  A control system verification framework is presented for unmanned aerial
vehicles using theorem proving. The framework's aim is to set out a procedure
for proving that the mathematically designed control system of the aircraft
satisfies robustness requirements to ensure safe performance under varying
environmental conditions. Extensive mathematical derivations, which have
formerly been carried out manually, are checked for their correctness on a
computer. To illustrate the proceedures, a higher-order logic interactive
theorem-prover and an automated theorem-prover are utilized to formally verify
a nonlinear attitude control system of a generic multi-rotor UAV over a
stability domain within the dynamical state space of the drone. Further
benefits of the proceedures are that some of the resulting methods can be
implemented onboard the aircraft to detect when its controller breaches its
flight envelop limits due to severe weather conditions or actuator/sensor
malfunction. Such a detection procedure can be used to advise the remote pilot
or an onboard intelligent agent to decide on some alterations of the planned
flight path or to perform emergency landing.
