I was thinking about how I should place my motors in my drivetrain. And whether or not I would require chaining. If I wanted a 6 wheel system. What is the most optimal layout of my motors, if I wanted to use 4?
I assume you’re using 4 motors. I wouldn’t recommend a 6 wheel drive, there’s no reason to have one this season, as you don’t really have to climb any obstacles.
you have a few basic options, with 4 motors and 4 wheels. you can direct drive all 4 wheels, which is the simplest solution, and since it requires no chain or gears, will have the least slop and the least friction. but, with how big v5 motors are, often times you don’t want to have 2 motors in the front of the bot where they may get in the way of other instruments you need. In that case, you can either use chain or gears to move power from 2 of the motors to power the front wheels. Or, you can only power the back 2 wheels, which is what I do. It sounds bad but its really not.
So, in other words, you use a 2 motor drivetrain? What wheels would you recommend using in the case where each motor has a wheel? What is your take on using mecanum drive?
no, I use 4 motors, powering the back 2 wheels.
All omni wheels always works well it seems.
mecanums have always seemed to have more disadvantages than advantages, but they aren’t bad.
i recently physically saw an example of a mecanum drive system. Which seemed to work pretty wheel, since the mecanum wheels are wide, allowing it to have more grip. But before was the middle wheel usually used for stabilty or making it easier to climb?
so the main advantage of mecanum wheels are that they allow strafing from side to side. I don’t think they actually grip the tiles any better, but i may be wrong.
the middle wheel what used mostly for scaling the platforms last season.
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But even this season, I’m seeing I lot of 6 wheel drivetrains.
That doesn’t mean they’re better than 4 wheel drives. After all, it’s still early in the season.
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that’s mostly due to people either being used to seeing 6 wheel drives from turning point and sometimes itz (the pipes had to be driven over), or modeling their base after robots from seasons where 6 wheels were superior
Does adding a wheel in the middle, make any differences aside from, climbing?
It can make it harder for opponents to push you side to side, and it adds more friction, because more moving parts.
motors towards the back. Two on each side ofc. I use pillow blocks to place the middle sprocket one whole on top of the c channel. You can also see the motor attached to that middle sprocket is vertical compared to the motor at the back, which is horizontal. So y raise the sprocket in the first place? Well a common problem is the chain carrying slack. To fix this, the chain needs to go around more than two points. Without changes in the height of the sprockets, the chain would only really only around the two sprockets at the end, almost ignoring the middle one. This is y teams add a standoff, it’s another point the chain has to go around. That makes the chain tighter, thus no slack. Instead of adding a standoff, I just thought “y don’t we make the middle sprocket the third point to wrap around?”. I don’t need to gear two motors together to drive just one sprocket as well; I save space by eliminating the gear box.
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or you could just chain one motor on each side to the front wheel, and direct drive the other wheel with the other motor.
Yeah ig but v5 motors r big. They’d take up too much at the front. wait i think im misinterpreting what ur saying
no no, you chain one motor to the front wheel, direct drive the other motor to the back wheel. both motors are at the back.
A mecanum chassis is really easy to push around because there is not much “wheel” touching the ground. More wheel surface area on the ground means more traction. In the case of traction, standard 4” wheels are the best, however turning can be finicky with them. Omni wheels allow for maneuverability and good turning while also having lots of surface area on the ground, which is why they are so popular. They offer the best of both worlds.
well even then u still have the problem of the chain only wrapping around two points. By chaining all three, u can make the chain wrap around three points. Also y wouldn’t just chain all three sprockets regardless? The chain can transfer twice the force/power/torque/whatever of two motors instead of just one
People in TP often used Omni drives and traction wheels in between in order to not be pushed from the side, however there is also an alternative where teams put flaps on the side of the robot to direct force upwards away from the chassis. Check out the 21s TP worlds reveal for an example.
448x TT ri3d and 5225a ITZ
because, why bother chaining all three sprockets together, which has more friction, longer chain so more likelihood of chain snapping, when you could just have each motor control a separate wheel?