Modeling and Adaptive Control of Flexible Quadrotor UAVs.

This paper introduces an analytical framework for the derivation of distributed-parameter equations of motion of a flexible quadrotor. This approach helps obtain rigid and flexible equations of motion simultaneously, in a decoupled form, which facilitates the controller design. An adaptive controller is implemented using the developed model to prevent excessive oscillations due to flexible dynamics and to compensate uncertainties. Furthermore, a delay-dependent stability condition is obtained for the overall system dynamics, including the human UAV operator with reaction time delay, the adaptive controller and the flexible quadrotor dynamics. It is demonstrated via simulations that the flexible arm tip oscillations are reduced when the closed loop reference model adaptive controller is used, compared to a conventional model reference adaptive controller.