the 10-kg drone suffered an uncontrolled crash “in a wooded area of Zurich’s university quarter only 50 yards away from a group of playing kindergarten children.”
One of the things that few people are aware about is quadrotor MTBF is very low relative to other common vehicles. For many drones, the expectation for failure dramatically increases just after 100-200 hours of operation. Figuring out points of failures, building systematic fault trees and increasing MTBF by order of magnitude or two would be big part of the drone delivery projects.
For commercial delivery service, it seems quite clear that we'll need either
1) "enterprise-grade" drones (like difference between consumer and enterprise SSD's),
2) reliable sensors to detect imminent failure before a flight,
and/or 3) easy replacement of failing parts.
I mean, for many hobbyists 100-200 hrs seems like a reasonable cost/benefit tradeoff... but not even close for commercial delivery services.
It doesn't really matter what fails, what matters is that there is no way to do a controlled descent once anything goes wrong on a loaded drone because there is no margin for error. A drone this heavy relies on the whole chain of components functioning perfectly.
I'm surprised it is as good as it is given the number of parts. If it were a winged drone you'd at least have a chance to glide it to a safe spot, but a drone that is kept up by spinning props can only crash uncontrolled. There was a video of downing one in a more controlled way but the only fault it could cover was single rotor failure and even then the amount of control was very limited.
These things have absolutely no business over areas occupied by people.
Not entirely true. The drone had a parachute system to allow a controlled descent in situations like this and an alarm to alert nearby people to its descent. The problem here was that the parachute's single tether was severed shortly after deployment.
The parachute would allow the drone to avoid a rapid descent. Most parachute systems are not steerable/flyable so they won't make it a controlled descent.
If it were a winged drone you'd at
least have a chance to glide it to
a safe spot, but a drone
Seemed to me the quadcopter response to communication failures was a much safer one. Is this still the case? It was quite some time ago.
Once you have a quadcopter you've got enough digital hardware and software that adding "return to base" is basically free since it's just an additional software routeine.
RC planes don't already have the required hardware/software to implement a return to base feature because they don't need it and of course nobody is going to greatly increase the cost and complexity of the product just to add that one feature.
That isn't really accurate at all.
Very few micro and mini quads have this functionality.
Return To Home functionality is common any medium and larger RC aircraft intended for FPV flying.
Often fixed wing RC with RTH functionality won't attempt to land, it return to home and enter a circular holding pattern until contact is re-established or the battery fails.
In comparison, a helicopter will have a clutch that can disengage the rotor from the engine and let it turn freely. The pilot still has the ability to control the rotor, so she has some control during the autorotation. At the end, just before landing/impact, she will perform a flare, using the rotational energy in the rotor to slow the helicopter's descent.
All of which are not present in a typical multirotor.
There are RC aircraft with collective pitch controls, like most RC helicopters and even some multirotors. These RC aircraft generally can autorotate, as well as do things that are probably not practical for full-scale aircraft to do, like fly upside down. :)
A collective pitch quadcopter flying upside down: https://youtu.be/MVL_Hf4ilLg?t=162
An RC helicopter doing, well, all sorts of acrobatics that hardly make sense: https://youtu.be/KmPchrGW1TQ?t=48
An RC helicopter autorotating: https://youtu.be/bxQ5kwqiPN4?t=136 (this one has an internal combustion engine, although that shouldn't make much of a difference for autorotation)
Just a guess: stronger strength to weight, and power to weight ratios, compared to the real thing. The tail rotor in particular appears to be quite a bit more powerful for the weight of the model than would be expected in a full size aircraft. And then also, these kinds of movements with a person inside? Haha! No!
Is it less mass and therefore momentum in the rotor/drivechain?
A real helicopter (or an auto-gyro) is best modeled as a rotating wing, as long as the blades rotate you can control the craft to greater or lesser extent. It still won't be pretty in a proper helicopter but at least you have a chance.
Very nice definition.
There isn't AFAIK such a neat distincion in English, in Italian the iron (the device you use for ironing, maybe flatiron?) has a specific name "ferro da stiro" so it is common to use it as a term of comparison for such a behaviour.
