pic: #NotSwerve

What spreads and speeds are you using on the transmissions, alongside what wheels? Also, will you have any active way of measuring your total current draw with the 6 CIMs?

[llamadon]

Hey Brian, these gearboxes are going to be implemented on a summer drive project aimed towards testing the benefits of a 6 cim WC drive. We hope that future games will still allow for west coast drives to be feasible designs, and that our work this summer can be used for seasons to come.

[llamadon]

Originally Posted by Andrew Lawrence

What spreads and speeds are you using on the transmissions, alongside what wheels? Also, will you have any active way of measuring your total current draw with the 6 CIMs?

We plan to use 4" hex bore Andymark performance wheels on live axles with blue nitrile tread. We will be testing a 2.92 spread ratio, set to roughly 7fps/18fps, a 3.64 spread at 5.5fps/18fps, and finally a 2.06 spread geared to 7fps/13.5fps. The 2.06 spread is being tested specifically to see what kinds of acceleration we will see with a lower top speed, but more torque. As for the current draw, we have not thought of any ways to measure that yet.

Originally Posted by llamadon

We plan to use 4" hex bore Andymark performance wheels on live axles with blue nitrile tread. We will be testing a 2.92 spread ratio, set to roughly 7fps/18fps, a 3.64 spread at 5.5fps/18fps, and finally a 2.06 spread geared to 7fps/13.5fps. The 2.06 spread is being tested specifically to see what kinds of acceleration we will see with a lower top speed, but more torque. As for the current draw, we have not thought of any ways to measure that yet.

Excellent idea of testing the different speeds and spreads. I'm not entirely certain what method they used, but Team Spectrum 3847 had a method of measuring their current draw on their robot this year. While you are testing spreads, I think it would be interesting to add this current meter to see how many amps you're pulling in certain situations. It could help you better assess what main breaker limitations you may have in the future.

[llamadon]

Originally Posted by Andrew Lawrence

Excellent idea of testing the different speeds and spreads. I'm not entirely certain what method they used, but Team Spectrum 3847 had a method of measuring their current draw on their robot this year. While you are testing spreads, I think it would be interesting to add this current meter to see how many amps you're pulling in certain situations. It could help you better assess what main breaker limitations you may have in the future.

Thanks! I will definitely inquire of this testing methods. I have read up a small amount on the effects of this number of CIMs on the breaker and have heard of a few blow outs. These blow outs tend to happen in an immediate change in voltage. IE. driving the robot forward and then immediately going backwards. Teams have implemented a part in the code that does not allow this immediate jump from 0 to 100 percent, and instead ramps it up steadily.

[AKSoapy29]

Originally Posted by llamadon

Thanks! I will definitely inquire of this testing methods. I have read up a small amount on the effects of this number of CIMs on the breaker and have heard of a few blow outs. These blow outs tend to happen in an immediate change in voltage. IE. driving the robot forward and then immediately going backwards. Teams have implemented a part in the code that does not allow this immediate jump from 0 to 100 percent, and instead ramps it up steadily.

Well we only tripped the breakers a few times on our shooter, lol. Load testing would be neat. I think we have a load tester in the cave actually, I saw it the other day.

[Arpan]

We used these gearboxes on our robot this year. They were fantastic, esp. considering how we abused them. A few notes :

1. LOCKTITE like the instructions say. We did not do this and it caused several screw failures throughout the season, resulting in worn teeth on some of our gears. The gears themselves are overbuilt - they survived the extreme chipping a CIM coming unmounted caused.

2. The 22 fps calculated speed is too fast to drive without proper code, and will blow your breakers whenever you hit anything. For FRC applications , I don't recommend going faster than 16 FPS.

I'd be very interested in seeing the results of your tests of different ratios.

[AKSoapy29]

Originally Posted by Arpan

We used these gearboxes on our robot this year. They were fantastic, esp. considering how we abused them. A few notes :

1. LOCKTITE like the instructions say. We did not do this and it caused several screw failures throughout the season, resulting in worn teeth on some of our gears. The gears themselves are overbuilt - they survived the extreme chipping a CIM coming unmounted caused.

2. The 22 fps calculated speed is too fast to drive without proper code, and will blow your breakers whenever you hit anything. For FRC applications , I don't recommend going faster than 16 FPS.

I'd be very interested in seeing the results of your tests of different ratios.

