Redundancy/Failsafe: Still no solution?

[RooEUC]

A year ago, or maybe longer, I started a thread in which we discussed redundancy ideas, ie. mechanical or electrical devices that could keep us upright in the event of a power system failure.  Nothing really practical was determined.  Today I see EUCs are being built to be increasingly larger, increasingly faster and to have much more range.  Many of you ride on public roads in and out of traffic.  But I still don't see any evidence that the face-plant risk has been addressed by way of a failsafe mechanism.  We are still at the mercy of the onboard computer, batteries and electrical components on every ride, trusting and hoping that one of the scores of components won't fail.  I think in time, every wheel will eventually fail and cut out unexpectedly.  

I enjoyed a decade of electric skateboard riding without an electrical failure causing me injury because 4 wheels provide exceptional protection in the event of a power failure and the board just comes to a stop.  EUCs are so much more enjoyable, comfortable and practical as a mode of transport for me.  But the constant fear of it cutting out makes me feel that in a few years I will probably retire from EUCs before I acquire some permanent injuries or death when the power system fails, unless the safety can be improved in that time. 

I know some of you work in the EUC business and some of you are engineers that work in somewhat related fields.  The OneWheel has a couple of options that help slightly in the event of a cut-out, such as 'Fangs' or additional wheels/sliders out in front that at least give the rider a chance to stay upright when the power goes, until they can jump off safely.  Is there any progress being made at finding a fail safe solution for EUCs? 

[Wonderwebb]

I'm new to euc and am surprised no one has come up with something  yet . I keep thinking of a magnetic  catch that would hold two small casters one front one back that would deploy under power loss much like a fire door magnetic  release.   Can you point me to the old thread so I can see what you came up with ?

[RooEUC]

3 hours ago, Wonderwebb said:

I'm new to euc and am surprised no one has come up with something  yet . I keep thinking of a magnetic  catch that would hold two small casters one front one back that would deploy under power loss much like a fire door magnetic  release.   Can you point me to the old thread so I can see what you came up with ?

That's one of them.  There was another where we discussed having a little wheel in front.  I think I photoshopped a concept.  If I find that thread I'll link it. 

 

 

Edited June 22, 2019 by RooMiniPro

[RooEUC]

Here it is:

 

[LanghamP]

25 minutes ago, RooMiniPro said:

Here it is:

 

This taken to another logical conclusion.

I'm joking but not really joking, because due to past crashes ala @Hunka Hunka Burning Love I've dramatically reduced my EUC mileage. I very rarely ride my EUC for pleasure, and use it strictly for low-speed short-range practical transportation.

I will point out that the EUC is incomparably more compact than my bicycles, of course stating the obvious, and so the EUC is incredibly practical.

Edited June 22, 2019 by LanghamP

[RooEUC]

I do love a nice, minimalistic e-bike.  That's a particularly nice example of one.  I converted a mountain bike and a street cruiser to electric a few years ago.  But they were far from being 'throw them in the back of the car beside the groceries' devices.  Yes, the tiny size and weight of EUCs make them so practical, considering how far they can take us, and how quickly. 

I have not yet had a fall.  I guess I have been lucky, after riding these self balancing things for 2 years as my most often used form of transport in my locale.  My EUC has enabled me to cut down how often I use the car quite dramatically in the warmer months.   But damn, one battery failure, mosfet failure or software bug could put me in a wheelchair for the rest of my life.  There must be a way to prevent this.  I remain hopeful that one of us, or someone much smarter can think up a solution within 5 years.  I feel like I'm on a ticking time bomb when I ride at any speed greater than a light jog.  I see plenty of people on this forum wreck themselves and I'm hoping not to add to the statistics.  Now that I have upgraded my wheel to 30kph and often ride at around 25kph, I know a cut out is going to hurt a lot and may leave me unable to do a lot of important things I need to do.          

