Unmanned Systems Technology 027 l Hummingbird XRP l Gimbals l UAVs insight l AUVSI report part 2 l O’Neill Power Systems NorEaster l Kratos Defense ATMA l Performance Monitoring l Kongsberg Maritime Sounder

34 Dossier | Hummingbird XRP Autopilot training Bishop’s first choice of autopilot was the triply redundant DJI 3 Pro, but security worries about foreign content in a product aimed at the US government and other sensitive customers – particularly concerning the software and updates to it – led the company to work with an undisclosed US supplier on an alternative. This new autopilot is now being developed and will ship with the first customer aircraft. During development, it was important to establish what a good centre of gravity would be so that the autopilot would not have to perform what Bishop calls “extraordinary calculations” to work out whether the UAV is level. In doing this, he also had to take into account the effects of fuel burn and payload deployment. “If I have 50 lb of payload stashed in discrete packages around the periphery of the aircraft, and I am deploying them one at a time – perhaps two of them on one side at 10 lb each – what effect does that have on the horizontal stability of the aircraft via the autopilot?” he says. The autopilot software includes code that runs the payload management system and advises the operator on load distribution during mission planning through the ground station’s GUI. If a combination of payloads has to be delivered to different destinations in a particular order, the software will warn the pilot if the combination of payload positions, weights and sequencing will cause a balance problem and show how to distribute the loads to correct it. To carry a single payload of 30 lb or more, the operator must use a sling to put it under the aircraft’s centre of gravity. The sling system includes a harness that attaches to four hard points on the main girdle. The lines from these points meet 4 ft below the main duct in a coupling to which a 15 or 20 ft strop that carries the payload is attached. A release mechanism can be installed either between the harness and the strop line or between the line and the payload, according to the needs of the mission. If the vehicle returns to base with the strop line, it lands sideways to keep it out of the way of the rotors. The Hummingbird XRP is described as an open platform that can support a wide variety of payloads. For example, its four main hard points can each support two payloads, so it could deliver eight packages to eight separate locations. It could land to deploy them or release them on parachutes, for example, or carry several different sensors or a combination of sensors and packages, Bishop says. Tunnel detection and mosquito control Each hard point is provided with a data and power connection, and up to 300 W of ancillary power is available for payloads. One of these is a ground- penetrating radar that an undisclosed government agency wanted to put on a UAV to detect tunnels, mines, IEDs and other buried threats in conflict zones. Initially, the agency in question simply told Bishop it wanted to carry 40 lb of payload for six hours – 10 lb more than the vehicle could carry for that duration. On further enquiry though, it emerged that the radar only drew a maximum of 200 W at 24 V, and that a significant proportion of its total weight was taken up by batteries, without which it would weigh only 24 lb, and that the Hummingbird’s onboard power was more than adequate. That sealed the deal, and Reference Technologies is now working with the agency, Bishop says. With agricultural and related markets in mind, Bishop has also designed and built a spray bar system to dispense chemicals from nozzles at the end of four of the eight arms so that they discharge into the flow from the rotors. The chemical payload is pumped to the nozzles from bottles attached to the hard points. That, he says, makes for a very efficient fogger. Reference Technologies is now building the first few production vehicles for customers and is hoping for many more with a myriad missions in mind. “The Ford Motor Company doesn’t care what you are using your F-150 for; it’s a utility, a tool, a platform, much like the Hummingbird XRP,” Bishop says. August/September 2019 | Unmanned Systems Technology The Hummingbird can be managed from a portable multi-screen GCS in the form of a rugged trifold computer from CP Technologies, although smaller and lighter handheld units are also offered as options (Courtesy of CP Technologies)