{3d printed robot} How to generate backspin?

This user has no status.
This user has no status.
New Member
May 2022
4
1
5
I'm building a 3d printed table tennis robot, with 3 wheels, it is almost complete, but I'm struggling with backspin, I don't know how wheels to rotate, also how to get a slow and spinny shot, or fast and spinny, btw: the robot wheels are able to rotate clockwise and counter clockwise.

I'm using hard sponge RC plane wheels, but they suffer plastic deformation and shots aren't as reliable a I wish, please tell me which ones will work, on a budget.

Also I'm wondering how close wheels have to be to the ball.

Thanks!
 
This user has no status.
This user has no status.
Active Member
Jul 2017
720
339
1,156
Watch a 3 wheel baseball pitching machine.
https://youtu.be/dbZPC7goOpo

The wheels always spin the same direction but if you want varying spin you need to spin the wheels at different speeds. For backspin the bottom wheel spins faster, for top the top wheels and side spin one of the side wheels
 
This user has no status.
This user has no status.
Member
Mar 2016
93
50
168
I am the founder of PongFox table tennis robot , I started something similar sometime back and we are now shipping. As mentioned by Dominikk85, the bottom wheel should be faster than the top two for backspin.

All the wheels should touch the ball equally and as far as the wheels the RC ones you use should work but you will have to post more details or pictures to take a look and check what the issue might be.
 
Top