L₁ Quad: L₁ Adaptive Augmentation of Geometric Control for Agile Quadrotors With Performance Guarantees

Quadrotors that can operate predictably in the presence of imperfect model knowledge and external disturbances are crucial in safety-critical applications. We present L₁ Quad, a control architecture that ensures uniformly bounded transient response of the quadrotor's uncertain dynamics on the special Euclidean group SE(3). By leveraging the geometric controller and the L₁ adaptive controller, the L₁ Quad architecture provides a theoretically justified framework for the design and analysis of quadrotor's tracking controller in the presence of nonlinear (time-and state-dependent) uncertainties on both the translational and rotational dynamics. In addition, we validate the performance of the L₁ Quad architecture through extensive experiments for 11 types of uncertainties across various trajectories. The results demonstrate that the L₁ Quad can achieve consistently small tracking errors despite the uncertainties and disturbances and significantly outperforms existing state-of-the-art controllers.