Edited June 23, 2019 by RooMiniPro

[LanghamP]

23 hours ago, RooMiniPro said:

My EUC has enabled me to cut down how often I use the car quite dramatically in the warmer months.   But damn, one battery failure, mosfet failure or software bug could put me in a wheelchair for the rest of my life.  There must be a way to prevent this.  I remain hopeful that one of us, or someone much smarter can think up a solution within 5 years.  I feel like I'm on a ticking time bomb when I ride at any speed greater than a light jog.  I see plenty of people on this forum wreck themselves and I'm hoping not to add to the statistics.  Now that I have upgraded my wheel to 30kph and often ride at around 25kph, I know a cut out is going to hurt a lot and may leave me unable to do a lot of important things I need to do. 

I don't want to agree with you, but all evidence is your perception of EUCs is exactly correct. I don't think there's a single other forum member who thinks otherwise.

Perhaps only buying the most powerful wheels from Kingsing, limiting yourself to 16 mph, taking a bicycle on the longer rides instead of an EUC, never ever ride down unfamiliar areas, and so on, will reduce but never eliminate crashes.

[mrelwood]

 

On 6/22/2019 at 12:20 AM, RooMiniPro said:

 I think in time, every wheel will eventually fail and cut out unexpectedly.

I’m not so sure about this. Many issues that the EUC may develop, have clear warning signs before cutting out during a ride. Charging issues, decreased range, wheel not powering up normally, etc. Even @EUC GUY’s test where he pushed an actual car around for 6 minutes with the 100V MSX, the wheel started sounding like a drill, enabling him to stop gracefully when the motor wires melted.

I have ridden my 16S for more than 9000km. During that time it has developed a dead battery cell twice, and snapped a bolt that holds the pedal bracket to the axle. Admittedly, my friend unfortunately over-leaned the wheel despite knowing about a battery issue, but none of the three events have caused the wheel to fail without clear warning signs.

 

On 6/22/2019 at 12:20 AM, RooMiniPro said:

But the constant fear of it cutting out makes me feel that in a few years I will probably retire from EUCs before I acquire some permanent injuries or death when the power system fails, unless the safety can be improved in that time.

While not through actual redundancy, general wheel safety has already been improved a lot during the last few years: larger battery capacity, more parallel battery blocks, more headroom in top speed and power, thicker wiring, thicker axles, larger Mosfets, etc. If one buys a new wheel with a good track record, the risk of a sudden cut-out due to wheel failure is extremely small. Take the MSX for example, it is one of the most popular wheels at the moment, yet I haven’t seen one single case of a sudden technical failure that would’ve caused the rider to crash.

Yes, everyone takes calculated risks every time we start riding. But a sudden wheel failure is no longer at the top of the list.

[Warxcell]

I got sudden cutout on my Nikola 100V - good thing it was at 5km/h - wheel was at 4000km. Turned out it blew two mosfets. So yeah, sudden failure is a thing. 

The only thing I can think of (I don't know if its possible) - to split windings inside the motor to two parallel windings, which are controlled by 2 controlboards - and they will work synchronized - and in case of board failure it will disconnect itself from motor and other board will remain in operation - it will lose only half of its power but keep you upright. (well unless you are full lean, but still better than nothing)

[Mono]

15 minutes ago, Warxcell said:

I got sudden cutout on my Nikola 100V - good thing it was at 5km/h - wheel was at 4000km. Turned out it blew two mosfets. So yeah, sudden failure is a thing. 

It feels like something is missing in this story 

It's no secret that, physics surprise, the highest electrical loads occur at the lowest speeds. What is missing: where did the load come from?

Edited March 20 by Mono

[Warxcell]

36 minutes ago, Mono said:

It feels like something is missing in this story 

It's no secret that, physics surprise, the highest electrical loads occur at the lowest speeds. What is missing: where did the load come from?

When prior cutout, on stopping the motor did something strange (like skipping magnetic or something) - then I was cruising at 5km/h and when I began accelerating (nothing crazy) - it face-planted me.

[Warxcell]

I remember from logs latest logged power was 2.7KW.

[Chriull]

1 hour ago, Warxcell said:

on stopping the motor did something strange (like skipping magnetic or something)

That's the firmwares motor current limitation so the mosfets won't fry (to often...)

Seems you overpowered the mosfets...

21 minutes ago, Warxcell said:

I remember from logs latest logged power was 2.7KW.

That's a senseless value reported from begode wheels since the beginning (don't know if they corrected it anytime?). Multiplying battery voltage with motor current gives nonsense...

