Rookie FRC Team 4209 TigerBytes Week 5 Update
 

Almost done!!

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

PACMAN! Love it.

-Brando

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

Depending on how many motors you guys are using, it appears that your bot could easily be changed to where all 4 cim motors are in drive. Instead of using 2 cims for the shooter use 4(or 2) 550's with CIM-U-LATOR gearboxes. This will greatly improve the power of your drivetrain. I also recommend adding 2 wheels in the center of your robot(should be very easy with the kitbot frame) to make it easier to turn.

These simple changes will greatly improve the preformance of your robot. Here's why, and here's some instructions if your feeling a little confused. I hope this helps and good luck this season.

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

If you take your robot onto carpet, you may find some difficulty in turning, since you've got four relatively "sticky" wheels, one at each corner. That's why he said this:
Another possibility would be to change either the front wheels or the back wheels to slick wheels from 2010 or omni wheels. If you do choose omnis, you may find the Dualies will give you a smoother ride (although they are a bit more expensive).
Looks like a solid design; with some minor tweaks you'll be a force on the field.

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

Thanks guys for the advice!! I've suggested omni wheels and I believe we will switch to them before the competition. Majority of the focus has been to get the shooter finalized because we honestly didn't know if we were going to be able to pull it off. I will share this information with the other mentors in our meeting this week. Thanks again for the information and help!!

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

Awesome design!Please add Pacman eyes and little ghost drawings on the side of your frame! And name it something appropriate of the theme. I look forward to seeing this rookie bot in competition! Good luck!

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

Haha!! That's actually what the kids have suggested we do!!

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

Thank you all for the suggestions. We don't yet have an accurate weight, but we believe we have some room to spare. If we confirm this, we should be able to at least add the extra wheels.

What is everyone's thought on non-powered center-drop wheels?

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

Non-powered wheels are rarely a good idea. Wheels support the weight of the robot; the weight they bear gives them traction and lets them help propel/turn the robot. If there are non-driven wheels in contact with the playing field, they provide neither propulsion nor steering capabilities, making them virtually useless. Especially as the drop wheels in a 6WD - that guarantees that half your drivetrain is always non-powered; theoretically those wheels would bear the most of the robot's weight as well. That would be a tremendous waste of resource.

Perhaps a professional can give you a more detailed, math- and physics-infused answer, but to my NEM mind, it makes sense.

In the kit of parts, there were some double sprockets. Looking at your drive train, perhaps you could replace the sprockets on your rear wheels with double sprockets; keep the inside chain run as it is, and set the outside chain to the middle wheel. That would be very simple to implement and cause minimal change to your chassis.

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

I'd be concerned about:

[R33]
Bumpers must be supported by the structure/frame of the Robot (i.e. each end of the Bumper must be rigidly attached to the Frame Perimeter, the gap between the backing material and the frame must not be greater than ¼ in. and no section of Bumper greater than 8 in. may be unsupported). See Figure 4‑7.

It doesn't look like you could adequately secure and support the bumpers for 8in onto the intake side of your frame. Just a thought to double-check.

Otherwise it looks good!

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

Team 4209 is doing an amazing job this year. You'll do Baton Rouge proud!

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

I have to take another look at the rules, but our front bumper pieces overlap the sides givi us roughly 3 1/2" of overlap plus about 6" of front support.

I'm asking because I'm not a bumper expert, does is fall within the guidelines?

Also, Taylor, thanks for the thorough response!

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

That sounds dangerously like you're in the "not okay" regime of bumper construction.

[R28]
Bumpers must be constructed as follows (see Figure 4‑4):
be backed by ¾ in. (nominal) thick by 5 in. tall plywood.
hard Bumper parts (e.g. plywood, fasteners, etc) may not extend more than 1 in. beyond the end of the Frame Perimeter(see Figure 4‑4).


Figure 4-4


use a stacked pair of 2-½ in. “pool noodles” as the bumper cushion material which completely covers the plywood. Cushion material may extend up to 2-½ in. beyond the end of the plywood.
be covered with a rugged, smooth cloth. The cloth must completely enclose all exposed surfaces of the plywood and pool noodle material. The fabric covering the Bumpers must be a solid red or blue in color. Visually, the red or blue must be as close to the corresponding color in the FIRST logo as reasonable (i.e. to a reasonably astute observer, they appear similar). The only markings permitted on the Bumper fabric cover are the team number (see Rule [R35]).
must attach to the Frame Perimeter of the Robot with a rigid fastening system to form a tight, robust connection to the main structure/frame (e.g. not attached with Velcro). The attachment system must be designed to withstand vigorous game play. All removable fasteners (e.g. bolts, locking pins, pip-pins, etc.) will be considered part of the Bumpers.
Each set of Bumpers (including any fasteners and/or structures that attach them to the Robot) must weigh no more than 20 lbs.

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

Nice robot. I dont know if it was the camera distortion or my eyesight but from the picture it looks like your drivebase isnt parallel. Again, probably just the way the picture is. Good luck with that pacman :D .

Re: Rookie FRC Team 4209 TigerBytes Week 5 Update
 

James, hank you for helping. I believe we looked at the pictures wrong when we designed our bumpers. We need to shorten the front bumpers so they only overlap the plywood backing of the side bumpers. Thank you again for drawing our attention to the issue!

Ross, the robot is not perfectly built. The frame is parallel, but the inside beams distort slightly downward. We built the front "arch" to force the frame back into shape, but it still says a little. We are continually monitoring the situation, but the problem seems to be purely aesthetical at the moment.