Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: funk1e on March 15, 2010, 01:46:32 PM

Title: holonomic mobile robot
Post by: funk1e on March 15, 2010, 01:46:32 PM
hi,
i'm very new here. ;D
my question:
is it possible to built holonomic mobile robot using just 2 Transwheels???
help me. currently i'm using 2 Transwheels. the position of the transwheels are left and right (straight)(my platform more or less like square). is it possible by apply different speed of left and right transwheels so it can move to the side (i'm sure it is possible when it is non-holonomic)
Title: Re: holonomic mobile robot
Post by: GWER57 on March 15, 2010, 01:51:32 PM
I think so, but you have to change the directions of one of your wheels to make them at a ninety degree angle. Thus you would have one wheel controlling your movement in the Y-axis (forwards and backwards) and the other the X-axis (left and right). I hope that helps, but you need to know that you need a third contact point so that your robot does not drag!
Title: Re: holonomic mobile robot
Post by: funk1e on March 15, 2010, 02:16:35 PM
hi GWER57 ,
thanks for the reply,

I think so, but you have to change the directions of one of your wheels to make them at a ninety degree angle. Thus you would have one wheel controlling your movement in the Y-axis (forwards and backwards) and the other the X-axis (left and right).
i think that will be a great idea!
but i already constract the chassis like this:
(http://i885.photobucket.com/albums/ac58/funk1e/geek/Watermark.jpg)
to turn one of the wheel 90deg seem like alot work to do~ any other idea?
Title: Re: holonomic mobile robot
Post by: waltr on March 15, 2010, 02:46:27 PM
I don't think it is possible with that wheel configuration to get it to move sideways. You need to have the wheels not in line to get a sideways force. I'm not even sure its possible with only two wheels to get sideways movement.

Hopefully someone will post here and prove me wrong.
Title: Re: holonomic mobile robot
Post by: SmAsH on March 15, 2010, 02:58:31 PM
With that wheel config, it cannot move sideways on its own, it can roll sideways but not drive sideways. Waltr is right, you need three omni wheels to achieve sideways motion.
Title: Re: holonomic mobile robot
Post by: GWER57 on March 16, 2010, 08:53:24 AM
My suggestion is if you don't want to do a lot of modding get rid of the two casters and add two more wheel assemblies where the casters used to be. That is probobly the easiest solution i can think of but make sure to look at admin's robot fuzzy as he uses a basic aluminum suspension to make sure all of the wheels touch the ground ;D.
Title: Re: holonomic mobile robot
Post by: funk1e on March 19, 2010, 11:09:51 AM
Thanks all for the reply  ;D
i already figure out the solution.
to make it move to side ways by 1st make it turning 90deg at center point n then go straight. It still holonomic in that way after i got advice from a qualified person :D. but i wish i had more wheels like those. coz it is very expensive here.
so,about adding two more to replace the ball castor will be just in my dream~ haha

thanks again all!