ACCIDENTs, CRASHs, Cutouts and Overleans.

[The Wizard]

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[The Wizard]

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[Hunka Hunka Burning Love]

Oh my.  Don't think it will work.  Stopping a wheel tilting forwards just stops the wheel... rider keeps on going? 

Best way to totally avoid faceplants?  Stay inside and watch TV.  Otherwise just ride within the wheel's capabilities.

I like the conceptual thinking though. 

 

 

[The Wizard]

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[Arbolest]

...Think I'm gonna have to side with Hunka on this one. I've toyed around with a similar idea for a couple years now (I like modding my Ninebot One E+ xD), and as far as I can tell, if a wheel says it can't do something, it can't do it, and the unpredictability of all the possible combinations of circumstances that might come into play during an event means that there probably isn't a single safety system that can be implemented to "prevent ALL, I repeat, ALL cutout and overlean faceplants".

    Just think about it... if you over-lean your wheel or it cuts out, you're going to go down. An extra half second given to you by the magic of engineering, however useful it may be in allowing your brain an extra moment to get your hands up and protect yourself, is NOT going to prevent you from whacking into the  ground.

    The only way I can see to prevent a face-plant in an EUC-riding situation is better safety gear on the rider, not the wheel. My personal suggestion would be one of the "airbag helmets"...

 

 

[The Wizard]

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[The Fat Unicyclist]

As I see it the problem comes down to two things... momentum and centre of gravity (CoG).

To make your wheel move your CoG needs to be forward of the axle, which is done by leaning forward. And it is then the momentum of the wheel keeping up with your CoG that stops you falling. 

And it is that fundamental principle of how an EUC works that also means you can't prevent a faceplant (other than by conservative riding).

No matter what measures you put in place to prevent an EUC "dropping you," in the event of a power failure two things are absolute... The EUC will lose momentum and your CoG won't!

So even if the wheel could roll to a stop, as your CoG is forward from the wheel axle, you will suddenly be helping it brake, and you will continue moving forward at a greater velocity than the wheel... Game over.

But if you are looking for a solution to this inevitable challenge, then there may be one way to achieve it... because of the principles of how an EUC works (see above) you would need to ensure three things;

1. Ensure the EUC doesn't "tumble," but stays (somewhat) level. 
2. Keep the momentum of your CoG the same as the momentum of the EUC, so that you aren't separated from the EUC. 
3. Provide a method to control the EUC during deceleration, ensuring balance is maintained. 

And that should prevent a facepalnt!

To resolve #1, we could take the skid concept further - they would need to be extended forward a lot more - well past the CoG of the rider. And it would be more practical to add a wheel at the front (to stop them digging in or catching anywhere). 

#2 could then be resolved by raising up a handle / bar from the front skid-wheel. As it is forward of the rider's CoG, weight could be put onto it if momentum is lost (keeping the CoG in the same position relative to the EUC).

And with both of these in place, #3 would be easy to achieve as all that would be required is some sort of steering mechanism (from the handle / bar to the skid-wheel) allowing the rider to manually maintain a state of balance. 

So there you have it we have actually invented a solution to... oohhh... actually we have just invented a bicycle.   

[Hunka Hunka Burning Love]

People have talked about mounting a small wheel up front "just in case," but again I don't know how helpful that would be.  These devices' sole purpose is to try to operate as level as they can and as a consequence balance whatever it is carrying.  They may tilt on occasion slightly depending on pedal responsiveness settings, warning tiltbacks, or brake assist, but once that system fails it's basically like balancing on a pinhead.  While in motion.  

Maybe if a secondary pedal balancing system kicked in when the main balancing system failed that could help.  It would have to disengage the linkage between pedal support and axle,  but if it could upright the pedals as the case tilts forwards theoretically it might help?  The complication and effort to do so as well as adding more potential points of failure may not be worth the extra cost.

[mrelwood]

5 hours ago, Hunka Hunka Burning Love said:

if it could upright the pedals as the case tilts forwards theoretically it might help?

I don't think so. When the wheel gets over-leaned or cuts out, it's not the pedals tilting that is the main issue, but the wheel not being able to reach your centre of gravity.

[The Fat Unicyclist]

4 minutes ago, mrelwood said:

I don't think so. When the wheel gets over-leaned or cuts out, it's not the pedals tilting that is the main issue, but the wheel not being able to reach your centre of gravity.

Exactly... Even if there was some method to keep the wheel level, as it has lost power and is decelerating the fact that the riders CoG (and downward force) is forward of the wheel it will actually push backward - effectively slowing the wheel more, further decreasing the distance between the face and the pavement.

[The Wizard]

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[Hunka Hunka Burning Love]

I love the drive  and can-do attitude!  It's an interesting thought puzzle.  Possibilities versus practicality.  

2 hours ago, mrelwood said:

I don't think so. When the wheel gets over-leaned or cuts out, it's not the pedals tilting that is the main issue, but the wheel not being able to reach your centre of gravity.

Yet if your feet have something that offers resistance you can often recover.  Picture a skateboarder who pops a wheelie and rides for a few feet on the back wheels.  When they land the board tilts forwards to stop at the level point.  With an EUC, the pedals are level until the works tips forwards.  If the pedal levelling system can detect a failure of the main system fast enough the shell can continue tipping forwards while the pedals tip back to counter keeping them level allowing the feet some resistance to counter the forward momentum.  With the Wizard's skids or faceplant wheels the whole thing could slide to a stop theoretically.  Maybe.  Heck if I know.  Who's got a computer simulation system???  

