Quadrotors that can operate safely in the presence of imperfect model knowledge and external disturbances are crucial in safety-critical applications. We present L1Quad, a control architecture for quadrotors based on the L1 adaptive control. L1Quad enables safe tubes centered around a desired trajectory that the quadrotor is always guaranteed to remain inside. Our design applies to both the rotational and the translational dynamics of the quadrotor. We lump various types of uncertainties and disturbances as unknown nonlinear (time- and state-dependent) forces and moments. Without assuming or enforcing parametric structures, L1Quad can accurately estimate and compensate for these unknown forces and moments. Extensive experimental results demonstrate that L1Quad is able to significantly outperform baseline controllers under a variety of uncertainties with consistently small tracking errors.

翻译：能够在模型认知不完善及外部干扰情况下安全运行的四旋翼无人机，对于安全关键型应用至关重要。本文提出L1Quad——一种基于$\mathcal{L}_1$自适应控制的四旋翼控制架构。L1Quad能够构建以期望轨迹为中心的安全管道，确保四旋翼始终运行于管道内部。该设计同时适用于四旋翼的旋转与平移动力学模型。我们将各类不确定性及干扰统一建模为未知非线性（时间相关与状态相关）的力与力矩。无需假设或强制设定参数化结构，L1Quad即可精确估计并补偿这些未知力与力矩。大量实验结果表明，在多种不确定性条件下，L1Quad能够以持续较小的跟踪误差显著优于基准控制器。