How an EMC problem can kill people and a company - Page 1
Forum section: electronics / general

author: nctnico
author_rank: Super Contributor
timestamp: October 01, 2018, 07:36:36 pm
content: Earlier this month an electric cargo bike got hit by a train killing 4 small children:https://nltimes.nl/2018/09/24/fatal-train-accident-prompts-cargo-bike-maker-inspect-3500-unitsOr better put: the electric cargo bike kept moving (appearantly the brakes didn't work at all) and it ran through the fence of the railway crossing onto the railway where it got hit by a train.Based on other news articles it seems this isn't an incident by itself and other users also complained about weird behaviour near railway crossings. IMHO this clearly points towards EMC problems (probably together with some other bad design choices) and it shows how aware designers need to be about EMC problems and how to mitigate them. The company who produces these cargo bikes is likely to go under especially since the Dutch government has revoked the road safety declaration making it illegal to use the particular cargo bikes.Let it be a warning not to take weird behaviour of an electric/electronic product lightly.

author: coppercone2
author_rank: Super Contributor
timestamp: October 01, 2018, 08:49:34 pm
content: it's kind of like ignoring that weird eye twitch people seem to develop after being sprayed with zombie blood.'it's fine the LCD does that some times'you sure?'yea we have been selling this for years'we need some ww2 era propaganda/infographics signs for the mechanical engineering department that makes everyone's life difficult. 'cable routes WHERE?!?!?!'

author: CM800
author_rank: Frequent Contributor
timestamp: October 01, 2018, 09:23:50 pm
content: "This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation."I wonder if the train system is at fault also then? Surely it should not be causing harmful interference.

author: Ampera
author_rank: Super Contributor
timestamp: October 01, 2018, 09:54:53 pm
content: I think the better question is who is making a road legal vehicle without some form of direct connection manual break, even a separate one for emergencies?So you're telling me, these electronically controller breaks decided to just stop working in what should be a closed, shielded system, because of EMI from a railroad crossing.RIP those 4 kids, that's some bullshit.

author: glarsson
author_rank: Frequent Contributor
timestamp: October 01, 2018, 09:55:04 pm
content: I don't think FCC rules are used on train systems in the Netherlands.Whst kind of bicycle brakes can be disabled by some weak electronic signal?

author: rsjsouza
author_rank: Super Contributor
timestamp: October 01, 2018, 10:24:23 pm
content: Quote from: glarsson on October 01, 2018, 09:55:04 pmQuite interesting question; I wonder if such brake systems go through the same scrutiny as automotive systems with their dual Cortex R5s in lockstep or other similar crazy paraphernalia.The EMC standard for EU is usually Directive 2014/30/EU, but it can share some similarities with FCC (probably not Class B for automotive systems).http://ec.europa.eu/growth/sectors/electrical-engineering/emc-directive_en

author: langwadt
author_rank: Super Contributor
timestamp: October 02, 2018, 12:32:32 am
content: Quote from: glarsson on October 01, 2018, 09:55:04 pmit is likely that the brakes worked but it might seem like they didn't if the engine kept pushing when it wasn't expected,like the Toyotas with "stuck" trottle problem. The rules for electric bike says the motor can only help when you turn the pedals,so a bit of noise of the crank sensor is probably enough to get the motor driving when you don't expect it

author: coppercone2
author_rank: Super Contributor
timestamp: October 02, 2018, 12:58:41 am
content: bit of noise causing life critical failure is shameful design

author: amyk
author_rank: Super Contributor
timestamp: October 02, 2018, 01:29:53 am
content: In a product like this, reasonable pressure on the brakes should be required to be capable of overpowering the motor.

author: langwadt
author_rank: Super Contributor
timestamp: October 02, 2018, 01:39:45 am
content: Quote from: amyk on October 02, 2018, 01:29:53 amand it probably can, but in the confusion and panic of the motor still pushing you might not realize thathttps://en.wikipedia.org/wiki/2009%E2%80%9311_Toyota_vehicle_recalls

author: Raj
author_rank: Frequent Contributor
timestamp: October 02, 2018, 05:53:35 am
content: A complete electrical cutoff switch is a must in every device that has potential to kill.Cars have keys, that you can turn to shut the off.table saws have foot/knee kill switch.petrol pumps have one too.

author: nctnico
author_rank: Super Contributor
timestamp: October 02, 2018, 06:14:32 am
content: Quote from: Raj on October 02, 2018, 05:53:35 amAccording to other Dutch articles: In another near accident the driver was smart enough to turn the 'ignition key' off and thus stopping the cargo bike. IMHO the proper way to design something like this is to disengage the engine through a relay (either interrupting or shorting it) when the brakes are applied.

author: Ice-Tea
author_rank: Super Contributor
timestamp: October 02, 2018, 06:31:04 am
content: I've been following this as well. Seems to be an interesting tale to tell to those who go 'EMC, meh'. Or 'we'll just import some chinese crap, what could go wrong'.

author: Raj
author_rank: Frequent Contributor
timestamp: October 02, 2018, 07:01:34 am
content: Quote from: nctnico on October 02, 2018, 06:14:32 amBTW, has anyone tried turning off their non electric car in any gear while it's moving.It turns into a pneumatic abs break without the use of any break. the engine itself makes the car stop.Maybe something with a piston cylinder and a solenoid valve can introduce similar safety feature in electric car

author: Ampera
author_rank: Super Contributor
timestamp: October 02, 2018, 07:58:37 am
content: Or just have breaks that need power/pressure to be off, and have a cut off switch for that power/pressure.

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: October 02, 2018, 08:08:40 am
content: It hasn't been proved that EMC is the cause, that is just a theory. Toyota proved that buggy software can be an issue by itself (which should be a surprise to absolutely no one).Several design flaws have been identified in these electric vehicles anyway, not surprised they got bannedhttps://nltimes.nl/2018/09/26/stint-cargo-bikes-safe-transport-kids-researcher-says

author: Kjelt
author_rank: Super Contributor
timestamp: October 02, 2018, 08:13:52 am
content: I am not sure it is EMC related but it could be.AFAIK the reported incidents did not all occur in the vicinity of railroad crossings.The revocation of the road license by the government was due to the fact that the manufacturer has changed the design since the approval and had not communicated these changes to the government agency. All I heard was that the electromotor was changed to a more powerfull version.Perhaps the brakes were not upgraded as well, i don't know.Anyway, the biggest issue is and was that these kinds of electrical equipment that can pose a danger to human life, if it is a cnc machine or other industrial machine or a vehicle like this, it should have an Emergency Stop Button activating a safety relais.In this case the driver should have pulled the ignition key which was tuck somewhere not easy reachable and also on the brake side so if the brakes were activated the driver should use the other hand to pull the key. Too much trouble for panick situations IMO.Just as with some other vehicles like lawnmowers it would have been a good idea to equip it with a cord acting like a kill switch.We have to wait till the final report is in to draw conclusions but for now it looks like a flimsy safety design.Edit: the way it should have worked is that the driver should release the throttle handle at the right and then the stint would shut down. This is illogical since if you have an emergency situation you want to control the verhicle with both hands, there should have been an easy reachable emergency button.

author: coppercone2
author_rank: Super Contributor
timestamp: October 02, 2018, 12:31:30 pm
content: im sure the reason why they did not have a kill switch is because BOM.No fucking way a manufacturing company that hired assemblers and managers and engineers managed to miss this detail. It was a design choice. There was a risk assessment matrix that someone decided to tick 'no risk'.In those assessments, when you tick 'no risk' it tends to make design easier and cheaper. At least it assures you have a signed fall guy tho. I call it a hot potato matrix.

author: nctnico
author_rank: Super Contributor
timestamp: October 02, 2018, 01:36:43 pm
content: Quote from: Kjelt on October 02, 2018, 08:13:52 amI think this is just to make the legal part simpler at the government's side. It is much harder to prove the EMC issue is there especially if the vehicle has passed relevant EMC testing. It wouldn't surprise if it turns out the rules which apply to these kind of vehicles aren't strict enough. Anyway, by revoking the road license the vehicle has to be tested for safety again.

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 02, 2018, 01:43:11 pm
content: It sounds like how the reaction is to any new and relatively unknown thing when something goes awry. Driverless cars also get scrutinized a lot more than regular cars, even though many more people die horrible deaths in the latter every day. Yeah, this company is screwed.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 02, 2018, 04:46:09 pm
content: Quote from: Raj on October 02, 2018, 07:01:34 amI have. With the particular (pretty average conventional, AFAIK) gasoline engine in my car, opening the throttle doesn't seem to do anything. It moves air (the exhaust sound changes), but there is little backpressure, so the load isn't much more than the resistance of the engine moving alone.A turbo diesel may be more effective, although there may be reasons not to do that (large air charge = high peak air temperature --> unintended combustion of residual fuel and engine oil --> actually generating more power than you're spending, or if your oil seals are very worn, runaway acceleration?). AFAIK, engines designed for that kind of braking have an air release, which I guess would occur near TDC, or as an exhaust restriction, and it is the pressure drop that consumes power. Downside being the incredibly loud noise thus generated, and the frequent sight of "engine braking prohibited" as you cross the city line...Tim

author: nctnico
author_rank: Super Contributor
timestamp: October 02, 2018, 05:30:07 pm
content: Quote from: T3sl4co1l on October 02, 2018, 04:46:09 pmThen I think your car is broken. Either gasoline or diesel engine brakes with the throttle closed due to compression. This is useful (and strongly recommended) when going down long slopes because your brakes will burn up if you use them. Having the ignition on or off doesn't matter if you have a mechanical coolant pump because that will keep circulating cooling water throughout the engine. Big trucks have an extra valve in the exhaust to create extra back pressure.

author: langwadt
author_rank: Super Contributor
timestamp: October 02, 2018, 05:43:28 pm
content: Quote from: nctnico on October 02, 2018, 05:30:07 pmDiesel engines doesn't have throttles, so they need different ways of achieving engine braking.There are two kinds, one is a valve in the exhaust, the other noisy one opens the exhaust valve at the endof the compression stroke dumping the compressed air out the exhaust

author: nctnico
author_rank: Super Contributor
timestamp: October 02, 2018, 06:17:55 pm
content: This is getting off-topic but in a regular car the (high) compression in a diesel engine is enough to achieve engine braking. Remember movement is converted into heat which is dissipated in the cylinder head and the remaining hot air is dumped into the exhaust when the exhaust valve opens. Only trucks have extra measures to get more braking from the engine.

author: langwadt
author_rank: Super Contributor
timestamp: October 02, 2018, 06:55:05 pm
content: Quote from: nctnico on October 02, 2018, 06:17:55 pmwith the throttle open you don't get as much engine braking because the air acts like a spring and give you much of the energy used to compress air back in what would have been the power stroke

author: onesixright
author_rank: Frequent Contributor
timestamp: October 02, 2018, 07:04:52 pm
content: Quote from: nctnico on October 01, 2018, 07:36:36 pmMakes you wonder how it passed the EMC test in the first placeA Engineer sleeping on the job? Politics?

