Modeling and adaptive control of a quadrotor

In this paper, we propose two variants of adaptive state space controllers for attitude stabilization and self-tuning of a four-rotor aerial robot, a quadrotor. First of all, the use of a Model Identification Adaptive Controller (MIAC) is proposed in terms of combining a recursive least-squares estimator with exponential forgetting with an integral discrete-time state space controller. Furthermore, a continuous-time Model Reference Adaptive Control (MRAC) scheme based on Lyapunov theory is applied to the simplified dynamics of a quadrotor, which guarantees global asymptotic stability for at least linear overall systems. The effectiveness of the suggested adaptive methods is demonstrated in simulations with a quaternion-based nonlinear dynamic model of a quadrotor derived in this work. The results are compared to a designed nonadaptive integral state space controller.