DPRG mailing list archives: [DPRG] Balancing robot difficulties

Wed Jul 11 19:33:36 CDT 2007

Hi Guys

I chose to use Faulhaber motors on my first balancing bot, as they have zero 
backlash which makes things very easy. And someone happened to just give me 
a couple of these lovely motors. The downside of harmonic drives is the 
minimum gear ratio is quite high. This may limit your top speed.

My new version is going to use brushless DC motors with just one timing belt 
stage which should perform very well. I have built my own brushless 
controller from scratch which has been quite a project in itself but is very 
interesting and educational. Its amazing how responsive brushless motors 
are. And because they have more poles they need less gearing. This also 
makes coasting/back driving smooth too.

Cheers
Kiwi Keith

----- Original Message ----- 
From: "dpa" <dpa at io.isem.smu.edu>
To: <dprglist at dprg.org>
Sent: Thursday, July 12, 2007 1:54 AM
Subject: [DPRG] Balancing robot difficulties

> Hi Luke,
>
> you wrote:
>
>> Dpa, would it be possible for you to give me a rough
>> estimate of how much backlash there is in your balancing
>> bots if you grab one of the wheels and twist it each way
>> to take up any slack?
>
> Just a rough guess this morning, it feels like about a degree of
> slop at the wheels.
>
> I think you'll really like the Pittman motors.  If we all need
> to go to harmonic drives then so be it, but you should be able
> to get a good robust balancing platform with the Pittmans.
>
> best luck!
> dpa
>
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