[python] Re: Unstable ride

  • From: Vi Vuong <vi_vuong@xxxxxxxxx>
  • To: "python@xxxxxxxxxxxxx" <python@xxxxxxxxxxxxx>
  • Date: Thu, 28 Jul 2011 11:33:02 -0700 (PDT)

The pole and camera are only ~2 lbs, which I can hold with my hand & arm and 
are quite a workout after a while (full body exercise?).  An elbow brace/strap 
would help.

Yes, the wobbling is mostly from loose mount / flexing, but the camera is high 
enough(10 ft) to change the lean angle of the bike.  Yes, I do need the whole 
street for the experiment like when I first learn to ride, which leads me to 
consider the setup in advanced / accelerated training.  Does it simulate sudden 
lost of control?  Can it amplify or counteract pedal/steering interference? 
 Chaotic double pendulum? http://en.wikipedia.org/wiki/Double_pendulum.  

So far, riding more difficult configurations makes me appreciate easier ones, 
but not sure of what aspects of the improvement...


>From: Dirk Bonné <dirk.bonne@xxxxxxx>
>To: python@xxxxxxxxxxxxx
>Sent: Thursday, July 28, 2011 12:47 AM
>Subject: [python] Re: Unstable ride
> Yes, flexing is bad. I had a hilarious time once, transporting a cabinet on a 
> one-wheeled trailer on my flevo. Both flevo and homebuilt trailer had a lot 
> of flex. I needed the whole road for balancing; people were staring in 
> amazement...
>OTOH, If the frame and connections are stiff, then there is no
    problem: On the pythoon there is now a strong luggage rack over the
    rear wheel. Even with my son in the box and a weeks worth of
    shopping on the rack the feel of the ride is changed in only minor
>The cog on Vi's ride cannot have changed much with that pole, as the
    weight isn't that high (Vi is able to hold tahat same pole
    horizontally on another video).
>On 28.07.2011 07:43, dirk@xxxxxxxxxx wrote: 
> Hi Vi,  
>>might the reason be your heavy weight camera extension, that shifts the cog 
>>far to high?  
>>if that rod is flexing due to its length, it might be counteracting your 
>>Vi Vuong <vi_vuong@xxxxxxxxx> hat am 27. Juli 2011 um 18:09 geschrieben: 
>>> While videoing the top view of Guinea Pig, I stumbled on a
        really unstable dynamics mode, sort of an inverted pendulum
        (10-foot + tripod head, compact
        camera) http://www.youtube.com/watch?v=_SAaxS2_LwI.  It feels like gust 
wind blasting from all direction... 
>>> The motion calms down later as I got a hang of it, seems to
        be controllable if it sinks with the pedaling / python motion.
         Let me know if anyone is interested in a more systematic study. 
>>> Vi 

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