new wheel design

[mechanicalbrain]

(i dont know if i posted the image correctly or not but i hope it shows if not it looks like an X with omniwheels on each end connected by chain to an outer center shaft and an inner shaft connected directly to the X)
hey im looking for advice. it was one in the morning and this idea hit me and i had to draw it. the little wheels are omniwheels and are rotated by the outer shaft and are connected to the outer shaft by bike chain. this would hapen during normal movement giving the robot a smooth motion. when the inner shaft is rotated it rotates the whole assembly rotates allowing it to
overcome heavy obstacles like stairs with no sweat. the rotation betwean inner and outer shaft would be switched by a gearbox. this means one motor can control each assembly. my only real concern is weight. i would have to experiment with making as much as possible out of plastics. any comments or ideas. note this design would kick $@#$@#$@# on stairs and other rugged terrain.

[sanddrag]

A picture is worth a thousand words. Maybe you can post a link to it or upload it into the gallery? I'd really like to see, sounds interesting.

[sanddrag]

A team did something similar in I believe 2004. http://www.firstrobotics.uwaterloo.c...s/wheels09.jpg

[mechanicalbrain]

yes that is very similar i guess the main difference is the omni directional wheels.

[sanddrag]

Would you plan to have four of these on a robot? How big would the overall diameter (or distance across X) be and what would be the diameter of the little wheels?

Also, instead of bicycle chain, consider using standard roller chain. Easier to get sprockets for.

[mechanicalbrain]

first of all: im curious what team that was in the picture. second: keep in mind its just a concept so far so i guess the wheels would be 2" omni wheels and eack X if i do a X would be 8" or so in diameter. im still trying to figure out how to control the axles independently or how to handle the weight. the origonial reason i thought it up was becuase omniwheels are very small and i was trying to figure a way to overcome obstacles.

The team in the picture was 1218, Cha-Bots. If you haven't gotten a chance to see their robot, (www.SOAP108.com generally has, well, everything), it was amazing to see. Their implementation of the idea was par excellence.

[Alex Cormier]

and if my memory serves me right it twas spam in '04 who used the same omni directional type of drive and was in the top 5 at nats too.

[Cory]

Originally Posted by Alex Cormier

and if my memory serves me right it twas spam in '04 who used the same omni directional type of drive and was in the top 5 at nats too.

SPAM used a holonomic drive in 2004, along with 1083, but it was nothing like 1218's tri wheels.

[mechanicalbrain]

any advice on how to make the outer wheels and the whole thing move seperately i was thinking a gear box of some kind similar to the type that would change speed.

[Alex Cormier]

Originally Posted by Cory

SPAM used a holonomic drive in 2004, along with 1083, but it was nothing like 1218's tri wheels.

what i saw on the pic was the 4 wheels at 45 deg. am i seeing that correctly?

[mechanicalbrain]

yes four wheels at 90 degrees and each one would rotate independently for going over normal surfaces and then the entire thing rotates for going over rough terrian like stairs.

[mechanicalbrain]

each seperate wheel would be an omni wheel and so the whole assembly would act as an omni wheel too.

[Madison]

Originally Posted by Alex Cormier

what i saw on the pic was the 4 wheels at 45 deg. am i seeing that correctly?

The leftmost picture is an elevation, not a plan view.

[mechanicalbrain]

i dont know if this will clear anything up or not but here is an updated picture (just a little clarification) like i said im not sure how to switch (the mechanism not the actual rotation) between small wheels and large wheel