DQ-NMPC: Dual-Quaternion NMPC for Quadrotor Flight

MAVs have great potential to assist humans in complex tasks, with applications ranging from logistics to emergency response. Their agility makes them ideal for operations in complex and dynamic environments. However, achieving precise control in agile flights remains a significant challenge, particularly due to the underactuated nature of quadrotors and the strong coupling between their translational and rotational dynamics. In this work, we propose a novel NMPC framework based on dual-quaternions (DQ-NMPC) for quadrotor flight. By representing both quadrotor dynamics and the pose error directly on the dual-quaternion manifold, our approach enables a compact and globally non-singular formulation that captures the quadrotor coupled dynamics. We validate our approach through simulations and real-world experiments, demonstrating better numerical conditioning and significantly improved tracking performance, with reductions in position and orientation errors of up to 56.11% and 56.77%, compared to a conventional baseline NMPC method. Furthermore, our controller successfully handles aggressive trajectories, reaching maximum speeds up to ${\text{13.66}} \, {\text{m/s}}$ and accelerations reaching ${\text{4.2}} \,{\text{g}}$ within confined space conditions of dimensions ${\text{11}}\, {\text{m}} \times {\text{4.5}}\, {\text{m}} \times {\text{3.65}}\, {\text{m}}$ under which the baseline controller fails.