author: jmelson
author_rank: Super Contributor
timestamp: October 02, 2018, 07:26:06 pm
content: Quote from: nctnico on October 02, 2018, 05:30:07 pmDiesel engines do NOT have throttles. There is no restriction of the intake air. Diesels regulate engine output by controlling fuel injected into the cylinders. Some newer gas engines have variable valve timing to regulate intake charge, and also may not have a "throttle" in the intake. These engines will not have meaningful engine braking in this condition.Many Diesel trucks (required in the US above a certain weight) have a Jacob's brake that varies valve timing to release compression at TDC to provide engine braking.Jon

author: nctnico
author_rank: Super Contributor
timestamp: October 02, 2018, 07:27:48 pm
content: Quote from: onesixright on October 02, 2018, 07:04:52 pmIn a Dutch article published todayhttps://www.ad.nl/binnenland/onderzoeker-er-is-nog-veel-meer-mis-met-de-stint-knudde-met-een-rietje~a5ff6951/a third party researcher calls the construction of the cargo bike the definition of 'amateur hour'. Since this researcher makes money from investigating electric/electronic equipment I suspect the wording is a bit strong.

author: nctnico
author_rank: Super Contributor
timestamp: October 02, 2018, 07:30:39 pm
content: Quote from: jmelson on October 02, 2018, 07:26:06 pmDid you ever drive a car with a diesel engine? I did (several) and engine braking worked just fine.

author: Berni
author_rank: Super Contributor
timestamp: October 02, 2018, 07:30:54 pm
content: Quote from: langwadt on October 02, 2018, 06:55:05 pmIt works like a spring with the throttle closed too. The resistance you get on the intake stroke of pulling the vacuum in you get back again on the compression stroke because that vacuum pulls the cylinder rather than you having to put in work to compress it, but the throttle doesn't completely close so the work is used up to pull air trough the small gap.Diesels with there fully open throttle cause engine breaking mostly due to the much higher compression ratio. They compress ambient air so much it can momentarily reach above 500 °C hence why the reluctant to burn diesel fuel instantly combusts when its squirted into the cylinder. But this very hot air is touching the much colder engine around it so a lot of the heat transfers into the engines metal components, this drop in temperature reduces the pressure and so you get less of the work back on the power stroke. No need for any extra devices to be added to the engine for this, but trucks do often have them in order to get even more braking effect from it, since even tho they weigh 10 times as much as a car the engines in them are not 10 times larger/more powerful. All of this is also why diesels don't enjoy starting on a cold winter morning (Lots of torque needed from the stater motor to get so much compression while the freezing cylinder walls rob away the crucial self ignition temperature).

author: Kjelt
author_rank: Super Contributor
timestamp: October 02, 2018, 07:38:13 pm
content: Today the owner of the company defended against the article and its conclusions since they were based on a reverse engineering of the electronics and a summation of what in theory could go wrong. The article stated that a break in one cable could spin the stint out of control.He never saw that in all the years with all 3600 stints in the field. Besides even with the broken cable If the driver would let go off the throttle handle the stint would still power down.So the owner argued that the researcher should focus on the wreckage of the involved stint to see what actually happened instead of the other way around.

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 02, 2018, 08:12:05 pm
content: Quote from: Mr. Scram on October 02, 2018, 01:43:11 pmThe problem with an E-brake in robo-cars is if it gets used and still crashes everyone will start pointing fingers and saying the computer could have prevented it.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: October 02, 2018, 08:25:06 pm
content: 1. Engine braking is strongly influenced by the gear engaged in the transmission. If it's a Manual in 4th or 5th, engine braking won't do as much as if it were in 2nd or 3rd. For an Automatic, "D" may not do much for braking, but "3" or "2" will.2. It appears a relevant standard for EMC for electric-assist bicycles is EN 15194:2017. Unfortunately, I don't have a copy, but section 4.2.15 is titled, "Electro Magnetic Compatibility". Several standards are listed as normative references. One would need to dig into them to see what the requirements were for the field strength used for radiated immunity.3. There are a lot of other standards in EN 15194 that are safety related. Reverse engineering is perfectly acceptable, because many safety-related methods are meant to be fail-safe, that is, it fails to a safe state, which is distinctly different from fail-proof, which means it can't fail (within the assumed conditions which it is allowed to operate).

author: rrinker
author_rank: Super Contributor
timestamp: October 02, 2018, 08:49:00 pm
content: Worse than the Toyota thing (though there was enough BS in that one too) was the Audi issue from the 80's that nearly killed Audi as a brand in the US. That one was 100% driver fault, there was NEVER an issue with the vehicles themselves. My best friend had one of the affected models. Couldn't overpower the brakes no matter what. And since there was no throttle by wire or brake by wire in those cars, there was no software failure that could cause the problem.That ANY motorized vehicle is designed with a power plant that can overcome the friction capability of the brakes is a travesty. That you could have absolutely no mechanical backup for an electronic brake in a motorized vehicle is a thumb in the face of common sense design.My manual car in 6th ear has significantly more engine braking than most automatics left in Drive. But most Americans are too lazy to drive manual cars and they have all but disappeared. Gotta keep a hand free to text while they drive, you know. It'll be a sad day if when I am ready for my next car, there are no more manuals to be had. I had intended to drive manuals until either my left leg or right arm fell off.

author: nctnico
author_rank: Super Contributor
timestamp: October 02, 2018, 09:19:19 pm
content: Quote from: Tomorokoshi on October 02, 2018, 08:25:06 pmThe vehicle in question isn't an electric-assist bike but a small electric vehicle. If you didn't look at the pictures: is looks like a Segway with a big plastic bath tub bolted onto it.

author: Kjelt
author_rank: Super Contributor
timestamp: October 02, 2018, 09:21:28 pm
content: Quote from: nctnico on October 02, 2018, 09:19:19 pm

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 02, 2018, 09:30:19 pm
content: Quote from: Kjelt on October 02, 2018, 07:38:13 pmThat sounds like an Apple level of excuse for a poor product. With a motor vehicle company that should definately be the end of the line. As has been stated, a proper kill switch would directly disconnect the power to the motor (or from the battery in an emergency). The only ways this switch could fail would be water (poor waterproofing was noted) or contact welding (inadiquate switch rating). So either way, that, plus a host of other issues shown means this trash should stay off the road.

author: coppercone2
author_rank: Super Contributor
timestamp: October 02, 2018, 09:45:22 pm
content: you could also cut a wire with a few pyrotechnic cutter in an emergency or short the battery out with a big contactor to blow it up if you wanna make the stop functionality more reliable.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 02, 2018, 11:21:30 pm
content: Quote from: nctnico on October 02, 2018, 05:30:07 pmI mean, it is, it has many things wrong with it; but I strongly suspect the fundamental operation of the engine has not changed over its lifetime.(And yes, the throttle is fully mechanical.) I invite you to come over some time and test it; I usually keep beer in the 'fridge (for after driving, you understand).Tim

author: station240
author_rank: Unknown
timestamp: October 03, 2018, 03:07:19 am
content: My assumption is it was an electric train, EMC from the moving connection to overhead wire, motors, etc is unavoidable.I was wonder who would be crazy enough to transport children using a cargo bike, turns out it's designed for that purpose.And there are 20,000 of these things around...

author: nctnico
author_rank: Super Contributor
timestamp: October 03, 2018, 06:11:04 am
content: Quote from: station240 on October 03, 2018, 03:07:19 amThis assumption is correct. The amount of crap an electric train emits is massive. When I worked in the centre of Amsterdam my CRT monitor (located on the 5th floor) would jump around a bit due to the magnetic field when a tram pulled up.QuoteYou have to realise that in the NL there is a very good infrastructure for bikes with seperate bycicle lanes everywhere. It is not like they are using these electric cargo 'bikes' to drive between cars. If these Stints where designed properly they are a good solution for hauling kids around because the alternative is bringing the kids to and from school using vans which is more prone to accidents around the school.

author: Raj
author_rank: Frequent Contributor
timestamp: October 03, 2018, 07:54:39 am
content: If the CEOs of these companies drive their own products, it's probably safe but you'll never see them even going near one.

author: abraxa
author_rank: Frequent Contributor
timestamp: October 03, 2018, 08:20:55 am
content: Quote from: CM800 on October 01, 2018, 09:23:50 pmOverhead wires are really long antennas, having high alternating voltage and high current pass through them. There's nothing you can do to prevent emissions there. If missing EMC was the cause then only the vehicle manufacturer is at fault.

author: nctnico
author_rank: Super Contributor
timestamp: October 03, 2018, 08:50:11 pm
content: Note that most of these videos seem to be filmed in China or at least in an Asian country.

author: langwadt
author_rank: Super Contributor
timestamp: October 03, 2018, 09:01:31 pm
content: Quote from: nctnico on October 03, 2018, 08:50:11 pmand large number of them being people mistaking brake and accelerator pedal

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: October 04, 2018, 05:20:03 am
content: Most cars lock the steering when the key is turned to lock. So be very careful if you plan on testing this on a running car.

author: Berni
author_rank: Super Contributor
timestamp: October 04, 2018, 05:46:41 am
content: Quote from: FlyingHacker on October 04, 2018, 05:20:03 amI think the wheel is still unlocked when the key is in the ACC position. But yeah in such a situation nobody would be that gentle with the key and turn it all the way to the OFF position.And yeah considering you don't hear the tires squeaking in a lot of the videos would point to quite a few being mistaking the accelerator for the brake. At these speeds brakes easily have enough power to lock up the wheels if you press the brake pedal hard, at the very least the non driven wheels would make a slipping noise. But to be fair a lot of people are not very good drivers and once they get into such a shocking situation of the car accelerating they don't think about what they are doing and just focus of stomping that pedal down even harder rather than checking if its the right one.Here they have added a "safe driving course" to be a part of getting your driving license. This course makes you drive a car trough simulated emergency situations by using a special slippery road surface that really does feel like driving on snow. They put drivers into situations where the car slides off course, avoiding obstacles down slippery hills etc... all in a safe controlled environment with plenty of asphalt runoff. This is one of the rare ideas from the government that is actually good. I'm sure quite a few crashes ware avoided by these drivers knowing how to handle these situations.

author: rrinker
author_rank: Super Contributor
timestamp: October 04, 2018, 02:14:21 pm
content: You can see it a lot of them - no brake lights, they are hitting the accelerator and not even TRYING to hit the brake. First one in that video even - the truck started going, then stopped for oncoming traffic, car just accelerated - gas not brake, not a system failure. Another obvious one is around 4:17 or so when the guy rams the rear of the bus - no brake lights, again hit the gas not brake. And right before that, the one that goes forward, than shifts to reverse and rams the car behind - no brake lights. The one where the car started going forward, making a left turn, then stopped, reversed into the car behind, then took off again - that's just an idiot who should not be driving a manual transmission car. They went from first to reverse!

