  This work proposes a systematic framework for modelling and controller design
of a Commercial-Off-The Shelf (COTS) unmanned rotorcraft using control theory
and principles, for brick wall construction. With point to point navigation as
the primary application, command velocities in the three axes of the Unmanned
Aerial Vehicle (UAV) are considered as inputs of the system while its actual
velocities are system outputs. Using the sine and step response data acquired
from a Hardware-in-Loop (HiL) test simulator, the considered system was
modelled in individual axes with the help of the proposed framework. This model
was employed for controller design where a sliding mode controller was chosen
to satisfy certain requirements of the application like robustness, flexibility
and accuracy. The model was validated using step response data and produced a
deviation of only 9%. Finally, the controller results from field test showed
fine control up to 8 cms accuracy. Sliding Mode Control (SMC) was also compared
with a linear controller derived from iterative experimentations and seen to
perform better than the latter in terms of accuracy, and robustness to
parametric variations and wind disturbances.
