Sideways Hanging - Yes or No

[MrForbes]

Yes, go for it, but before you get too far along, you might want to make sure it will not cause damage to the TOWER.

[Wetzel]

The pipe should kink before the tower tips over. A word of warning though. You kink the tower pipe, consider how long it will take to disassemble the field and find a replacement pipe (it's likely there will not be a spare shipped with the field, meaning shop time) and reassemble the field. Then consider how many teams are waiting, and that they know you are why they can't play.

Do math.

Wetzel

[T3_1565]

I'm sure anyone designing this type of hanging would wanna have a wide grip anyways... and the wider the grip on the bar, the less likely the bar would bend or break.

Our team has talked about this hanging method and started design a system with a 28" wide grip. Far more then what was calculate by Kevin

EDIT: our system is similar to the boy on the bar, but uses mechanical leverage and should be much much safer then a "hook and lift" method

[kshin18]

its going to be difficult hanging sideways since rules state the robot has to be hanging 12 inches off the ground and side ways would require more lift

[Wetzel]

Originally Posted by kshin18

its going to be difficult hanging sideways since rules state the robot has to be hanging 12 inches off the ground and side ways would require more lift

For SUSPENDED or ELEVATED robots? Can you cite what rule you are talking about? Not to mention that 12 inches is 12 inches, no matter how you lift. (And 12 inches is not the 18 to ELEVATE)


Wetzel

[Swampdude]

To re-iterate my point of having a 250lb + cg that's as much as 4-6' away from the SIDE of the tower. If you have a 130lb bot 4' tall but in horizontal position (Meaning your base has over 120 lbs in it and its suspended 4' from the side of the tower) Then another bot hooks on to your base adding another 130lbs and also shifting the cg even further from the tower (then possibly even a 3rd bot hooks on), I can almost guarantee the tower will fall over and it could bend the pipe depending on design and how the bots climb on (bouncy etc.) I doubt the tower structure weighs more than 50lbs and only has an 18" plate sticking out? But 250-370lbs of bots hanging 4+ feet away will topple it. I'll be surprised if they don't nix the idea. Maybe I'm wrong.. we'll see...

[T3_1565]

The Q&A is now up. Can anyone ask about this? I cannot because I do not have access to my teams "official" login.

EDIT: One thing that I forgot to mention, its would be much harder to topple the top if you hanging sideways at a low elevation (just about the platform say) also, the platform would supply an increased resistance to bending and breaking the bar. I think this is totally doable

[Wetzel]

Originally Posted by T3_1565

The Q&A is now up. Can anyone ask about this? I cannot because I do not have access to my teams "official" login.

EDIT: One thing that I forgot to mention, its would be much harder to topple the top if you hanging sideways at a low elevation (just about the platform say) also, the platform would supply an increased resistance to bending and breaking the bar. I think this is totally doable

What would you like asked? Hanging off the side is allowed, no one is debating that. If you ask if it will damage the field, the response is going to be "we can't comment on specific designs" or "if you break the field we break you."

Wetzel

[T3_1565]

"Is the tower strong enough to support the weight of three robots hanging from a vertical bar as oppose to the standard horizontal bar?"

and asking them if your allowed to hang off the vertical bar is a completely good question to me.

[Kevin Sevcik]

Originally Posted by T3_1565

EDIT: One thing that I forgot to mention, its would be much harder to topple the top if you hanging sideways at a low elevation (just about the platform say) also, the platform would supply an increased resistance to bending and breaking the bar. I think this is totally doable

The platform does not provide any structural reinforcement to the tower. It's a wooden box that rests on the tower's base plates with no connection to the vertical pipes. So don't expect that to save the tower.

Originally Posted by Wetzel

For SUSPENDED or ELEVATED robots? Can you cite what rule you are talking about? Not to mention that 12 inches is 12 inches, no matter how you lift. (And 12 inches is not the 18 to ELEVATE)


Wetzel

18 inches isn't the 20 inches needed to elevate either. Don't confuse the tunnel height with the platform level.

