FLOAT Drone for Physical Interaction: Lateral Airflow Reduction, Wrench Modeling, and Adaptive Control

2026-07-05

AI Summary

This work addresses the challenge of achieving stable contact forces, compact mechanical design, and minimal lateral airflow interference in close-proximity physical interaction tasks with unmanned aerial vehicles. To this end, the authors propose FLOAT Drone—a fully actuated coaxial drone that innovatively integrates coaxial counter-rotating propellers with servo-controlled aerodynamic surfaces. This configuration leverages downwash to generate six-degree-of-freedom interaction forces while maintaining a compact form factor and substantially reducing target-facing lateral airflow. A high-fidelity aerodynamic model accounting for rotor-surface coupling effects is developed and combined with constrained nonlinear force allocation and adaptive control to enable precise real-time force tracking. Experimental results demonstrate that the proposed approach significantly outperforms linear allocation baselines in control accuracy, effectively mitigates ground effect and payload disturbances, and successfully accomplishes drawer pushing and pulling tasks within a 2 cm clearance gap.

Abstract

Aerial physical interaction represents a promising direction for next-generation unmanned aerial vehicles (UAVs), but it requires an aerial platform that can exert contact forces while maintaining stable flight. For close-proximity tasks, this translates into three coupled design requirements: multidimensional wrench generation for stable contact, compactness for maneuverability and safety in confined spaces, and reduced lateral airflow toward the target when generating horizontal force. This article presents FLOAT Drone, a fully actuated coaxial UAV with servo-driven control surfaces for close-proximity physical interaction. The coaxial dual-rotor layout provides a compact propulsion layout, while the control surfaces, immersed in the rotor downwash, generate lateral forces and moments for 6-DoF wrench generation. A force-matched computational fluid dynamics (CFD) comparison with a tilted-rotor alternative quantifies the reduction in target-facing lateral airflow. To account for nonlinear rotor--control-surface coupling in the rotor wake, a high-fidelity polynomial aerodynamic wrench model is identified from precision force measurements and embedded in a constrained nonlinear allocator for real-time wrench tracking. Comparative flight and interaction experiments show that the proposed framework improves control accuracy over linear allocation baselines, rejects ground-effect and payload disturbances, and enables close-proximity drawer push--pull manipulation through a $2~\mathrm{cm}$ handle clearance.

Problem

• aerial physical interaction
• wrench generation
• lateral airflow reduction
• compact UAV design
• close-proximity manipulation

Innovation

• aerial physical interaction
• coaxial UAV
• wrench modeling
• adaptive control
• lateral airflow reduction