MERGED: Universal Hanging System/Standardized Partner Suspension

[thefro526]

Originally Posted by Tytus Gerrish

What's the big deal? The robots only need a static part that resembles the tower bar. Seems completely straight forward to me.

Seconded. I would also suggest making it a very bright color that's easy to see from 15 feet away or so.

And just some food for thought, there are going to be a lot of teams that aren't going to be sold on hanging from your robot, I for one am completely opposed to the idea of trusting anyone enough to attempt to hang their 150lb (yes I said 150lbs, 120lb robot + 13lbs + 15lbs bumpers = ~150lbs) robot from our robot and vice versa, so you're going to have to sell whatever hanging mechanism you have to your alliance and prove that it has a safe working load of 300lbs for two robots and 450lbs for three robots.

[GaryVoshol]

fro has a good point. If the top robot's grip fails, it will fall down onto your suspended robot.

[PAR_WIG1350]

Think more like '07, or, mount the bar so your alliance partner hangs next to you. using 2 grippers, grabbing 2 different sides of the tower, will counter any balance issues.
...@................@............................. ..............
....Y=========Y==O................................ ......
........................../........................................
........................./.........................................
......................../..........................................
......................./................O=======@..........
....................../................/I.............Y...........
.....................O==========......_____I_____. ..
......................I__ robot1___I.....I__robot2___I..
......................\_/...........\_/......\_/..........\_/..
......................(_)...........(_)......(_).. .......(_)..
O hinge/joint
@ Bar
Y grabber
(_) Wheel
.... nothing
robot 1 hangs from the tower
robot 2 hangs from robot 1

Now, robot 1's grabber is redundant to some extent, if the right, load bearing gripper fails, robot 2 will hit the ground, but robot 1 won't fall on top of it. if both of robot 1's grippers fail, they still only fall near each other, rather than directly on top of each other.

[Nurnburger]

One key thing about placing the bar underneath your robot is the tipping factor. If someone latches onto it, it could tip your robot sideways. Though this isn't a problem for winch systems, arms could get busted off sideways. Also, if someone's hook slides all the way over the side of the bar, it could get caught is some things that maybe it shouldn't.

I think it might make sense to put two supports on the bar in addition to the end supports. This would allow suspended robots to stay more or less in the center of your robot, and it would provide more support to that bar.

[Chris is me]

While the double robot grab idea sounds alright, I don't know how many (or if any) teams will actually add a second lifting arm to their robot for the purposes of using an attempt at a standard "handle" that has no guarantees of being itself present on any robots. Just something to consider.

[Kevin Sevcik]

Oh, oh, oh! I've got a standardized lifting system that I KNOW every team on the field is going to have..... wheels. Seriously. Given that most people don't read CD, and are unlikely to have a lift system that can latch at less than 60", I think wheels are your best bet for a universal lifting interface.

[Kims Robot]

Seeing how in 2000 & 2004 a lot of teams used some sort of hook or over the bar latching type mechanism here would be my suggestions for a 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 )


And really, that should be enough of a standard.

[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.

[Jon Stratis]

Originally Posted by thefro526

Seconded. I would also suggest making it a very bright color that's easy to see from 15 feet away or so.

And just some food for thought, there are going to be a lot of teams that aren't going to be sold on hanging from your robot, I for one am completely opposed to the idea of trusting anyone enough to attempt to hang their 150lb (yes I said 150lbs, 120lb robot + 13lbs + 15lbs bumpers = ~150lbs) robot from our robot and vice versa, so you're going to have to sell whatever hanging mechanism you have to your alliance and prove that it has a safe working load of 300lbs for two robots and 450lbs for three robots.

To be safe, ALWAYS double your maximum working load. If you're lifting a 150 lb robot, you need to design it to safely lift 300 lbs. For 2 robots, 600 lbs. For 3 robots, 900 lbs.

Designing a system that can lift that much weight is going to be a pretty hard task with the materials provided. On the other hand, lifting yourself isn't nearly as hard - and with an appropriate locking mechanism in place, you can hold much more weight than your motors could ever lift. It seems that designing a system that can first touch the tower, extend to the finale configuration, grab the bar, and lift itself up would be key - then the first robot could get into position whenever they wanted (even before the 20 second finale). The other two come up and lift onto that robot in the last 20 seconds and you're golden.

[Bochek]

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

[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?

[frank.pendzich]

We're considering a strategy where we don't hang from the horizontal rails at the top of the tower, but the verticle supports. Are the towers secured so they can support a robot hanging off the side of the tower?