  This paper develops an adaptive autopilot for quadcopters with unknown
dynamics. To do this, the PX4 autopilot architecture is modified so that the
feedback and feedforward controllers are replaced by adaptive control laws
based on retrospective cost adaptive control (RCAC). The present paper provides
a numerical investigation of the performance of the adaptive autopilot on a
quadcopter with unknown dynamics. In order to reflect the absence of prior
modeling information, all of the adaptive digital controllers are initialized
at zero gains. In addition, moment-of-inertia of the quadcopter is varied to
test the robustness of the adaptive autopilot. In all test cases, the vehicle
is commanded to follow a given trajectory, and the resulting performance is
examined.
