SpiderMAV: Micro Aerial Vehicles With Bio-inspired Tensile Anchoring Systems
Longevity and endurance become important factors for drones when on a longer duration fight. Also, specific tasks may require drones to stabilise mid-air or perch on a fixed surface. The ability of drones to perch high on walls or ceilings is what gives them the positional advantage. Letting drones perch also allows for some downtime. However, typically, drones require use of substantial amount of its battery power to stabilize itself or land on a difficult surface.
Until now, drones have used a variety of perching techniques adapted from the use of claws, spines and adhesives. An experimental drone, built by the Imperial College London could potentially change the way drones work (or perch). The drone, christened SpiderMAV, is equipped to shoot ‘webs’ (a la Spider man) to create stable perches for itself as and when required.
Spiders can create stable perching locations for themselves in mid-air using silk web structures, supported by tensile anchors. The SpiderMAV takes its inspiration from the Darwin’s bark spider, an orb-weaver spider capable of spinning silk webs twice as strong as that of any other spider and up to a length of 25 meter. Its silk is known to be the toughest biological material there is.
The SpiderMAV is a customized DJI Matrice 100 drone, fitted with an external perching module mounted on its top and a stabilising module at the bottom. The perching module functions using a magnetic anchor, a launcher and polystyrene thread. The drone uses compressed gas to launch the anchor against a magnetic surface, ideally a metal beam or ceiling. When the anchor gets attached to the base surface, the drone uses an actuated spooling system to keep the thread taut and thus hang securely from the base. The drone can then slow down or shut its motor off. The bottom module works in a similar fashion, using magnetic anchors and then reeling in the thread to stabilize the drone in a fixed position.
Testing in a controlled environment showed marked improvement in the stability of the MAV in all three axis directions. In terms of perching, the drone’s power consumption practically falls to zero, thereby significantly improving its overall endurance/longevity. This approach allows energy-efficient perching, while providing stability that could prove to be extremely helpful in a windy environment.
Given the preliminary stage of design testing, the MAV is yet to have a working system to disengage itself from the anchoring system. Potential solutions to this problem include the use of electromagnets, switchable magnets, variable strength magnets or even a good old fashioned full throttle pull by the drone.
The anchoring system of a drone could also be adapted, depending on the surrounding environment of its use: magnetic anchors if inside a building, claws if in forest areas or adhesives if the nearby base surface is likely to be glass. What remains to be seen is whether it is possible to create an all-in-one anchoring system that could be adjusted so as to attach to other, non-magnetic surfaces.