 

2 hours ago, Warxcell said:

I got sudden cutout on my Nikola 100V - good thing it was at 5km/h - wheel was at 4000km. Turned out it blew two mosfets. So yeah, sudden failure is a thing. 

The only thing I can think of (I don't know if its possible) - to split windings inside the motor to two parallel windings, which are controlled by 2 controlboards - and they will work synchronized - and in case of board failure it will disconnect itself from motor and other board will remain in operation - it will lose only half of its power but keep you upright. (well unless you are full lean, but still better than nothing)

If such in such a construct mosfets fry by overload on one board the mosfets of the other board will be fried just an instant later...

... and the added complexity of synchronizing two boards, decoupling a faulty board, etc will lead to much more possible faults

[Rawnei]

Does electronic faults happen in our wheels? Sure.

Is it common? Doesn't seem very common to me.

Most failures I've seen or heard about like for example fried MOSFETs usually involved some stunt like extreme climbing, jumping with hard landings etc something that simply demanded more from the wheel than it could handle, those type of failures usually happen at fairly low speeds with fully geared riders that are aware of the risks, newer wheels also have better failsafes for that type of failure as well as beefier components to prevent it from happening in the first place.

Then we have risk of water intrusion causing a short but thankfully that is being improved all the time also.

Hearing about someones wheel just stopped completely working mid ride at high speed for no apparent reason feels like it's very rare and then it usually comes down to a QC problem from which I think it's better to focus on improving the assembly and QC processes, if those things are not good adding even more components won't help, worst case more compnents could potentially just make that problem worse.

Another thing that could be improved is better safety mechanism like dynamic tiltback and accurate PWM reporting over Bluetooth so you can have accurate alarms, those are some real quality of life upgrades for the safety of the rider, we're slowly getting there also but not quite there yet but on the right track at least.

Edited March 20 by Rawnei

[txwheel]

I think the solution to this will be based on redundancy in vital systems - we see this approach to risk reduction working very effectively in various real world examples - commercial aircrafts can land even if one of the two jet engines fails, and a RAID hard drive system radically reduces the risk of data loss by saving data to two drives so that when one fails, recovery can be achieved from the surviving drive.

Applying this to EUCs, perhaps there can be two control boards that operate together by default, but in the event of a failure of one board, there would not be a cutout  because the surviving board would continue to function, allowing the user to come to a stop.  As an additional measure, having battery packs in parallel would allow the failure of one pack to merely reduce capacity without reducing voltage.  If these two redundant systems are intelligently combined, I suspect the rates of electrical failure could be brought down to an extremely low level.

If an individual component fails on one of the boards, even if not causing complete failure of that board, that component’s failure could throw an error code allowing the entire offending board to be replaced, allowing for early intervention.  

Perhaps each board could also have a manufacturer recommended MTTF or mean time to failure, with indicated board replacement every X years or miles ridden, or some algorithm that combines both to intelligently advise of replacement timing.

It would also be smart for the wheel manufacturers to log reported mileage based on control board serial numbers, and periodically upload this data along with performance and degradation diagnostics to allow for aggregate data and statistical analysis to quantify risk of continuing to ride with a board of a particular age and usage rate.  

There would be a cost premium for this level of “fail-safe” design, but I’m sure many of us would be willing to pay that premium.

 

 

Edited March 21 by txwheel

[Planemo]

4 hours ago, txwheel said:

Applying this to EUCs, perhaps there can be two control boards that operate together by default

I believe the original Segway had dual boards for redundancy.

And we already have paralleled packs on EUC's. Unplug any single pack on an EX30 for example and the wheel will keep working (albeit a halving of amp output of course).

We just need to combine the above two things to have much safer wheels, oh and the Inmotion(?) drive method of only needing hall sensors whilst static. 

[Rawnei]

Personally I think it's solving the wrong problem for reasons I wrote above.

I don't think it would solve that much and I wouldn't want the extra associated cost for double components and what changes it would require in space constraints, just imagine you need to fit 2 motherboards instead of 1 you need twice the size controller compartment.

