[chbot] Balancing robots

[Charles Manning]

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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