Use of differentials in antweights

Simon Windisch · Post by **Simon Windisch** » Mon May 30, 2005 5:42 pm

I had an idea for an antweight design that had one motor driving two wheels via a differential and another motor that would be connected to the centre internal gear of the differential to steer it. It would be very nimble, possibly a full body spinner. Just a little tricky to build. Has anyone else thought about this?

Simon

Adam Hargreaves · Post by **Adam Hargreaves** » Mon May 30, 2005 7:01 pm

*tries to picture that design* *Fails*

Rhys · Post by **Rhys** » Mon May 30, 2005 8:45 pm

Not too sure I'm getting this either. Do you mean like how a dodgem works?

Post by **BeligerAnt** » Mon May 30, 2005 9:24 pm

Differentials do my head in! Too many cogs for a sparky like me!

I seem to remember Firestorm being described as using some kind of "differential drive" in RW (being different to "normal" tank-type drive). Maybe it's what you have in mind Simon.

I'm off work this week

(decorating

) but I'll ask my mech eng friends about this next week if no-one else comes up with anything useful.

Simon Windisch · Post by **Simon Windisch** » Mon May 30, 2005 10:26 pm

Well I couldn't work it out myself until I discovered that we had a lego differential kit. Seeing it in action makes it so much easier to understand.

I'll see if I can do a diagram.

Simon

Simon Windisch · Post by **Simon Windisch** » Tue May 31, 2005 5:12 pm

Hi there,

I've made three movies of the differential in action
http://homepage.ntlworld.com/s.windisch ... locked.wmv
http://homepage.ntlworld.com/s.windisch ... locked.wmv
http://homepage.ntlworld.com/s.windisch ... normal.wmv
To see all three http://homepage.ntlworld.com/s.windisch/

Pete, could you host these for me? I'll write a web page explaining how differentials work and what the movies mean.

Simon

Andrew_Hibberd · Post by **Andrew_Hibberd** » Tue May 31, 2005 5:26 pm

Thats amazing, should work to

, i would like to see that in action

Simon Windisch · Post by **Simon Windisch** » Tue May 31, 2005 10:53 pm

I found some info on Firestorm's differential drive. First a video http://www.gbone1.force9.co.uk/rw99/videos/diff3.ram then a picture, including the blueprint! http://www.gbone1.force9.co.uk/rw99/pic ... ential.jpg

So I've watched the video a few times and it looks like first the whole diff is being spun, rotating both wheels equally, then the two diff mounted motors are spun, resulting in the wheels spinning in opposite directions. He's a clever guy!

Do you remember Firestorm IV fighting Tornado (I think) and them both being nearly dead, but Firestorm was just about limping forwards? He must have been spinning his diff-mounted motos in a see-saw fashion to nudge the robot forwards.

Remote-Controlled Dave · Wed Jun 01, 2005 5:48 pm

It was the semi-finals of the 6th wars, and it wasnt Tornado, it was Hypno-disc.

Post by **BeligerAnt** » Wed Jun 01, 2005 9:23 pm

Now I'm left struggling with a) how you get the power to the motors which are rotating with one of the drive shafts, and b) how you make all this ant-scale!

I think you've set yourself a mighty challenge here Simon! Good luck!