This thesis describes the development of a pilot override control system that prevents aircraft
entering critical regions of space, known as prohibited volumes. The aim is to prevent another
9/11 style terrorist attack, as well as act as a general safety system for transport aircraft.
The thesis presents the design and implementation of three core modules in the system; the
trajectory generation algorithm, the trigger mechanism for the pilot override and the trajectory
following element. The trajectory generation algorithm uses a direct multiple shooting strategy
to provide trajectories through online computation that avoid pre-defi ned prohibited volume
exclusion regions, whilst accounting for the manoeuvring capabilities of the aircraft. The trigger
mechanism incorporates the logic that decides the time at which it is suitable for the override to
be activated, an important consideration for ensuring that the system is not overly restrictive
for a pilot. A number of methods are introduced, and for safety purposes a composite trigger
that incorporates di fferent strategies is recommended. Trajectory following is best achieved via
a nonlinear guidance law. The guidance logic sends commands in pitch, roll and yaw to the
control surfaces of the aircraft, in order to closely follow the generated avoidance trajectory.
Testing and validation is performed using a full motion simulator, with volunteers
flying a
representative aircraft model and attempting to penetrate prohibited volumes.
The proof-of-concept system is shown to work well, provided that extreme aircraft manoeuvres
are prevented near the exclusion regions. These hard manoeuvring envelope constraints allow
the trajectory following controllers to follow avoidance trajectories accurately from an initial
state within the bounding set. In order to move the project closer to a commercial product,
operator and regulator input is necessary, particularly due to the radical nature of the pilot
override system
