A multivariable adaptive controller for a quadrotor with guaranteed matching conditions

This paper develops an adaptive control system for a quadrotor unmanned aerial vehicle. It employs a state feedback output tracking design for multi-input multi-output systems, using a less restrictive matching condition than a state tracking design, and offers a simpler controller structure than an output feedback design. Some key characteristics of the quadrotor dynamics are derived for adaptive control design which deals with system uncertainties from changing operating points. The plant-model matching is ensured despite of system parameter uncertainties which cannot be handled by an existing state tracking design. The adaptive law is based on a parametrization using an LDS decomposition of the high-frequency gain matrix, which ensures closed-loop stability and asymptotic output tracking. A simulation study is carried out on the nonlinear quadrotor model, and results are presented to demonstrate the desired adaptive system performance.