MERGED: Universal Hanging System/Standardized Partner Suspension

[Salbert]

Hey, team 1523 (MARS) and I were thinking of having some type of universal hanging system. In other words, a system developed for robots to hang off of each other without worrying about dimension issues. It would greatly simplify the bonus and make it much easier to get those extra points at the end. Comments?

[DezNacario]

Good idea. Team 1334 has been toying with the idea of making the dimensions the same as the poles on the tower for simplicity's sake.

[EricH]

From a strategy point of view, an EXCELLENT idea.

A suggestion: build it similar in dimension to the bars on the alliance station side of the towers. This will greatly simplify design processes, as everyone can find those dimensions and is hopefully figuring out if and how they can attach to them.

[engunneer]

unfortunately that bar is pretty wide, and it may be hard to provide the full unobstructed length to give to other robots.

What area of free space should be left around the pipe? 4", 6"? if there is a simple standard hook design that is common, that could help choose this clearance.

Also, is it better to support robots with two clamps? 1 clamp in the middle? ideally, you give them as long a bar as possible, only held up on the two ends, but that still probably won't take everyone's mechanism.

[Enigma's puzzle]

Excellent idea, if you aim to attach to the bumpers i think that that would give you the most uniform fit between robots. That is where i would personally look.

[ttldomination]

Team 1261 will be keeping our rails at the same dimensions of the poles on the towers. We figure that if everyone is ready to hang off the towers, than they can just as easily hang off our rails.

- Sunny

[GaryVoshol]

Excellent idea, if you aim to attach to the bumpers i think that that would give you the most uniform fit between robots. That is where i would personally look.Don't hang off the bumpers! It's usually not a good idea to lift using the bumpers; you definitely don't want anyone hanging on them.

[Passion]

Team 1261 will be keeping our rails at the same dimensions of the poles on the towers. We figure that if everyone is ready to hang off the towers, than they can just as easily hang off our rails.

- Sunny

That is a little hard to imagine, consider you are going to have 3 robots hanging off on the same side of the tower.

[EversmannJ]

One of the major point-scoring opportunities this year is hanging your robot off of another allied and elevated robot. To make the most of this scoring opportunity, it is important that, in as many matches as possible, there is a robot in your alliance which can either be suspended by your robot, or one which yours can suspend from.

In an effort to see that each design is "compatible" with as many potential allies as possible, we at Westwood (http://www.westwoodrobotics.org/index.html) believe that it would benefit everyone if we developed a standard: a certain model/style of robots suspending themselves from eachother that we can take advantage of in as many rounds as possible. If we pull this off, it will take much of the guess work out of pre-match planning on competition day; we will simply be able to say: "Who has the proper attachment point in place?" or "Who here can attach to the usual point?" and, chances are, the only thing remaining between us and those three points would be some fancy driving. :cool:

Food for thought:
"All robots have a bar of square channel which, once the robot suspends itself, will be accessible from the back and approximately 4 feet from the ground. All robots wishing to be suspended from such robots must be able to attach to the bar and raise themselves to the required height."

[Chris is me]

Wouldn't the best standard bar to grab be one similar to the bar already on the field? Why not base a standard on that?

I don't think attempts at standardization will work well simply because you'd have to grab more than one different kind of object. Making one's grabber work on several surfaces is something that needs to be considered as a possible design choice, though, as the lack of standardization could force it.

[Ricky Q.]

Note: Merged two thread on this topic together and moved to a category.

[demosthenes2k8]

Um, chris? I'm pretty sure that a standard would make a single system, so the robot would only have to grip one type of object. Your argument needs to be inverted.

I like the standards ideas, but I'm not sure how easy it'll be to get everyone to go along with it.

[DMetalKong]

Wouldn't the best standard bar to grab be one similar to the bar already on the field? Why not base a standard on that?


Having a bar the same size as the one on the field is probably the best way to go. This way the only variation in attachment points is the height at which they are placed.

[EversmannJ]

Note: Merged two thread on this topic together and moved to a category.

Sorry about that; I had searched for "Standardized" to make sure this hadn't been done... Which obviously didn't work.

[Mr. A]

Hey, team 1523 (MARS) and I were thinking of having some type of universal hanging system. In other words, a system developed for robots to hang off of each other without worrying about dimension issues. It would greatly simplify the bonus and make it much easier to get those extra points at the end. Comments?

