Discussion about "how do I ride a bike" on the "bicycle design and engineering" LinkedIn group.

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Andrew Dressel

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Jul 6, 2015, 11:20:14 AM7/6/15
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I don't know of a good way to connect these two groups, but thought this discussion taking place there might be thought provoking here.

How Do I Ride a Bike?

It sounds simple and it should be, but I crashed my KTM 450 in the Sahara Desert whilst racing in the Tuareg Rally, so my brain injury is so severe that it has effected my balance, however this is improving. I can no longer ride a regular bike. So, any suggestions about how I can ride my bike again?

Mark Harrison likes this
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  • Simon Head

    John Harland

    Solid-state gyroscopes and position sensors are part of a lot of phones and E-pads of various sorts. A suitable app for such a device might generate signals comparable to the information from the semi-circular canals of the inner ear.

    What is needed is some way to send the information to the brain, possibly by small electrodes or vibrating pads on the earlobes or the scalp.

    It does depend, of course, on whether the balance problem originates with the semi-circular canals or with the part of the brain that processes the inputs.

    If the processing is okay, the brain should adapt quite quickly to signals from another source. A lot of balance information already comes from other sources, such as our feet and our vision, so we are not asking the brain to do something unprecedented.

    1 day ago
  • Simon Head

    Carl Peterson

    Innovative solution John for using a alternate reference source! 
    I have experienced vertigo when flying over the sea at night and the visual reference to aircraft's Artificial Horizon was enough to re-establish my positional orientation. The concept of using an alternate reference source to confirm or establish stability has merit.

    20 hours ago
  • Simon Head

    John Harland

    The artificial horizon is a great example, Carl.

    When I am holding the bike still, such as when preparing for a steep and rutted descent, even holding a thin outer branch of a tree can help because I can feel any lateral movement through my fingers faster than through other senses.

    14 hours ago
  • Simon Head

    Carl Peterson

    John....I have also had that same experience. I would guess it is one of the reason many people use canes to walk because it provides that same type of tactile reference.

    10 hours ago
  • Simon Head

    John Harland

    Yes, indeed, Carl.

    Another point I am making, though, with both the adjustable-resistance bankable sidecar and with the external reference source, is that it is reasonable to expect some recovery of balance; and that we can assist that recovery, rather than entirely substitute for whatever ability remains.

    8 hours ago
  • Simon Head

    Charlie Brumbaugh

    Get a 20" Strider which is light and purely simple to redevelope your balance again.

    44 minutes ago
  • Simon Head

    Andrew Dressel

    As attractive as it may first appear, it is not clear that adding additional wheels in some way (either with a trike, sidecar, or training wheels) might be able to facilitate the ability to "ride, maybe race, a conventional bicycle."

    To do so, a three-or-more-wheel design would have to still allow and require countersteering, just less so, perhaps with slower response times and/or lower gains.

    On one end of the spectrum, with additional wheels rigidly attached, countersteering simply does not work, of course, and so such a contraption should be expected to facilitate no improvement in the ability to ride a bicycle.

    On the other end of the spectrum, with additional wheels spring-loaded so as to perfectly counter the roll moment created by gravity acting on the leaning mass, turning simply does not work. See ruina.tam.cornell.edu/research/topics/bicycle_mechanics/brike_paper18.pdf

    So then the trick is to find or create a design that allows for countersteering but that somehow has lower requirements for it. Can anyone point to such a design that already exists?

    My own experience with adjusting the a semi-stable a tilting trike (www.jetrike.com) is that riders are confused by the combination of mechanically enforced stability and the continued requirement to countersteer. Perhaps we just didn't find the sweet spot.

    36 minutes ago
  • Simon Head

    Andrew Dressel

    One approach that I don't think we've touched on yet is steer-by-wire. I know of at least one steer-by-wire bicycle, at TU Delft, but haven't yet read if they've looked into whether it can help someone who is unable to balance a conventional bicycle.

    Anyone else have an information on this angle?

    (Oh, and I meant to write "my own experience with adjusting the semi-stabilty of a tilting trike...." above)

    25 minutes ago
  • Simon Head

    Andrea Antonucci

    I don't think this last solution would help in balancing the bike...

    The gyrobike is instead really interesting! 
    Maybe coupled with a fatbike or a 27+ is a good compromise between fun to drive and helping driving

    10 minutes ago
  • Simon Head

    John Harland

    Very interesting, Andrew. Thanks for digging it up.

    I have long wondered about the steering of the old Renault Dauphine that used spring pressure to assist in centring the steering. Seemed to me it would feel weird. Has anyone driven one, and can comment?

    As the authors point out, however, "The arguments precluding control are heavily dependent on the linearity of the system, and the non-linear inverted pendulum in zero gravity seems to be controllable." I was not thinking of spring systems linear to the pull of gravity so I think the answer remains inconclusive.

