

Book Preface

The two first CEAS (Council of European Aerospace Societies) Specialist Conferences on Guidance, Navigation and Control (CEAS EuroGNC) were held in Munich, Germany in 2011 and in Delft, The Netherlands in 2013. ONERA The French Aerospace Lab, ISAE (Institut Supérieur de l’Aéronautique et de l’Espace) and ENAC (Ecole Nationale de l’Aviation Civile) accepted the challenge of jointly organizing the 3rd edition. The conference, chaired by Daniel Alazard and Felix Mora-Camino, took place on April 13–15, 2015, at ISAE-SUPAERO, Toulouse, France, one of the leading aerospace engineering schools in Europe. The Organizing Committee composed of Christelle Cumer and Nadine Barriety, and the International Program Committee composed of about 50 eminent scientists and engineers, strongly contributed to the success of this event. About a hundred papers were selected for presentation at the conference and this book contains the forty best contributions. The topics addressed here represent the most actively researched areas in guidance, navigation and control.

It is well known that the challenges are often more demanding in aerospace than in many other fields. The control of aerospace vehicles remains a difficult task because of ever larger flight domains, more complex and coupled dynamics, and wider variety of flying vehicles. Among the most promising control techniques, adaptive control has gained significant interest due to recent developments ensuring fast adaptation to environmental changes while preserving robust stability. A renewed interest in robust control is also observed. Recent advances in non-smooth optimization and developments of efficient softwares have contributed to bridge the gap between theory and practice, allowing these techniques to be used in many industrial applications. It is now possible for example to design very simple controllers such as PIDs using H∞ based techniques.

Visual servoing, also known as vision-based control, has emerged more recently with the development of small, accurate and affordable cameras. This technique uses feedback information extracted from vision sensors to control the motion of a vehicle or a robot. The ever-growing computer power makes it now possible to process the rich information provided by these sensors, which is an essential step towards the control and the guidance of vehicles with fast dynamics. Many theoretical and practical results have already been presented, but solid mathematical analyses and proofs, real-time issues and efficient hardware implementations of image processing algorithms still deserve to be further investigated.

Then before flight testing, each aerospace vehicle has to go through a rigorous certification and qualification process to prove to the authorities that the flight control system is safe and reliable. Currently significant time and money is spent by the aeronautical industry on this task. Monte-Carlo simulations are used in most cases, but it is often difficult to isolate worst case scenarios or to confidently assert that no such scenario exists. Fortunately, many stability, performance, loads and comfort criteria can be reformulated as robustness analysis problems. Promising techniques such as multi-objective optimization under uncertainty using for example evolutionary algorithms can thus be applied to determine parameters/inputs/flight conditions for which the criteria are violated or poorly satisfied. A considerable effort is currently underway to enhance these techniques, motivated by the increase in computer power and the advent of multi-core processors,which allow to performparallel computing at a reasonable cost.