Design and Control of a Coaxial Dual-rotor Reconfigurable Tailsitter UAV Based on Swashplateless Mechanism

TL;DR

This paper presents a reconfigurable tailsitter UAV with a coaxial dual-rotor setup and a swashplateless mechanism, enhancing wind resistance, power efficiency, and structural simplicity, validated through extensive flight tests.

Contribution

It introduces a novel reconfigurable wing design combined with a coaxial dual-rotor and an improved swashplateless mechanism for better performance and efficiency.

Findings

Reduced power consumption with the dual-rotor configuration

Enhanced stability and reduced vibration with the optimized swashplateless mechanism

Successful validation of stable transition flights across the entire flight envelope

Abstract

The tailsitter vertical takeoff and landing (VTOL) UAV is widely used due to its lower dead weight, which eliminates the actuators and mechanisms for tilting. However, the tailsitter UAV is susceptible to wind disturbances in multi-rotor mode, as it exposes a large frontal fuselage area. To address this issue, our tailsitter UAV features a reconfigurable wing design, allowing wings to retract in multi-rotor mode and extend in fixed- wing mode. Considering power efficiency, we design a coaxial heterogeneous dual-rotor configuration, which significantly re- duces the total power consumption. To reduce structural weight and simplify structural complexity, we employ a swashplateless mechanism with an improved design to control pitch and roll in multi-rotor mode. We optimize the structure of the swashplateless mechanism by adding flapping hinges, which reduces vibration during cyclic acceleration and deceleration. Finally, we perform comprehensive transition flight tests to validate stable flight performance across the entire flight envelope of the tailsitter UAV.