FRC Blogged-Kit of Parts Drive System Option

[Ether]

Originally Posted by SenorZ

I smell modular robot systems...
Easy attachment of "superstructures" means easy removal of superstructers.

Not if you weld, epoxy, or shrink-fit them on

[jvriezen]

I'm disappointed in the CD community. This was the first game hint. We now know that the robot rules will allow rectangular framed robots that needn't be square. Surely someone can take that information along with choices of phrasing in the blog post and make logical inferences to conclude that this year is a water game.

[coalhot]

Originally Posted by jvriezen

I'm disappointed in the CD community. This was the first game hint. We now know that the robot rules will allow rectangular framed robots that needn't be square. Surely someone can take that information along with choices of phrasing in the blog post and make logical inferences to conclude that this year is a water game.

Probably the reason for more sheet metal and extrusion instead of the c-channel is because it's now going to be easier to waterproof; instead of the old, obsolete, leaky c-channel system.

I also do want to see it before we have to make a decision. Since our machining capabilities are still uncertain, it would be nice to know what the drive was and how customizable it is, before deciding either way (I just want to put colsons and 6 cim gearboxes on it )

Originally Posted by AdamHeard

Curious what they mean by this, as the KOP drive (ever since it's inception in 2005) has always been sheet metal

If it ain't broke, don't fix it.

[Lil' Lavery]

Originally Posted by jvriezen

I'm disappointed in the CD community. This was the first game hint. We now know that the robot rules will allow rectangular framed robots that needn't be square. Surely someone can take that information along with choices of phrasing in the blog post and make logical inferences to conclude that this year is a water game.

The previous kitbot frame had been referred to as being made from "c channel" as opposed to "sheet metal" like the upcoming one. Based on that, we know that things beginning with the letter c ("c channel," "carpet") are out and five letter words ("sheet," "metal," "water") are in.

Bam, water game.

[CENTURION]

Originally Posted by AdamHeard

Curious what they mean by this, as the KOP drive (ever since it's inception in 2005) has always been sheet metal

The KOP drive so far has been extruded aluminum C-channel, not sheet metal.

I have a feeling this new drivetrain is going to look eerily similar to the VexPro DIAD Chassis

[Akash Rastogi]

Originally Posted by CENTURION

The KOP drive so far has been extruded aluminum C-channel, not sheet metal.

I have a feeling this new drivetrain is going to look eerily similar to the VexPro DIAD Chassis

Actually, Adam is correct. It is bent 5052-H32 sheet metal. Not extruded. The corner connectors are the extruded parts.

[CENTURION]

Originally Posted by Akash Rastogi

Actually, Adam is correct. It is bent 5052-H32 sheet metal. Not extruded. The corner connectors are the extruded parts.

Really? Interesting, I'll have to take a closer look at that C-channel next time I'm at the buildsite.

[Nemo]

Great to hear that the kit bot is getting an upgrade - I'm very curious to see what it looks like. Hopefully it's possible to put in 2 speed gearboxes with slight modifications.

I like the C-Base frame (we've used it in some fashion for 3 straight years). But I'm excited to see improvements. In my opinion, the biggest drawbacks of C-Base are as follows:
1) Not setup for direct drive
2) Track width not maximized: wheel treads are at best about 2" from the outside of the frame perimeter
3) Limited electronics room: belly pan area too narrow / wheel channels too wide

It's fantastic to hear that this is a direct drive ready frame. On items 2 and 3, I think there's a decent chance we'll see a bit of an improvement with Corner Connect presumably going away. If wheels can be 0.5" closer to the outsides and wheel channels can be 1" narrower, I'll be a pretty happy guy.

[Ether]

Originally Posted by AllenGregoryIV

I'm guessing the standard 12.75:1 toughbox mini with 6" wheels. That's 10.9fps unloaded and 8.83fps with standard JVN loads.

For students with inquiring minds...

In the spreadsheet, the 8.83 number is calculated directly from the 10.9 number by multiplying by a "Speed Loss Constant" (default is 81%).

This constant is not computed within the spreadsheet from user-entered info about physical loads and motive forces in the drivetrain: you get the same 8.83 answer from the spreadsheet if you change the number of motors, stall torque of motors, the mass of the robot, or gearbox/drivetrain friction.

The best way to determine what value you should use for the "Speed Loss Constant" for your drivetrain is to build the drivetrain and measure its top speed, then divide that by the theoretical unloaded speed.

[Whippet]

Perhaps they wanted to make it easier to attach superstructures because this year's superstructures will need a lot of structural support to do some heavy lifting? I'm calling stacking game.

[FrankJ]

Wild speculations about what this means about the game.

First big assumption: You can build a competitive robot using the KOP chassis as designed.
Second implied assumption 6 in wheels based on stated speed.
Third implied assumption direct drive places the gear box center line on the wheel.

So with a 3" high nano box & 6" wheels, you have 1.5" ground clearance at the center of the robot. 8" wheels give you 2.5" of ground clearance in the center of the robot.

Leads to Big assumption based on this is no big obstacles the robot has to go over.

Wheels & stated speed also implies no water game. Again. Sorry guys.

One limitation of a direct drive box is the difficulty of changing ratios.

[FrankJ]

Originally Posted by CENTURION

Really? Interesting, I'll have to take a closer look at that C-channel next time I'm at the buildsite.

If you look on Andymark's web site, you find the drawing it is made from.

So it is true that it is made from sheet stock. In modeling terms & usage I think of them as more of a shape though.

In a previous lifetime I use to have I beams occasionally made from plate metal. Once they were made, people called I beams & would look at you funny if you called them plate.

[Nemo]

Originally Posted by FrankJ

Second implied assumption 6 in wheels based on stated speed.
(snip)
One limitation of a direct drive box is the difficulty of changing ratios.

It could be 6" wheels with 12.76:1 gearing or maybe 4" wheels with the 8.46:1 gearing option.

If it's 6" wheels, the gearbox options give the options of switching to 13 ft/s or 16 ft/s, at least.

It's too bad Toughboxes aren't setup with a 50:12 initial stage instead of 50:14. Then we'd also have the option of switching the first stage to 50:11 or 48:14 for a bunch more options.

[Calvin Hartley]

Originally Posted by Ether

Not if you weld, epoxy, or shrink-fit them on

Use velcro. Bam, removable.