[Planemo]

I take your point re cost and size but the current motherboards are pretty small, the EX30 is smaller than even the MSX for example. I'm sure a spare one could be fitted somewhere quite easily at the design stage. Re cost, I would happily pay an extra £400 ish (board cost + additional wiring) just for that feelgood factor and I would assume many others would too. Or even offer two versions of the same wheel - one with and one without the redundancy.

I'm totally with you re it maybe being overkill - I mean how many boards fail these days - but I do worry about the 'lifed' components, specifically the capacitors. The other option of course is to just replace the board as and when...but how long is too long to wait?! Capacitor life will vary on temperature and length of use, bit of a gamble. In any event I would still 'prefer' redundancy and it would be a nice option to have for those that want it.

[Timwheel]

I do agree that nowadays most issues with euc are user errors. Our boards are beefed up like never before, I'm surprised at the absolute beating my master can withstand, the insane current it can draw, the hills I can go up to at 50+ kph.. It is very rare that cut offs occur at high speed thanks to PWM alarms and tilt-back (I owe most of my peace of mind riding to @Freestyler, that 70% PWM tilt back on the master is absolutely incredible, such safe margin that enable me to ride only thinking about my surroundings...Thank you so much man), but you can still do something stupid at very low speed under very high load because of how electric motors pull current near stall.

It might feel good to have multiple systems but you just add potential points of failure ( how do you hand over control ? Will it be smooth enough ? Won't it create a sudden spike in current that would fry instantly the additional board ? So you beef up the additional board, but why not beef up the original one in the first place ? etc..)

EUC have never been as safe as today, and we can hope this trend keeps going for the better.

 

[alcatraz]

How about having a dummy wheel in front and back to balance on until the wheel comes to a stop? Maybe a switch that shorts out the motor wires and as such acts as an engine brake, once you've put some weight on those dummy wheels.

Edited March 22 by alcatraz

[Glock43x]

one of the reason why I don't go over 25 mph 90% of the time and I always ride on smooth paved trails.

[Funky]

1 hour ago, Glock43x said:

one of the reason why I don't go over 25 mph 90% of the time and I always ride on smooth paved trails.

People still will say you can get hurt going 5mph and even worse than going 60mph.. Because at 60mph you will get slung at speed and "slide" out till stop.  (Doesn't matter that 18wheeler was following you, or you slide in concrete barricade going 60mph..) 

 

I gladly will take slower falls everyday.. As you still can run out of them if you ride at walking/running speeds.(If you got fast reflexes and notice in time wheel diving forwards, nose down.) And same time if you fall - the road rash will be smaller.

 

On 3/22/2024 at 7:27 AM, alcatraz said:

How about having a dummy wheel in front and back to balance on until the wheel comes to a stop? Maybe a switch that shorts out the motor wires and as such acts as an engine brake, once you've put some weight on those dummy wheels.

In that case why use dummy wheels? Take the middle wheel out of question and you got two wheeled skateboard.  You still can stop if it stops working, etc.. Not like a EUC, where if something dies (battery/board/motor) you faceplant. 

It makes me wonder - who ever invented EUC was a maniac! Real mad lad!!!  They just needed to add another wheel and all these problems would have been fixed. So simple, i don't know why they didn't thought about adding another wheel. Same EUC body, but instead of having one wheel in middle, we could have one in front and one in back. Middle could be filled full with popcorn, ehh i mean cells.

Edited March 24 by Funky

[alcatraz]

5 hours ago, Funky said:

In that case why use dummy wheels?

I'm talking about small dummy wheels like training wheels. 

I'm not in love with the idea but it would seem like an easy fix.

[Dancer]

1 hour ago, alcatraz said:

I'm talking about small dummy wheels like training wheels. 

I'm not in love with the idea but it would seem like an easy fix.

Balancing left to right will be very difficult with dummy wheels in front and/or back. 

[Funky]

1 hour ago, Dancer said:

Balancing left to right will be very difficult with dummy wheels in front and/or back. 

Are you sure about that?

I could imagine them being in the way, if you wanted to accelerate or brake very hard..

But balancing left/right - they are not in the way at all. Front/Back of euc having extra small wheel.  If those wheels would be under pedals - then yeah, they are in the way.