Design, aerodynamics and autonomy of the DelFly

TLDR

One of the major challenges in robotics is to develop a fly‑like robot that can autonomously fly around in unknown environments. The paper discusses the current state of the DelFly project, aiming to develop smaller and more autonomous ornithopters. The authors adopt a top‑down approach to iteratively reduce size while increasing autonomy. The study shows that a parametric wing stiffener redesign yields a 5 % increase in power efficiency, improves lift and enables additional onboard sensors, while the top‑down approach also enhances autonomy through better vision‑based obstacle avoidance and pressure‑sensor‑based height control.

Abstract

One of the major challenges in robotics is to develop a fly-like robot that can autonomously fly around in unknown environments. In this paper, we discuss the current state of the DelFly project, in which we follow a top-down approach to ever smaller and more autonomous ornithopters. The presented findings concerning the design, aerodynamics and autonomy of the DelFly illustrate some of the properties of the top-down approach, which allows the identification and resolution of issues that also play a role at smaller scales. A parametric variation of the wing stiffener layout produced a 5% more power-efficient wing. An experimental aerodynamic investigation revealed that this could be associated with an improved stiffness of the wing, while further providing evidence of the vortex development during the flap cycle. The presented experiments resulted in an improvement in the generated lift, allowing the inclusion of a yaw rate gyro, pressure sensor and microcontroller onboard the DelFly. The autonomy of the DelFly is expanded by achieving (1) an improved turning logic to obtain better vision-based obstacle avoidance performance in environments with varying texture and (2) successful onboard height control based on the pressure sensor.