Quote:
Originally Posted by Chris is me
I'm really impressed by the quality of both the design and manufacturing of this prototype. Design wise, I like the use of 1.5x1 tubing below to save weight and 1x1 (16 wall?) tubing up top for bumpers / superstructure / etc. Manufacturing wise, the nice surface finish on everything and the very well done belly pan and gearboxes stand out. This is art!
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Thank you! Yeah, the 1x1 was 1/16 wall. The superstructure is designed to hold up to 200lbs. It has a minimum safety factor of 40. We used roloc pads for the surface finish, it works great!
Quote:
Originally Posted by GeeTwo
Yes, it's definitely a good looker!
Now it makes a more sense to me.. those long holes in the belly pan were for gearboxes, not wheels. I was trying to figure out how you would mount the gearbox from the first post.
Were you planning this as a competition-capable robot (ready for bumpers), or more as a demo? If the latter, I probably would have made the upper layer a square rather than an octagon to better protect the wheels from bumper interaction. As a showpiece (or Recycle Rush), it's spot on. [Now that I notice there are no mount points for manipulators or bumpers, I'm guessing the latter.]
With the upper frame as well as the lower, it looks quite stiff for a 4-wheel holonomic drive. This may cause you some unusual behavior on uneven ground, with the weight being on two or three wheels. The cantilevered wheels may provide a bit of suspension to compensate for slight irregularities like a plate under the carpet, but probably not something larger. If you plan to drive on carpet on solid floor, again, not a concern.
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Thanks! This is actually supposed to be a display robot at a certain event (we're not allowed to talk about it until then). The upper structure is supposed to hold up to 200lbs.
Its very stiff for a holonomic drive, especially with all the weldments across the frame. It pretty much doesn't drive on anything that isnt perfectly flat haha.. unless someones sitting on it! With the 200 lbs on the chassis, we have no problem driving it around on a bumpy floor. Check out the original post for some videos!
Quote:
Originally Posted by rlance
We also built a holonomic robot using the omni-wheels just for fun in the past few weeks. It does not look nearly as nice as yours, but it was a great experience for the programmers and drivers and gives us a second option for a drivetrain. Since ours wasn't intended for competition we used BAG motors on VP Gearboxes to run the wheels, which got really hot after about 3 minutes of use. I noticed you have heat-sinks and fans on your CIM motors. Did you have an experience in the past that influenced that decision?
Because of the nature of the wheels, these robots don't have great traction and aren't made for pushing matches. That being said, did that influence your decision on gearing, such that you are going for speed over power?
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Cool!
We havn't had any experience using BAGs for drivetrains. Our CIMs actually didn't get very hot at all.. In fact, the wheels got hotter than the CIMs due to all the friction! We have heatsinks on there because this thing will be driving around for 8 hours with up to 200 lbs on this thing! So we're just planning for the worst.
We would never use this kind of drivetrain in a real game! (unless its 2015 lol). We had to gear very low (16:1) so we wouldn't trip the breakers every other minute (since its supposed to carry up to 20lbs).
Even if we did gear low for defence, it would be almost useless since we would get pushed all over the place anyways!
The only thing more dangerous than a Programmer with a screwdriver is a Hardware Designer with the root password... - kmcclary [more] 
09-12-2016, 10:14
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