SUMMARY

Many multirotor controllers achieve globally stable attitude control through the usage of quaternions, as it does not inherent any singularities, unlike other alternatives such as Euler angles. However, globally stable position or velocity control of quadrotors have rarely been achieved; most controllers limit their attitude within a certain range to avoid singularities that occur during position control of quadrotors. This thesis focuses on presenting a globally stable quaternion-based dual loop nonlinear control scheme. Globality of the control scheme is both achieved in 1) the sense that all errors exponentially converge to zero regardless of the initial state errors and 2) the controller can stabilize at and pass through any point of attitude during position control.