![]() |
pic: OMNI Drive
|
Re: pic: OMNI Drive
Though I've never had direct experience with this, I'm sure it would have many of the main problems associated with mecanum wheels, though probably a bit worse. The main concern is that you'll get pushed around, since omniwheels have so little traction.
If there was no chance of defense, it might be a good idea. However, I get the idea that there will be a lot of pushing this year. |
Re: pic: OMNI Drive
Disclosure: I have never personally worked with this type of system, but I have seen it used both in person and in video.
When the omniwheels are centered on the frame like this, the robot tends to get tippy in the corners when turning. A way to overcome this is to make the frame low to the ground or 'wheelie bars' in the corners. |
Re: pic: OMNI Drive
Quote:
|
Re: pic: OMNI Drive
Quote:
|
Re: pic: OMNI Drive
Like with a mechanum drive system, one key to this being a viable drive train is lots of practice with it under realistic conditions. Because omniwheel systems drive differently than tank-style, the driver's brain has to be re-trained.
|
Re: pic: OMNI Drive
Quote:
That is to say: the diagonal speed will be ~140% of either pair of wheels' speed. See: ![]() I imagine that this drive base would be quite tippy given the small base of support. The setup below is more common because the base of support is larger, and the fastest drive speeds are now aligned with the major faces of the chassis. ![]() |
Re: pic: OMNI Drive
Wheres you Fuel intake? hope you are not relying on Hoppers. I suspect many games within first 30 secs will have all fuel on floor...and going to loading station is a slow process.
|
Re: pic: OMNI Drive
Quote:
|
Re: pic: OMNI Drive
If you keep the wheels in the same locations but rotate the chassis 45 degrees (or vice versa), you get what is sometimes referred to as Killough Drive (edit: pictured in post#7). This eliminates (or at least greatly reduces the "tippiness" at the corners. It is also kinematically the same as mecanum.
|
Re: pic: OMNI Drive
Quote:
Mec fwd/reverse kinematics is same as standard wheel. |
Re: pic: OMNI Drive
Quote:
Quote:
|
Re: pic: OMNI Drive
|
Re: pic: OMNI Drive
While each wheel has different kinematics between Omni and mecnanum, as a 4-wheeled system they behave the same. You just swap the "diagonal" behavior in one system for the cardinal directions in the other.
Quote:
|
Re: pic: OMNI Drive
Check this pdf on page 12
http://www.simbotics.org/files/pdf/drivetraindesign.pdf |
Re: pic: OMNI Drive
Team 341 did a variation of this in 2007 and 2008.
However, we placed the wheels at the corners. Our nickname for this configuration was "Z-drive". If you do this, you have to be resigned to the fact that everyone can push you around at will. We were OK playing a "run and gun" game in 2007. It allowed us to always face the goal with the tubes and just drive sideways. Then in 2008 you were not allowed to contact each other, so we did not have to worry about defenders. We won the Philly Regional with this drive configuration in those two years. That being said, it has a limited range of uses for most games. |
Re: pic: OMNI Drive
Quote:
Quote:
Quote:
And thanks for keeping us honest, Ether! |
Re: pic: OMNI Drive
If you haven't built a holonomic drivetrain before, don't design one in the middle of build season. Just use a tank drive. If you're really set on it, then i would suggest mecanums, which can be added to a standard chassis fairly easily, or, if you really want the omnis, put them in the corners diagonally.
|
| All times are GMT -5. The time now is 10:50. |
Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi