[chbot] Balancing robots

[Michael Pearce]

> This is a level of stability and control not achievable with simplistic PID
> or Fuzzy controllers.

Actually the Segway used a good number of dsPICs to do it all.... so
not as much processing power as you may have presumed.... (Note: dsPIC
is _NOT_ a dsp- it is a 16 bit digital signal Controller up to 40MIPS)

Was definitely in the 2007 version.... may be different now.

Mike

On Mon, Oct 20, 2008 at 1:11 AM, John Stowers <john.stowers at gmail.com> wrote:
> This was created by Dean Kamen, i.e. Mr Segway. I expect it uses some of the
> control technology inherited from that project.
>
> Presumably, like the segway, it uses one or multiple voting, optimal state
> space controller/s.
>
> This is a level of stability and control not achievable with simplistic PID
> or Fuzzy controllers.
>
> John
>
> On Mon, Oct 20, 2008 at 1:34 AM, Charles Manning <cdhmanning at gmail.com>
> wrote:
>>
>> Pretty neat.
>>
>> I think there are a few things which really help keep this thing stable:
>>
>> 1) Moment of inertia.  A heavy item placed relatively far from the wheels
>> is far easier to balance than a light one. That's part of the reason Hanno
>> has the batteries on the top of the pole of his robot . Having an object the
>> size of a human helps.
>> 2) Relatively unlimited budget. Hanno is trying to make a cheap consumer
>> item while these flash wheelchairs cost many thousands.
>>
>>
>> Some horizontal reference, typically accelerometers because they are
>> small, cheap and reliable, need to be part of any gyro-based solution
>> because gyro sensors give you the rate of rotation and you need a horizontal
>> reference to cancel out any offset (normally done in a Kalman filter). If
>> you don't cancel out this offset then the machine would seem to be slowly
>> rolling.
>>
>> -- Charles
>>
>>
>>
>> On Sun, Oct 19, 2008 at 5:23 PM, QtuTrains <Howard at qtutrains.com> wrote:
>>>
>>> If you think Hanno's balancing robot is interesting just take a look
>>> at this:
>>>
>>> http://www.powerchair-review.fsnet.co.uk/ibot-4000-transporter-full-
>>> review.htm
>>>
>>> The manufacture's site is http://www.ibotnow.com/ but I couldn't get
>>> it to respond when I looked.
>>>
>>> Its a wheelchair that can rise onto two wheels and balance with a
>>> person sat in it.
>>>
>>> It can also climb stairs!
>>>
>>> We saw one today at the Canterbury museum (not an exhibit!) and the
>>> owner said it was the only one in New Zealand.
>>>
>>> It looked amazingly stable - much less oscillation to keep upright
>>> than Hanno has achieved thus far. Naturally it uses gyroscopes for
>>> balance, perhaps accelerometers too but the owner wasn't too much
>>> into the technical details.
>>>
>>> The point of balancing is improved manoeuvrability and visibility
>>> through increased height which was obviously useful in the museum.
>>>
>>> Howard
>>>
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>>
>>
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>
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