In my defence, a quick search shows this story:
So apparently it's not a stupid suggestion and Amazon are thinking along the same lines.
I only ask because it seems making drones land safely is hard. I mean, a paracute with a whistle is a great idea until it drifts in front of a car moving at high speed, or lands on a deaf person or shorts out a high-voltage cable. They all have problems. If there was a way to convert the failed drone into widely dispersed very small objects, the harm may be much lower.
It's because many drones, even "commercial" ones, are built using hobby parts with poor QC. If you use high end components then the reliability will be up by a two orders of magnitude, as will the price.
(Also as mentioned by others, multirotors and especially quadrotors have many single points of failure and so even with reliable parts the whole contraption isn't very reliable.)
In the case of failure of a prop in this configuration (the most common failure in my own experience with quads and octos), it is possible to program the n-copter to automatically change to flying in 7 prop mode or 6 prop mode or 5 prop mode, and so on and so forth as a redundancy feature. This could help with a not insignificant amount of crashes but obviously comes with increased costs.
My bet is on the power electronic semiconductors, mostly MOSFETs, in the motor controllers. Life time of these components decreases exponentially with the temperature difference they see in the semiconductor junction, i.e. the difference between hot (current is flowing, heating the junction with a power of I^2 * R_ds_on) and cold.
To make this deltaT_junction small, you need to choose big components, but at the same time you want to save weight, which is fundamentally at odds with overdimensioning everything.
I'd think the motor and rotor itself would be much more likely to be the problem.
Most hobbyist multirotors use smaller controllers (which are essentially a PWM'd set of mosfets) zip-tied or otherwise affixed to the arms of the machine, with short connections to the motors and to the controller/and power-supply distribution board on the body.
Consumer multi-rotor craft will generally have the ESCs integrated on a motherboard or daughterboard in the main body of the craft (cheaper to manufacture), well away from the prop wash and enclosed (not good for cooling).
I'm not sure what commercial (or large-scale) multi-rotor craft use, but it is probably similar to the others.
Again - I'm not saying it hasn't been done, or couldn't be done; in fact, it seems like a good idea. I can even envision how it could be integrated on the motor itself (board on the back with mosfets, with an extended shaft with fan for cooling the mosfets (inrunner motor), or with the fins of the mosfets in the wash of the prop, or something like that for an outrunner motor).
It wouldn't surprise me if such motors don't come on the market (or maybe they already exist - I haven't looked)...
Ok - well, apparently the idea isn't a new one:
...and it has been tried and sold to some success. So I imagine such motors are still available somewhere. TIL.
Obviously there are still other single points of failure such as the battery or controller, but at this point there's no excuse for crash landing a commercial drone just because a single motor (or rotor) has failed.
There is a reason why pro grade filming setups carrying $40,000 to $150,000 cameras are all coaxial octocopters or flat octocopters. Even a hexacopter cannot 100% reliably recover from a single motor failure.
Personal opinion, any craft that is over 3 to 4kg and spends time over people needs to be an octo.
Zipline is, imho, the real out of the box thinker. Catapault launch plus the snag line is Short takeoff, effectively-vertical landing, main downside is you need ground gear to land without damage. Main upside is weight savings for peak power (takeoff) is reduced, landing gear gone, and your engineering space is shrunk to solely the problem of steady state flight.
I foresee the paradigm of winged mothership for last-hundred-mile, plus n-rotor drones for air-to-land leg of delivery.
As you point out it provides a lot of advantages in not needing to carry the extra weight for a VTOL, no landing gear, extra energy boost on launch. It's very close to the optimal energy usage in watts for motor, per size of craft, that can be achieved right now.
The other advantage of using a single motor fixed wing craft is ability to use lithium ion batteries which are relatively higher Wh/kg density. These are not as capable of instantaneous high amps as lithium polymer are. The best commodity, commercially available lithium ion batteries are in the range of 210 to 248Wh/kg right now. The best lithium polymer batteries are about 178Wh/kg.
FPV hobbyist fliers who build fixed wing and flying-wing craft use lithium ion for longer range.
If you look at the pilot projets for drone delivery in Canberra, it's all VTOLs.