We talked about this a lot on the drive back from Manchester. Another approach is for each robot to have a bar on top that is a handle allowing it to be lifted from above. I wondered if the kit bot that was shown at kickoff which had this type of bar was a hint. The advantage is that it would be easy for any robot to have the handle and not need a lifting mechanism. Even a simple goalie robot could be lifted if they can get to the hanger. The lifters on the other hand would need additional functionality.

[Chris is me]

Um, chris? I'm pretty sure that a standard would make a single system, so the robot would only have to grip one type of object. Your argument needs to be inverted.

I like the standards ideas, but I'm not sure how easy it'll be to get everyone to go along with it.

My post's wording sucked so I'll edit it (tends to happen to me a lot) but I was basically saying making a standard mount based on something other than the field bar would not be advisable. If teams include a section of field-like bar on their robots, then existing grabbers can be adapted to it.

[Shawyan]

I fully agree that there should be some standardized hanging system identical (at least in size and shape) as the tower par.

Unfortunately, many teams will have a problem for this because of space. I see this getting in the way of pendulem type kickers (especially considering this changes the weight distribution)

Ideally, the bar would go across the middle of the robot, at hopefully two points. Any more than that and connecting is too difficult.

Also, if the connection is not perfectly balanced, Tipping will be an issue, and it may fall under the platform (20" if I'm not mistaken), and no points will be awarded for that extra robot.

Just some potential problems that need to be worked around for a standardized system.

[EversmannJ]

Another approach is for each robot to have a bar on top that is a handle allowing it to be lifted from above. ...it would be easy for any robot to have the handle and not need a lifting mechanism.

The idea of making a robot capable of grabbing both the field's bar and another robot's is really good. Anyone who's robot can't lift itself for some reason should definitely go for that.

[vansivallab]

I do not think its a good idea to put the par on top of the robot, though you could raise the other robot (the one that is suspended off of your robot) higher, you would restrict the designs of many teams since, unless they come up with a way to raise and lock it into place, their robots will be too tall to fit in the tunnel. But we can make it so that the bar is at 18 inches, so the robot can fit through the tunnel, but I guarantee you if we do that someone will place their vital components near that bar (electronics, $1000 CRIO, etc) and which could get ripped out by another robot.

I just feel, in this case where we want to make wide sweeping standards, its a good idea to make it simple, so even a rookie team can install it w. out quams. So I think we should go back to hanging it at certain length from the ground (im thinking 5 inches) so it can act as a guard and the robot can use the tunnel as per their design. As our dear old friend Murphy says, "Anything that can go wrong will go wrong." So lets keep it simple, since I don't want to see robots falling from 7 feet.

[dtengineering]

Wouldn't it make more sense to link the robots together while they were still on the ground... and just have one robot do the lift?

Jason

[Donut]

While nice to try to set up a standard, to have wide sweeping success I think the only standard that is likely to work is one based upon a replica of the actual tower bar teams can hang from. Why?

The majority of teams at competition will not have seen any threads on this on Chiefdelphi and will be unaware of any standards you create.

Many teams don't even use CD and those that do still may never notice a thread like this. So, the best way to ensure that their robot could hang from yours, is to design your robot with a system that lets them replicate the motions of hanging from the tower. Then they can hang from you with zero modification of their robot and no prior knowledge of what your design was.

Something to keep in mind here.

[Salbert]

I guess as long as you have a simple, easy grip bar extending along the entire rear of the robot below the bumper, it shouldn't be hard for other robots to grab. It should stick out as far as possible.

[Salbert]

Wouldn't it make more sense to link the robots together while they were still on the ground... and just have one robot do the lift?

Jason

Lifting as many as 360 pounds (3 bots) would result in the lifting arm and robot being ripped apart if there wasn't enough power.

Or in a less violent scenario, it simply wouldn't be able to lift anything and stay on the ground.

But lining up 3 robots in a chain before lifting up in 20 seconds would take too long.

[IdaNeStr3088]

This idea is great:)
Team 3088 was thinking about building a small metal frame in the back of the robot, like the attach point to the trailer in last year's game(Lunacy) but make it more wide and more accessable for the other robots to reach.
If you have a comment about the idea or you ahve other ideas feel free to do so.

-Idan::safety::

[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.

[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?

[thefro526]

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.

[GaryVoshol]

5. Protect your own robot's innards from the wandering probe of your partner's hook.

[Kims Robot]

I changed my mind... dont bother trying to suspend other robots (using the hanging method)

http://forums.usfirst.org/showthread.php?t=13726

In my mind, its too risky that you will touch some part of the tower, its not wide enough to comfortably fit a standard robot base with enough wiggle room that hanging from another robot there is no way you would touch it (plus what if you were touching the other side of the platform or anything on the tower... no points). You are better off hanging yourself on another bar for 2 points than risking loosing the three.

