Codice identificativo insegnamento: 091357
Programma
sintetico: the course provides the basic knowledge on the
angular motion of a rigid satellite, on sensors and algorithms for attitude
determination, on actuators and attitude control laws.
Attitude
Dynamics and kinematics of spacecraft
 Spacecraft
Dynamics: Angular momentum and Energy,Euler equations – Torquefree motion
of a rigid body  stability  simple spin stability (with and without
energy dissipation), dualspin spacecraft  numerical and analytical
analysis.
 Attitude Representation and kinematics: Mathematical
representation of rotational motion using (i) Direction cosine matrices
(ii) Euler axis and angle (iii) Quaternions (iv) Gibbs vector (v) Euler
angles. Frames of reference
 inertial frame, body fixed frame and the
LVLH frame.
 Space environment modelling: Developing approximate models
of environmental disturbance torques due to air drag, solar radiation
pressure, magnetic torque, gravity gradient.
 Implementation in
Simulink: Implementing the dynamic and kinematic equations of a spacecraft
in low Earth orbit for analysis, control development and actuator sizing.
Attitude
Determination and Control
 Detumbling: development of
basic detumbling control algorithms for spacecraft in the case of
continuous actuation and "onoff" actuation typical of thrusters.
Stability analysis of the controlled system via enery based methods.
Consideration of disturbances in the proof of stability. Angular velocity
measurement with gyros.
 Attitude pointing and 3axis stabilization:
Control algorithms for pointing and 3axis stabilization in Earth orbit
based on the Local vertical Local horizontal frame and linear control
methods such as LQR for continuous and discrete controls. Stability
analysis of spacecraft motion in Earth orbit.
 Attitude determination:
Determination algorithms (for pointing and 3stabilization applications)
based on Linear state observers in the LVLH frame using single vector
reference sensors e.g. Earth horizon sensors and Sun sensors
 Static
determination methods: using combinations of sensors to compute the
attitude of the spacecraft e.g magnetometers, Sun sensors, Earth horizon
sensors and star sensors. The development of algorithms based on algebraic
methods e.g TRIAD and numerical methods e.g. qmethod, QUEST method,
constrained and unconstrained optimization.
Advanced
spacecraft attitude control
 Introduction to nonlinear
control design: Attitude control design for spacecraft based on Lyapunov
control functions. An application to detumbling and slew motions.

Attitude control for typical spacecraft actuators: Based on the control
laws developed in the previous sections (ideal control) develop control
laws for real actuators such as reaction wheels, control moment gyros,
magnetic torquers and thrusters. Use SIMULINK to size actuators. Develop
unique control laws for thrusters and magnetic torquers including the case
where you cannot provide torque instantaneously in every direction.

Robust control: Designing attitude controls that are robust to
uncertainties and disturbances using sliding mode control and extended
state observers.
 Nonlinear tracking control: Designing attitude
tracking references and controls that can undertake continuous motion such
as pointing to the Earth while motioning to maximise power generation.