Flight Dynamics Challenges of Highly Augmented Configurations: Flight Control Systems, Instability vs. Agility, Stabilizability & Robust Stability

The Institute of Flight System Dynamics mourns the loss of Prof. Dr.-Ing. Matthias Heller, who passed away on 02. April 2020. He was a brilliant lecturer, a great researcher and a wonderful friend. Our thoughts are now with his family and his loved ones. Matthias leaves behind four wonderful girls – his wife and three daughters.

In order to support his family, a donation page has been established: https://www.betterplace.me/matthias-heller
Every small amount is welcome. More information can be found here.

Key Facts
Contact Prof. Dr.-Ing. Matthias Heller
David Seiferth, M. Sc.
Language of Instructions German
Language of Materials German
Type / ECTS Lecture, Exercise / 3 (Elective Lecture Module)
Semester Winter Semester
Time and Place Lecture:
Related Links Poster, Flyer
Prerequisites The interdisciplinary module/course is aimed for students as well as PhD students of different study degree programs (e.g. aerospace and mechanical engineering, physics, electrical engineering, informatics, ergonomics, etc.) who like to gain well-founded knowledge in the field of flight dynamics, flight control systems as well as stabilization capability of modern flying systems.
Prerequisites are interest in the field of flight system dynamics, flight control systems and/or robust stabilization as well as in gaining (background) knowledge in the corresponding technical areas as control / stabilization theory and system dynamics.Attendance of the course “Introduction to Flight System Dynamics and Flight Control” is recommended, but not required.
Content / Educational Objectives It is the objective of the one-semester lecture to impart basic knowledge up to the state-of-the-art concerning the manifold flight dynamics challenges within the development of modern FbW aircraft (from preliminary design up to testing, clearance and certification).
The perpetual evolution of modern ‘Fly-by-Wire’ (FbW) Flight Control Systems (FCS) during the last decades offers a wide range for optimizing the aircraft regarding its performance and flight envelope without imposing the previously necessary compromises considering stability and flying qualities. Hence, today’s high performance FbW aircraft exhibit at least “relaxed stability” – up to airframe instability – in a certain range and thus, feature highly control configured dynamics which allow to exploit the airframe agility potential combined with specifically tailored stability and control characteristics over the entire flight envelope. The complex FCS’s of these so-called Control Configured Vehicles (CCV) together with the high demands on agility (maneuverability) and precise tracking introduce novel challenges and problems concerning adequate stabilization, robustness, reliability, and thus, safety of the overall aircraft system.

Lecture contents and breakdown

  • Introduction; Motivation: Instability versus Agility
  • Flight Dynamics “nowadays” within the design cycle
  • Flight Control Systems: Types and Structures
    System specific: Aerodynamical, hydraulic, elektrohydraulic, Fly-by-Wire
    Flight dynamically: Conventional, augmented, highly augmented/ superaugmented
  • The Stability Issue: Static / Dynamic (In-)Stability and (In-)Stability Criteria
  • “Respect the Unstable” – Airframe Instability versus Agility, Flight Dynamics Layout and Stabilization Capability of modern FbW Aircraft
  • Conceptual, Structural and Robustness Aspects of modern active Flight Control Systems
  • Uncertainty Modeling and μ-Analysis
  • Case Studies, In-operation Aircraft Systems and advanced topics

Learning Objectives
Upon successful completion of the module, students are able to:

  • understand the fundamental relationships of flight dynamics stability/instability properties, agility, stabilization capability as well as the specific control characteristics of modern Fly-by-Wire (FbW) aircraft
  • to constitute and reflect the associated „state-of-the art“
  • to capture the manifold interdisciplinary problems in the development of modern highly augmented aircraft (from preliminary design up to testing and certification) as well as in particular the relationship between airframe instability, agility and the elementary stabilization boundaries
  • apply independently the methods taught for analysis and evaluation of control and stabilization capability on current and future aircraft configurations, where the typically required active FbW flight control system has to be considered a priori
  • analyze and evaluate the stabilization capability potential of existing and future aircraft / control system designs („Stabilization Capability Criterion”)
  • implement measures for effective exploitation or increase of stabilization potential
  • develop a suitable flight controller structure for current industrial applications
    SAS/CAS/CSAS/FCS – highly/super-augmenting, independently
Teaching Methods / Materials Integrated Lecture / Course
The individual course units comprise each of the basic elements: lecture, interactive talk, exercises and computer practice (tutorial), in an integrative manner.
Within the lecture, the theoretical principles of the relationship between airframe (in-) stability and agility as well as the fundamental boundaries of the stabilization capability will be derived and presented via Power Point slides along with writing on the board. Comprehensive Lecture Notes (script) will be provided to the students which they should supplement with their own notes and remarks. In the course of an interactive talk the students are asked targeted questions or they may ask questions, respectively, in order to deepen the understanding and the proper application of e.g. stability analyses, agility increase with consideration of the stabilization potential and structural flight controller design.
In the course of the accompanying exercises the contents imparted in the lectures will be applied to typical practical problems, e.g. the evaluation of agility enhancement due to unstable layout of a current high performance aircraft; supported by simulations and calculations using modern analysis tools (MATLAB / Simulink). Furthermore, additional problem sheets will be provided to the attendees which can be solved during the exercises or voluntary at home in order to deepen the insight and practice of the techniques taught. The elaborated Matlab/Simulink functions for further investigations and illustrations within the exercise will be handed out to the students with the intention to establish a framework for their own (future) flight dynamics analyses and evaluations of new highly augmented aircraft designs.
Additionally, each term an ambitious and deepening guest lecture to be held by an outstanding expert from the industry or the research centers (e.g. AIRBUS, DLR, Hochschule München) will be provided highlighting specific current topics concerning the design of highly augmented aircraft at first hand.
Exam Exam type: oral
Reference Literature List of recommended literature provided with first chapter of lecture notes.

This lecture is part of the Munich Aerospace Teaching Collaboration.