author: macboy
author_rank: Super Contributor
timestamp: October 04, 2018, 02:25:56 pm
content: Quote from: langwadt on October 02, 2018, 12:32:32 amQuote from: amyk on October 02, 2018, 01:29:53 amBoth of you are not considering that this is an electric vehicle, so the primary (only?) braking is using the motor as a generator. With no separate braking system, the operator can't "overpower" the motor no matter hard hard they try to apply the brake.

author: Jeroen3
author_rank: Super Contributor
timestamp: October 04, 2018, 02:47:29 pm
content: I just want to warn everyone that although it might look like a design or EMC problem. Nothing has been proven yet.Since children died, there is lots of emotion, and an enormous amount of clickbait and biased news. The target audience, parents with young kids, is very large. And everyone with leverages these emotions.A government institute did an preliminary investigation. To feed to the extremely hungry media.https://www.rijksoverheid.nl/documenten/brieven/2018/10/01/bijlage-2-feitenrelaas-eerste-verkennend-technisch-onderzoek-stintIn this report they mention at the beginning that they are not capable of fully investigating the vehicle.And are outsourcing this to a german firm.All facts around now are either from this report, or by "experts" hired by the media. If you haven't watched these, they are biased.In this preliminary researchon the vehiclethey've concluded many things:- The firmware and diagnostics are Chinese.- The motor was changed, from 800 to 1200W.- Several disconnects in the "0-wire" sometimes cause the vehicle to go full speed.- Gear select does not work then.- The mechanical brake is not strong enough.- The mechanical throttle handle spring can break.- The "on/off" switch is on the brake lever side. Which is deemed the wrong side in a runaway situation.But the thing that really underlines why they mention being incapable:- High current cables (16A) were improperly routed, and heat could accumulate in the enclosure. This could lead to problems with the solder used that apparently melts at 72 C. While the engine has a thermal cutoff at 82C.Anyone seen either 72 or 82 C solders?Now I'm going to give a very unpopular opinion:Until there arefacts, instead of many articles with speculation (like here) it can very well still be possible that the operator was distracted and accidentally move the throttle and panicked.That due to the accident many people went investigating the vehicle does not mean something was wrong with this vehicle. This will be researched.Remember that during an incident like this, if it has a technical reason, there is always more than one thing wrong or defective. Either multiple technical failures or combined with operator abnormality.I think this since many of them were in use, a technical problem like this would have been reported on. By either the drivers, the owners (they are often lease), mechanics of insurers. Which didn't happen. So, indeed "magnetic fields in the rails" are already listed as cause, because people don't know.For all we know now, it can very well still be a software fault, which frightens me even more than an EMC problem.

author: b_force
author_rank: Super Contributor
timestamp: October 04, 2018, 03:48:15 pm
content: Yes EMC is very likely.Although it has been many years, i actually worked on a project for a company dealing with these high voltage lines for trains.The EMC introduces quite some issues. For that reason every conducting object has to be grounded around railway tracks.You can actually see this, since the wires are bolted on fences, benches and such.But in the end it's not a software or EMC fault.It's lack of a decent backup system if everything fails.Such a unit needs a mandatory easy to access kill button and brakes for these kind of situations.Pretty much like a kill button on (heavy) equipment.I guess our rules and regulations aren't that far yet unfortunately.

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 04, 2018, 03:56:58 pm
content: Quote from: b_force on October 04, 2018, 03:48:15 pmPeople keep speaking of kill buttons, but electric cars don't have those and electric bicycles don't have either.

author: lamello
author_rank: Contributor
timestamp: October 04, 2018, 04:08:56 pm
content: I am stunned by the fact that this stint has several primal DESIGN faults.1) It is unacceptable that the breaks can't stop the vehikel if the motor is in full power.2) There is on easy to reach emergency break.Only for the first reason alone it had never been allowed on the road.Verstuurd vanaf mijn SM-T800 met Tapatalk

author: b_force
author_rank: Super Contributor
timestamp: October 04, 2018, 04:24:12 pm
content: Quote from: Mr. Scram on October 04, 2018, 03:56:58 pmSorry, I don't follow how this is an argument that explains why some kind of safety mechanism is a bad thing?

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 04, 2018, 04:27:24 pm
content: Quote from: b_force on October 04, 2018, 04:24:12 pmI'm merely pointing out that they're not as required as some people are purporting here. You can live without them just fine, apparently.

author: b_force
author_rank: Super Contributor
timestamp: October 04, 2018, 04:29:45 pm
content: Quote from: lamello on October 04, 2018, 04:08:56 pmThat is exactly my point.I am just wondering. But most of these devices are never really used on a big scale.Mostly they are just toysSo therefore it wasn't a big deal in the past.

author: nctnico
author_rank: Super Contributor
timestamp: October 04, 2018, 04:31:34 pm
content: Quote from: Jeroen3 on October 04, 2018, 02:47:29 pmIt could be a possibility but given the fact the government has revoked the road worthiness license there is much more going on here than an operator error. Such a decission can result in a major damage claim if it turns out there are no good grounds for it. Remember there is video footage of the accident (not publicly available) so the government's investigators have been able to see exactly what the operator was doing before the crash.Having many cargo bikes on the road without problems doesn't mean there are no problems lurking. One of my customers has a large number of devices installed in the field (tested for CE compliance). In a particular case they found out that it was being affected by an electric motor mounted nearby. As a result the design got altered so the device works in that situation. That is one out of thousands of devices which had a problem in a particular situation. My customer choose to act on it and improve the product.Anyway: it will be interesting to see if the investigation can reveal the root cause of the accident and if so what the cause is.

author: b_force
author_rank: Super Contributor
timestamp: October 04, 2018, 04:32:33 pm
content: Quote from: Mr. Scram on October 04, 2018, 04:27:24 pm?Well it is clear apparently not. Otherwise those kind of accidents wouldn't happen.Keep in mind that you have to read "kill switch" as; "something to prevents the whole system to go crazy".

author: nctnico
author_rank: Super Contributor
timestamp: October 04, 2018, 04:40:44 pm
content: Quote from: Mr. Scram on October 04, 2018, 04:27:24 pmOn normal cars the ignition key cuts the power to the ignition (or close the fuel valve on a diesel). I would like to think that these systems are designed with some safety behind them. Even with key-less entry systems the electronic/electrical system of any car would need to be tested according to automotive standards.

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 04, 2018, 04:41:41 pm
content: Quote from: b_force on October 04, 2018, 04:32:33 pmYou can't draw that conclusion, as that would suggest the lack of kill switch is the single cause of the accident. Again, I'm merely pointing out that hundreds of thousands of electric cars and bicycles are on the road without one. That makes it hard to claim it's absolutely required. The safety of electric vehicles doesn't seem to be dependent on the presence of kill switch.We should also be mindful not to take this accident as a representative example, not yet at least. Maybe the investigation will tell us this was bound to happen, but for now it seems hundreds of thousands of children have been transported with these vehicles and four have perished in a single accident. That in itself doesn't warrant the conclusion that these vehicles are inherently unsafe.

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 04, 2018, 04:42:44 pm
content: Quote from: nctnico on October 04, 2018, 04:40:44 pmUnless I'm misunderstanding things, this vehicle has the same feature.

author: lamello
author_rank: Contributor
timestamp: October 04, 2018, 05:06:18 pm
content: Quote from: Mr. Scram on October 04, 2018, 04:42:44 pmThe ignition switch will stop the stint. There are only some issues.1) to reach the ignition key, the driver has to release the break. The stint will accellate (more panic).2) the driver of the stint doesn't sit, it stands. In case of an emergency the driver has to release one hand of the stick ( and keep his balance) to reach the ignition switch ( possible hesitation).Verstuurd vanaf mijn SM-T800 met Tapatalk

author: Berni
author_rank: Super Contributor
timestamp: October 04, 2018, 05:09:34 pm
content: I don't think it needs a big red stop button on it. Cars have keys in them and this has too. But they are getting replaced by buttons, im guessing there is some fail safe design behind those. Electric cars usually have big contractors on the battery to disconnect it (very useful in a electrical fire). In the electrical hydroplaning jetsky thing we designed the electronics for, there was a bracelet kill switch that also caused these big battery contractors to disconnect while also stopping it in software at the same time.But i do think this should have mechanical breaks on it even if the motor is used for braking. Even if the motor is used for that then the same handlebar lever should be used to operate that function so that light pulls on it activate regenerative braking and harder pulls operate the mechanical brake calipers. That way if the regenerative braking fails the driver in panic will pull it all the way to quickly get into mechanical braking.But yes it could even be operator error as far as we know. If it happens in cars it could happen just as well here.

author: b_force
author_rank: Super Contributor
timestamp: October 04, 2018, 05:15:41 pm
content: I am not drawing conclusions but frm a technical point of view i just find it strange that there doesn't seem to be such a mechanism.Btw. There is a reason that in a lot of countries those electric bikes without peddling assistance are illegal.As for electric cars, i don't know.But it the end. It's still not an argument to say other things don't have it.In fact if we look back in history most regulations bad accidents first need to happen before changing or introducing laws and regulations.So in this case you could also see it as a way to prevent other horrible things happening in the future.

author: Kjelt
author_rank: Super Contributor
timestamp: October 04, 2018, 08:05:47 pm
content: Quote from: Jeroen3 on October 04, 2018, 02:47:29 pmI thought that was weird but the following wiki states melting point starting at 90oChttps://en.wikipedia.org/wiki/SolderI wonder if they did not mean the melting of the plastick isolation of the wire.

author: coppercone2
author_rank: Super Contributor
timestamp: October 04, 2018, 09:25:34 pm
content: they probobly forgot a 1 or 2a key on a bike is retarded because you might be going down a hill or on a slope or some shit and you need to balance the wheel when your hands. It needs to be non fumbly and quick. Or bumpy road.. alot harder to drive with 1 hand. Your sitting comfortably in a car, one hand has alot more power then on a bike when your using your body to balance it. Even without power steering in a car you can kinda anchor yourself into the seat and really stiffen your back to get power out of one hand, if you do that on a bike its easy to lose balance.I would like a handle bar you slam on or something to break a faux-joint to cut power. Preferably not a button but from some kind of body reflex. Like a torque wrench.So you can maintain full driving position with maximum control but just do something with your hands to exert some kind of force on the steering bar to break the circuit,

author: nctnico
author_rank: Super Contributor
timestamp: October 04, 2018, 09:34:27 pm
content: Quote from: Kjelt on October 04, 2018, 08:05:47 pmI think someone got a few things mixed up in that text. A thermal cut-off on an electric motor has nothing to do with the wiring. Maybe a typist put it together from some hand written notes.

author: Kjelt
author_rank: Super Contributor
timestamp: October 04, 2018, 09:43:50 pm
content: Quote from: nctnico on October 04, 2018, 09:34:27 pmPretty shocking for an official government reply, very sloppy.

