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DRONES: AFRICAN BLOODLINE


Inch - epaper ⋅ Ausgabe 2/2019 vom 06.06.2019

While the western world is endlessly discussing and testing drone delivery services, in Rwanda, Ziplines drones are already delivering emergency blood packs on a routine basis, thereby reducing the response time to minutes rather than hours.


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Während bei uns der Einsatz von Lieferdrohnen noch diskutiert und getestet wird, liefern in Ruanda die Drohnen von Zipline Blutkonserven bereits routinemäßig aus und reduzieren die Lieferzeiten damit von Stunden auf Minuten.


< ALL PHOTOS: ZIPLINE >

Rwanda is known as the land of a thousandhills , and our car seems to go over every one of them as we drive from the ...

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Rwanda is known as the land of a thousandhills , and our car seems to go over every one of them as we drive from the small town of Muhanga to the even smaller town of Kinazi. The 50-kilometer trip into western Rwanda will take us well over an hour. We’re on our way to rendezvous with a blood-carrying drone that will make the trip in under 14 minutes.

The drone is operated by Zipline, a California-based company focused on delivering medical supplies in areas with poor infrastructure. And not long after we arrive at Kinazi’s hospital, thefixed-wing drone materializes out of the blue. In ablink -and-you’ll-miss-it moment, the dronedescends , opens a set of doors in itsbelly , and drops a small package thatparachutes to the ground. The drone immediately begins toclimb andvanishes over the hills as astaff member crosses the hospitalparking lot to pick up the package – a shipment of blood ordered by WhatsApp less than half an hour earlier.

We then climb back into our car to start ourbone-jarring return drive to Muhanga, one of Zipline’slaunch sites , winding our way over dirt roads. By the time we make it back, the drone is flying smoothly toward another hospital elsewhere in Rwanda, with a fresh package of blood in its belly.

DELIVERING PARCELS, PIZZA … AND BLOOD

Delivery by drone is a futuristic idea that hascaught the public’simagination , and there are plenty ofattempts to turn it into a commercial reality. Amazon, Google, and Domino’s Pizza have allpulled off carefully controlled demonstrations and pilot projects, deliveringitems such assunscreen , burritos, and (of course) pizza tobackyards and fields. But the world is waiting to see whether any company can find a business model that makes drone delivery asustainable and profitableendeavour .

The answer may be here in Rwanda, where Zipline is delivering blood to 25 hospitals and clinics across the country every day. Zipline isbetting that transporting lifesaving medical supplies, which are often lightweight and urgently needed, will be the killer app for delivery drones. (…)

For hospitals in need of critical medical supplies, Rwanda’s roads pose a real problem. Hospital administrators worry most about blood and blood products, which have a shortshelf life and strict storagerequirements . It’s also difficult topredict how many packs of each blood type will be needed at a given facility, and when. In an emergency, it can take up to 5 hours for a Rwandan hospital to receive a blood delivery via road, which could easily mean death for a patientin need .

Threeentrepreneurs – William Hetzler, Keller Rinaudo, and Keenan Wyrobeck –founded Zipline in 2014 with thegoal of solving such problems through on-demand deliveries by drone. Rwanda was the ideal test bed, with itschallenging terrain, relatively small size (about the same area as the U.S. state of Maryland), extensive wireless connectivity, andreceptive government . (…)

Zipline has twofulfilment centers in Rwanda, which itrefers to as “nests.” The Muhanga nest, which we visited, is about 50 km from the capital of Kigali, and a two-hour drive, thanks tolumbering trucks thatclog the main roads. Its small cluster of buildingsabuts amaize field, and the locals who work the fieldgrudgingly move out of the way whenever a drone passes low overhead.

Several times a week, blood and blood products arrive here by truck. When one shipment arrives during our visit, Israel Bimpe, Zipline’shead of nationalimplementation , turns to us with a smile, saying: “The blood is here!” Workers spring into action, transferring the packs of whole blood, plasma, andplatelets intorefrigerators . When an order comes in from a hospital via phone, website, WhatsApp, or SMS, a workerwraps the needed packs inpadding andstuffs the bundle into a bright red box, which has a wax-paperparachute attached.

