Angled Bumpers
 

For our robot, we wanted a ball pickup system for balls on the ground to be added to our ball storage system. We are running it non-stop, so we wanted the whole front end to be an intake. The bumpers get in the way and leave only about 10 inches for the intake. We were wondering if we could have the front corner bumpers at a 70 degree (or smaller) angle instaed of a right angle. The Rules, as far as we know, don't mention the angle of bumpers, but all the images of bumpers show right angles. We wanted to make it a funnel to go into the intake.

Re: Angled Bumpers
 

If you wrap a piece of string around your ROBOT and pull it taut, that defines the FRAME PERIMETER that the BUMPERS need to be attached to.

This means the angles of the frame cannot be less than 90 degrees, because you would then have a piece of that tightly pulled string that was flapping in the air without a place to attach a BUMPER.

Re: Angled Bumpers
 

All corners do not need to be 90 degrees. You must meet - R22.
ROBOTS are required to use BUMPERS to protect all outside corners of the FRAME PERIMETER. For adequate protection, at least 6 in. (~16 cm) of BUMPER must be placed on each side of each outside corner (see Figure 8-1). If a FRAME PERIMETER side is shorter than 6 in. (~16 cm), that entire side must be protected by BUMPER (see Figure 8-2).

Re: Angled Bumpers
 

I think what you are asking is.

Can we angle the bumper at the opening to the intake to help game elements funnel into the robot / intake system?

I believe this rule answers this scenario.

I am paraphrasing....

R29.
BUMPERS must be constructed as follows .
a) backed by 3/4" robust wood.
&
c)stacked pair of 2.5" pool noodle

Having an angle at the bumper opening will no longer provide the 2.5" of pool noodle required..


Of course keeping in mind all the other bumper rules including those mentioned above.

Good luck this season

Aloha!

Re: Angled Bumpers
 

Someone posted a CAD render on DAY 1 with the configuration mentioned. It's going to be a long year for the inspectors...

A legal configuration for legal bumpers includes the following relevant items:
R22: 6" on either side of a corner in the Frame Perimeter (not necessarily the robot's frame--wrap a rubber band around the frame instead of string, maybe?)
R29G: Secure attachment to Frame Perimeter

Now, the described configuration fails to meet R29G, as it's not on the Frame Perimeter, and fails to meet R22 because it's not protecting the corners of the Frame Perimeter.

Re: Angled Bumpers
 

Sorry - I was thinking that you meant the entire bumper assembly and not just the foam noodle part of it.
If you are strictly talking about angling the ends of the foam noodles themselves, instead of cutting the foam off relatively square at the end of the bumper - that would violate the 2 1/2" bumper requirement.
The end would be covered by less and less foam as the angle approaches the backing wood, which violates the 2 1/2" of foam requirement.

Re: Angled Bumpers
 

Yes indeed. Welcome to the 2017 game.

Re: Angled Bumpers
 

Your best bet if you want a full-front intake is to make your robot intentionally short and build an intake that deploys over top of the bumpers to collect balls.

Re: Angled Bumpers
 

Asked on Q and A: https://frc-qa.firstinspires.org/qa/136

Re: Angled Bumpers
 

I was actually talking about the entire bumper system. We were going to angle the robot frame and the bumper backings to make the balls roll inward.

Re: Angled Bumpers
 

I suggest you reread the rules regarding bumpers and the frame perimeter, then reread GaryVoshol's post, and then watch this video. Note that the video references a 120" frame perimeter limit, which is an old rule and does NOT apply to this year's competition. However, it's a good explanation of the frame perimeter.

The answer to your initial question is no; you cannot have convex faces in your frame perimeter simply by the definition of a frame perimeter by the rules.

Re: Angled Bumpers
 

I would put your odds of getting through inspection that way at about 5%, and your odds of having to be reinspected within a match or two at 99% when someone comments about it.

The big key here is: Frame Perimeter != robot frame. If you look at the attachment, the blue line is your robot frame as described. The red line is your Frame Perimeter. Bumpers are located on, and attach to, the Frame Perimeter.

Re: Angled Bumpers, concave design
 

We at Team TNT2404 think we can use a concave design. Please check our image link above. It's a quick drawing to show "the maw"; we will have bumpers around perimeter as required. See Figure 8-1 in the 2017 Manual and description of Example following R01. Based on those figures and examples, we would like to know which rule the attached "concave" design might be breaking.

jjb.bailey
Mentor-rookie year
Parent-third year

Re: Angled Bumpers, concave design
 

Image broken

Re: Angled Bumpers, concave design
 

Here's the image:

If the blue part is actual robot frame, then no, this is NOT legal. Those aren't bumpers, because they're not on your frame perimeter. Your frame perimeter is a straight line that goes from one side of that opening to the other. In that drawing, your frame perimeter is basically a square. And you need bumpers for atleast 6 inches in both directions on each and every corner of that square, supported at both ends by robot structure.

Again, your drawing there won't pass inspection and you'll be making major changes to your robot on Thursday. Please don't do it.

Re: Angled Bumpers, concave design
 

Definitely not legal. You're not defining your frame perimeter properly. See R01. Take your frame, wrap a string around it, and that's the frame perimeter. I've taken the image you posted and drawn the frame perimeter in red, and the necessary bumpers in front in green.

http://i.imgur.com/8HqBrGM.png

Re: Angled Bumpers, concave design
 

It took a bit of work to find the link, but the word link above links to what I think you're interested in. I'm not completely sure what I'm supposed to be looking at, but trying to figure it out, this is my best guess:

The blue polygon is your chassis frame, and the grey rectangles are segments of bumpers.

If this is the case, your design is right out. The FRAME PERIMETER is the smallest CONVEX polygon which includes all of your robot, excluding bumpers and bolt heads. In your case, the FRAME PERIMETER is a rectangle which includes all of your "maw". This rectangle is the one which requires 6" of bumper support at each corner. Most of the grey rectangles are inside the FRAME PERIMETER, and are not BUMPERS.

Re: Angled Bumpers
 

Just a word of caution:

I happen to know that a fair number of inspectors and Lead Robot Inspectors are on CD. Posting designs that have previously been posted and identified as not being legal may invite extra scrutiny at events.

Something like the proposed design might even get you an early inspection--at least long enough for the random passing inspector who happens to spot it to point you in the right direction to make the necessary changes before pits close on the first day!

Re: Angled Bumpers
 

Solution to avoid all of this: use an intake that extends beyond your frame perimeter and has mecanum wheels or some other way to center balls that are being pulled in. I don't know your whole robot design, obs, but just removing those awkward angles (which definitely aren't going to be 6 inches, and then you need another 6 inches on either side of the gap in the center there) and using a flat front for your robot with a flip out intake, you could fix this whole problem easily.

Re: Angled Bumpers
 

...and give up 3 to 4" of hopper size because you have to pull the frame perimeter back to fit in the maximum volume. That is, unless you do an expanding hopper design like Big Bad Bob, but now you have a pretty critical part of the robot sticking out that you can't retract away from a collision - so it's a foul and damage risk.

Re: Angled Bumpers
 

As a general rule of thumb, I'd like to summarize a few points.

If you place your robot in the smallest box possible that it can fit in, and the box has NO concave faces, that box is your frame perimeter. Your bumpers MUST be around that box (the frame perimeter), NOT your robot frame. This is explicitly defined in the game manual and has been a rule for as long as I can remember. do NOT have any concave bumpers, as you will not pass inspection and will need to do major modifications to pass.