[FTC]: FTC drive train CAD examples?

[BSV]

Does anyone know of an online CAD library of old FTC robot designs? In particular, I am looking for examples of how different drive trains are put together so we can explore (a) how to use the CAD software (it is a bunch of CAD newbies, including the mentors) and (b) the strengths and weaknesses of different type of FTC drive trains.

We've got a couple of the kids working in Creo Parameteric so far, since it's free. If you have any pointers to the easiest-to-follow online tutorials for it, we'd appreciate that as well. Local CAD mentors have not materialized, yet, though we are looking... thanks!

[skatefriday]

Originally Posted by BSV

Does anyone know of an online CAD library of old FTC robot designs? In particular, I am looking for examples of how different drive trains are put together so we can explore (a) how to use the CAD software (it is a bunch of CAD newbies, including the mentors) and (b) the strengths and weaknesses of different type of FTC drive trains.

We've got a couple of the kids working in Creo Parameteric so far, since it's free. If you have any pointers to the easiest-to-follow online tutorials for it, we'd appreciate that as well. Local CAD mentors have not materialized, yet, though we are looking... thanks!

While I know PTC sponsors FTC, we've been using Autodesk Inventor
for the last 2 years. Youtube has been invaluable as far as teaching
ourselves how to use the software.

I don't think there are yet a whole lot of teams doing complete CAD
modeling, so I am not aware of any database of models specifically
geared to FTC.

[BSV]

It turns out that there is a full robot in PTC's "How to Model Almost Anything" training.

Now, we need to learn some basic things like how to make parts rotate around an axis. CAD software has a way-too-steep learning curve.

[cadandcookies]

You're looking for the "Pin" constraint. When you're placing the part you want to be able to rotate, select it from the drop down menu.

[BSV]

Originally Posted by cadandcookies

You're looking for the "Pin" constraint. When you're placing the part you want to be able to rotate, select it from the drop down menu.

Thanks - we found that one ("pin"), but no one could figure how what the second constraint that Creo was asking for should be. Then, when they got a second constraint to connect (not sure which one), it was not obvious how to test that it could move. Online videos show a gear (for example) just being grabbed with the mouse and it spins freely, but we were never able to duplicate that behavior.

We also looked at how to link two gears together, and think we figured that out (sort of), but haven't been able to test it due to not being able to make parts move.

[MattRain]

Hold Ctrl and Alt, then click the gear.

[BSV]

Originally Posted by MattRain

Hold Ctrl and Alt, then click the gear.

When I do that it rotates the entire assembly, not just the gear.

[MattRain]

When I build at least, I create my frame of the robot and what-not. When I want to get into the wheels and gears, I do the following. From there I take a gear, and I set it to Pin, and align the hole of the frame and the centered gear and the face of which I want touching/facing the frame. From there I build off the gear, i.e. wheels, axles, collars. If you set your gear to pin when first placing it, it should only move the gear, and whatever has been "attached" to the gear when you hold alt and ctrl.

[BSV]

Originally Posted by MattRain

When I build at least, I create my frame of the robot and what-not. When I want to get into the wheels and gears, I do the following. From there I take a gear, and I set it to Pin, and align the hole of the frame and the centered gear and the face of which I want touching/facing the frame. From there I build off the gear, i.e. wheels, axles, collars. If you set your gear to pin when first placing it, it should only move the gear, and whatever has been "attached" to the gear when you hold alt and ctrl.

OK, here is my sequence:

I load a C-channel piece.
I load a gear.
I select "pin".
I click on the center of the gear, then the center of one of the C-channel holes.
It lines up, says "coincident" on the middle of the gear.
Status at the top says: "connection definition is incomplete"

Where do I go from here? If I switch back to "user defined", it lets me click the green checkmark and says "partially constrained", but the gear will not spin around the axis.

Thanks for your help. Sorry I am so dense.

[MattRain]

Set to pin, click the inside of the gear, and the inside of the c-channel circle. or flatstock in my case.

It should now align itself to the hole of you c-channel. Click the outside face of your channel.


Turn the camera and click the closer facing side of the gear (to your channel)


Once thats done, it should turn orange. Meaning its full complete. (Make sure the C channel you are working with is also full complete(orange). If its your first piece, make it "default" where it says "Coincident"))


No problem when it comes to the questions, I can help you out to the best of my ability.

[BSV]

Originally Posted by MattRain

(Make sure the C channel you are working with is also full complete(orange). If its your first piece, make it "default" where it says "Coincident"))

Ah, this was exactly the problem (at least for what I was experimenting with - not sure about our team members who were having the same issue). I was able to pin two gears on a C-channel and have them properly driving each other within two minutes of reading your explanation. I will share with our kids right away.

They are also watching the Creo training seminars (RoboTalk), so hopefully we can get up to speed in a reasonable mount of time.

Thanks for your help!

[MattRain]

No problem, glad I could help