author: langwadt
author_rank: Super Contributor
timestamp: October 04, 2018, 09:48:54 pm
content: Quote from: Kjelt on October 04, 2018, 08:05:47 pmgoogling says 66.3In33.7Bi is 72'C

author: coppercone2
author_rank: Super Contributor
timestamp: October 04, 2018, 09:50:31 pm
content: thats way too expensive for this job

author: langwadt
author_rank: Super Contributor
timestamp: October 04, 2018, 10:45:32 pm
content: Quote from: coppercone2 on October 04, 2018, 09:50:31 pmit also absolutely no sense to use 72'c solder except for maybe a blob in a thermal fuse

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 04, 2018, 11:01:25 pm
content: Quote from: coppercone2 on October 04, 2018, 09:25:34 pmYou don't balance a bicycle at anything but near standstill with your hands, and definitely not this four wheeled vehicle. While I do think that this vehicle may benefit from a more intuitive kill switch, I'm not buying that a car's ignition switch is that much better.

author: coppercone2
author_rank: Super Contributor
timestamp: October 04, 2018, 11:43:26 pm
content: you definatly adjust your body on a turn and even more so if its bumpy/gradient is changed during turning.have you ever lost a turn in a four wheeled vehicle (i.e. bad highway ramp going too fast when you need to correct after you already feel the lurch from being thrown into a slide?)Most people won't keep one hand on the wheel when their vehicle is slipping. If your driving with one hand your gonna freaking jump on the wheel with the other one (though your an idiot if you drive with one hand)same for ATV

author: chris_leyson
author_rank: Super Contributor
timestamp: October 05, 2018, 01:34:35 am
content: At level crossings you have to raise the height of the overhead lines to allow for lorries. In the UK the height of the overhead line is 5.6m at level crossings and 6.75m on a high load routes. You have to raise and then lower the overhead line at level crossings so arcing between the line and pickup is going to be more likely.If it's a main line then 25kV is used throughout most of the World and these days a balanced 50kV autotransformer system seems to be the "gold standard" because you only need a grid tap every 75km or so but that beside the point.From an EMC point of view you've got a 25kV AC line at a height of 5.6m for sake of argument so an arc from the line to the train would produce a vertical electric field strength of perhaps 6kV/m if the train looked like a short circuit when the line reconnected. At some frequencies you might even get a 12kV/m transient because of resonance.What are the EMC emission standards for 25kV traction systems under transient conditions ? I've just done some "on the fly" ballpark estimations for vertical electric fields and I haven't even considered the magnetic field transients when you have potetially 50A current paths disconnecting and reconnecting.Level crossings and electric trains, perhaps more likelihood of a transient EM event due to the "gradient" of the overhead lines and potentially some very high transient field strengths. Do automotive standards test to this sort of transient field strength ? I can't see cheap control electronics housed in a plastic enclosure as having much immunity at all so I wouldn't rule out EMC. EMC problem, just trying to keep the subject on topic because it's an engineering forum. What the hell has breaking using a petrol or deisel engine and gear box got to with anything FFS.10V/m CW EMC immunity aint the same as 10kV/m transient. If it turns out to be EMC related then that's a lack of due diligence on behalf of the manufacturers and those who create and enforce the standards.

author: rs20
author_rank: Super Contributor
timestamp: October 05, 2018, 02:04:45 am
content: Quote from: b_force on October 04, 2018, 05:15:41 pmThings like lathes, milling machines etc have emergency stop buttons because if something suddenly goes haywire, there is no other way to quickly remove energy from the system and ostensibly recover to a safe situation.In a vehicle; there's already a "make everything stop right now I don't want to be moving button": the brake.To observe a situation where the brake has failed, and to say "my goodness there clearly needs to be an emergency stop button here" is kind of weird. Approximately 0% of users would know where it is, the manual would have a hard time describing when to use it ("dear user, if the brakes fail (WTF!?), press this button"). If the driver in this incident had 5 seconds to think things through, he could have steered to a different location or done any other number of evasive maneuvers. It's just ridiculous to assert that an emergency stop button would have entered the driver's mind as an option in that fraction of a second, even if one was present.So how about this: let's make the bloody brakes work instead of going on about "emergency stop" buttons.Quote from: b_force on October 04, 2018, 05:15:41 pmSomething needs to happen, yes. You've failed to demonstrate that an E-stop button is that solution, though.

author: Berni
author_rank: Super Contributor
timestamp: October 05, 2018, 05:33:41 am
content: Yes just put the regenerative motor braking and a mechanical brake on the same lever. So on a soft press you only have the electronic motor braking and on a hard press the mechanical brake joins in. Also the sensor that detects this lever being pulled needs to be redundant so that the vehicle can detect a bad sensor.This way the user does not need to know about any emergency button, will instinctively use the mechanical brake when needed and there are multiple layers of failures that needs to happen before you get into a runaway situation.

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: October 05, 2018, 06:33:17 am
content: Quote from: Berni on October 05, 2018, 05:33:41 amBest idea yetBad design of user interfaces kills people, not just mechanical faults or lack of special overrides.

author: b_force
author_rank: Super Contributor
timestamp: October 05, 2018, 10:09:24 am
content: Quote from: rs20 on October 05, 2018, 02:04:45 amI haven't failed anything.I clearly wrote that people have to read something like a kill switch loosely as: something that prevents the system to get into a situation like this.I don't really care if that is done by better brakes or a real mushroom kill switch.What is failed is that people don't read properly.A solution could be anything. We can go talk about details until the cows come home, but there is a lot more besides just the technical part of the story.Think about aesthetics, costs, implementation, if it fits the marketing story etc etcI can give a billion technical solutions, but what is it worth talking about them if we don't know the context and vision the company is looking for?

author: coppercone2
author_rank: Super Contributor
timestamp: October 05, 2018, 11:29:02 am
content: rs20, whats wrong with training the user?It's like saying people would never figure out how to use the radar avoidance, back up cameras, etc... most people are actually pretty interested in cars, its a big expensive machine and they like to read car mags, etc... most people save up over the years for a nice onethe DMV requires you to know how to turn on a slip condition...their not THAT dumb. the biggest problem is that turning off power completely would effect the anti lock breaking system, if its turned off accidentally. You might want to keep that active some how.. but thats another can of worms.breaks are often not maintained and they fail. simple as that. the degradability of a switch is 0 compared to a break pad. All you need is like a hydraulic leak or some other stupid thing.in the case of a malfunctioning throttle:weird hard to align ceramic thing (which is often purchased as an after market counterfit) under high temperature and stress controlled by complex hydraulics that needs regular expensive *both in hydraulics and in ceramics* replacement and inspection to be fully effectivevsopen switch to electric circuit

author: MrW0lf
author_rank: Frequent Contributor
timestamp: October 05, 2018, 11:40:58 am
content: Quote from: coppercone2 on October 05, 2018, 11:29:02 amUsed on ATVs also etc. Sometimes it just makes sense to leave vehicle...

author: coppercone2
author_rank: Super Contributor
timestamp: October 05, 2018, 11:47:10 am
content: you know what happens when a jet out of those ski's enters your anus? death

author: Simon
author_rank: Unknown
timestamp: October 05, 2018, 01:35:47 pm
content: Thank you for that mental picture.

author: BrianHG
author_rank: Super Contributor
timestamp: October 05, 2018, 03:38:18 pm
content: Quote from: Simon on October 05, 2018, 01:35:47 pmArrrrrrrggggg, thank you for making me think about those words hard enough to generate that mental picture.

author: mac.6
author_rank: Regular Contributor
timestamp: October 05, 2018, 03:54:36 pm
content: Quote from: nctnico on October 04, 2018, 04:40:44 pmOn diesel motor there is a specific condition that prohibit engine shutoff: oil intake by air filter.Yep on most diesel there is an overspill port from oil (not fuel) tank to the air intake. Normally only vapor oil is taken by air intake so doesn't end up on the road.If something overflow oil tank (hint: water ingress, voluntary overflow or fuel leak), you can't stop your car unless you stop air intake. There is some vids on youtube about this.

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 05, 2018, 03:57:54 pm
content: Quote from: Berni on October 05, 2018, 05:33:41 amYou'd need some way of making clear that the mechanical brake is engaged. Otherwise people would get terrible mileage and wonder why.

author: langwadt
author_rank: Super Contributor
timestamp: October 05, 2018, 03:58:34 pm
content: Quote from: coppercone2 on October 05, 2018, 11:29:02 amhydraulic brakes are very reliable and cars have two separate hydraulic circuits so unless you brake pedal falls off you never lose more that half your brakes

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 05, 2018, 03:59:53 pm
content: Quote from: b_force on October 05, 2018, 10:09:24 amPerhaps you weren't as clear as you assumed.If you meant some shotgun concept then sure. You need something to stop a vehicle in a hurry. I don't think anyone even considered anything else.

author: MrW0lf
author_rank: Frequent Contributor
timestamp: October 05, 2018, 04:19:57 pm
content: Quote from: coppercone2 on October 05, 2018, 11:47:10 amIt works the other way around!Great fun btw.

author: nctnico
author_rank: Super Contributor
timestamp: October 05, 2018, 04:41:05 pm
content: Quote from: langwadt on October 05, 2018, 03:58:34 pmI agree. Brakes on a car are extremely reliable. And if they fail (or the road is slippery) you can also opt to steer into the side of the road towards some bushes or whatever else is there instead of taking a chance on a head-on collision.

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 05, 2018, 04:48:05 pm
content: Quote from: nctnico on October 05, 2018, 04:41:05 pmThe driver of this vehicle may have had the same option. It's possible that panic and not wanting to crash a vehicle with children into a fence or hedge led to unforeseen consequences and a much more serious accident. The car acceleration video is a good example of people not always responding in an optimal manner. Note that I'm not blaming the driver nor am I making claims that this is what happened.

author: coppercone2
author_rank: Super Contributor
timestamp: October 05, 2018, 05:19:39 pm
content: sometimes you just end up crashing head on you know, i had this happen where I felt I would basically fall off steep hill into unknown area filled with logs and roll or crash into a pile of logs/metal/some other shit for railroads that could decapitate me (from ATV).I decided to just crash into the other person out of fear, because I knew getting thrown forward would be less dangerous then having the ATV on top of me or getting rail-road building materials to my head.IMO the resulting head on collision on the turn was the best option. No real injuries. When your driving fast in a dangerous area on one of those fucking things it feels like your doing some Tomb Raider action sequence...In retrospect I looked in the area and it appeared I could have driven off to the side, but I had just driven close by to a bunch of dangerous shit pretty fast and it was not really clear what was ahead of me when I noticed I am about to crash into some even greater dumbasses (mostly due to high bushes).The ATV's pretty much slid into each other fully breaked on gravel (at least mine did, not sure about the other party).But to be fair I did not know the area that well and on the side of the gravel path there were a few big (rain?) holes that would swallow the ATV up. It was such a bad area to drive holy shit.

author: Simon
author_rank: Unknown
timestamp: October 05, 2018, 05:22:17 pm
content: err what about the clutch?