(sorry for hijacking, but I dont see the point in spending time on a system like this anymore)

[Rizner]

I changed my mind... dont bother trying to suspend other robots (using the hanging method)

http://forums.usfirst.org/showthread.php?t=13726

In my mind, its too risky that you will touch some part of the tower, its not wide enough to comfortably fit a standard robot base with enough wiggle room that hanging from another robot there is no way you would touch it (plus what if you were touching the other side of the platform or anything on the tower... no points). You are better off hanging yourself on another bar for 2 points than risking loosing the three.

(sorry for hijacking, but I dont see the point in spending time on a system like this anymore)

I believe if a robot tried to suspend from you and touched the side of the tower accidentally, they would still be elevated. In my opinion you could take the risk of getting the 3 points, and as long as nothing falls or breaks, the worst case is both robots are still elevated (given that it stays above the platform) and nothing is lost for trying.

[Kims Robot]

I believe if a robot tried to suspend from you and touched the side of the tower accidentally, they would still be elevated. In my opinion you could take the risk of getting the 3 points, and as long as nothing falls or breaks, the worst case is both robots are still elevated (given that it stays above the platform) and nothing is lost for trying.

They would still count as elevated, but you would not, so now instead of the 4 points (2 elevated) you would get if you both just hung by yourselves, you get 2 points (1 elevated) because you were trying for the 5 points (1 elevated 1 suspended)

[Donut]

They would still count as elevated, but you would not, so now instead of the 4 points (2 elevated) you would get if you both just hung by yourselves, you get 2 points (1 elevated) because you were trying for the 5 points (1 elevated 1 suspended)

To be ELEVATED a robot must be in contact with the TOWER and above the PLATFORM plane (20"). How does another robot above 20" touching you cause you to no longer satisfy the ELEVATED condition? As long as both of you are above 20" and both end up touching the tower some how you would still get the 4 points for both robots being ELEVATED, robot to robot contact has no effect on whether a robot is considered ELEVATED.

Just make sure your suspending mechanism is likely to keep your partners above 20", if so there's a relatively small difference between 4 and 5 points for your alliance.

[Kims Robot]

To be ELEVATED a robot must be in contact with the TOWER and above the PLATFORM plane (20"). How does another robot above 20" touching you cause you to no longer satisfy the ELEVATED condition? As long as both of you are above 20" and both end up touching the tower some how you would still get the 4 points for both robots being ELEVATED, robot to robot contact has no effect on whether a robot is considered ELEVATED.

Just make sure your suspending mechanism is likely to keep your partners above 20", if so there's a relatively small difference between 4 and 5 points for your alliance.

Ahh... understood, I guess for some reason I had it in my mind that the second robot may be likely to hang below the 20 inches, but that's a good point that if both are above the 20" that you still get the 4 points. I guess I didn't think of it that way :)

I still think if it were my choice I wouldnt bother adding a bar to my robot unless I had size & weight and the ability to support another robot... meaning I wouldnt design it in from the beginning. If it fit afterward fine, but I think we are likely to see maybe 1 hanging suspension per regional unless anyone designs a super tiny robot that just zips around the field and hangs!

[Phcullen]

Wouldn't it make more sense to link the robots together while they were still on the ground... and just have one robot do the lift?

Jason

Then you put the responsablty to lift 360lbs on one robot

[Kevin Sevcik]

Then you put the responsablty to lift 360lbs on one robot
Yes.... But then you have to figure out how long it's going to take for one robot to hook, latch and lift, and THEN for another robot to hook, latch, and lift. Which seems quite time consuming to me.
Ahh... understood, I guess for some reason I had it in my mind that the second robot may be likely to hang below the 20 inches, but that's a good point that if both are above the 20" that you still get the 4 points. I guess I didn't think of it that way :)
You were thinking that because it's the most feasible way of getting all this done in a reasonable timeframe. Otherwise, you're talking about the first robot lifting +50" and then the second robot grabbing and lifting as well.

[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.

[Chris is me]

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.

Assuming the third robot has high enough ramps, that is correct.

Wouldn't you rather have 3 hanging robots on your alliance who get 6 (or 8) points rather than 4?

[Jon Stratis]

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]

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]

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]

^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