This paper proposes a nonlinear disturbance observer based controller (NDOBC) for quadrotors utilizing the rotation matrices for attitude dynamics. The proposed observer does not make the assumption that the disturbance is constant or its upper bound is known. The only assumptions are that the disturbance and its derivatives are bounded and hence can handle constant disturbance as a special case. The proposed disturbance observer can handle large class of disturbances and the NDOBC is shown to be locally input to state stable with respect to the derivatives of the disturbances present in attitude dynamics as well as translational dynamics. The proposed controller as well as the nonlinear disturbance observer has been formulated on the nonlinear manifold SE(3) where the rotational dynamics evolve on SO(3) while the translational dynamics evolve on . Simulation results as well as implementation on a hardware setup establish the effectiveness of the proposed NDOBC.

中文翻译：

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基于非线性扰动观测器的四旋翼几何控制

本文提出了一种基于非线性扰动观测器的控制器（NDOBC），用于利用姿态动力学的旋转矩阵的四旋翼飞行器。提议的观察者不假设扰动是恒定的或其上限是已知的。唯一的假设是扰动及其导数是有界的，因此可以将恒定扰动作为特殊情况处理。所提出的扰动观测器可以处理大类扰动，并且 NDOBC 被证明是局部输入到状态稳定的状态，相对于姿态动力学和平移动力学中存在的扰动的导数。所提出的控制器以及非线性扰动观测器已在非线性流形 SE(3) 上制定，其中旋转动力学在 SO(3) 上演化，而平移动力学在. 仿真结果以及在硬件设置上的实现确定了所提出的 NDOBC 的有效性。