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 05, 2018, 05:30:01 pm
content: Quote from: Berni on October 05, 2018, 05:33:41 amNo sensors and computer rubbish to have EMC issues in the first place. Just use a switch with two consecutively opening NC contacts. If the switch fails, the brakes just get stuck on.

author: coppercone2
author_rank: Super Contributor
timestamp: October 05, 2018, 05:31:02 pm
content: needed a boat anchor or aircraft carrier runway arrestorboth of our speeds were down right shameful considering all the obstacles and lack of visibility in the area.. but god damn what a rush

author: Berni
author_rank: Super Contributor
timestamp: October 05, 2018, 07:06:41 pm
content: Quote from: Cyberdragon on October 05, 2018, 05:30:01 pmWell due to electric vehicles predominantly using brushless motors makes some sort of computer in the chain unavoidable. At the very least there is a CPU in the motor controller that has to receive some sort of electronic signal to tell it what to do. The breaking power should be variable or the ride would be very unpleasant so it would need a actual sensor rather than a switch. But you design that sensor in a safety critical way such as having mechanical stops that prevent the sensor from ever going to 0% and 100% so that you can assume the extreme values to be an error and go into a failsafe mode (max breaking under software), same happens if the two sensors start to show different values by more than a few percent. Additionally if any braking is requested that would also cause it to ignore all throttle commands. If all of this does fail then pulling the brake lever fully would apply enough mechanical brakes to stop the motor even at full throttle. Meaning that a significant electrical failure and mechanical failure of the brakes must happen simultaneously before there is a runaway.Additionally you enforce various safety checks in the software. Anything that is constantly refreshed needs a watchdog timer, checks must be performed on all routine call parameters to make sure they are within reasonable ranges. Magic numbers should be placed around important memory structures(especially ones on the stack) to catch memory being accidentally stomped by a rouge pointer. Have handlers for any CPU traps and faults. If any of these get tripped it should send the system into a failsafe mode that requires a power cycle to get out of. But its quite hard explaining these sort of concepts to average programmers. They don't understand that hardware can sometimes fail or glitch out or might not properly sanity check there inputs, when it works in normal test cases its fine enough for them. I seen it a lot when we get a few badly soldered PCBs from the board assemblers, the fault often makes the software act really strangely and is impossible to troubleshoot. What they do with these weird acting boards is then take them to the programmer that hooks it up via JTAG and single steps trough the program to find where things hang up or go wrong. Then when we finnaly make them put in a self test feature we get something along the lines this: routine that counts the number of I2C devices on the bus if we expected 6 unique devices and we got 5 then they show "I2C Error 5" on the screen.

author: lamello
author_rank: Contributor
timestamp: October 05, 2018, 07:30:27 pm
content: OR, put working mechanical brakes on the vehikel......Why go hightech when lowtech works???Verstuurd vanaf mijn SM-T800 met Tapatalk

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 05, 2018, 08:50:16 pm
content: Quote from: lamello on October 05, 2018, 07:30:27 pmThat's the problem we've been debating, whether mechanical breaks alone would fail if the motor got stuck on.QuoteYou can have a digitally controlled motor all you want, but you do not need a computer to stop it, as long as you have control of the motor windings.http://ieejournal.com/Vol_3_No_2/Different%20Braking%20Techniques%20Employed%20to%20a%20Brushless%20DC%20Motor%20Drive%20used%20in%20Locomotives.pdf

author: nctnico
author_rank: Super Contributor
timestamp: October 05, 2018, 10:02:55 pm
content: Quote from: Cyberdragon on October 05, 2018, 08:50:16 pmWhat I'm wondering about is what a car would do if you press the brake and accellerator at the same time on a modern car (with an electronically controlled throttle / fuel injection). It might be that the brake overrules the accellerator. The reason for this assumption: Many years ago I drove a VW every now and then which was used as a vehicle to test all kinds of things with. At some point my co-workers wired the brake lights together with the normal lights. Turning on the lights (and thus the brake lights) caused the engine to stutter like it was out of gas.

author: lamello
author_rank: Contributor
timestamp: October 05, 2018, 10:21:13 pm
content: I have tried that with a volvo v50.It breaks like hell. Just likes it should be.Verstuurd vanaf mijn SM-T800 met Tapatalk

author: langwadt
author_rank: Super Contributor
timestamp: October 05, 2018, 10:24:06 pm
content: Quote from: nctnico on October 05, 2018, 10:02:55 pmthe brake overrides the throttle. Toyota didn't have it but added it after the big a controversy about stuck throttle,though the brakes had no problem overriding the engine at full power

author: Siwastaja
author_rank: Super Contributor
timestamp: October 11, 2018, 12:26:49 pm
content: Quote from: Mr. Scram on October 04, 2018, 03:56:58 pmKill buttons do not exists because people (marketing, politicians and legislation)expectthat "normal people" feel uneasy around them. This is the classical "do not remind about the bad things" concept.Yes, I'm serious. It's a known issue that a lot of people do not use seat belts. It's a similar issue psychologically. Luckily, seat belts got into the legislation at the correct time slot, with some good sense for sane safety culture back then.The designers for such systemsdefinitely wantto design a product that is safe without an emergency stop switch. I would, too! I just know I cant't do it, hence the emergency stop switch exists (actually two of them symmetrically in my product, so that people don't need to waste time trying to remember which side it was...)There's no problem with heavy machinery such as lathes, since deep down we think that a machinist is OK with all this, and doesn't need sugar coating the world around them.But for general public, the "stupid people", as legislators and product managers erroneously think - the switch is a "disgrace" to their "safe product"; admitting that something could go wrong is not good for business value.Accidents, on the other hand, are quickly forgotten. Unless there are stop switches, which are the problem because they remind you about the accidents all the time.Let me give you an actual real-life example where this shows very well.Until recently, a lot of old elevators, some hundred years old, were still in use here; now there has been a trend to upgrade them. These old elevators do not have inner doors. The safety issue here is of course obvious. Until about early 1980's, they were like this. This being said, all of these old things do have a simple safety feature:A stop button!It isn't a big red mushroom thing, but nevertheless a button which says "stop". It's not dramatic: it stops the elevator. If you push it accidentally, no harm done: press the floor button again and off we go.Now, most of these old elevators have been upgraded (completely rebuilt and replaced with new stock elevators) to modern "safety standards". What this means, there are inner doors (and I'm sure controlling them involves 100000 pages of safety paperwork and 100000 lines of autogenerated and "formally verified" microcontroller code.)But there is no STOP button! Total number of stop buttons I have seen in any modern elevator designed after year 2000: absolutely zero.Now, the typical accident nowadays with these elevators goes like this:1) You have a dog. Your dog is in leash. You walk inside the modern, "safe" elevator2) Someone presses a button. Doors start to close slooooooooowly.3) Your dog suddenly gets an idea to go outside.4) You quickly push "open the doors" button, but you are late: the safety-certified MCU with its safety-certified and formally verified code is no longer registering inputs because that's not in the specification.5) The doors continue closing, sloooowly. Everyone starts to freak out. The elevator starts moving slowly and steadily to keep up the ironic atmosphere of waiting your dog to be killed by the stuck leash between the inner doors.6) People try to franctically push all switches and do everything they can. There is no way. Your dog is killed in a slow process.The doors are fine, but the "safety sensors" are not up to task and do not prevent these accidents from happening. But, because everything is perfectly engineered to the rules, with millions of pages of safety standards completely followed, against all common sense, the STOP button has been legally removed from the elevators.The bottom line:The modern safety culture just totally sucks. It's as bloated and inefficient as modern software. (And, funnily, it often is based on a large piece of software. If anyone sees a problem with that, the typical solution is to double the amount of software to make it "redundant". Go figure.)

author: Jeroen3
author_rank: Super Contributor
timestamp: October 11, 2018, 12:34:43 pm
content: I have seen stop buttons in some non-public elevators. But you cannot restart it after pressing it. You need a key.Similarly, jumping in a moving elevator will issue the emergency stop.Why?

author: coppercone2
author_rank: Super Contributor
timestamp: October 11, 2018, 12:35:48 pm
content: well I am a proponent of EDC, you should have a knife on your belt if you are walking something with a leash. That's common sense to me, I feel unease roping down an animal.Same for wearing clothing with a zipper... if you catch on fire you wanna be able to cut it off immediately. If the zipper gets stuck. Also for cutting stuck seat belts, or even removing shoe laces.IMO elevators suck and fuck with me psychologically. A good elevator IMO would have a indicator of where the elevator is on every floor, not with dummy lights but an actual bar graph type deal that shows its actual height in the building, so anyone can see if the thing is fucking stuck. Some windows into the elevator shaft would not hurt too. I don't use the things anyway. Last thing I wanna do is urinate on the floor next to a stranger because my legs hurt. But they should be built better for crippled people anyway. And if you use it frequently you would have an analog parameter to look at, like its speed and how smooth its moving, so you have an idea that its working properly. Any degradation in expected behavior might tip off a elevator technician early.

author: Siwastaja
author_rank: Super Contributor
timestamp: October 11, 2018, 12:57:24 pm
content: Quote from: Berni on October 05, 2018, 07:06:41 pmThe greatest thing in brushless motors, safety-wise, is that theydoneed the "computer in the chain". Because theystopinstantly, if the computer generating the 3-phase waveforms stops. And making a complex computer stop is simple. Short the Vcc line for the MCU, and the motor stops, 100% guaranteed. Cut the power to the MOSFET/IGBT gate drivers at the same time to be extra sure.There are quite a few incidents with conversion EVs when done with brushed DC motors. You know, poorly specified contactors do weld short...You can even make your safety switch short two phases of the BLDC motors together, and it will brake. But this is ugly. A reliable mechanical brake is of course a must in a passanger vehicle capable of some serious speeds, and it should indeed work through the normal braking interface. It's not going to ruin the range. The amount of energy retrieved back during heavy braking (quick stops) in miniscule.

author: coppercone2
author_rank: Super Contributor
timestamp: October 11, 2018, 01:04:38 pm
content: I wonder realistically how much of the consumer base they would lose if they put a Kill switch on it? Is it some long term dastardly plot to eliminate mechanical breaks in the future? (it's so good we don't even need a kill switch?)Who came up with this design philosophy?

author: coppercone2
author_rank: Super Contributor
timestamp: October 11, 2018, 01:10:06 pm
content: https://www.quora.com/Why-do-older-elevators-have-emergency-stop-buttons-whereas-newer-elevators-dontThis is interesting though, it gets into the whole robocop thing of machines making better decisions then man.. It's also a potential rape boxBut eventually with cars becoming networked and having collision avoidance AI radar and shit you have to make a serious decision to push a e-stop button... will the law give man the power? And what if it gets hacked? I could see it happening in 3rd world countries for kidnappings.I think I will take the stairs though, thanks. Heart health and all. And if I get a electric car I will wire a kill switch.

author: Marco
author_rank: Super Contributor
timestamp: October 11, 2018, 06:02:31 pm
content: Quote from: Mr. Scram on October 04, 2018, 03:56:58 pmMy sis works with mentally challenged people and the slightly larger electrical cart they have has one. The Stint should have had deadman's cord in my opinion, too trivial to fall off. Commercial vehicles for passengers should have higher safety standards than consumer vehicles.On a normal bicycle you can throw the steering wheel 90 degrees, you can always stop right quick by falling over. In a car you have two mechanical breaking systems with enough power to fight the engine. The Stint has less control than a bicycle and the breaks did not have sufficient power to fight the engine at full power. The thing was a mess and an accident waiting to happen.

