Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: stopgo on September 17, 2007, 06:48:02 PM

Title: Wheels - holonomic vs. non-holonomic
Post by: stopgo on September 17, 2007, 06:48:02 PM

I'm considering building a robot similar to Taurus 2.  I'm wondering about some of the disadvantages of holonomic robots.  It looks like using a holonomic system will create a bit more computational overhead, but not too much.  Localization will be very important to me - will a setup such as Taurus 2's significantly degrade my ability to do accurate dead reckoning? Taurus 2 uses 8 identical servos.  If I should upgrade my 4 wheel motors later, I could probably get away with using weaker motors for the 4 'swivel' motors, right?

Lastly, I'm making a 4-wheeled robot.  If I decide to just do differential drive, how would I go about attaching my 2 motorless wheels?

Title: Re: Wheels - holonomic vs. non-holonomic
Post by: Admin on September 27, 2007, 05:03:55 PM

A lot of your questions can be answered here:
http://www.societyofrobots.com/robot_omni_wheel.shtml
(its not the Taurus 2 design, but still covers the same concepts you asked about)

Quote

Lastly, I'm making a 4-wheeled robot.  If I decide to just do differential drive, how would I go about attaching my 2 motorless wheels?

Will your two motorless wheels have just one motor or none at all? Might be better to just use a castor instead of having 2 useless wheels dragging?

Sorta like this (my 2nd robot ever):
(http://www.societyofrobots.com/images/materials_HDPEexample.JPG)

Title: Re: Wheels - holonomic vs. non-holonomic
Post by: stopgo on October 05, 2007, 05:13:56 AM

Thanks, I agree.  I went with a ball castor.

Title: Re: Wheels - holonomic vs. non-holonomic
Post by: JesseWelling on October 05, 2007, 06:57:21 AM

You will also get better odometry out of a 2 wheel differential drive with caster instead of a 4 wheel differential. Good Odometry will of course help you in localization.