April 18, 2014      

A team from the University of Sheffield has successfully tested a prototype 3D-printed unmanned aerial vehicle (UAV) as part of a project designed to enable cost-effective, rapid drone manufacturing.

Engineers at the Advanced Manufacturing Research Centre (AMRC) tested the 1.5m (4.9 feet)-wide prototype UAV as a radio-controlled glider.

?We tested the prototype as a radio-controlled glider in order to prove the aerodynamics and to get experience of trimming the balance point and control surfaces,? Garth Nicholson, project lead and senior design engineer at AMRC, tells Robotics Business Review.

The airframe was produced using a 3D printing technique known as fused deposition modeling (FDM) in which a material is built up in layers to print an object.

FDM enables rapid prototyping of complex designs and could potentially lower UAV manufacturing costs to the point where drones could be rapidly designed and deployed for single missions, or even disposed of after a single use.

First test flights

The cost of the raw materials used in printing the airframe components compares favorably with an equivalent airframe constructed by any conventional method, says Nicholson.

?If we combine the low raw material cost with the reduced manufacturing time and associated costs, we believe we could produce UAV airframes of this size quicker and cheaper than using conventional means,? says Nicholson, adding that the AMRC team tend not to use the term drone ?since it has military connotations for some people.?

No precision tooling for injection moulding or composite layup is required during FDM and no manual intervention is required once the machine is running. The process also ensures parts that are of consistent quality and can be easily modified without changing tooling or retraining operators, says Nicholson.

The team is currently manufacturing a propulsion system consisting of two electric ducted fans mounted in pods on the central spine of the UAV’s airframe. The pods will also be rapid manufactured by FDM.

The device’s blended wing body design should make it ?straightforward? to fit additional sensors and other systems such as GPS guidance within the airframe, says Nicholson, adding ?there?s plenty of room in there.?

The 3D-printed UAV being hand-launched on its first test flight.

Designing disposable UAVs wasn?t something the team initially set out to achieve, says Nicholson. ?It?s simply how the ?cheap and rapid manufacture? angle was interpreted by some commentators, and subsequently repeated by several websites. [?] We are now investigating ways in which these requirements could be achieved, since it is apparent that there is a lot of potential interest in this aspect of UAV design,? says Nicholson.

There are two scenarios in particular that could be suited to disposable UAVs: one-way flights and missions in contaminated environments.

?For a search or humanitarian mission you could effectively have double the range over a conventional UAV, which would have to return to its launch point, or land at a location from which it could be recovered,? says Nicholson.

Disposable UAVs could also be used to fly through clouds of hazardous particles on air-sampling missions, then either disposed of or decontaminated and recycled.

The team hopes to complete the prototype by the end of 2014. The project doesn’t have a fixed deadline, but the final goal is to design and build a 3 meter (9.8 feet) wingspan version, capable of autonomous operation with an extended flight envelope, says Nicholson.

?You could consider our current airframe as a small scale proof of concept [?] Whether the [3 meter] version will utilize a fully rapid-prototyped structure is not finalized yet, but it will definitely incorporate some novel design and manufacturing technology, so watch this space.?