If a drone is large and powerful enough to carry packages long distances, then that drone is likely too big and noisy to be landing in amongst trees, houses and bystanders. The BMT Sparrow system could help, by autonomously steering lowered loads.
Initially announced in 2022 with military use in mind, Sparrow was created by British maritime engineering firm BMT. A refined version of the technology has now been granted a patent by the UK Intellectual Property Office.
First of all, there are already systems in which a drone-integrated winch lowers packages to the ground on a cable. While these setups allow the drone to stay high up and out of the way, the aircraft has to subtly maneuver back and forth in order to guide the load to its target. This can be particularly difficult if crosswinds are blowing the package all over the place.
BMT Sparrow addresses this shortcoming by moving the winch (and its cable reel) into a module which is snugged up against the underside of the drone while it's in transit. Once the aircraft reaches its destination, the module lowers itself down by reeling out its cable, the top end of which is attached to the drone's undercarriage.
Utilizing onboard cameras, IMUs (inertial measurement units) and other sensors, the module is able to gauge its position relative to its target – that target could be the front steps of a home, a small landing pad at an army base, or pretty much anything else. If winds start blowing the module off-course, it compensates by activating one or more of its four side-mounted electric pusher propellers.
That said, those pusher props themselves could pose a danger to bystanders, or be damaged by hitting branches or whatnot. For that reason, the actual parcel is contained in a separate box which is suspended below the main Sparrow module by another shorter cable.
Zipline's recently announced Platform 2 drone delivery service is in fact somewhat similar, although it keeps the winch in the drone, and the lowered module just has a single propeller.
Along with its described usage, BMT Sparrow could conceivably also be utilized in scenarios wherein two modules (connected to one drone) simultaneously deliver packages to two nearby locations, or even in which a module makes its way down from a circling fixed-wing drone.
The BMT company is now seeking industry partners to help with commercialization of the technology.
Source: BMT
