[chbot] Balancing robots

[John Stowers]

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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