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 11, 2018, 07:15:29 pm
content: Most consumers of Elevator equipment have no idea how to properly configure or maintain the device. Even if they think they do...they don't. The elvator techs do, but they only fix what's needed and only so often, and since a lot of people can't identify a fault when it occurs, you get crap likeQuoteWhich looks like some sort of way overadjusted sensor (better not be deliberate). It should never stop unless there is a real problem, this would be likely be classified as a serious fault.

author: RobK_NL
author_rank: Frequent Contributor
timestamp: October 11, 2018, 07:16:23 pm
content: Quote from: Marco on October 11, 2018, 06:02:31 pmMy own, human powered, cargo bike weighs about 45kg, has meticulously maintained breaks, but in case of an emergency, it would still require the weight and power of that same human to stop the thing just short of dead.A Stint weighs just under 300kg empty and has a ~1000W motor. Try and stop that ...They are quite agile, though, so the drivercouldhave made a sharp turn. But I can well imagine the confusion and the growing panic when there's no response from the vehicle and before you know it, it's too late.These things were specifically designed to move children, they even have frigging seatbelts because, you know, "safety first". So why not a kill switch?

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 11, 2018, 07:23:12 pm
content: Quote from: Marco on October 11, 2018, 06:02:31 pmCan you show us an electric car, shuttle or bus with a safety stop? I don't think there are many road vehicles that have one, if any.While I appreciate the criticism and ideas of the people here, I have to admit many sound rather hindsighty. As is the case with so many accidents, in hindsight all the critics come out to point out the obvious flaws that apparently weren't so obvious before the accident.

author: jmelson
author_rank: Super Contributor
timestamp: October 11, 2018, 07:34:08 pm
content: Quote from: Jeroen3 on October 11, 2018, 12:34:43 pmCable-suspended elevators have multiple safety systems. One of them is a slack cable sensor. They generally have 4 cables, each of which could support the elevator cab, at least for a short time. A sensor detects if ANY cable loses tension. This will happen BEFORE the cable totally fails, but as a few of the strands break. It becomes longer than the other 3 cables, thus going slack. This generally requires all cables to be replaced before the elevator can be returned to service.The hoist engine at the top of the shaft has a mechanical brake that can wear out. This brake holds the car in place when the drive shuts down after a few minutes of non-use. If the brake fails, the empty car would start to move up, as the counterweight weighs more than the empty car. There's a system to detect movement when the car is not supposed to be moving.Finally, there's an overspeed sensor. This consists of a FIFTH cable, smaller than the main cables, connected to a wheel at the top with a latching flyball governor. It is set to trip at JUST above the normal elevator speed. If the elevator exceeds the normal speed, the flyball governor flips, and has to be reset by the elevator repairman. Jumping in the elevator while it is moving can get the overspeed cables bouncing and flapping, and causing it to trip the overspeed sensor. it might also get the suspension cables to flap enough to trigger the slack cable sensor.If these sensors trip, they cut power to the emergency brakes on the car, which are designed to halt a fully-loaded elevator car while descending, and are designed as fail-safe. Loss of power will trip them, too.Jon

author: lamello
author_rank: Contributor
timestamp: October 11, 2018, 07:59:16 pm
content: Quote from: Mr. Scram on October 11, 2018, 07:23:12 pmEvery of those vehicles have one, it's called: working breaks.The stint has a combined motor and breaks. So if the motor goes crazy, there is a great possibility the breaks are not responding.This and combined with a weak mechanical break, a plain example of a bad design, safety as an afterthought.I am also interested how this vehicle is allowed by the government on the public road.

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 11, 2018, 08:09:55 pm
content: QuoteIt should not do that, that's improper maintenance. Everyone in the elevator jumping might cause that, but one person causing it is an overactive sensor that should be recalibrated. Unless you happen to be...well...excessively large.

author: cdev
author_rank: Super Contributor
timestamp: October 11, 2018, 08:27:20 pm
content: This is my favorite elevator scene..

author: ruffy91
author_rank: Regular Contributor
timestamp: October 11, 2018, 08:32:13 pm
content: Pleas stop breaking cars.This is a huge environmental issue if all your cars have pedals which cause your car to break so you have to get a new car every time you hit it..

author: Berni
author_rank: Super Contributor
timestamp: October 12, 2018, 05:46:25 am
content: Quote from: Cyberdragon on October 11, 2018, 08:09:55 pmYou can generate pretty significant forces by jumping. A plank that can hold the weight 3 people can be easily broken by 1 person jumping on it. If whatever you are standing on also has a pronounced enough resonance frequency you can sense it and tune jumping to match it. This uses the mass of the structure itself to exert even larger forces. And id imagine elevators can have a resonance under a few Hertz as a combination of the cable stretch and the mass of the cabin (You can clearly feel the oscillation if you jump).Yeah you could probably make it a lot less likely to trip from a person jumping unless they really try hard and catch resonance but i'm sure most people prefer the safety systems to be on a hairline trigger just in case something does go wrong (Even tho elevators are incredibly safe things)

author: nctnico
author_rank: Super Contributor
timestamp: October 13, 2018, 09:01:19 pm
content: Off-topic: Elevators and karma. True story. One of my relatives helps people to make travel arrangements like booking flights and train tickets. About 6 persons from a larger group found it necessary to go into an elevator which was specified for 4 persons. As a result the elevator got stuck between two floors. This made them miss the train so over 1000 euro worth of train tickers down the drain and on top of that they got charged with another 1000 euros for needing to be resqued from the elevator. Speaking of expensive mistakes.

author: LapTop006
author_rank: Unknown
timestamp: October 14, 2018, 12:24:37 pm
content: Quote from: nctnico on October 13, 2018, 09:01:19 pmHah, reminds me of the lifts at $JOB[-1], for a while they were regularly breaking down, and while the tech's would always get people out quite quickly, it got annoying fast (I only got stuck once).One of our building neighbours was a government department, who, as the story goes, moved out after the minister got stuck in the lifts.

author: b_force
author_rank: Super Contributor
timestamp: October 29, 2018, 08:29:52 am
content: Today on the news, the company is filing for bankruptcy.I feel actually sad for them.I can understand that investigation was needed, but because of all the drama (thanks to the media), their name basically isn't worth anything anymore.

author: Kjelt
author_rank: Super Contributor
timestamp: October 29, 2018, 10:16:21 am
content: Quote from: b_force on October 29, 2018, 08:29:52 amTheir product is under investigation, it was declared not road safe, all outstanding orders were cancelled and their rental business stopped overnight.Since that was their only product, revenues stopped over night, no income and a lot of paychecks to pay : over and out.

author: nctnico
author_rank: Super Contributor
timestamp: October 29, 2018, 11:05:00 am
content: Quote from: b_force on October 29, 2018, 08:29:52 amIMHO the company (called Stint) should have handled things better. From what has been in the news they went into some kind of denial mode and went against the findings of the government agencies. That is a fight you'll always lose. The frustrating part of dealing with government agencies is that even when they are wrong they are still right.

author: Kjelt
author_rank: Super Contributor
timestamp: October 29, 2018, 11:12:02 am
content: Quote from: nctnico on October 29, 2018, 11:05:00 amI agree but don't think it would have changed the outcome.The government covered their asses almost immediately when the accident occurred trying to prevent that they would be sued by allowing an unsafe vehicle on the road, or as they say prevent future accidents (read as: prevent future lawsuits).So the outcome would have been the same, no road allowance, no income from new sales or rents: game over.

author: b_force
author_rank: Super Contributor
timestamp: October 29, 2018, 11:12:39 am
content: Quote from: nctnico on October 29, 2018, 11:05:00 amThat's what I mean I feel sad for them.Also if this wasn't been in the news so big and the government didn't respond so dramatic, the whole investigation procedure would have been different.I said it before, I agree that some critical safety system seems to be missing, but this way time, effort, money and even maybe a potential very nice product is just completely being wasted. (not to talk about the workers who have to find a new job, also not very nice to have on your CV)That's what you get when people only think about the problems, and not about solutions, so unfortunate.

author: Kjelt
author_rank: Super Contributor
timestamp: October 29, 2018, 11:15:25 am
content: This does not have to be the end.The inventor/owner can still wait till the storm is over in the mean time invent all necessary safety systems to upgrade the 3500 stints that have been sold and then when the time is right sell these upgrades and restart sales with the safe version.

author: b_force
author_rank: Super Contributor
timestamp: October 29, 2018, 11:17:59 am
content: Quote from: Kjelt on October 29, 2018, 11:15:25 amPaid how?

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 29, 2018, 11:19:19 am
content: Quote from: b_force on October 29, 2018, 11:12:39 amAs I understand it, an entire vehicle category is effectively being eliminated because of one accident. You have to wonder whether this improves things, as people will now flock to regular vehicles for transportation with all the associated risks and costs. There's a fair chance that things have actually been made worse, but that the cost is hidden in numbers people are already used to.

author: Kjelt
author_rank: Super Contributor
timestamp: October 29, 2018, 11:20:35 am
content: Quote from: b_force on October 29, 2018, 11:17:59 amWhat do you mean paid how ?You mean how the inventor gets paid in the meanwhile?He pays himself from his savings of his massive earnings he made the previous years on selling the 3500 units.

author: b_force
author_rank: Super Contributor
timestamp: October 29, 2018, 11:23:47 am
content: Quote from: Kjelt on October 29, 2018, 11:20:35 amNo the people you need to make these improvements happen.

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 29, 2018, 11:26:04 am
content: Quote from: b_force on October 29, 2018, 11:23:47 amHow do you develop a product?

author: b_force
author_rank: Super Contributor
timestamp: October 29, 2018, 11:28:29 am
content: Quote from: Mr. Scram on October 29, 2018, 11:26:04 amThat depends per person.But a product like a Stint definitely not just by yourself.

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 29, 2018, 11:29:23 am
content: Quote from: b_force on October 29, 2018, 11:28:29 amSo how do products with teams of more than one person get developed?

author: b_force
author_rank: Super Contributor
timestamp: October 29, 2018, 11:30:44 am
content: Quote from: Mr. Scram on October 29, 2018, 11:29:23 amAt least with some money to pay the wages.