The instantaneous watts required for forward flight with wings at a reasonable speed are much lower than the watts required for the same weight of craft, same general dimensions, same speed, forward flight with four, six or eight rotors.
Furthermore, safety critical systems are all about layers. Yeah redundant motors are good, parachute is nice, but what about passive measures?
Maybe drones should have stub wings which, in addition to lift boost, have deadman switches which cause one to spring 180° on power loss, forcing the hull to autorotate in the event the chute fails.
Ok, the gps dies, the motors fail, chute fails to deploy, and the wing ripped off, you are dropping at full speed. Well now the rapid descent causes a pressure differential (artificial eustacian tube, if you will) which trips some azide charge, inflating an airbag.
It's like they are putting in bare minimum of effort with the quad+parachute.
Rapid descent sensors don't necessarily need to be pressure based at all. While in controlled flight there is a limitation (as governed by flight controller and ESCs) for how rapidly a quad, hex or octo can descend. Accelerometer data can be used to trigger a parachute and/or airbag system. A multiply-redundant array of small accelerometers that can detect freefall is very tiny and light weight.
Most higher end flight controllers have double or triple accelerometers onboard.
Four large motors and four 28" CF props produce less thrust than four arms, each arm with two motors stacked, and eight props.
Octos are not a conservative, redundant, fail tolerant design decision just for the sake of protecting expensive gear. Many of them still have 1+0 non redundant power systems.
Problem is that most of the components (batteries, motor controllers, flight controllers) are built by and for hobbyists. Motor burns a winding? ESC spontaneously lets the smoke out? Whatever, they're $15 bucks each. The field of "commercial grade cargo multirotor" is still in its infancy. The balance of safety and cost for the components hasn't been struck in the market. You either deal with random chinese components and control algorithms written by intrepid RC airplane nuts, buy very expensive industrial/aerospace grade components, or roll your own solution.
There are some quad copter controllers that try to deal with single motor failures, but they're mostly experimental (at least on the hobby end to the space) since they need to be able to reverse a motor, which most motor controllers used in these applications are not build to do.
Found a vid: https://m.youtube.com/watch?v=bsHryqnvyYA
Losing them, crashing them, having people steal them or throw them in a lake - those are things to include in your VC funded "operating costs" and to mitigate/offload the risks in your TOS...
(Small print: "The delivery customer shall be wholly and solely responsible for any damages and costs incurred by their delivery and any company equipment used in the completion of the customer's delivery, including but not limited to the drone crashing into a playground full of children." Just like Tesla's abrogation of responsibility when their "autopilot" software is driving the car they sold you...)
So while they gently introduce such rules (mostly centered around see and avoid for now, also identification), the main way they use to ensure safety is restrict where and who can fly them.
You know they can't be trusted, so you don't fly them above sensitive areas.
As processes mature, reliability increase and trust is gained, you will see drones expand the airspace in which they are allowed.
It's already happening for BVLOS (beyond visual line of sight) flights which requires a waiver from the FAA in the US (with paperwork such as risk assessment, collision tests on mannequins and so on), as well as specific equipment/processes.
Pretty much no one besides DJI has the scale for custom made, except on a few select components.
Drones are still in their infancy, those companies are still trying to see if they have a business model and improving/creating technologies.
You can't expect mature processes from this environment.
Fixed wing drones have the big problem that they need to go fast to stay in the air. Which requires a lot more motion planning.
My point is that multicopters are a lot simpler mechanically. No articulation, no transmission, just propellers on an electrical motor, controlled by pure electronics with no mechanical components in the loop except the drive coils.
Arguably multicopters are easier to control automatically (with modern electronics), though that wouldn't be THAT big a factor today, I guess.
Also electrical engines can deal a lot better with variable load and RPM. Multicopters with combustion engines (driving the rotors directly, not through a generator) seem to be quite uncommon.
Still, if multicopters are supposed to be routinely used in the presence of people, they need similar standards of maintenance and failure control as would bigger aircraft, be they manned or unmanned...
