Bioinspired flight control.

David Lentink Department of Mechanical Engineering, Stanford University, USA E-mail: [email protected] The invention and deployment of small flying robots (drones) is beginning to influence our everyday lives. Their applications are frightening to some and exciting to others. From military surveillance, to city courier services, to near-future flying camera phones, this technology is bound to end up on everyone’s doorstep. Setting privacy issues aside, the biggest challenge in successfully integrating the versatile use of drones in our society is to make them safe and reliable. Whereas we have succeeded in doing so with large passenger aircraft, it has proven remarkably difficult to adapt this technology on a smaller scale to flight in urban environments. From windy street canyons to highly cluttered alleys and parks, keeping drones in the air is actually a more difficult task than first imagined, as any hobby drone pilot can confirm. Making these flights more useful and versatile is yet another challenge. How can we adapt and innovate our technology to succeed? Flying animals have adapted remarkably well to the new aerial environments we have created. Setting wind turbines and glass windows aside, birds, bats, and insects do well under circumstances our drones do not. And, frankly, drones that can robustly detect and avoid closed windows or turbine blades have yet to be invented. Flying animals can be found everywhere in our cities; from scavenging pigeons to alcohol-sniffing fruit flies that make precision landings on our wine glasses, these animals have quickly learned how to control their flight through urban environments to exploit our resources. To enable our drones to fly equally well in wind and clutter, we need to solve several flight control challenges during all flight phases: take-off, cruising, and landing. Ideally, we would also further expand these capabilities to include novel tasks such as pick-up and delivery, photography and streaming video, all culminating in sophisticated situational awareness by fusing images with data from advanced sensors. Remarkable utility could be achieved by figuring out which principles enable animals to outperform our drones. In this special issue, fourteen distinguished research teams with biology and engineering backgrounds present their ideas to advance the capabilities of current drones, inspired by animal flight control. The contributions integrate biological studies—ranging from flying insects and bats to flying snakes—with engineered bioinspired solutions to improve the take-off, obstacle avoidance, in-flight grasping, swarming, and landing capabilities of drones.