Thank you, this is very useful to know! 22 fps does seem too fast. I think I have only driven with 16, and it was plenty, and easy to control. I am really interested to see how our new drive train will handle!

[Boe]

Originally Posted by Arpan

2. The 22 fps calculated speed is too fast to drive without proper code, and will blow your breakers whenever you hit anything. For FRC applications , I don't recommend going faster than 16 FPS.

There were a fair number of very successful teams this year that ran 6 CIM drive trains geared to >20fps before losses. Its possible to do but you have to be careful with you dont blow your breakers.

[RKazmer]

Originally Posted by AKSoapy29

Oh yeah, and the first shooter was 100% pneumatic, and we were constantly working on it. Tip for anyone in the future: Don't use a pneumatic shooter unless you get it working REALLY well.

This is very true. It took three weeks of prototyping to get the shooter right on our robot this year. We even had to tweak it after that due to other pieces for better ball control and stability. However, having a pneumatic shooter was great since we didn't have to have stored energy on the bot versus a spring or motor driven shooting system.

Main lesson for using pneumatics to power a catapult: Start early and have multiple designs that can be tested quickly.

[llamadon]

Originally Posted by Arpan

We used these gearboxes on our robot this year. They were fantastic, esp. considering how we abused them. A few notes :

1. LOCKTITE like the instructions say. We did not do this and it caused several screw failures throughout the season, resulting in worn teeth on some of our gears. The gears themselves are overbuilt - they survived the extreme chipping a CIM coming unmounted caused.

2. The 22 fps calculated speed is too fast to drive without proper code, and will blow your breakers whenever you hit anything. For FRC applications , I don't recommend going faster than 16 FPS.

I'd be very interested in seeing the results of your tests of different ratios.

Thanks Arpan! I will definitely post the results of our testing for you to veiw

I will remember the locktite! As for the speed I was actually having an mental debate with myself, and that is: Why gear for a high speed like say 22 fps? How often will you actually attain that speed? Being able to accelerate quickly is much more beneficial (in my mind) then being able to reach a high speed after spending a notable amount of time accelerating. Just a thought, and one of the reasons for the testing

Originally Posted by llamadon

Thanks Arpan! I will definitely post the results of our testing for you to veiw

I will remember the locktite! As for the speed I was actually having an mental debate with myself, and that is: Why gear for a high speed like say 22 fps? How often will you actually attain that speed? Being able to accelerate quickly is much more beneficial (in my mind) then being able to reach a high speed after spending a notable amount of time accelerating. Just a thought, and one of the reasons for the testing

Teams that gear for that speed use it in cases where you would want to cross the entire field extremely quickly in one straight shot (think 2011 or 2013). That being said, it's still something interesting to test. Most robots that run these speeds are on the lighter side (90-100 lbs), which helps them abuse the higher speeds with greater acceleration.

[Travis Hoffman]

These were sufficiently evil enough for our purposes in 2014.

4" Colsons on corners, 4" blue nitrile performance in the middle, 2.92 spread, max robot weight, roughly 5 fps / 15 fps split

And yes, Loctite everything per instructions.

[nathannfm]

Originally Posted by ClockworkGold

Heck no

It looks like I missed the back story here. If it's not too painful would someone from 2169 mind recounting their season of swerve and what problems you had with it for other teams who are dead set on at least trying swerve as an off season project so they may learn from your season?

[llamadon]

Originally Posted by nathannfm

It looks like I missed the back story here. If it's not too painful would someone from 2169 mind recounting their season of swerve and what problems you had with it for other teams who are dead set on at least trying swerve as an off season project so they may learn from your season?

We used the "Wild Swerve" modules from Team 221 robotics parts. We did not order them prior to build season. I think they were ordered by the end of week 1. Arriving mid week 2, we assembled them and attached them to our drive base. Our programers were coding prior to receiving the modules, confident in their code. We implement the code, not up to snuff. We keep editing and revising, problems arise left and right (using 3D printed encoder mounts was one of said issues.) We focused so much on our swerve that other mechanisms suffered. We over complicated the code, and the start up routine for each match (we had a "hard zero" button to "reset" the encoder values to 0) and in the end we didn't move for half our regionals. My advice is do your trouble shooting and learning before the build season, and only implement swerve for the build season if you already have a polished code for it, and have designed and planned the mechanical implementation of the drive before kick-off.