What do you guys think of a 280 rpm base with a mecanum drive? As far as programming, we can manage to get it consistant with Odom and pid. As far as driving, our drivers are comfortable with such speeds from previous games. Also, the base might have more than just the 4 mecanum wheels (meaning the 3 wheels for odom and maybe 2 wheels to reduce friction and rolling resistance like what some teams have done (210y, mjs and a couple more teams did that last year and mjs is doing than this year). And obviously this is just and idea.
I think an x drive is probably a better option if you have the room, but that should work as well. I’m a bit confused how the idea that adding 2 extra wheels could possibly reduce friction and rolling resistance though.
Physics doesn’t matter, more wheels equals more gamer. On a serious note, I think @Almotawayasir was talking about having 2 odomotry wheels instead of 3.
ahhh that makes sense. I’m pretty sure you need 3 wheels for a holonomic drive though… unless you do some magic with the inertial sensor.
Ya, our programmer is using only two odometry sensors on a holonomic but is using other sensors to make up for the third sensor because we already had them from last year and we only bought two odometry sensors this season. We are trying to save a buck here and there.
I meant the using 3 for the odom (1 for each side and then one horizontal one). As far as what xenon said about an x drive, no I don’t have enough space with my design. And yes, I did mean 2 more wheels to reduce friction and rolling resistance (the more wheels the less the wheels will sink meaning there is less rolling resistance. Also the 2 extra wheels would be using the green inserts to lower the friction, otherwise they wouldn’t do much. So in total, 4 mecanums, 3 wheels for the odom and 2 wheels to reduce the friction.
I don’t think it works that way…
I mean I had a 99 in AP phsyics last quarter and I don’t think that is how it works.
I had 103 (extra credit) in robot taxonomy last year. All jokes aside, can you explain why? I am though it had it right but by no means am I great at physics. I thought that using extra wheels with the green inserts would reduce the pressure on the motors to make them work less.
if you support your shafts correctly it won’t decrease how much work the motors have to do, in fact, it will increase it because it adds extra point of friction.
You don’t need to support your axles with more wheels, you should use bearings at proper points to create a robust and as frictionless as possible drivetrain.
So I guess back to my question (without the part about all the wheels and what not) would 280 rpm work? is it going to over heat very quickly? is it a good idea? I am not too worried about pushing honestly, I am trying to make something fast for skills since we won’t compete in person for a while.
Y’all out here with near 100’s while doing robots proves you are not the leading source of info for robotics
Sorry, I don’t understand your point (it would be nice if you answered my question since it seems like you understand the situation)
We ran 200 rpms last year and are doing that this year, 280 should be fine. I think some teams are using up to 600 rpm. If you want speed, you could prob get away with 400 on an aluminum chassis with well aligned bearings and an as frictionless as possible gearing. (This is if you are using four motors.)
The only times I’ve seen anyone put 600 rpm motors on a drivebase in direct drive, it was either as a joke, or because they wanted to see what it would look like (Or both). It was way too fast to control, and even though it was just a drivebase, it accelerated pretty slowly.
The only viable way I see 600 rpm cartridges being used on a drivebase is by gearing it down 3:7 to get to 257 rpm*. If you go too fast it will be much harder to control, accelerate a lot slower, and will burn out much faster.
*You could also use 600 rpm while gearing it 3:5 to get 360 rpm, but I think that is way too fast.
Nah fam, ever watch fast and furious. The right driver can make speed work.
600 rpm? that’s crazy, I don’t know if anyone in the world right now is actually good enough at driving to make big use of that. My chassis tend to be very smooth (they spin for so long when there are no motors and I am generally really picky about that). Asides from that, I’ll probably stat building sometime in the future after I finish what I have on hand (programming of our 4th. robot).
I know a team that has a 280 rpm mecanum drive and they can barely strafe. They have a good quality build. I’m not sure if other teams have similar problems.
The only reason for that is because of tourqe issues. It takes a lot more power to strafe than to go forward, back, and turning. And from the beginning, the wheels do have more friction when driving.