Unmanned Systems Technology 021 | Robot Aviation FX450 l Imaging Sensors focus l UAVs Insight l Liquid-Piston X-Mini l Riptide l Eurosatory 2018 show report l Zipline l Electric Motors focus l ASTS show report

78 In operation | Zipline Package order A new mission begins with a message from a doctor by SMS, WhatsApp, phone call or e-mail (depending on the hospital) that lays out the details of the order. For example, if a mother has begun haemorrhaging in childbirth, she may bleed to the point that she uses up the finite number of units of her blood type the hospital has in storage. In that event, the order will lay out details of the patient’s blood type, platelets, location and the order quantity needed to prevent endangering the mother’s life. The order is received by a lab technician at the Zipline distribution centre (which consists of secure medical laboratories and stores, UAVs and associated components, and hangar and workshop facilities) who will retrieve the units of the desired blood type from the in-house refrigerated facility. This consists of a sterile room containing refrigerators with multiple rows of blood packets. These maintained stocks are received from the National Blood Center in Kigali (about 55 km north-east-east by road from the city of Muhanga, where the distribution centre is located). A high-speed UAV is a key requirement of Zipline’s delivery model, which operates on a ‘just in time’ basis to minimise the period of time in which blood products are removed from cold storage. The blood products are then padded and sealed in a parachute-equipped box and stamped with a QR code that contains the mission, destination and flight path details. One of the Zip fuselages is retrieved from the hangar, the box is loaded and shut inside the payload bay, and the UAV is fitted onto a launch catapult. Pre-flight checks Two launch catapults can be found under the large, tent-like structure that forms a typical Zipline hangar, giving the flight team the ability to quickly change the launch trajectory depending on wind direction. Although the team’s catapults were originally kept out in the open, the need to launch with some protection against weather conditions has since prompted the use of tented hangars. In addition to the launchers, UAVs and associated parts, there is a recovery system and a company control tower. As Rinaudo explains, “This is where we maintain contact with military and civil aviation authorities during every flight. You’ll also find a flight ops team and logistics teams.” After the Zip is installed into a launch catapult, a dorsal opening on the fuselage allows examination of the craft’s cabling and connectors atop the motherboard. This opening is then covered over following the mounting of a 10 m wing section that snap-fits into place as the upper housing of the hull. A battery pack is installed in front of the wings using two clip fasteners – one either side of the battery bay. The fuselage, wings and power systems will not be cleared for launch without having passed Zipline’s flight systems checks, however. The company’s developments in the area of pre-flight safety and maintenance checks are cited as one of the key factors contributing to the recent reduction in operation turnaround times. These changes are largely the result of trial and error, Rinaudo says, and from working within the context of the medical industry that Zipline services. “We’ve therefore sought to automate as many of our own checklists as possible, develop technologies to take on pre-flight tasks from human workers, and build in triggers and safeties so that the UAV cannot launch unless a step-by-step series of processes has been carried out first.” Before the flight and power hardware can be installed, the flight operations team uses a smartphone loaded with pre-flight scanning software developed in-house to scan the QR code on the box containing the medical supplies. Using the phone’s wi-fi connection to the UAV, this tells the Zip its destination, mission and flight path. Following this, the software is used to scan QR codes on the Zip’s control surfaces. Each scan sends a wi-fi command signal for the flight computer to run tests on each surface to ensure they are receiving and responding to control inputs from the autopilot (similar to conventional methods, but without needing to connect or disconnect a cable from a laptop). The scans collectively take up to 30 s to perform. The software will also indicate if there is any degradation in a flight control surface (by detecting the range of movement through the sensors in the UAV). “The degree of accuracy about this step is crucial,” Rinaudo says. “If you were just checking by observing an aileron’s movement, you might be August/September 2018 | Unmanned Systems Technology In the distribution centre’s hangar, 30 sets of fuselages, battery packs, wings and two catapult launchers are kept at the ready