A READY-MADE DRONE KIT

A technician places the box and parachute in the belly of a drone behind aspring-loaded hatch , then snaps a modular battery pack into the drone’s nose. Two people carry the drone to a 13-meter-long electric catapult powered by abank ofsupercapacitors , then run through apre-flight checklist with theaid of a smartphone app. Zipline confirms the drone’s flight plan with the RwandaCivil Aviation Authority andrequests flight clearance , while the company’s technicians do their best to convince enthusiastic local kids to move a safe distance away from thelaunch . Finally, with asatisfying zzzing, the catapultflings the drone skyward,accelerating it to 100 kilometres per hour in half a second. Itswiftly rises over the Rwandan countryside to acruising altitude of 120 meters. It’s a dramatic moment – and at Muhanga it happens 20 to 30 times a day.

While others experiment with pizzas and parcels Zipline transports life-saving blood packs.


As soon as a drone – which the company calls a Zip – leaves the catapult, it’s fully autonomous. While both Zipline and the Rwanda Civil Aviation Authoritytrack theaircraft and can redirect it at any time, in practice the Zips are mostly forgotten about until they return home, mission completed. In the air, each Zip follows apredetermined flight plan,relaying data on its position and status through Rwanda’s wireless network.

Our visit to the Kinazi hospital, one of the closer delivery sites, shows us the other end of a Zip’s journey. About 5 minutes before the drone arrives, hospital staff members get an automatic textalert telling them to send someone outside to await the delivery. At Kinazi, that means waiting at the edge of a small grassy fieldadjacent to the hospital’s parking lot. During our visit, the staff member arrives only after the drone hasdropped its package, which just goes to show that blood delivery by drone isn’tthe least bit exciting in Rwanda anymore.

Zips can carry relatively largepayloads long distances because they’re fixed-wing aircraft, which are significantly more aerodynamically efficient thanrotorcraft (such as today’s common quadcopters). Launching a fixed-wing drone from a catapult is easy, but landing it safely – withoutlanding gear or a lengthy runway – is achallenge . Zipline’ssolution is arecovery system that the teamaffectionately refers to as Tall Bob. Its two 10-meter-high towers each have a vertically mounted rotating arm, and a cable isstrung between the arms. As a returning Zip flies between these two towers, the arms rotate upward, in a fraction of a second, tosnag the cable on a tiny metalhook below the Zip’stail . The drone is pulled to a stop within a few meters, then the arms allow the drone to swing down and back between the towers. In principle, it’s similar to the way planes land onaircraft carriers .

To reset the system, workers simply lift the Zip off the wire atground level , and then rotate the arms back up to prepare for the next capture. The Zipline team has grownaccustomed to theremarkable precision of its drone-capturing system, but during our visit we never get tired of seeing the wirepluck Zips out of the sky.

COME RAIN OR SHINE OR WIND

While Zips can’tlaunch whencrosswinds are too intense, they can handle both high winds and rain once they’reairborne , so weather-relateddelays at the launch site tend to bebrief . But the system isn’tflawless : Zips will turn around if stronghead winds drain too much of their battery power, anddespite dual motors and redundantailerons for flight control, mechanicalfailures do sometimes happen. If the Zip can’t make it back to the nest, it can autonomouslydeploy a parachute to bring itselfgently to the ground. Ziplineestimates that the emergency parachute deploys in around one in a thousand flights.

With dozens of orders coming in every day, Zipline needs to be sure that it always has drones ready to fly. So its engineers designed the Zips to be as modular as possible, allowing technicians to easilydetach different pieces for repairs. While such repairs are common, particularly on thestrain-bearing wings, there are always more than enough components to snap together into a fullyassembled drone. A bank ofchargers ensures that acharged battery pack is always ready to beslotted into a drone beingprepped for launch.

When a blood pack is ordered by a hospital via SMS or WhatsApp,


within ten minutes it is packed in an insulated box


The Zipline facility in Muhanga takes,on average , 10 minutes to launch an order. But Zipline’s engineers think that’s 9 minutes too long. Bimpe says thatincremental changes to the process will eventually enable them to fulfil an order in less than 60 seconds. “We just need toimprove it a bit more,” he says. “It’stweaking operational procedures and improving software to reduce that time to one minute. We receive an order and as soon as we finish packing, we just put it on the Zip and it’s ready to go.” (…)

The fixed-wing drone is then launched from a catapult


which itself is stowed in a freshly assembled drone


and autonomously flies to the hospital,


where it drops the box with a parachute


Despite the intense focus on keeping the drone’s weight down, today’s Zips can carry a payload of only 1.3 kilograms. “Right now, with this generation, we can deliver twounits of blood,” with some capacity tospare , says Eric Watson, a systems engineer at Zipline. The remodeled Zip that the company is currently working on will have a lighter chassis, a more efficient battery, and a payload of 1.75 kg,enabling a single drone to carry up to three units of blood at a time. It will also have areceiver fortransponder signals from other aircraft, a backup communication system that uses a satellite link, and on-board sense-and-avoid equipment that will, Watson says, “be able todetect and avoid uncooperative aircraft in our airspace.” Thisadvanced feature will likely become a safety-critical system for delivery drones as the skies get morecrowded .

