93853 - Advanced Guidance and Control of Aircraft and Spacecraft

Learning outcomes

The objective of the course is to provide the students with modern guidance and control techniques which are applicable to all flying vehicles without distinction. The course is intended for students in aerospace engineering oriented to both atmospheric and space flight. The focus is on application of multivariable robust optimal control theory for guidance and control of fixed and rotary wing aircrafts and spacecraft. The project of the autopilots currently implemented in commercial (airliner) and general aviation aircraft is proposed jointly with modern guidance and control systems for satellites, space-stations and microsatellite. An appealing feature of the course is the ready and extensive use of MATLAB®/Simulink® codes in the many solved examples illustrating guidance and control design and analysis. Furthermore, at the end of the course, the operation and programming of commercial autopilots are practically taught by using a certified flight simulator.

Course contents

 The course can be divided into two parts, denoted as 1) and 2), the first theoretical and the second applicative

1) THEORY

• OPTIMAL CONTROL: the control of Linear systems with Quadratic Cost index (LQ Optimal Control) is treated deeply. This theory is widely applied to the design of commercial autopilots. It is worth observing that also the basic theory of state observers and optimal state observers (Kalman Filter), necessary in the overall LQ control scheme, in case of some lacking measurements, is provided too

• INTELLIGENT  CONTROL SYSTEMS (ICS) particularly those based on Artificial Neural Networks (NN) is provided. The course covers both the model-based and model-free ICS, thus providing the student with powerful tools to design modern advanced guidance and control systems based on learning schemes such as feedback error learning, NN based disturbance observers, Neuro-adaptive optimal control based on deep NN.
  

2) APPLICATIONS: starting from a review of Flight Dynamic notions and the classical Single-Input-Single-Output (SISO) autopilot design methodology, the following applications are proposed

• OPTIMAL CONTROL BASED COMMERCIAL AND GENERAL AVIATION AIRCRAFT AUTOPILOTS:     Stability Augmentation Systems (SAS), Attitude Control Systems (ACS) and Flight Path Control Systems (FPCS). Within this topic, the design and the programming of  the autopilot currently used in general and commercial aviation are treated in detail.

• SPACECRAFT OPTIMAL GUIDANCE AND CONTROL : manoeuvring guidance and attitude control of satellites and space-stations

• INTELLIGENT ATMOSFHERIC AND SPACE FLIGHT CONTROL SYSTEMS (IFCS):  intelligent guidance and control of Autonomous  fixed/rotary wing aircraft and  Satellites, in presence of disturbance and faults

 

DETAILED COURSE CONTENTS

PART 1, THEORY

OPTIMAL CONTROL

1. Optimal Control Law. Optimal Control Problem definition, Hamiltonian function, solution of the LQ optimal control problem; solution of the minimum energy and minimum time optimal control problem; Pontryagin maximum principle.
2. Feedback Optimal Control. Solution of the optimum control problem: Differential Riccati equation, optimal feedback gain. Steady state optimal regulator: algebraic Riccati equation, stability of the steady state regular. Set points different from the origin.
   
3. State observers and dynamic feedback control. Identity observer, sub-optimal control problem by means of dynamic feedback
4. Notes on probability and stochastic process theory, Stochastic Optimal Observer. Optimal state estimate, Kalman Filterr

INTELLIGENT CONTROL (Neural Networks, Machine Learning)

1. Neural Adaptive Control: feedback learning, learning backstepping,Neuroadaptive Optimal Control, Direct adaptive control using Reinforcement learning, Deep-NN control
2. Fundaments of Machine Learning applied to Fault Detection and Isolation and Predictive Maintenance of Aircraft and Spacecraft

 

PART 2, APPLICATIONS

AIRCRAFT      

• Flight Dynamics summary. Six degree of freedom rigid body model. Military Flying qualities. Longitudinal and lateral-directional dynamics and model in case of coupled dynamics. Linearized models: longitudinal and lateral-directional modes. Dryden turbulence description and wind shear model.

