Modding AM14U3 for WCP DS Gearboxes

[KohKohPuffs]

Recently became part of a newly-formed FRC team, and I'm wondering if it is practical to mod the AM14U3 to be able to mount WCP DS gearboxes. I've looked over the CAD of the chassis, and it appears to be quite doable with the resources we currently have. In addition, it also looks like the ToughBox gearboxes that come with the chassis will still be compatible with the chassis after the modifications.

However, these gearboxes don't come cheap; are the benefits of the WCP DS gearboxes worth the $600, or could we possibly use that money for something more worthwhile? Note that this really depends on the funds we we'll have coming into the build season. If we can't afford to spend money on the gearboxes, then obviously we'll scrap this idea, but if we do have the budget to purchase them, then what would be the best option?

[Knufire]

Originally Posted by KohKohPuffs

However, these gearboxes don't come cheap; are the benefits of the WCP DS gearboxes worth the $600, or could we possibly use that money for something more worthwhile?

IMO, shifting isn't worth it in most games (EDIT: For the average FRC team), ESPECIALLY for a rookie team.

[R.C.]

Attached is a link on how to integrate both a VEXpro BallShifter and WCP SS into the AM14U style chassis:

http://content.vexrobotics.com/vexpr...ive-System.pdf

[KohKohPuffs]

Originally Posted by Knufire

IMO, shifting isn't worth it in most games, ESPECIALLY for a rookie team.

If the game requires heavy defense, then shifting could be an advantage. Also note that this team is built from people like me who already have experience in FRC, so I guess in some way, we aren't really going to kill ourselves by attempting to do something we have no clue into how we're going to do that.

However, I agree that for a team like us, implementing a shifting system would be way too early for us. I mean, of course we could do it given the resources available. The problem I think would mainly be a lack of experience in terms of handling a two-speed drivetrain, as well as the other, more beneficial ways we can spend $600 on as opposed to spending it on gearboxes. For instance, we could probably build a manipulator for that much money, and we would probably be better off doing that due to our limited budget. (I don't have exact numbers on what our funds are, but I do recall someone asking if I can budget-constraint the design)

[Knufire]

Originally Posted by KohKohPuffs

If the game requires heavy defense, then shifting could be an advantage. Also note that this team is built from people like me who already have experience in FRC, so I guess in some way, we aren't really going to kill ourselves by attempting to do something we have no clue into how we're going to do that.

However, I agree that for a team like us, implementing a shifting system would be way too early for us. I mean, of course we could do it given the resources available. The problem I think would mainly be a lack of experience in terms of handling a two-speed drivetrain, as well as the other, more beneficial ways we can spend $600 on as opposed to spending it on gearboxes. For instance, we could probably build a manipulator for that much money, and we would probably be better off doing that due to our limited budget. (I don't have exact numbers on what our funds are, but I do recall someone asking if I can budget-constraint the design)

I helped start a rookie team that did shift their rookie season (2014, and it was pretty much a stock Versaframe WCD). Shifting isn't "hard"; it's not going to take away from your resources much other than money. With a couple mentors with previous experience, the time taken to implement shifting isn't going to seriously hurt the rest of your bot.

However, it's a rookie team. You're going to have rookie students that are rookie drivers, and for all the theory you can pour behind shifting being beneficial, it's not worth it if the driver doesn't know how to use it. We realized this our rookie year and built single-speed drives since. Shifting just isn't the "low hanging fruit" when it comes to ways to optimize your performance for your resources.

Also, save your money. Sometimes there are harder design problems that can be solved by throwing money at it for a nice COTS solution. Things like a DART, while expensive, can sometimes take the hardest part of a simple robot and make them even easier.

[frcguy]

Originally Posted by Knufire

IMO, shifting isn't worth it in most games (EDIT: For the average FRC team), ESPECIALLY for a rookie team.

We ran the 2 CIM ball shifters from VexPro our rookie season and they worked great for us. Our drivers report that it was great to be able to shift into the higher gear and traverse the field fairly quickly, and they took very little time to integrate in to the AM14U3.

[Knufire]

Originally Posted by frcguy

We ran the 2 CIM ball shifters from VexPro our rookie season and they worked great for us. Our drivers report that it was great to be able to shift into the higher gear and traverse the field fairly quickly, and they took very little time to integrate in to the AM14U3.

But we're you actually going as fast as you could have? The average "sprint distance" (e.g. distance you drive without anything causing rapid deceleration) was relatively short in Stronghold. The smaller this distance is, the lower the gear ratio is that minimizes this time.

I'll see if I can use Ether's acceleration model and come up with some actual numbers for Stronghold.

This is also assuming you're not shifting for acceleration (starting in low gear and upshifting at a certain speed).

[ollien]

Originally Posted by R.C.

Attached is a link on how to integrate both a VEXpro BallShifter and WCP SS into the AM14U style chassis:

http://content.vexrobotics.com/vexpr...ive-System.pdf

Since this time, the AM14U has changed dramatically enough to make mounting the gearboxes weird.

I've cadded it out before with the AM14U3 and 2CIM DS. With some creative drilling, it can totally work. I can't, however, seem to make it work for the 3CIM.

[R.C.]

Originally Posted by ollien

Since this time, the AM14U has changed dramatically enough to make mounting the gearboxes weird.

I've cadded it out before with the AM14U3 and 2CIM DS. With some creative drilling, it can totally work. I can't, however, seem to make it work for the 3CIM.

Gotcha

Could you explain or show pics of what's going on. I won't be at a desktop for a while but very curious what changed.

[ollien]

Originally Posted by R.C.

Gotcha

Could you explain or show pics of what's going on. I won't be at a desktop for a while but very curious what changed.

Yep! It's actually not as drastic as I remember it being. You could probably mount the 3CIM fine, but you'd need to create some double holes.

Here are two pictures of the AM14U1 inner plate, showing some dimensions.





And here are two pictures of the AM14U3 inner plate, showing the same dimensions.





On the AM14U1 you have a lot more room to work with in order to mount the gearbox. For the 2CIM, you should be fine with the AM14U3, but the 3CIM doesn't seem possible without a larger plate.