Downwash-aware Control Allocation for Over-actuated UAV Platforms

TL;DR

This paper introduces a novel control allocation framework for over-actuated UAVs that considers downwash effects, optimizing thrust distribution to enhance stability and efficiency in complex aerodynamic conditions.

Contribution

It is the first formal derivation addressing downwash effects in over-actuated UAV control allocation, improving stability and efficiency.

Findings

Framework effectively compensates for downwash effects

Optimizes thrust allocation for stability and efficiency

Validated through simulation and experimental tests

Abstract

Tracking position and orientation independently affords more agile maneuver for over-actuated multirotor Unmanned Aerial Vehicles (UAVs) while introducing undesired downwash effects; downwash flows generated by thrust generators may counteract others due to close proximity, which significantly threatens the stability of the platform. The complexity of modeling aerodynamic airflow challenges control algorithms from properly compensating for such a side effect. Leveraging the input redundancies in over-actuated UAVs, we tackle this issue with a novel control allocation framework that considers downwash effects and explores the entire allocation space for an optimal solution. This optimal solution avoids downwash effects while providing high thrust efficiency within the hardware constraints. To the best of our knowledge, ours is the first formal derivation to investigate the downwash effects on over-actuated UAVs. We verify our framework on different hardware configurations in both simulation and experiment.