¹Learning and Dynamical Systems, Max Planck Institute for Intelligent Systems, Tübingen & 72076, Germany.
²Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart & 70569, Germany.
Achieving both agile maneuverability and high energy efficiency in aerial robots, particularly in dynamic wind environments, remains challenging. Conventional thruster-powered systems offer agility but suffer from high energy consumption, while fixed-wing designs are efficient but lack hovering and maneuvering capabilities. We present Floaty, a shape-changing robot that overcomes these limitations by passively soaring, harnessing wind energy through intelligent morphological control inspired by birds. Floaty's design is optimized for passive stability, and its control policy is derived from an experimentally learned aerodynamic model, enabling precise attitude and position control without active propulsion. Wind tunnel experiments demonstrate Floaty's ability to hover, maneuver, and reject disturbances in vertical airflows up to 10 m/s. Crucially, Floaty achieves this with a specific power consumption of 10 W/kg, an order of magnitude lower than thruster-powered systems. This introduces a paradigm for energy-efficient aerial robotics, leveraging morphological intelligence and control to operate sustainably in challenging wind conditions.
The robot's design and some experiments.
A visualization of our actuation principle to illustrate the effect of the input on the dynamics
The robot performs a static target tracking, shown in red, with the real-time error in position and orientation displayed at the bottom.
The robot performs a dynamic target tracking with the target position moving vertically, following a sine wave, shown in red. The error in position and the z-control command are displayed to the right.
The robot performs a yaw angle tracking with the target orientation following a sine wave with an amplitude of π/2. The target orientation is illustrated with a red arrow.
Comparison of the flight performance of two different scales of quadcopters with and without vertical airflow. Micro Crazyflie 27 g quadcopter, and a custom-built 40 × 40 cm, 940 g quadcopter.
The robot is capable of maintaining flight across multiple experiments with different disturbances.