Avian-informed drones feature morphing wing and tail surfaces, enhancing agility and adaptability in flight. Despite their large potential, realising their full capabilities remains challenging due to the lack of generalized control strategies accommodating their large degrees of freedom and cross-coupling effects between their control surfaces. Here we propose a new body-rate controller for avian-informed drones that uses all available actuators to control the motion of the drone. The method exhibits robustness against physical perturbations, turbulent airflow, and even loss of certain actuators mid-flight. Furthermore, wing and tail morphing is leveraged to enhance energy efficiency at 8m/s, 10m/s and 12m/s using in-flight Bayesian optimization. The resulting morphing configurations yield significant gains across all three speeds of up to 11.5% compared to non-morphing configurations and display a strong resemblance to avian flight at different speeds. This research lays the groundwork for the development of autonomous avian-informed drones that operate under diverse wind conditions, emphasizing the role of morphing in improving energy efficiency.

NCCR Robotics researchers at EPFL have developed a drone with a feathered wing and tail that give it unprecedented flight agility. The northern goshawk is a fast, powerful raptor that flies effortlessly through forests. This bird was the design inspiration for the next-generation drone developed by scientists of the Laboratory of Intelligent Systems of EPFL led by Dario Floreano. They carefully studied the shape of the bird's wings and tail and its flight behavior, and used that information to develop a drone with similar characteristics. "Goshawks move their wings and tails in tandem to carry out the desired motion, whether it is rapid changes of direction when hunting in forests, fast flight when chasing prey in the open terrain, or when efficiently gliding to save energy," says Enrico Ajanic, the first author and PhD student in Floreano's lab. Floreano adds: "our design extracts principles of avian agile flight to create a drone that can approximate the flight performance of raptors, but also tests the biological hypothesis that a morphing tail plays an important role in achieving faster turns, decelerations, and even slow flight."

A robot with wings that move like a hawk's can fly more stably and nimbly than other flying robots – and it uses less power, extending flight time. Enrico Ajanic at the Swiss Federal Institute of Technology Lausanne and his colleagues borrowed from the biology of the northern goshawk (Accipiter gentilis) to make a 284-gram drone with a maximum wingspan of 1.05 metres. The craft includes 27 feather-like plates – nine on each wing and a further nine on the tail – so that it moves through air as a goshawk does. The goal was to develop a drone that can fly long distances across cities, but manoeuvre around buildings and objects that it is likely to encounter. "Multicopter drones can hover and move well, but can't fly long distances," says Ajanic.