Originally Posted by Swampdude

To re-iterate my point of having a 250lb + cg that's as much as 4-6' away from the SIDE of the tower. If you have a 130lb bot 4' tall but in horizontal position (Meaning your base has over 120 lbs in it and its suspended 4' from the side of the tower) Then another bot hooks on to your base adding another 130lbs and also shifting the cg even further from the tower (then possibly even a 3rd bot hooks on), I can almost guarantee the tower will fall over and it could bend the pipe depending on design and how the bots climb on (bouncy etc.) I doubt the tower structure weighs more than 50lbs and only has an 18" plate sticking out? But 250-370lbs of bots hanging 4+ feet away will topple it. I'll be surprised if they don't nix the idea. Maybe I'm wrong.. we'll see...

I will agree with you that hanging lots of robots off of other robots can be a dangerous endeavor in many ways. I'm having difficulty believing that anyone is going to design a robot that is capable of suspending 250+ lbs of robots at a 6' lever arm from the side of the platform. That's a very serious moment to put on any part of one of our robots.

More to the point, I'm seriously doubting that you can flip the tower before you fail the vertical pipes. Flipping the tower is going to require applying that huge moment to the tower somewhere. Which is going to be transmitted through the vertical pipes. Which are going to break if you put that kind of moment on them. Plus, there's the ball return which is going to resist your efforts at flipping the tower. So... I think worries about flipping the tower are a bit less immediate than worries about breaking it.

[Swampdude]

FYI
Guess that means we're good to go!

[Ken Leung]

Originally Posted by Swampdude

FYI
Guess that means we're good to go!

Yup! My only question is, in the event of damage (gripper causing damage to the pole, 3 robots hanging at the same point causing damage to the structure, etc), who is responsible?

Let's say the teams hanging all went through reasonable measures in preventing their robots from creating excessive forces and causing damages while hanging. In the event of a tower failure, is it FIRST's responsibility to make the tower stronger, or is it team's responsibilities to change their design such that failure will not occur again (like redesigning to hang from the horizontal bars)?

Interesting thing to think about.

[johnr]

I think a team that is going to do this is not so much thinking about holding other bots,but that they can hang from their home zone and open up more space for other teams. If this team can climb in 10 seconds they would be able to score up to that point, then head over to the pole. Now does the other team leave a defender back or does he leave early to hang. Oh, so many variables this year.

[Doc Wu]

I'd agree that if the rules don't prohibit it, it is allowed, but I'd hate to spend a lot of time designing, building and perfecting it, just to have it thrown out by a rules clarification in week 5 of build.

It wouldn't surprise me to see that happen, especially if there was concern about damage to the field.

[sanddrag]

Originally Posted by Swampdude

To re-iterate my point of having a 250lb + cg that's as much as 4-6' away from the SIDE of the tower. If you have a 130lb bot 4' tall but in horizontal position (Meaning your base has over 120 lbs in it and its suspended 4' from the side of the tower) Then another bot hooks on to your base adding another 130lbs and also shifting the cg even further from the tower (then possibly even a 3rd bot hooks on), I can almost guarantee the tower will fall over and it could bend the pipe depending on design and how the bots climb on (bouncy etc.) I doubt the tower structure weighs more than 50lbs and only has an 18" plate sticking out? But 250-370lbs of bots hanging 4+ feet away will topple it. I'll be surprised if they don't nix the idea. Maybe I'm wrong.. we'll see...

This is the specific scenario I'm worried about. You could in theory have one SUSPENDED robot (call it a Blue Alliance robot), outside of the tower, say on the midfield side. Then another blue robot hanging off of it (toward the red side), than yet anotherblue robot hanging off of it, toward the red side. At potentially 465 lbs, this is getting to be a somewhat large cantilevered load, imposing a fairly large moment on the tower structure. Perhaps the ball return would keep the tower from toppling? Is it tied in? And remember, it's not just the weight of these robots. There is extra force required to accelerate them to these positions, and overcome stuck conditions that may occur.