Society of Robots - Robot Forum
Mechanics and Construction => Mechanics and Construction => Topic started by: dmclifton on February 23, 2011, 03:41:25 PM
-
I was thinking of trying out some omniwheels, and I found these at good pricing:
http://www.robotshop.com/ProductSearch.aspx?qs=omni+wheel (http://www.robotshop.com/ProductSearch.aspx?qs=omni+wheel)
The 'Dagu' wheels seem to fit the bill price-wise and in terms of size of what I was thinking. Thing is, they all have these funky hex openings, and no real way to connect them. I was planning on using some simple servos, such as ROB-09347 from Sparkfun. Thing is, I'm not sure how I could mount these wheels - I was hoping somebody might have run into something similar and have an idea of something that won't just fall apart in the first half hour.
Also, if anybody has had luck with another omni wheel elsewhere, would love to hear about that and give it a look.
Haven't been able to find any good omniwheels elsewhere - there's the 'transwheel' thing that seems to be available via ebay and nowhere else, but they just look very shoddy in terms of construction. There's also mecanum wheels, which certainly have their benefits - but the price is higher than what I was hoping to spend.
-
Hi,
Thing is, I'm not sure how I could mount these wheels [...]
Depending on your options, a 6 sided bar could be drilled out (on a lathe) to fit your drive axle and a couple of set screw threads made.
If you haven't got the tools for that, you could find some tubing with an inside diameter fitting your axle and the outside either with threads for a nut, 11mm from flat side to flat side (what you would use an 11mm spanner for). Mount two nuts at a suitable distance (slightly narrower than the center hole in the wheel) and use screw lock or cyanoacrylate to bind them. Finally, hold the wheel in place with two further nuts and washers.
-
No lathe available here - though I might be able to poke around and find somebody willing to spot me some time on one.
Don't suppose you might know a common place to find tubing like that?
-
You didn't say which Dagu wheels ;)
That said, I don't recommend any of those Dagu wheels. They all have low friction - ie your wheels will spin, slipping on the floor, and your robot won't go anywhere.
You want the outer wheels to be high friction rubber or a polyurethane.
I recommend the wheels in my omni-wheel robot tutorial.
http://www.societyofrobots.com/robot_omni_wheel.shtml (http://www.societyofrobots.com/robot_omni_wheel.shtml)
http://store.kornylak.com/searchresults.asp?cat=32 (http://store.kornylak.com/searchresults.asp?cat=32)
-
I did look over that tutorial (which is what got me thinking about the omni wheel setup) but couldn't seem to find the site selling them - thanks for the link!
The link in your tutorial on the words 'I used this omni wheel for my robot' must have gotten broken at some point, though looking at the URL I am guessing you are trying to point to the one they call FXA309, right?
-
The link in your tutorial on the words 'I used this omni wheel for my robot' must have gotten broken at some point, though looking at the URL I am guessing you are trying to point to the one they call FXA309, right?
yeap
They changed the link on me . . .
-
Hi guys -
Yes FXA309 would work for you, or any model with rubber coated wheels (it will say on the bottom of each description in the store http://store.kornylak.com/SearchResults.asp?Cat=3 (http://store.kornylak.com/SearchResults.asp?Cat=3) )
You can see more about the Transwheel here http://www.kornylak.com/wheels/transwheel.html (http://www.kornylak.com/wheels/transwheel.html)
In the picture at the bottom you can see there are threaded brass inserts available for these wheels, for $1 extra, and you can chain-drive them with sprockets.
Basically however you need to drive them, if you don't see a solution, just email me directly and we'll figure it out for you.
Andrew Kornylak
[email protected]
-
Hi guys -
Yes FXA309 would work for you, or any model with rubber coated wheels (it will say on the bottom of each description in the store http://store.kornylak.com/SearchResults.asp?Cat=3 (http://store.kornylak.com/SearchResults.asp?Cat=3) )
You can see more about the Transwheel here http://www.kornylak.com/wheels/transwheel.html (http://www.kornylak.com/wheels/transwheel.html)
In the picture at the bottom you can see there are threaded brass inserts available for these wheels, for $1 extra, and you can chain-drive them with sprockets.
Basically however you need to drive them, if you don't see a solution, just email me directly and we'll figure it out for you.
Andrew Kornylak
[email protected]
Already ordered and received, service was good thanks - will be attempting some work with my drill to mount, but if that fails I might be reaching out to you on those inserts :)