Grappling hook?

[Sean Raia]

Is it possible to have a hook shoot up at an angle with strong rope attached and latch on to the tower (assuming its in the height limits). then is it possible to reel the rope in?

This is just an idea our team has had and im wondering if it can be accomplished.

[vg674]

The only problem I would see is with the entanglement of robots or being hazardous to people. Rules <R03> to <R06> seem to say that it is essentially too dangerous to do so, and understandably so. I can only imagine a grappling hook shooting the wrong way and ramming into players or refs or destroying the field... not so great. Good idea though!

[Sean Raia]

Yeah that was one of our concerns, and i doubt we will be using the grappling hook idea. But would it be possible to shoot the grappling hook out or reel the rope in and lift a 120 pound robot in the first place?

I want to know weather or not we should consider it as a plausible idea.

[nnfuller]

From:
http://www.chiefdelphi.com/forums/ne...reply&p=897181

Originally Posted by Kevin Sevcik

To bring a little more "training" to the discussion... you just have to look at the maximum power of your motors to determine the absolute fastest you can get a robot up.

Power = Work / Time
Work = Force * Distance
so
Power = Force * Distance / Time
or
Power = Force * Speeeeeeeed

The CIM motors max out at 343W = 252 lbf*ft/s

So the fastest an optimally geared CIM will lift a bot is about 1.5 ft/s. Or you lift in about a second.

Mind, this assume you're instantly at the max power point, no friction losses, spherical chickens, the works. But, lifting your robot 20" in, say, 5 seconds is easily doable if you gear it right. The gearing it right being key. Max power occurs at 1/2 stall torque. But I'd really aim for 1/4 - 1/3 stall torque for your full load, for safety and losses and all that.

[vg674]

With the right material, I would say that that wouldn't be a problem at all. There are many ways to lessen the strain, and I think it would be quite easily possible to engineer a way, be it pulleys or a fancy combination of motors to use a grappling hook to hang from the bar, and even great in the respect of not needing power while removing the robot. Again, I see the main concern as safety, and I think that will be the deciding factor.

[JohnFogarty]

We thought of this exact thing as well last night. Though we may have an idea on how to control it.

[JIMBO4341]

I don't think this is possible as I think it's likely that you would exceed your vertical allowance. The bars are 84'' high your maximum is 90'' so there's only 6 inches of leeway for your shot to fly over the bar and grapple. Also if you happen to miss you would almost surely exceed your horizontal allowance. They teased us with the grapple bot in the kickoff video .

[roborat]

I saw several bots hang in 04 using hooks but the all had some type of arm extend up with hook on end to catch the bar and the hook and cable were velcroed so they would release from the arm and winch up the bots. Only purpose of the arm was to place the hook.

[JohnFogarty]

make sure the cable atached to your grapple is shorter than what the max is.

[coldfusion1279]

There are ways of using cables without "shooting" them up there. A shot is also inaccurate, dangerous, and possibly could go over the height limit... Try and think of more controlled ways to have a hook go up... you're on the right track with cables...

[Sean Raia]

I think our team is actually going with a scissor lift mechanism with hooks on the top. we want to be able to go under the tunnel. I just thought the grappling hook was a neat idea for discussion, and im from what i read its possible and legal if it doesn't go outside the dimensions.

[viperred396]

we decided to opt out of the hook because the max hight during FInal Configuration is 90 in and the towers height is 84 in so the hook only has 6in to make it over and we didn't want to risk going to high.


<G40> also might say its a no go because of the entanglement issue


edit: sry i re-said things others did i didn't notice them until i reread the thread

[Al Skierkiewicz]

Of course you can lift a robot using a hook and cable as described. We have done it. There will some risk involved this year...

<G31> BALL RETURN and RETURN BARS Protection - ROBOTS may not contact the BALL RETURN or the RETURN BARS (black tape). Violation: PENALTY for inadvertent contact; plus a RED CARD for obviously intentional contact or damaging contact.

[bobmonkey836]

Originally Posted by Sean Raia

Yeah that was one of our concerns, and i doubt we will be using the grappling hook idea. But would it be possible to shoot the grappling hook out or reel the rope in and lift a 120 pound robot in the first place?

I want to know weather or not we should consider it as a plausible idea.

it's very plausible. if you could get the accuracy, you should have the strength pretty easily after that. after all, mountain climbers+ gear tend to be well over 120 lbs, and those ropes will easily hold the weight.

[Mr_I]

Originally Posted by roborat

I saw several bots hang in 04 using hooks but the all had some type of arm extend up with hook on end to catch the bar and the hook and cable were velcroed so they would release from the arm and winch up the bots. Only purpose of the arm was to place the hook.

Case in point, Team 811:

The black pole on the right telescoped out ~15 feet to put the grappling hook over the 10' chin-up bar, and then a window motor (legal then) pulled Red Streak II into the air v-e-r-y s-l-o-w-l-y .