    7 minutes ago

Bill Semenoff

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May 31, 2017, 9:42:36 AM5/31/17
to Single Track Vehicle Dynamics
I'm working on a design similar to the Brike. I have to confess it's been a few years since I did any coursework in control theory, but my thoughts after reading the paper are that the assumption of a sinusoidal springback response being optimal was never really questioned.  Also that  the Whipple model is an oversimplification for this problem. It would be interesting if someone developed a more realistic bicycle model by adding one or more hinges to account for the  ability to trackstand (or lack of that ability if I understand the original poster's problem). 
We know (anecdotally) how this is done with modern conventional bikes and wouldn't it seem to require an additional hinge at the wrists ?

Robert

Andy Ruina

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May 31, 2017, 6:05:59 PM5/31/17
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Hi:

 

After June 13 or so I'd be happy to Skype with anyone who wants to about these things.  I have no quick

easy response to the posting below.

 

 

 

From: "st...@googlegroups.com" <st...@googlegroups.com> on behalf of Bill Semenoff <billse...@gmail.com>
Reply-To: "st...@googlegroups.com" <st...@googlegroups.com>
Date: Wednesday, May 31, 2017 at 4:42 PM
To: "st...@googlegroups.com" <st...@googlegroups.com>
Subject: [stvdy] Re: Discussion about "how do I ride a bike" on the "bicycle design and engineering" LinkedIn group.

 

I'm working on a design similar to the Brike. I have to confess it's been a few years since I did any coursework in control theory, but my thoughts after reading the paper are that the assumption of a sinusoidal springback response being optimal was never really questioned.  Also that  the Whipple model is an oversimplification for this problem. It would be interesting if someone developed a more realistic bicycle model by adding one or more hinges to account for the  ability to trackstand (or lack of that ability if I understand the original poster's problem). 

We know (anecdotally) how this is done with modern conventional bikes and wouldn't it seem to require an additional hinge at the wrists ?

 

Robert

On Monday, July 6, 2015 at 8:20:14 AM UTC-7, Andrew Dressel wrote:

I don't know of a good way to connect these two groups, but thought this discussion taking place there might be thought provoking here.

 

How Do I Ride a Bike?

It sounds simple and it should be, but I crashed my KTM 450 in the Sahara Desert whilst racing in the Tuareg Rally, so my brain injury is so severe that it has effected my balance, however this is improving. I can no longer ride a regular bike. So, any suggestions about how I can ride my bike again?

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Mark Harrison likes this

See previous comments

·         imon Head

John Harland

Solid-state gyroscopes and position sensors are part of a lot of phones and E-pads of various sorts. A suitable app for such a device might generate signals comparable to the information from the semi-circular canals of the inner ear.

What is needed is some way to send the information to the brain, possibly by small electrodes or vibrating pads on the earlobes or the scalp.

It does depend, of course, on whether the balance problem originates with the semi-circular canals or with the part of the brain that processes the inputs.

If the processing is okay, the brain should adapt quite quickly to signals from another source. A lot of balance information already comes from other sources, such as our feet and our vision, so we are not asking the brain to do something unprecedented.

1 day ago

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·         imon Head

Carl Peterson

Innovative solution John for using a alternate reference source! 
I have experienced vertigo when flying over the sea at night and the visual reference to aircraft's Artificial Horizon was enough to re-establish my positional orientation. The concept of using an alternate reference source to confirm or establish stability has merit.

20 hours ago

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·         imon Head

John Harland

The artificial horizon is a great example, Carl.

When I am holding the bike still, such as when preparing for a steep and rutted descent, even holding a thin outer branch of a tree can help because I can feel any lateral movement through my fingers faster than through other senses.

14 hours ago

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·         imon Head

Carl Peterson

John....I have also had that same experience. I would guess it is one of the reason many people use canes to walk because it provides that same type of tactile reference.

10 hours ago

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·         imon Head

John Harland

Yes, indeed, Carl.

Another point I am making, though, with both the adjustable-resistance bankable sidecar and with the external reference source, is that it is reasonable to expect some recovery of balance; and that we can assist that recovery, rather than entirely substitute for whatever ability remains.

8 hours ago

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·         imon Head

Charlie Brumbaugh

Get a 20" Strider which is light and purely simple to redevelope your balance again.

44 minutes ago

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·         imon Head

Andrew Dressel

As attractive as it may first appear, it is not clear that adding additional wheels in some way (either with a trike, sidecar, or training wheels) might be able to facilitate the ability to "ride, maybe race, a conventional bicycle."

To do so, a three-or-more-wheel design would have to still allow and require countersteering, just less so, perhaps with slower response times and/or lower gains.

