Re: TOP HEAVY!!!!
 

Are you doing a one wheel or a two wheel shooter? If it's a one wheel shooter, the easiest thing you could do is remove one of the CIM motors from the shooter. The shooter's top speed would be the same, although it would take longer to spin up to its top speed.

Edit: if it is a two wheel shooter, you can probably put a sheet of something behind one wheel and convert it to a one wheel shooter.

Depending on what the robot looks like, it might be feasable to lower the entire shooter before you bag. I know we have mentioned it, since our wide configuration robot is tippy and it wouldn't be that hard to shorten our conveyor. That would sacrifice some shooting height to gain stability, which could potentially be a good trade.

Re: TOP HEAVY!!!!
 

I would also added the bumpers for the simple fact that you are adding mass to the base of the bot, therefore, lowering the CG.

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Get some 775s or 550s and CIM-U-LATOR gearboxes and drop several pounds per motor up top. Add the CIMs back to the drive train down low.

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Absolutely agree here. Just look up the equations for angular momentum and kinetic energy of rotation and you will see why a tall robot may not behave well. Reducing the height (if you can) will pay back large dividends in stability. It is really difficult to increase the weight of your base by 25% late in the build and not go over weight. But decreasing the height the same amount is often quite possible, and may not even be that difficult.

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I guess I should have posted a link about 5 weeks ago...sorry!

http://www.chiefdelphi.com/media/papers/1974

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Lots of good suggestions so far. One thing that hasn't been mentioned, probably because it isn't a great solution, is that a robot with low-friction wheels (e.g. omni wheels) will slide instead of tipping. Not great, but if all else fails, it's something to try.

Re: TOP HEAVY!!!!
 

(emphasis added)
CIM == 2.8 lb each
775 == 0.75 lb each
CIM-U-LATOR == 0.5 lb each

Total weight savings == 3.1 lb (top only)

If you add the CIM's to the bottom, it's a net gain of 2.5 lb. Is that in your weight budget?

If you can (I know it's late in build season), shortening the robot as others have suggested can be a big improvement. CoG goes down, angular momentum goes down, stability goes up. Our team did this, and we believe the advantages outweigh the disadvantages.

Re: TOP HEAVY!!!!
 

Get rid of your 80/20 "camera mount" up top including the uprights, leave the shooter support.

Replace with some of that wonderful lexan you got accidentally.:D

Look to relocate the battery in the center behind your lift mechanism, instead of at the back of the robot.

Also, consider moving the transmissions and motors forward, in between the front two wheels (instead of the back).

I'm currently looking at small pictures on my phone . . have you guys actually gotten the scale to weigh it yet?

The bumpers will help your top bottom a bit, but you NEED to fix the fore/aft problem.

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I posted about Team 4's "Tip-proof" robot in CD a few years ago.

It has an educational and entertaining YouTube clip showing what you can do with a very low CG.

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You're right, it's just a few pounds for both motors, clearly.

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Has it occurred to you to not go over the bump?
Use the ramps... or do you have a problem there too..??

Having those big CIMS up high is where to start... see if you can bring them down or use a lighter alternative motor...

But first put your bumpers on and see if you still have the problem

You don't have to go over the bump...
You can play the game by going over the ramps...

There is danger going over the bump... you can be defended and knocked over..(not as strategy...but defense being played....)

On your own ramp you cannot be defended...

just a thought...

Re: TOP HEAVY!!!!
 

Even with a complete robot, there's still a lot that can be reworked in most cases. First, make sure the heavy components (e.g., battery) are down low and ensure the heavier electronic components are lower on the side pieces.

Also, how offset are your wheels on the drive train? If they are more than 1/8", then you've probably put too much sway in the robot. Normally 1/16" offset is sufficient. This is especially true if your robot has the wide front and a narrower length.

Don't give up until the end of competition--I've watched a team build their entire robot at a competition site.

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MATT look at your inbox!!! And we are not a rookie team for those who are wondering this is our first year with 6WD.

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Wow lucky you, our collaboration robot went up the bridge and took a disastrous spill