Team 1565 Unique Drive System

Here is Team 1565’s “Linkage” drive system at about beginning of Week 3. http://www.youtube.com/watch?v=RvN4K2ieR5g Some programming bugs in it still, but its still really cool.

ps. our mentor who is video taping seems happy lol.

I have always dreamed of building a drive system like this, but you guys actually did it. Excellent job. You are definitely in line for an innovation award if you play your cards right.

can we see some up close or a description of how it works

I can get pictures up of it tomorrow when I can get them downloaded on my computer, description will follow lol

Awesome! About how much pressure does it take to swivel the modules each time?

it takes about 30psi to move the linkage now, It moves better now than in the previous video :smiley:

Yowzers, that is way too cool! Looks like there is a single cylinder on the bottom (pointing lengthwise) that holds all of the wheel modules in the ‘forward’ position when extended and holds them all in the sideways position when contracted. Very creative way to give your robot more mobility, and it doesn’t use any extra motors!

Nice work.

Nice concept. Looks like you’ve got good power any way you go. Any specific reason for the decision of omni wheels? Would ~0.75" wide traction wheels work just as well or no?

I love your drive system. If you guys do not win creativity i will be shocked.:eek:

Amazing! How much does that weigh, because with almost full weight, all 4 cims and already a pretty big strain on the compressor, are you going to have any sort of device?

Unique is a huge understatement. Very nice, and that looks darn near unbeatable going around the ‘racetrack’.

Don

That’s the most amazing thing I’ve seen all week. :] It’s a thing of beauty.

I completely agree with the π-o-neers. Say hi to your FTC team 470 would ya? im on FTC 232 they’ll know me;)

-Misfit

As i’m watching the video, i’m thinking:

wouldnt it be cool if the wheels all rotated half way (45 degrees), then all the wheels are 90 degrees to each other and it becomes holonomic drive…

but…yeah. totally unnecessary. Definately a sweet looking system. Congrats! i’m impressed!

funny story about that… They did. We had a three stage so we can drive in omni for standard avoiding robots, but programming it turned out harder than we thought, and because nothing else on our bot needs air, we decided to just go for the two stages

total our robot weighs 101 pounds (arm and shell included) the whole drive system weighs about 54 pounds and it built like a rock lol :smiley:
and because of the way it is built there is no stress on the linkage part of the robot no matter what the weight is, it is deispersed onto the frame, and moves very easily on the pivot points

ps sorry about double post

Couple more questions:

Could the 1.5" bore piston be replaced with 2 separate 3/4" bore pistons that are identically mounted but move in opposite directions to achieve the same effect?

Can the omnis be replace with traction wheels for more traction or is there too much skid when the wheels orthogonally rotate 90 degrees while the robot is at speed?

The picture of the under carriage that shows the linkage is great by the way. I noticed at the end of the video one of the guys saying that the linkages were flexing when under power – perhaps you could replace the main linkages with angle aluminum and simply cut one side of the angle down to where it’s a skinny “L” to alleviate this problem. You could also reduce the stress on the first 2 linkage bars by going to a 2 piston setup that uses roughly the same amount of air. However, you know better than I do if you need a 1.5" bore piston to give you enough force in the first place.

Wow impressive, definitely gets my vote for creativity.

Couple of questions:

What made you choose this design over a crab style with 1 motor controlling wheel orientation?

Are you worried about getting pushed (on purpose, or inadvertently) having all omniwheels?

Could the 1.5" bore piston be replaced with 2 separate 3/4" bore pistons that are identically mounted but move in opposite directions to achieve the same effect?

You can use 1 3/4" bore if you wanted, but we only had a 1.5" at the time, and decided why bother replacing it if we already have a mount made for it.

Can the omnis be replace with traction wheels for more traction or is there too much skid when the wheels orthogonally rotate 90 degrees while the robot is at speed?

No the omnis cannot be replaced, nor have we tried, because of the skidding it does, when switching the wheels at speed. It would seem to me (which is why we didn’t try) that the linkage would probably destroy itself if traction wheels were on it.

What made you choose this design over a crab style with 1 motor controlling wheel orientation?

We wanted to do something unique, and we have no experience with crab or omni for that matter. We decided to make an in-between bot that was easier to build than crab, yet stronger than omni

Are you worried about getting pushed (on purpose, or inadvertently) having all omniwheels?

No we aren’t, if someone pushes us, the only way we would move easily is if pushed perpendicular to the wheels (so along the rollers) in which case, we can switch the wheels. Omni wheels are good for traction when being pushed striaght with the wheels. Overall we should have as much pushing power as any four wheel drive bot, from every direction.

Thanks for the comments everyone!!

This is an amazing robot, great job!

I wouldn’t go quite that far…keep in mind that when you push up against another robot, much of the weight is transferred to the rear wheels, and you only have two drive motors back there. A normal skid steer 4 wheel drive bot has power to both front and rear wheels on each side from a common transmission, so it has twice the torque available at the rear wheels as yours does.

But this years game seems to be more conducive to quick, highly maneuverable robots like yours, so that should not concern you.