The limiting factor of a quad's ability to fly is the motor and unexpected failure of the battery. Higher end brushless motors have a life expectancy in the tens of thousands of hours. Battery failure is already mitigated in consumer drones by having independent packs each of which provides enough current to continue operation.
Quads do occasionally just fall out of the sky because a defective bearing ceases or a defective cell sags, but it's very rare. Most of the time they crash due to operator error.
On a quad there a 4 motor controllers on board, and only one needs to fail, greatly increasing the odds of overall failure.
None of this is even really relevant. GP quoted a figure from a paper that pulls the figure out of thin air and doesn't justify it in any way. The figure can be disregarded. I'm just pointing out that the figure seems much lower than mtbf of any of the critical components of a quad.
Anyway, I think there are a few things to point out here:
This program was in place to test the efficiency of sending biological samples between hospitals quickly.
I'm not entirely sure why this is a problem we need to solve. Is it really better to use drone delivery of blood samples to central hospitals than to add another testing machine at the remote location? Seems like the answer could be no.
It's really weird to get a letter in the mail telling you that a blood delivery drone crashed in a lake nearby.
This program seems like it's an answer in search of a problem.
I imagine shipping samples to a shared facility is significantly more cost effective, otherwise it wouldn't be being trialled.
Could it be a case of being cheaper to use drones instead of setting up an actual lab?
Besides crashes, another issue with autonomous vehicles traveling without passengers is going to be hijacking for payload and parts. Maybe not in Switzerland, but in the US there are already people stealing packages right on other people's properties, now they can do the same in the middle of nowhere, plus grab a large drone in the process and resell parts. Capture, cut power, disassemble, deactivate the GPS if it has its own power source, done.
Something tells me that a German newspaper wouldn't be using yards. Sure enough, looking at the source, it's a mistake in Google's translation model
> Dass die mehr als 10 Kilogramm schwere Drohne vom Typ Matternet M2V9 in einem Waldstück des Zürcher Universitätsviertels nur rund 50 Meter entfernt von einer Gruppe spielender Kindergartenkinder zu Boden krachte, erwähnte der staatliche Logistikkonzern indes nicht.
Bing translate gets it right though.
Probably I would have translated it as "less than 60 yards" ;-).
Planes ARE the safest way to travel: maybe drones are the safest in certain conditions, like for these urgent hospital deliveries in Switzerland, or in dangerous/isolated settings. And maybe drones will become safer and safer, like with parachutes in the article.
Okay the parachutes will need Dyneema strings instead of simple ones, just like parachutes were used before Dyneema was invented. Oh wait, someone's working on Dyneema parachutes for drones: https://www.textilemedia.com/latest-news/mobiletex/drone-par...
As you can see, there's no reason to throw the baby out with the bathwater. Find how you can save lives and make the world better, not how to use emotions to exert power and kill Freedom. The world needs innovation more than ever, be it electronic cigarettes or self driving cars or drones.
Western airliners are very safe, but the USA averages one GA accident per day:
Helicopters have much worse failure modes, even in multi-million dollar aircraft. Small drones are the worst of all, and should not be flown over populated areas.
The FAA historically has regulated that aircraft fly 500' and above over non sparsely-populated areas for a reason. Or you lose your license.
Drone deliveries fundamentally violate that, as regardless of where your warehouse is located, you're deliberately flying towards a populated area (ie. customers.)
The above is why the FAA has justly been slow on allowing drones into the airspace, and why you have to register them.
A constructive comment I can add is that I can only see delivery drones being safe with a built-in fixed wing that allows it to glide to the ground power-off below 10 mph.
Source: commercially-rated airplane pilot.
As for the risk of a plane over a populated area, I think it's safe to say that a 4kg drone is a much lesser threat than a Cessna weighing 200 times more, and that's a very small plane. So it's really not fair to compare a drone crash and a plane crash (we're not talking military drones here, I hope you've read the article).
"...I can only see delivery drones being safe with a built-in fixed wing that allows it to glide to the ground power-off below 10 mph": and it seems many people disagree but feel free to prove them wrong and show the world how you can glide a drone to the ground in a dense city to deliver blood at a hospital.