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 29, 2018, 12:56:10 pm
content: Quote from: b_force on October 29, 2018, 11:30:44 amHow can startups pay for this?

author: Berni
author_rank: Super Contributor
timestamp: October 29, 2018, 01:15:15 pm
content: Quote from: Mr. Scram on October 29, 2018, 12:56:10 pmBy bullshiting investors to give them money. Just like solar roadways, fontus, ubeam etc

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 29, 2018, 01:36:22 pm
content: Quote from: Berni on October 29, 2018, 01:15:15 pmI wouldn't quite describe investments and loans like that, but there you go. That's how it's done. If the owner of the IP of this company can show there's still a viable business, there will no doubt be someone who is prepared to provide them with money to get it going again.

author: cdev
author_rank: Super Contributor
timestamp: October 29, 2018, 01:42:01 pm
content: Its good we've discovered now that AC currents running in railroad tracks may sometimes play havoc with the control electronics in some EVs if those electronics aren't designed properly with grounding and shielding throughout so that everything is resistant to them. That seems like common sense.PuttingSTRAPPING all the boards grounds at a common ground potential and perhaps shielding all the cables inside of a metal braid sleeve would likely fix it..That seems like a best practice that most designers would/should be doing but its possible some forgot to, so putting that as a requirement in regulations is a good thing. They probably don't need to specify a testing scenario, just describe the good practices needed to avoid the problem.

author: glarsson
author_rank: Frequent Contributor
timestamp: October 29, 2018, 01:48:49 pm
content: If it plays havoc with electrics in electrical vehicles then it will play havoc with electronics in other types of vehicles. We haven't seen this, so the problem either does not exist of it is already solved. What's left is an incompetent bicycle manufacturer...

author: eugenenine
author_rank: Frequent Contributor
timestamp: October 29, 2018, 01:49:58 pm
content: Quote from: nctnico on October 02, 2018, 05:30:07 pmMore likely his car has an automatic transmission and the difference between the input and output shaft is pretty low when coasting so the torque convertor allows it.Wife's car was like that, you could take your foot off the gas on the highway and it could take miles before it coasted to a stop.Even worse was Chrysler's auto transmission which would shift to a higher gear when going downhill to allow coasting. I had to replace the brakes in ours every fall after driving in the mountains of WV because it prevent ed you from engine braking. Yes it would actually over-ride what you had selected with the shift lever.

author: nctnico
author_rank: Super Contributor
timestamp: October 29, 2018, 02:12:46 pm
content: Quote from: b_force on October 29, 2018, 11:23:47 amYou also have to take into account that Stint is likely to receive some big claims. Even with an investor the company may not be financially viable. That doesn't mean someone can buy the IP and produce an improved version (which will take an investment as well). From the information available it seems Stint slapped together some circuit boards from China and made something which works. There isn't even an English version of the software to read the information from the motor controller.

author: cdev
author_rank: Super Contributor
timestamp: October 29, 2018, 02:27:24 pm
content: Bicycles are different than cars because of the way the chassis is divided into two parts, with the front wheel rotating and the front handlebars serving as an anchor for the various electronics and "control surfaces". That makes it entirely possible that assuming 'grounding' between the main part of the bike's body and the handlebars (through greasy roller bearings?) wouls not be wise without additional strapping. But people do it, bike mechanics in particular are used to only running a single positive wire for tail lights, etc. Fine for a light but inadequate for digital electronics.. If I was designing an e-bike I would definitely - right at the start- make sure all PCBs were strapped together with a flexible, thick conductor that could not be detached without disabling the entire bike. I could see bad design though, especially when they were designing a really cheap ebike, using a cheap cable harness which might not always make positive contact, or worse, just assuming that the two were grounded when in fact they were not, and that causing problems - even if there was a ground loop larger than an inch or so - a really powerful magnetic field might induce a voltage causing some onboard computer to throw an error and reboot, lets say. (enough to make bits flip?) Reboot might well mean vehicle immobility while the computer recovers. That may be what happened.Really the worst possible thing that could happen on a train track with a train coming!Brakes should always be manual and non-electronic if possible! But on some cars, even the brakes are computerized. (this is done to prevent the loss of control that happens when brakes seize up on ice or similar) "anti-lock brakes" a highly desired safety feature.

author: eugenenine
author_rank: Frequent Contributor
timestamp: October 29, 2018, 02:30:33 pm
content: Quote from: Marco on October 11, 2018, 06:02:31 pmActually you don't. That was part of the Toyota problem. The brakes can stop a vehicle at speed but when the accelerator was stuck full on the brakes quickly overheated and faded to less that useful. We have random safety stops here and they had me set the parking brake then try to move the vehicle to make sure the parking brake held but if your vehicle is already moving at 70+ mph it takes a lot more force to stop it than it does to hold it already stopped, I haven't seen many parking brakes capable of stopping a vehicle moving at high speed.

author: cdev
author_rank: Super Contributor
timestamp: October 29, 2018, 02:51:02 pm
content: The moment either a story like this which indicates a design mistake that could be dangerous emerges or even when they become aware of a potential defect internally, that hasnt impacted anyone, either way, an effected company should go into high gear, not just offering a free retrofit, they should pay to have the retrofit done on their dime, as quickly as possible.If a customer wants a return rather than retrofit, they should offer to buy it back, maybe for a price that is somewhere between the new price and its resale value without any potential issues. And eat the cost difference.Turning a potential disaster into an opportunity to build customer loyalty.If society doesnt incentivize that kind of behavior and strongly deincentivize corporate irresponsibility it wont be long before we have a world where corporations ignore consumer safety, choosing to fight lawsuits rather than fix things. At least here in the US its an ugly secret that lawyers rarely take many kinds of cases on contingency, because even in really egregious cases of error or even intentional abrogation of responsibilities on all levels, for decades - on a big corporation's part, (and that happens all the time with profitable products) the value of a human life varies a lot with many peoples lives simply not being valuable enough in terms of damages to make a lawsuit 'worth it' for an attorney. (Its based on lost income and 'pain and suffering'.) The perception of plaintiffs in cases where some policy or product is at error getting huge damages in court is not backed up by statistics, instead the statistics show a dismal picture of people being injured and not ever getting the justice they need. (or if they have insurance often that insurance contains a 'subrogation' clause which means the insurer gets whatever money they might win, to repay them for whatever money was paid on their behalf, first)There is a general perception in society that things are supposed to get better for people but honestly, we really need to work much much harder to get businesses to do the right thing, as a matter of habit, otherwise even though we know more now than we once did, it won't translate into more safety.

author: b_force
author_rank: Super Contributor
timestamp: October 29, 2018, 03:45:37 pm
content: Quote from: Berni on October 29, 2018, 01:15:15 pmThat doesn't happen overnight plus they already have a bad reputation (doesn't matter if it was their fault or not)I guess filing for bankruptcy makes a lot of sense.They're not responsible anymore for any claims and customer service.Once people forgot the name you bring out something similar under a different brand and a different look.

author: nctnico
author_rank: Super Contributor
timestamp: October 29, 2018, 04:13:08 pm
content: Quote from: cdev on October 29, 2018, 02:27:24 pmThat is not quite right. Even without power braking, anti-lock brakes, etc working the brakes on a car will still work. You'll have to put your foot down harder but they will work. OTOH I doubt that the brakes are powerfull enough to stop the car with the engine running at it's peak output power.

author: helius
author_rank: Super Contributor
timestamp: October 29, 2018, 04:20:34 pm
content: The ABS is typically pneumatic, while the main brakes are hydraulic. So the calipers have both fluid and air (or vacuum) actuators. Even removing the ABS module will leave the hydraulic brakes functional (any car with a brake fluid tank has that manual system, assisted with a pressure booster).

author: glarsson
author_rank: Frequent Contributor
timestamp: October 29, 2018, 05:53:10 pm
content: Quote from: helius on October 29, 2018, 04:20:34 pmNone of the cars I have looked at has an ABS system matching this description.

author: helius
author_rank: Super Contributor
timestamp: October 29, 2018, 05:59:59 pm
content: I should have prefaced it with "in my experience..." as I don't claim universal knowledge. Still, I'm curious how else a vehicle with a central master brake cylinder can implement ABS with individual wheel slip detection and response.

author: nctnico
author_rank: Super Contributor
timestamp: October 29, 2018, 06:41:01 pm
content: Quote from: helius on October 29, 2018, 05:59:59 pmPerhaps read first before making assumptions. A car with ABS definitely doesn't have pneumatic and hydraulic actuators on the calipers! There is a hydraulic ABS unit (often called an 'ABS pump') sitting in between the hydaulic line from the master cylinder and the hydraulic lines to the individual wheels. I don't know how this unit works internally but Google should be able to tell.

author: glarsson
author_rank: Frequent Contributor
timestamp: October 29, 2018, 07:16:04 pm
content: Quote from: helius on October 29, 2018, 05:59:59 pmThe ABS system for a car normally has four or three channels. A three channel system does not treat the rear wheels individually.Each channel has a valve in the ABS unit that can release hydraulic pressure and therefore lighten the brake power. The ABS electronics use wheel sensors to sense wheel rotation nd then decides what wheel/wheels, if any, needs reduced braking force. When a valve pulses the hydraulic pressure you can feel, and hear, vibrations in the brake pedal.The hydraulic pressure is created, just like in non-ABS brakes, by the master cylinder with assistance of vacuum servo, vacuum pump, and/or hydraulic pump.If the car has stability support, e.g. ESP, it is usually integrated into the ABS unit. An extra set of valves is used to add hydraulic pressure to one of more brake calipers.

author: helius
author_rank: Super Contributor
timestamp: October 29, 2018, 07:31:36 pm
content: I see. Thanks for educating me on the specifics.In the video nctnico posted, you can see 12 small cylinders in the ABS controller. As they are not covered in DOT4, I presumed that they were pneumatic valves, but without a full understanding. They are actually only the outer inductor part of a hydraulic valve whose inner part is sealed into a separate block.With the electrical part removed, the hydraulic ABS valves remain in their normal position, which allows pressure to actuate the calipers when the brake is pressed. When the valves are pulsed by the ABS system, they unload the pressure from the calipers which reduces brake force. There is also a motor in the unit to provide braking force independent of the master cylinder for traction control (which combined with electronic throttle control, can reduce power to the wheels if they are spinning due to too much torque).

author: eugenenine
author_rank: Frequent Contributor
timestamp: October 30, 2018, 02:01:20 pm
content: There are a lot of people who don't understand ABS. I've heard people telling how they swerved around another car and "ABS saved their life" then later having to make a panic stop on a wet road and tell about how the pedal went to the floor and the car made noises and don't understand that was the first time they actually engaged the ABS. Or others claiming how ABS can pump the brakes millions of times a second and fail to understand that the fluid will dampen the pulses so the pads aren't moving a million times a second. Or that ABS is still reactive in that it takes a short amount of time to detect wheel stoppage (depending on how long of a delay is programmed to prevent false positives) so that it can't beat good driving where the driver can be pro-active. Its been shows that people with ABS simply drive faster since the abs will; save them (simplifying here for brevity). As vehicles become more and more appliance like we are going to have more and more accidents where the vahicle manufacturer is to blame since they didn't make it idiot proof enough.

