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This article proposes a new practical robust attitude state feedback controller of a low-cost hexarotor micro aerial vehicle under the effects of noise in angular velocity measurements and multiple uncertainties (called the equivalent disturbance), which consist of external time-varying wind disturbance, nonlinear dynamics, coupling and parametric uncertainties. The proposed method is designed in two simple steps. Firstly, a nominal cascade controller is designed to reduce noise in angular velocity measurements and to achieve good attitude tracking performance in nominal conditions. Then, a second-order robust compensator is integrated into the closed-loop system to reduce the effects of the equivalent disturbance. The proposed control design is a linear time-invariant controller which is easily implemented in practical applications. Compared to other advanced attitude controllers, the proposed controller incurs lower computational costs and can easily be implemented in a low-cost embedded microcontroller system. In addition, a practical computational design procedure and an intuitive online tuning method for the proposed controller are presented in this article in order to provide a complete reference to micro aerial vehicle developers. The simulation and experimental results are presented to demonstrate the robustness of the proposed controller in operation in outdoor environments, to show good steady-state and dynamic tracking performance of the closed-loop system and to prove that the tracking errors are ultimately bounded within desired limits.

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The aim of this paper is to propose an optimum linear control algorithm that is able to stabilize the attitude of a hexarotor micro aerial vehicle (MAV) in indoor environment. The work will then compare it with the classical control PID (proportional-integral-derivative) and optimal control LQR (linear quadratic regulator) techniques. The proposed attitude controller is based on an outer-inner loop structure PID plus LQR (PID+LQR) control method where the controller combines the positive features of each sub-controller (PID and LQR). The key contribution of this work is the proposed attitude controller can improve robustness and transient response thus leads to faster response in indoor flying environment. The attitude tracking errors are proven to be ultimately bounded with specified boundaries. Simulation results on the hexarotor demonstrate the effectives of the proposed attitude controller.

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