• COMMERCIAL AND GENERAL AVIATION AUTOPILOTS DESIGN. On the basis of Optimal Control theory is presented the design of the following Flight Control Systems. Stability Augmentation Systems (SAS): pitch rate SAS and other longitudinal dynamic SAS; lateral-directional SAS: yaw dumper, roll rate dumper, spiral mode stabilization. Attitude Control Systems (ACS): pitch ACS, roll angle ACS, wing leveler, sideslip suppression ACS, turn coordination ACS. Flight Path Control System (FPCS): altitude hold system, speed control system, direction control system, heading control system, VOR-coupled automatic tracking system, ILS localizer coupled control system, ILS glide-path-coupled control system, ILS based automatic landing system

• AUTOPILOTS IMPLEMENTATION: Steady state control: determination of the inputs (command surfaces deflection and throttle) corresponding to a given steady state flight condition; determination of the optimal gain satisfying the flight qualities. Methods to arm and engage autopilots. Vertical mode autopilots (case of airbus 319/320/321) : Climb Rate and Airspeed hold, altitude capture and hold, glide slope capture and hold, flare and touchdown. Lateral mode autopilots (case of airbus 319/320/321) : bank angle and sideforce ACS, heading capture and hold, track capture and hold, localizer capture and hold. Gain scheduling methodology. Notes on guidance methods: navigation mode. Notes on the design of an integrated navigation, guidance and control system. Notes on control of missiles. Notes on model based linear and nonlinear Fault Detection and Isolation methods.

• GUIDANCE METHODS: intercept problem missile-target, Intelligent Control applied to Generic Trajectory Tracking and to guidance of hypersonic missiles

SPACECRAFT

MANEUVERING/GUIDANCE AND ATTITUDE CONTROL OF      SATELLITES AND REENTRY VEHICLES:

• SATELLITES: application of optimal control to rendezvous and docking problems between satellites. Stabilization and trim maneuvers: optimal control implemented by Reaction Wheel, Momentum Wheels and in general by rotors with fixed or variable axis. Attitude control of spacecraft subject to gravitational and/or aerodynamic disturbance. Active damping of spacecraft libration.
• Diagnosing of rotors faults of a spacecraft using combined Machine Learning/Model Based techniques.
• Intelligent Control of Satellites in the Presence of Faults on Actuators

• REENTRY VEHICLES: intelligent guidance and control applied to Reentry Vehicles, even hypersonic, in the presence of parametric disturbances and uncertainties

NOTES ON THE FORMATION CONTROL OF AIRCRAFT OR  SPACECRAFT       

MATLAB/SIMULINK (M/S): Realization (M/S) of the autopilots and control systems described in the previous points. Implementation of autopilots and their use by simulator licensed at ENAC certified flight school

Readings/Bibliography

PART 1

1. Notes of Prof Castaldi (downloadable at virtuale.unibo.it) 
    
2.  B.D.O. Anderson, J.B. Moore. Optimal Control: Linear Quadratic Methods. Prentice Hall Information and System Sciences Series 
   
   
3. S.A. Emami, Paolo Castaldi, A. Banazadeh. Neural network-based flight control systems: Present and future. Annual Reviews in Control 53 (2022) 97–137 https://doi.org/10.1016/j.arcontrol.2022.04.006
   
   
4. M. Tibaldi. Progetto di Sistemi di Controllo. Pitagora Editrice. Bologna

PART 2

1. Notes of Prof Castaldi (downloadable at virtuale.unibo.it)
   
   
2. D. McLean. Automatic Flight Control Systems. Prentice Hall Series in Sytems and Control Engineering
   
   
3. A.E. Bryson, Jr. Control of Spacecraft and Aircraft. Princeton University Press.

Teaching methods

Lessons in classroom plus laboratory autopilot design tested on matlab/simulink flight simulator.

Laboratory for flight controller and avionic devices .

Assessment methods

ORAL EXAM

Optional Project regarding an autopilot design or more generally the design of a Navigation, Guidance and Control System in Matlab/Simulink or UNIX/ROS/GAZEBO

Teaching tools

Lessons in classroom plus laboratory autopilot design tested on matlab/simulink flight simulator.

Hangar laboratory with flight controllers and avionics available.

Office hours

See the website of Paolo Castaldi