A QUESTION OFECONOMICS

While the technology involved in drone delivery is impressive, the economics are more uncertain. Experts say Zipline’s high-tech solution for blood delivery is a newtwist on an old story. “Go to any hospital in Africa and you’ll find agraveyard of machines,” says Jonathan Ledgard, who was the Afrotech director at the École Polytechnique Fédérale de Lausanne in Switzerland until 2016. “The whole history of Africa is medical equipment that was too expensive.”

Ledgardnotes that Zipline currently receivessubsidies from the Rwandan government to make its serviceaffordable for hospitals. Hesuggests the company may be in trouble if those subsidies end. “The price points they have tocharge once the subsidies end are far, far, far too high fordeveloping countries ,” Ledgard says.

Zipline isreluctant todisclose how much its Rwandan fulfillment centers cost to operate or how much it gets paid by the Rwandan government per delivery. The company hasadmitted that routine blood deliveries by drone arecurrently more expensive than routine deliveries by ground vehicle, which move more blood per load. But Ziplineargues that the economics change in emergencies. (…)

Similar to an aircraft carrier, returning drones are snatched out of mid-air with a wire. The system even works in heavy rains.


As of press time, Zipline’s drones have flown a total of over one million kilometres. As Ziplinescales up its operations, it will likelyclock its next million kilometres in under six months. In addition to its expansion into Ghana, Zipline is also part of a pilot program run by the U.S.Federal Aviation Administration , which will test medical deliveries inrural areas of North Carolina later this year.

The Rwandan government recentlyawarded Zipline a new, three-yearcontract , which includesprovisions for delivering other medical products beside blood, such as medicine andvaccines . That service expansion means that Zips will soon be making drops to many small clinics, not only to hospitals. Zipline is also planning to assemble its drones in Rwanda rather than importing them from the United States. Clearly, Zipline is in Rwanda to stay.

It’s getting dark at Zipline’s Muhanga nest as we pack our bags and get ready for the long,winding drive back to Kigali. Red landing lights turn on along theapproach path that the Zips follow – the drones don’t need the lights, but they look cool. In the distance, we can hear thefaint buzz of another Zip returning home after making its delivery of blood. Anywhere else on Earth, it would be futuristic. In rural Rwanda, it’s just routine.<<< Evan Ackerman and Michael Koziol >>>

Dieser Beitrag ist ein Auszug aus einem Artikel, der ursprünglich in IEEE Spectrum, Mai 2019, erschienen ist. Die Veröffentlichung erfolgt mit freundlicher Genehmigung der IEEE. Der vollständige Artikel findet sich unterhttps://spectrum.ieee.org/robotics/drones/in-the-air-with-ziplines-medical-delivery-drones

https://flyzipline.com

Webseite des Drohnenlieferservice Zipline mit Informationen zur Technologie.

http://ruralreporters.com/drones-to-the-rescue-ziplines-blood-deliveries-save-lives-in-rwanda

Ausführlicher Artikel über Zipline aus lokaler Sicht.

Links, Vokabeln & mehr unter
www.inchbyinch.de/inch21/zipline


HOW ELECTROMAGNETIC CATAPULTS WORK

Electromagnetic catapults are based on linear induction motors. A linear induction motor is similar in construction to acircular motor that has been opened out flat. The magnetic field nowsweeps across the flat motorface instead of rotating. The stator is laid out in the form of atrack andconsists of a multi-phasewinding in a laminated ironcore . Whenenergized from anAC supply a travelling wave magnetic field is produced.

The reaction plate orsledge is the equivalent of the rotor, which can be a simpleconductive sheet of aluminium, copper or steel.Currents induced in the reaction plate by the stator travelling field create a secondary magnetic field. It is the reaction between these two fields which produces the linearthrust .

Compared to their mechanical or steamcounterparts , electromagnetic catapults allow for asmooth acceleration which can be controlled and adjusted to reach therequired endvelocity .

PICTORIAL PNEUMATICS