Quote:
Originally Posted by LLogan
I have been waiting for somebody to create this.
Looks like you have the best of both worlds. Where are you going to place the piston? I'm having a hard time visualizing where you'll be mounting it.
What configurations are you going to have your wheels in? I.e. four traction only, four mecanum only, 4 traction + 4 mecanum, etc.
|
The wheels are going to be actuated by two pistons -- one along each side of the robot. It's hard to visualize because all of the hardware associated with that system is still missing. We'll add a vertically mounted arm to each wheel pod that the piston will push or pull upon. This creates a four-bar linkage where none of the links are grounded. The 1x1 cross piece that the pods are currently zip-tied to will act as a stop for the pod rotation and, effectively, ground one link of the four bar.
In retrospect, it would've made more sense to actuate each wheel pod individually, but the system we're implementing is a bit lighter. As a result, we can only run on all mecanums or all traction wheels.
Quote:
Originally Posted by AdamHeard
I like it, what is the speed difference?
|
There is an additional 22:32 reduction between mecanum and traction right now, in addition to the difference in wheel size -- 4" vs. 6". We may experiment with this some more.
Quote:
Originally Posted by spiffyspleen
That looks amazing,are you guys going to be at the Portland Regional this year?
|
Yep!
Quote:
Originally Posted by Joyride_67_1902
I like it!
However a few questions
Why did you chain all the drive wheels, instead of power one of the directly and derive power off that wheel?
How much does it weigh? (without a super structure)
Where does the piston mount?
|
I tried to make direct drive of the mecanum wheel a reality, but AM's "long" output shafts were not quite long enough to make it plausible. It would've simplified a lot of things, certainly.
I am not certain of its weight. We'll try to weight it today, but I'd guess it's around 50/55 lbs.
Quote:
Originally Posted by Bjenks548
That is going to be a very fun drive train to watch, just like 217 and 148 last year. How much does it weigh? and Why did you put the mecanum wheels on the outside?
|
Mecanum wheels are outside because they're geared faster than the traction wheels and we wanted the widest wheelbase possible to accommodate rapid changes in direction. Putting the traction wheels on the inside also makes it easier for the robot to turn while they're in place.
Here's some brief video of the first test of the mecanum wheel set. It's nothing too earth-shattering, but I understand that, by the time they left last night, our programming group has field-oriented drive running well.
http://www.youtube.com/watch?v=RA-jd48tPFM