A Collision‐resilient Flying Robot

Abstract

Flying robots that can locomote efficiently in GPS-denied cluttered environments have many applications, such as in search and rescue scenarios. However, dealing with the high amount of obstacles inherent to such environments is a major challenge for flying vehicles. Conventional flying platforms cannot afford to collide with obstacles, as the disturbance from the impact may provoke a crash to the ground, especially when friction forces generate torques affecting the attitude of the platform. We propose a concept of resilient flying robots capable of colliding into obstacles without compromising their flight stability. Such platforms present great advantages over existing robots as they are capable of robust flight in cluttered environments without the need for complex sense and avoid strategies or 3D mapping of the environment. We propose a design comprising an inner frame equipped with conventional propulsion and stabilization systems enclosed in a protective cage that can rotate passively thanks to a 3-axis gimbal system, which reduces the impact of friction forces on the attitude of the inner frame. After addressing important design considerations thanks to a collision model and validation experiments, we present a proof-of-concept platform, named GimBall, capable of flying in various cluttered environments. Field experiments demonstrate the robot's ability to fly fully autonomously through a forest while experiencing multiple collisions.

Science, technology and the future of small autonomous drones

“…The different speed and torque requirements of these two locomotion modes could be reconciled by adapting the wing morphology to the specific situation 26 , similar to the way vampire bats (Desmodus rotundus) use their powerful front limbs when flying or walking 27 . Alternatively, multi-modal locomotion could be obtained by adding large wheels to the sides of hovering drones 28 , by embedding the propulsion system in a rolling cage 29 , or by completely decoupling the spherical cage from the inner rotors by means of a gimbal system 30 (Fig. 2b); the latter design allows the drone not only to roll on the ground in any direction, but, because the rotors are protected by a cage, also to safely collide with obstacles or humans without attitude perturbations.…”

Touchdown to take-off: at the interface of flight and surface locomotion

“…Current small flying robots are useful for inspection, imaging, surveillance and communication, provided these missions can be split-up in short cycles to accommodate the limited flight time. Furthermore, they need to fly sufficiently high to avoid collision with myriad obstacles in the near-ground environment, unless they can mitigate collisions [17]. The utility of aerial robots will be much improved, and their mission extended, if they can perch and locomote on these obstacles to collect physical samples and sense at lower energetic cost [18].…”

Chattering-Free Tracking Control of a Fully Actuated Multirotor with Passively Tilted Rotors

“…There are a few papers [3,4] that deal with configuration parameters important for the design of multirotors intended to perform different tasks such as disaster site observations or search and rescue missions [5,6].…”