On one end of the spectrum, with additional wheels rigidly attached, countersteering simply does not work, of course, and so such a contraption should be expected to facilitate no improvement in the ability to ride a bicycle.

On the other end of the spectrum, with additional wheels spring-loaded so as to perfectly counter the roll moment created by gravity acting on the leaning mass, turning simply does not work. See ruina.tam.cornell.edu/research/topics/bicycle_mechanics/brike_paper18.pdf

So then the trick is to find or create a design that allows for countersteering but that somehow has lower requirements for it. Can anyone point to such a design that already exists?

My own experience with adjusting the a semi-stable a tilting trike (www.jetrike.com) is that riders are confused by the combination of mechanically enforced stability and the continued requirement to countersteer. Perhaps we just didn't find the sweet spot.

36 minutes ago

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·         imon Head

Andrew Dressel

One approach that I don't think we've touched on yet is steer-by-wire. I know of at least one steer-by-wire bicycle, at TU Delft, but haven't yet read if they've looked into whether it can help someone who is unable to balance a conventional bicycle.

Anyone else have an information on this angle?

(Oh, and I meant to write "my own experience with adjusting the semi-stabilty of a tilting trike...." above)

25 minutes ago

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o    Delete

·         imon Head

Andrea Antonucci

I don't think this last solution would help in balancing the bike...

The gyrobike is instead really interesting! 
Maybe coupled with a fatbike or a 27+ is a good compromise between fun to drive and helping driving

10 minutes ago

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o    Reply privately

o    Report spam

·         imon Head

John Harland

Very interesting, Andrew. Thanks for digging it up.

I have long wondered about the steering of the old Renault Dauphine that used spring pressure to assist in centring the steering. Seemed to me it would feel weird. Has anyone driven one, and can comment?

As the authors point out, however, "The arguments precluding control are heavily dependent on the linearity of the system, and the non-linear inverted pendulum in zero gravity seems to be controllable." I was not thinking of spring systems linear to the pull of gravity so I think the answer remains inconclusive.

7 minutes ago

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damian...@googlemail.com

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Aug 31, 2020, 2:25:42 PM8/31/20
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A few too many groups within groups for me to work out where to comment, so I'll try here. Do feel free to correct me politely as to the best location.

I addressed an adjacent problem with the steer-by-wire Prodrive "Naro" some years back. It was essentially a proof-of-concept project but was technically very successful from my perspective.

- Physics was essentially a "bicycle catamaran" with an ability to clamp the catamaran in an arbitrary bank angle for low speed control
- At low speed it was just another four-wheeled vehicle
- Having thought about it for a long (long!) time I could ride it with a conventional steering wheel by applying angle-based control when it was clamped and opposed torque-based control when it was unclamped
- Literally nobody but me could ride it above about 10mph (I expected most people but not to get it, but I was surprised really nobody could do it)
- I added (as had been the plan all along) a multimode steer-by-wire system that also did conventional "angle copying" at low speed and then used the wheel input as a bank command when unclamped
- Everybody could ride it - we never ran it above about 50mph because that seemed fast enough for me on steering software that *I* wrote

The steer-by-wire system was embarassingly simple and there was only a single comedy moment while calibrating it. I was shocked that it went from model to reality so uncontroversially.

I also (again, adjacent) met Mick Doohan in a bar once and asked him how to drift a motorcycle. I coded up his reply into my multibody motorcycle model and sure enough it worked. Feels like a story you couldn't make up, but I can at least prove part of it with the working multibody model, even if I can't prove the Mick Doohan part. Although that surely seems more plausible than me working out how to drift a bike on my own...

It was actually the clarity from the Modelling Mick exercise that made me foolhardy enough to attempt the Naro.

Finally (also adjacent) I proposed and did preliminary modelling for a variable stability motorcycle which was a torque overlay system in the steering to add agility at low speed and weave damping at speed when I was at Polaris. Apart from the fairly hideous functional safety implications it was, from a physics point of view, disappointingly prosaic.

Happy to discuss it with anyone that's interested.  

Damian

Andy Ruina

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Aug 31, 2020, 3:03:50 PM8/31/20
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Damian:

 

I don't know who you are or where you are so don't know how to write to you.  Might you chat on Zoom with me

some time?  You can write to me outside the group.

 

 

— Andy Ruina,                     Mechanical Engineering, Cornell

ru...@cornell.edu; or andy....@gmail.com;      http://ruina.org

Zoom: https://cornell.zoom.us/my/andyruina;  password: Andy Ruina

227 Bryant Ave, Ithaca, NY 14850;                    607 327-0013

 

damian...@googlemail.com

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Sep 6, 2020, 8:05:22 PM9/6/20
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I did reply to Andy directly but don't know if it went into a spam filter somewhere. Would be great to talk over zoom if it's of interest!
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