Now here's a thought experiment: Let's say humans have a choice of only two models of cars: A and B. Car A fails less often, kills fewer people overall but none of the failures are due to human mistake. It just speeds up randomly and uncontrollably sometimes and kills whoever is on the way. Engineers have raised their hand that this cannot be fixed for a few years. On the other hand, car B fails only when a human makes a mistake even though its statistically 10X more overall failures per year. Which car society would approve?
In 2017, UPS had 5 fatalities per 14 billion miles driven, or 3.6 fatalities per 10 billion miles. Given that a UPS truck has tens or hundreds of packages the fatalities per package-mile is much lower.
Using UPS would be far safer than using delivery drones, even delivery drones reach the reliability and safety levels of commercial airliners.
Fly them preferentially over roads/railwaylines/rivers/canals/buildings instead of sidewalks/schools/parks.
Require them to be insured for personal and property damage (in much the same way as cars are in many places), have the companies operating them be subject to the same sort of existential threat as Boeing is under right now if they fuck up.
I don't think this should be an industry lead by "move fast and break things" style engineering, but I suspect if could usefully exist with a lower regulatory standard/cost than commercial airlines...
Doesn't this mean that neither Matternet nor the Swiss Post tested the failure modes of this drone enough?
If it never happened before, they didn't test it enough to get any estimate for a MTBF for this particular part.
But this is to be expected from the Swiss Post, they do sloppy work and blame others, just read their dementi:
>As such, we have asked Matternet to implement various urgent measures:
>[...]The shrill whistle, which alerts people near the drone when it is making an emergency landing, will be made louder.
The whistle couldn't be heard in that accident...
Sound like somebody didn't test a single emergency landing in that forest and asked the numerous strollers whether they have heard anything
Is 1500 trips a low / mid / high figure with regards to collisions?
Not to mention I can virtually eliminate any possibility of dying in a traffic accident by remaining in my backyard, where I might still be struck in the head by a delivery drone. What risky behaviours am I meant to avoid there, being outside? You should instead compare the risk somebody following reasonable safety precautions would have in each scenario.
The entire USPS fleet travels ~1.28B miles / year, with the LLVs traveling 764M miles.
The LLVs travel about 18 miles per day, 300 days per year, which gives you an estimated 43 million LLV trips per year.
Assuming all 30,000 motor vehicle accidents are LLVs, that amounts to 1 accident every 1433 LLV trips.
Of course, on each LLV "trip", it delivers letters and parcels to hundreds of addresses; each drone delivery is presumably one.
(The USPS also averages 1 accident every ~43,000 miles; this is significantly above the US average of 1 accident per 165,000 miles driven. I would assume the increased rate is (1) USPS vehicles drive slow and stop frequently along their routes; I would guess many accidents are other vehicles driving too fast and trying to pass in unsafe areas (2) distracted driving; drivers are performing other tasks eg retrieving the next addresses mail while driving and (3) every USPS accident is likely reported; drivers are responsible for the condition of their vehicle and small fender-benders that we might not report are likely included in USPS statistics.)
So an accident once per 1443 llv trips * ~400(average packages per llv trip) -> an accident per ~600k packages -> will need an accident per 600k drone trips * ~ 10mile/trip -> an accident per 6M drone miles.
It's really odd sometimes how duplicate, late posts get more comments and upvotes than the original. Perhaps the time of posting is too important.
You can find everything in the report (in German) https://www.sust.admin.ch/inhalte/AV-berichte/ZB_SUI-9903.pd...
Just enter the coordinates of the crash in Google map, you can see there's no school around.
How many deaths per 1,000,000,000 package delivery happen with trucks? Truck deliver is not a zero death thing. I'd even want to see truck air pollution factored in somehow.
If drones have a lower %, we should view falling death boxes as acceptable. Even though it does have a strangely dystonia aspect to it.
But something like sky divers getting killed does not bother me because I can avoid it, by not sky diving. Just like I can choose not to drive and so avoid almost any chance of being killed by another driver. It is the randomness and the fact you cannot avoid it that, I think, makes to less acceptable.
That's news to me.
I was thinking trucks get into accidents with public transportation, as well as run over pedestrians and bicyclists.
