A 26-Gram Butterfly-Inspired Robot Achieving Autonomous Tailless Flight

2026-02-06

AI Summary

This study addresses the challenge of achieving stable autonomous flight in tailless flapping-wing micro air vehicles, which is hindered by strong fluid–structure and wing–body coupling. The authors present AirPulse, a 26-gram butterfly-inspired ornithopter that replicates key biomechanical features such as low aspect ratio wings, wing flexibility, and large-amplitude, low-frequency flapping. Notably, it achieves the lightest onboard closed-loop autonomous flight reported to date for a tailless biplane flapping-wing vehicle. The core innovation lies in the Stroke Timing Asymmetry Rhythm (STAR) generator, which establishes a quantitative mapping between flapping parameters and aerodynamic forces and moments. Integrated with carbon fiber–reinforced flexible wings, a low-frequency high-amplitude actuation system, and onboard attitude control, AirPulse successfully executes climbing and turning maneuvers in free flight, offering a novel, lightweight, and collision-resilient micro aerial platform for confined-space inspection and ecological monitoring.

Technology Category

• Intelligent Robots: Motion and Path Planning
• Planning, Routing, and Scheduling: Activity and Plan Recognition
• Humans and AI: Planning and Decision Support for Human-Machine Teams

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• Search and Retrieval-Augmented AI: Agentic search

Abstract

Flapping-wing micro air vehicles (FWMAVs) have demonstrated remarkable bio-inspired agility, yet tailless two-winged configurations remain largely unexplored due to their complex fluid-structure and wing-body coupling. Here we present \textit{AirPulse}, a 26-gram butterfly-inspired FWMAV that achieves fully onboard, closed-loop, untethered flight without auxiliary control surfaces. The AirPulse robot replicates key biomechanical traits of butterfly flight, including low wing aspect ratio, compliant carbon-fiber-reinforced wings, and low-frequency, high-amplitude flapping that induces cyclic variations in the center of gravity and moment of inertia, producing characteristic body undulation. We establish a quantitative mapping between flapping modulation parameters and force-torque generation, and introduce the Stroke Timing Asymmetry Rhythm (STAR) generator, enabling smooth, stable, and linearly parameterized wingstroke asymmetry for flapping control. Integrating these with an attitude controller, the AirPulse robot maintains pitch and yaw stability despite strong oscillatory dynamics. Free-flight experiments demonstrate stable climbing and turning maneuvers via either angle offset or stroke timing modulation, marking the first onboard controlled flight of the lightest two-winged, tailless butterfly-inspired FWMAV reported in peer-reviewed literature. This work corroborates a foundational platform for lightweight, collision-proof FWMAVs, bridging biological inspiration with practical aerial robotics. Their non-invasive maneuverability is ideally suited for real-world applications, such as confined-space inspection and ecological monitoring, inaccessible to traditional drones, while their biomechanical fidelity provides a physical model to decode the principles underlying the erratic yet efficient flight of real butterflies.

Problem

• flapping-wing micro air vehicles
• tailless flight
• butterfly-inspired robotics
• fluid-structure interaction
• autonomous flight

Innovation

• flapping-wing micro air vehicle
• butterfly-inspired flight
• tailless control
• stroke timing asymmetry
• onboard autonomous flight