Mecanum Drive

VEX V5 General Discussion General Forum
#1

Hello, I would like to build a mecanum drive train powered by 4 393s directly. However, I am bumping into the issue of the lack of space. Hence I would like to know what is the best way to mount a mecanum drive.

I have tried a few ways

  1. Directly powering 4 mecanum wheels with 4 motors. The issue was that the front 2 motors took up a lot of space in the middle of the robot, leaving little space for anything else.

  2. Using sprocket and chain for the front 2 wheels. The problem with this was that the drive train ended up being rather thick anyway due to the sprocket taking up a lot of space. Spacers also have to be added to prevent the chain front rubbing the wheels.

  3. Fold out front wheels. I have tried this but it didn’t turn out so well. It was rather unstable and I have no idea how to build this properly.

Any help would be appreciated! :slight_smile:

#2

Just a few questions
About how much space do you need in the front? Is this a competition robot? How much space do you have with motors in the front?

#3

Something we’ve done before if we are running low on space and using the 5-height C-Channel is to put the motors in between the bars. We put another piece of C-Channel on the inside and attach it with standoffs to the bar and then use chain between a sprocket on the wheel axle and a sprocket on the motor axle. It shouldn’t be any wider than your current setup and you could easily move both motors onto the inside. The major issue is that maintenance is nearly impossible because the screws on the motor are inaccessible so you would need to take it off to tighten it.

#4

Yes this is a competition robot. I am just trying to figure out the best way to mount mecanum wheels so that I can have more space for whatever mechanism I would need. Let’s just assume this is a robot for Sack Attack and I want a pneumatic scoop robot.

#5

I have an idea for flip out wheels if you want it. you can use plates or turn the c-channels outwards to give yourself more space for the wheel.

#6

Could I have a more detailed explanation for this please? I have tried fold out wheels but I have no idea how to lock them in place. Also, it was rather unstable.

#7

I’ll draw out a picture.

#8

http://steeleaglevi.weebly.com/uploads/9/8/8/0/9880582/7726007_orig.png

Here you go. It might take some more explaining, but here’s a visual.

#9

Hmmm, this looks good. I think I’ll try out both eddie’s and 7706’s ideas. Thanks a lot! :slight_smile:

If anyone else has any ideas, please do post them!

EDIT:

I would also like to ask what is the best way to mount encoders without taking up too much space as well.

#10

If you’re talking about the red quadrature encoders, there aren’t a whole lot of good ways of keeping them out of the way. When we used them we would always use a bevel gear on the drive axle and then have the encoder parallel to the axle with a bevel gear on it so that it isn’t taking up as much space width wise.

#11

I would put the encoders only on the back wheels and just link them with LS gears. 1:1

#12

Hey guys I tried to build this today, but it ended pretty thick. What am I doing wrong? And are there any other ways? :slight_smile:

http://distilleryimage5.ak.instagram.com/a8ea3f84a8c611e2ada222000a9f3cf6_7.jpg

#13

You dont need that much space for the chain… 4-5 washers on each side of the sprocket should be enough

#14

black bearing blocks on the other side of the metal
the white spacers are too fat as 7706 said, use washers and use 3mm clearance on either side

#15

Thanks a lot guys for the help :slight_smile:

But after seeing Toss Up, I think we have other plans for our drive train :cool:

#16