  A model helicopter is more difficult to control than its full scale
counterparts. This is due to its greater sensitivity to control inputs and
disturbances as well as higher bandwidth of dynamics. This works is focused on
designing practical tracking controller for a small scale helicopter following
predefined trajectories. A tracking controller based on optimal control theory
is synthesized as part of the development of an autonomous helicopter. Some
issues in regards to control constraints are addressed. The weighting between
state tracking performance and control power expenditure is analyzed. Overall
performance of the control design is evaluated based on its time domain
histories of trajectories as well as control inputs.