author: cdev
author_rank: Super Contributor
timestamp: October 30, 2018, 02:16:58 pm
content: I just wanted to mention a thought that I had. People on sites like this don't realize it but user communities like this one are really important in the feedback loop - the process of getting manufacturers to build safe equipment everywhere. If it wasn't for the voices of people saying "look at this horrible design" when one is found, and peer pressure, even across international and language borders, the situation would get totally out of control.This thing with train crossings, there is a good chance that this is an occult cause of a fair number of fatal accidents, and it needs to be told, because the people who experienced it may not have gotten or get to tell the story because they are dead.Very strong magnetic fields may exist wherever roads cross energized tracks- The smaller electric trains or trolleys usually have the power in overhead wires, they are farther away so likely not a major problem, but sometimes they go below and then they may be, I dont know, it seems quite plausible to me.In the pre-MP3 era, I used to ride electric trains (The Bay Area's 'BART', SF's Muni Metro) wearing various Walkman style tape players - a lot - and often heard a whine in my headphones from the magnetic fields in the environment.A strong magnetic field combined with bad design (especially grounding and intercommects between different parts of an e-vehicle) might cause an error in a microcontroller severe enough to make them reboot on a train crossing.

author: helius
author_rank: Super Contributor
timestamp: October 30, 2018, 02:37:38 pm
content: With overhead catenary power, the return path is through the rails (and you will see short jumpers welded to the track to ensure electrical continuity across track switching points). Even in railways that are not electrified, there is current passing through the rails for signaling.

author: cdev
author_rank: Super Contributor
timestamp: October 31, 2018, 03:58:43 am
content: I've seen those small wires but there is absolutely no way that they could carry enough current for a trolley car by themselves. The track sections are always connected by metal plates with (bolts? rivets?) too, but they always look dirty and/or rusty and likely not perfect conductors either.

author: Kjelt
author_rank: Super Contributor
timestamp: December 13, 2018, 10:54:49 am
content: Today the results of an independent investigation by TNO has been published.Although I haven't seen or read the final report, the minister has continued the roadban for this vehicle.The media say (translated from quote below)TNO has conducted an investigation of the stint vehicle on six important vehicle safety points.On all six points the vehicle failed the safety norms.Problems can occur with the brake of the vehicle, the brakedistance en an uncontrollable acceleration of the vehicle can occurr where by the driver no longer has control over the vehicle.Looks like the company can be blamed for not taking care of these issues.Quote from:www.nu.nl

author: Jeroen3
author_rank: Super Contributor
timestamp: December 13, 2018, 01:29:31 pm
content: Publications.https://www.tno.nl/nl/over-tno/nieuws/2018/12/presentatie-veiligheidsanalyse-stint/TNO-2018-R11484TNO-2018-R11485Conclusion points, translated:- None of the investigated vehicles brakes meet the 4 m/s2deceleration.- None of the investigated vehicles offer a seat for the driver, increasing the risk of the driver falling of the vehicle. Losing control.- Losing the "nuldraad", (negative wire) of the throttle results in undesirable acceleration. This can only be prevented by moving the throttle to 0%. However, it is deemed unlikely a driver in this situation would perform this action.- The automatic parking brake can result in dangerous situation when activated spontaneously. Many failure modes activate the parking brake.When on a dangerous location the vehicle can only be moved when manually lifting the parking brake.QuoteEMC tests conclude the drivetrain of vehicle H304 is not unacceptably influenced by electromagnetic radiation, including high field strengths or other orientations than described in the standard.The LCD is affected by electromagnetic radiation. This does not comply to the standard.There is also a recommendation document. But I'm not a translation service.

author: Ice-Tea
author_rank: Super Contributor
timestamp: December 13, 2018, 02:08:31 pm
content: In other words: it's junk, but it did not accelarate due to radiation related to the train stuff, right?

author: Jeroen3
author_rank: Super Contributor
timestamp: December 13, 2018, 03:56:17 pm
content: Above report is an investigation into the safety of the type of vehicles by TNO.Not a forensic investigation in the crashed vehicle.They have found that, using standardized electromagnetic interference testing, the drivetrain functions as specified. (Appendix 6 VN/ECE Reglement 10).The display stops functioning between 47 tot 57 MHz.There still is no report on the technical cause of the crashed vehicle.

author: Berni
author_rank: Super Contributor
timestamp: December 13, 2018, 04:54:11 pm
content: Tho EMI immunity testing never exposes it to a strong 50Hz magnetic field. They stay in the MHz range for immunity testing because that's where its possible to produce lots of RF power with those antennas.

author: metrologist
author_rank: Super Contributor
timestamp: December 13, 2018, 05:32:50 pm
content: Quote from: Raj on October 02, 2018, 07:01:34 amYep. Everything was fine until the turn...

author: RobK_NL
author_rank: Frequent Contributor
timestamp: December 13, 2018, 07:57:10 pm
content: Quote from: Kjelt on December 13, 2018, 10:54:49 amAgreed, but our erstwhile government (f-ing Camiel Eurlings ... again!) is equally to blame for circumventing European legislation in order to "get these things on the road!"

author: jmelson
author_rank: Super Contributor
timestamp: December 13, 2018, 08:33:39 pm
content: Quote from: helius on October 29, 2018, 04:20:34 pmNo. The brake booster is pneumatic (or vacuum-actuated, to be pedantic). But, the ABS system is all hydraulic. There are CERTAINLY no air/vacuum cylinders or lines in the brake calipers. Just look at one, sometime, there's just ONE pipe/hose to the caliper. The pneumatic booster is on the firewall, attached between the brake pedal and the master cylinder.There are failures in the ABS control valve that will cause one wheel to lose all braking, but since the ABS system has to have individual control of each wheel, then it should only affect one wheel. These failures should be rare, as this is a safety-critical system, but due to corrosion and contaminants, it can happen.Today, most cars have VSA as well as ABS, so the system can not only interrupt braking pressure to any wheel, it can also apply the brakes on any wheel that is spinning due to low traction. So, there is a lot more stuff between the brake pedal and the wheel cylinders.Jon

author: Kjelt
author_rank: Super Contributor
timestamp: December 13, 2018, 09:13:12 pm
content: Quote from: RobK_NL on December 13, 2018, 07:57:10 pmYes saw the news they were really not paying attention back then

author: Halcyon
author_rank: Unknown
timestamp: December 14, 2018, 12:59:05 am
content: Quote from: CM800 on October 01, 2018, 09:23:50 pmI've never quite understood this rule.How does a device not "accept" interference? If it were a choice, why wouldn't you design a device to reject interference, particularly of the type which causes undesired operation?

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 14, 2018, 01:16:14 am
content: Quote from: Halcyon on December 14, 2018, 12:59:05 amIn their definition of "accept" seems to mean "take" or "endure".

author: nctnico
author_rank: Super Contributor
timestamp: December 14, 2018, 01:18:59 am
content: Quote from: Jeroen3 on December 13, 2018, 01:29:31 pmBut that doesn't say the standard is adequate and nothing can go wrong due to a pulse which has more energy. We'll have to wait until the accident report is ready to see if they have been able to find the root cause of the accident and if they did find the cause, what is the cause.

author: Halcyon
author_rank: Unknown
timestamp: December 14, 2018, 05:38:41 am
content: Quote from: Mr. Scram on December 14, 2018, 01:16:14 amSure and that's how I interpreted it, but if a device "accepts" interference but doesn't operate correctly because of it, how is that considered "accepting" or "enduring". To me if a device accepts interference, it performs more or less the same as it would without interference.For example, if a computer suffers from interference but continues to operate, that to me is endurance. If a computer locks up or reboots due to interference, that product doesn't "accept" interference.The wording is just very strange in my opinion.

author: nctnico
author_rank: Super Contributor
timestamp: December 14, 2018, 03:39:07 pm
content: I agree. My guess is that an external electrical field shouldn't damage the device. For a machine this probably means going into a safe state and/or recover into a safe state.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 14, 2018, 05:37:49 pm
content: The FCC doesn't care about function, only emission. They recommend you do the usual tests (immunity to conducted, radiated and transients), but do not require it.CE does however require both.Tim

author: coppercone2
author_rank: Super Contributor
timestamp: December 14, 2018, 10:16:30 pm
content: Quote from: Berni on December 13, 2018, 04:54:11 pmthe military does this test with Helmholtz coils. I have some threads on this.

author: Berni
author_rank: Super Contributor
timestamp: December 15, 2018, 09:02:50 am
content: Quote from: coppercone2 on December 14, 2018, 10:16:30 pmI would like to see one these glorified segways put into such a coil.Tho in the case of this incident the train was likely running on 750V DC. So there would be a constant field, but the contacts bouncing as the train moves probably causes some very sharp transients in the current. Such sharp transients would be particularly nasty for interference since the sharper the change the more voltage the field will induce in conductors.Out of curiosity do these trains make compass needles go crazy around them when they go full throttle?EDIT: Yes it seams to be 1.5kV instead of 750V for that train.

author: nctnico
author_rank: Super Contributor
timestamp: December 15, 2018, 11:26:56 am
content: The trains in the NL run from 1500V DC.

author: Berni
author_rank: Super Contributor
timestamp: December 15, 2018, 12:46:50 pm
content: Ah yeah my mistake. 750V is only used in some towns there. But it is not the new 25kV 50Hz AC system (Likely not as bad magneticaly due to lower currents).

author: eugenenine
author_rank: Frequent Contributor
timestamp: December 19, 2018, 12:44:12 pm
content: Also the lab tests are probably;y done on normally working samples. The one that hit the train could have had a failed filter cap which let more EM into the system causing the failure.

author: coppercone2
author_rank: Super Contributor
timestamp: December 19, 2018, 01:43:34 pm
content: scary shit that vehicles can become unsafe to fields like that now with robots and increased electronics.I wonder if car inspections in the future will feature EM test chambers.

author: Kjelt
author_rank: Super Contributor
timestamp: December 20, 2018, 04:47:40 pm
content: Quote from: coppercone2 on December 19, 2018, 01:43:34 pmThat is already the case for the design.I visited KemaKeur (now Dekra) around 2009 or so and there were four Lotus sportscars lined up to be tested in the EMC chamber.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: December 20, 2018, 05:17:31 pm
content: Here is heavy equipment being tested at up to 200 V/m:https://www.elitetest.com/testing-services/emiemc-testing/truck-automotive-emc-testing/emc-testing-heavy-equipmentConsumer equipment is typically 3 V/m, with industrial equipment at 10 V/m.

author: nctnico
author_rank: Super Contributor
timestamp: December 20, 2018, 07:10:26 pm
content: Quote from: Tomorokoshi on December 20, 2018, 05:17:31 pmAutomotive levels are much higher. IIRC up to 75V/m.