The fact that it doesn't appear random doesn't mean it isn't.
Getting killed by medical malpractice is also random, yet we don't really fret over our extremely error prone medical system. We don't even argue for removing doctors working 24 hour shifts, while we wouldn't allow a street sweeper to do the same.
Yes, if drone delivery is safer we should switch. (Though there are better mortality measures than frequency of fatality.)
We’re not close now. In aerospace, frame is fate. Quadcopters are optimised for maneuverability and cost, not safety or reliability. They have no inherent redundancy and limited margins of safety. The reason they were chosen for this application is they’re cheaper to MVP, given the standing supply chain.
Compare that to the number of things that must go wrong for a truck to seriously injure someone. (Here: speed failure, braking failure, airbag failure, et cetera.)
If you want to appeal to the general public you'll need to stop treating people like perfectly rational mathematical calculators and start treating them like people who are embedded in a cultural context where car accidents are accepted as part of life and drone accidents are not. Statistical arguments are not convincing.
Is this not the definition of pandering?
I'm not saying you are wrong, I just want to be clear what you are saying: less logic, more pandering.
Things Tyson pointed out (Medical errors, flu, suicide, car accidents, homicides) are preventable too, but he's making an unfair comparison.
We're already doing a lot to prevent deaths from the reasons he stated (better training, vaccination, suicide hotlines and more available mental healthcare, safer cars and better driver training, [many things]), but we're not doing nearly enough to prevent deaths that are caused by pure hatred towards those that are unlike them. Deaths from those reasons aren't going up by any significant amount while deaths by hate crimes are, which is one of the big reasons why people are taking problem with this, they want to prevent deaths of many innocent people before they happen.
I mean specifically: # of hate crime deaths per 100,000.
I wonder what the score is for postal vehicles (similarly for crashes with other vehicles and the like)
This particular drone crashed near a school -- if it had hit a child, there would be demands to ban drone deliveries, and you just know that politicians never miss an opportunity to grandstand about public safety, particularly when children are involved.
It's better to back off for now, improve the drones, and try again later, because one or two bad accidents could end the entire project. We are more likely to end up with drone deliveries when the drone companies are sensitive to managing the public reaction.
I think the answer is a resounding no, we would not even consider allowing playgrounds today. And that's quite pitiful.
Taleb wrote an interesting article on how the most intolerant within a society eventually come to determine its fate, nearly regardless of their size.  It may be only a few percent of society that would not allow playgrounds, but so long as these people complain loud enough - they will win. Because their aversion to any sort of risk whatsoever is unlikely to be countered by a group that happen to be equally fervent 'playground enthusiast.' And so the path of least resistance is to simply ban playgrounds. Hahah, hopefully this post doesn't give somebody the idea to go start an attention seeking social media campaign to ban playgrounds. It might very well succeed!
 - https://www.cdc.gov/HomeandRecreationalSafety/Playground-Inj...
 - https://medium.com/incerto/the-most-intolerant-wins-the-dict...
It is actually very bad. Amazon ships ~2M packages per day by one estimates. Assume only 10% of these gets drone delivered. This would translate to 66 crashes each day. If only 10% of these crashes happen on people, it would be 6 people randomly getting killed each day.
I'm guessing its != 0
You can do a thought experiment: Let's say airplanes failed at 100X of current rates but it was relatively still less number of deaths if people drove that distance by themselves. Would you be able to argue airplane failure rate was still acceptable? For drones, I bet there would be an immediate movement for banning the whole thing if there was a single drone ever fell on playing kindergartners randomly. This is one situation where just bringing data and making rational arguments don't work.
Let's punish drones then...
For me? Absolutely. For most of the people I spend time with? Yes. For the majority of the population? No.
This is why bringing numbers and logic to the arena is so important.
Otherwise, we spend billions avoiding 10 deaths while we could avoid other deaths for mere thousands. Much like coal and nuclear. The level of lunacy is hard to deal with for me.
> Delivery truck crashing into car is a human mistake.
Actually, all drone mistakes are human mistakes. Even if the drone was put together by machine, it was a human process that created it.