[Jerome]

I believe the Wizard is not trying to prevent a fall. The "face plant" possibility riding a euc is unlike falling from a bike, roller blades, scooter, electric skateboard .. Falling for any reason always has possible disastrous consequences, the sudden face first fall however has its own brand of terror. It is likely "face plants" will be used in any future attack on the safety of eucs. The wizard has had some serious falls, but chooses to come up with improvements. Lesser people will use serious falls to try and ban eucs even if their falls were the results of improper use. The solution to cut-offs or over leans can be solved by the control boards. The wheel instead of stopping would free roll when cutoff/over-lean events happen. This wouldn't stop someone from falling, but would be more like brakes failing. This is not likely to happen as it would require re-engineering control board functionality and creating a new assembly-parts paradigm. Unless Honda/Yamaha get interested and come out with a wide wheel self standing euc with sophisticated safety protocols, euc will remain a small niche market used by risk takers. There is a "ONEWHEEL guru who has added safety front wheels to his ONEWHEEL  I personally will never add any rods/wheels/? to my euc. I realize every time I ride it bad things could happen. I ride and dress accordingly. Best of success wishes to those who make mods that adds to their euc's safety.

[The Fat Unicyclist]

I appreciate the difference, but a faceplant. being the result of power failure, means a loss of momentum and without momentum you will faceplant - regardless of how many prongs, skids or wheels you have added.

This is physics people... Not something you can circumvent!

If you really want to prevent a faceplant, there are only two options;

1. Prevent the loss of momentum caused by power failure (perhaps with a secondary system - like the IPS S5?)
    
2. Ride backward - which will at least save your face.

[The Wizard]

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[Hunka Hunka Burning Love]

Re-reading the Whiz's second post I think the key is placing the faceplant wheels attached to the pedal pins is the key.  With the supports angled up slightly when the wheel fails it would be like dropping down from a pop-a-wheelie onto two front wheels as long as the downward angle isn't too extreme.  Hmmm very interesting... people still would likely keep moving forwards as the wheel slows down due to the ride lean so I don't know if that would work.  Unless with the slight tilt they could recover.... somehow I think it might be doubtful as mrelwood mentioned as the CoG is forwards... hard to say...

[scap]

I would like to think you could build in a second controller board that could be hot swapped in upon failure. The hard part would be detecting all types of failures. It is my VERY limited understanding that the common failure is a MOSFET goes out. It should be possible to build in a circuit that would monitor this and switch in the second control board. In addition this could be used to control thermal issues while riding up a mountain for instance; One board is getting hot so switch to the other for example. Lastly there is the issue of a low battery not being able to provide the juice needed for a surge of power requested by the rider. The manufacturers could incorporate super capacitors in this situation that would be able to give the power needed to keep the rider upright and issue a warning or tilt back. 

 

I would like to see both of these or similar concepts be included in future EUC. I decided to go with a V10F as my first unicycle mainly because of its perceived safety.  For all the faults that have been found with it I haven't heard of one cut off or "face plant" (maybe I just missed it) and this makes me think I made the right decision. 

Thoughts...

[The Wizard]

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[Hunka Hunka Burning Love]

  I don't mind admitting when I'm wrong.  Post 'em up!  Take us down that yellow brick road...

https://postimages.org/

You can upload a bunch at a time, choose direct links, copy, paste here, manually enter a return after each link, wait for forum to process image, repeat ...

[The Wizard]

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[Hunka Hunka Burning Love]

More photos, less apologies.  We're all pretty tough adults here.  Well, most of us.  Heck we only need one wheel to ride on.   We can take it.  Prove us wrong.

[The Wizard]

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[Hunka Hunka Burning Love]

  Uh what?  I just asked if you could upload the prototype photos so we can see them.  Where are you getting this idea that I don't believe it is possible?

The forum has a limited upload capability for users so I gave the image hosting link.  I then asked to take a look at your prototype photos.  Hold on here, am I being punk'd?  Hello?  There's no place like Edmonton, there's no place like Edmonton...

I don't confuse easily, but when I do it's a doozie, oh my!  

[The Wizard]

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[mrelwood]

6 hours ago, Jerome said:

The wheel instead of stopping would free roll when cutoff/over-lean events happen.

Isn’t that what wheels already do at cut-off, free-roll? Unless the wheel is blocked by a blown Mosfet that is.

4 hours ago, scap said:

keep the rider upright and issue a warning or tilt back. 

Regarding over-speed and low battery, others than Gotway already does this, but some riders feel that it limits their freedom and liberty. So they ride a Gotway and remove the tilt-back.

Blowing Mosfets have been fought with a double amount of larger and a lot more powerful Mosfet types. I haven’t heard of them blowing yet.

Quote

3 hours ago, The Wizard said:

already claim I have made something that WORKS

 

Do you mean that it has prevented a faceplant? You have been given the means and instructions to upload photos for us to discuss, since we are interested in what you have done and how it works. Come on, let’s continue inventing!

My theoretical thinking is that an actual power-cut-off-faceplant wouldn’t benefit greatly from these additional wheels unless they are at the center of gravity. Even then, if the cut-off happens during acceleration, when the rider tries to jump there is no platform to jump from. The force of jumping will only push the wheel away, as if there was nothing there.

I’m not theorizing this to turn anyone down, just to take part in the discussion and hopefully guide it towards a solution that would actually work.

I think manufacturers have already done a pretty good job of bettering the mechanics and electronics to prevent just this. Wizard, did you use your Ninebot or other wheels during your cut-offs? Were there overleans involved, or all plain technical malfunctions?