MERGED: Universal Hanging System/Standardized Partner Suspension

[The Megan 2207]

Originally Posted by Bochek

Sorry, i haven't read the whole thread, but has anyone thought of the one part that ever team MUST have identical? Bumpers?

I wouldn't trust bumpers to hold a robot. It's not a good idea to carry your robot by the bumpers, so it certainly wouldn't be a good idea to suspend another robot from your bumpers. (Yes, this idea has been discussed earlier in the thread.)

[HazzardFuzzBomb]

But with a strong recommendation to not lift (as in just picking up the robot by hand) by the bumpers, how would you plan to support a 150lb robot by your bumper?

[Mr. A]

Originally Posted by jerry w

I wonder why everyone thinks we have to hang from the tower??
If 2 robots were sitting on the third robot, and the first 2 are touching the tower, then they are both ELEVATED.
Thus a ramp robot could provide a very quick way to score 4 points for the alliance. No hooks, no cranes, no claw.

People had a lot of trouble getting up ramps in the Rack and Roll competition. Lining up and driving straight was a big issue. This was in a competition where robots were designed for the purpose. The ramps were very low as well. In this case with the 84" diam. footprint rule, the ramp would be quite steep.

On hanging - I agree that the standard field size bar under the robot makes the most sense as something for robots to grab on to, so I happily endorse this standard.

1. SOMEWHERE on your robot put a bar that is the same OD as the 1.5" x.083 Wall 1020 CRS DOM Tube, and if possible use the same material.
Make the decision of WHERE to put it based on YOUR robot design. It shouldn't really matter to the other robots unless they have preprogrammed heights (in which case they or you can reprogram it for where your bar will be!) and as long as it is the right OD and strong enough to hold a 120lb robot, it will work and will be reasonably universal. If you wanted to get real fancy, put one on either side, so its easier to hang 2 robots off you.

2. Leave at LEAST 10" of free space between your mounting brackets.
This will give teams enough to "grab onto" and will account for different mechanisms. If you can leave even more room (ie put the mounting on the corners of your robot frame) its much more likely you could get 2 robots to hang off of you.

3. Make sure YOUR elevation mechanism can handle 300-450lbs hanging off of it. You may not need to LIFT this much if you get in place and let the other robots latch onto you, but you need to SUPPORT that much weight.

4. Paint it Bright Green. No vision target lights this year, so we are free to use whatever color, and that will be the most viewable from a distance. (Got this idea from a previous post )

[billfunk29]

In order to prevent the large cantilever load from a "piggy back" robot, how about the second robot drive under the first suspended robot. Assume the lifted robot can go through the tunnel and therefore could fit under. Since the bumpers are pretty well defined a simple pair of "L" brackets could provide a nest. Then the first robot climbs a little higher lifting both. Both CGs are only a few feet from the tower.

[vivek16]

I am predicting that a lot of bots will use 2 hooks spaced apartsince it's more stable. You should plan accordingly with your hanger rod.

[RRLedford]

Some thoughts:
Forget the heavy bars, and just have dangling loops of 1000 lb kevlar cable hanging from near bottom center of first elevated robot, so weight pulled there won't tilt it too much
The first robot hanging ideally should drop these cables loops to hang at one or two (low/high) agreed upon heights from its undercarriage, so that they can then easily be engaged by next bot just driving under them with a static hook mounted at the pre-agreed height. Then if 1st bot up tower still has enough remaining power to pull both itself & tow the other bots further up (at 250-400 lb force) add 3 or 6 more points. Also, if bot on floor can pull with its its hook too, even better. The key is locating these pull points as near to vertical axis of center of mass as possible to avoid excess tilting.

-RRLedford

Note: The bots hooking on may cause the elevated robot to dip below height needed to score 2.

[vivek16]

^again, for robots who are using 2 hooks for stability, it would be unwise to have said dangling loops. Also, you would need some way to deploy those without having an entanglement hazard during the match

[RRLedford]

Originally Posted by vivek16

^again, for robots who are using 2 hooks for stability, it would be unwise to have said dangling loops. Also, you would need some way to deploy those without having an entanglement hazard during the match

The point of the shallow parabola hanging Kevlar is so hooks would tend to slide to center (where it belongs) on loading their weight. A simple release scheme using gravity drop some slack cable work. One end could remain attached to whatever device would be pulling partners up off the floor, so a double acting air cylinder could easily lower the cable(s) and them pull back up when hook(s are engaged.
-RRLedford