03-04-2016 22:32

PayneTrain

Re: pic: Simple hook delivery system

Y'all are absolutely crazy. I love it. I caught some of the live stream; let me know if you have any prettier video available.

03-04-2016 22:36

s_forbes

Re: pic: Simple hook delivery system

I should have put a video link in the description... Here's footage of the scaling from the side of the field during semis 1-2 at Las Vegas: https://www.youtube.com/watch?v=ojyvzLD55qM

03-04-2016 22:56

Richard Wallace

Re: pic: Simple hook delivery system

It's a mini-bot!

03-04-2016 23:04

connoc1

Re: pic: Simple hook delivery system

This is awesome! Did it ever miss the bar in matches/practicing on a bar? If it did, did it fall back onto the robot or break the extension length rule? Thanks!

03-04-2016 23:59

trumpthero786

Re: pic: Simple hook delivery system

Built at an event? That's absolutely insane. How does the clamp stay open/shut (more worried about the shut part). Do you have any close up pictures of the system, particularly the rubber bands or latex you were talking about? And then how are you winching up? Is it a PTO or separate gearbox?

I know 118 did it already, but honestly, this one is so much cooler. Amazing work.

04-04-2016 00:07

BotDesigner

Re: pic: Simple hook delivery system

What is terrifying about this is that it could be cheesecaked on almost all stronhold robots. I bet cheesecaked scalers like this are going to be a familiar sight come Champs.

04-04-2016 00:07

Roboshant

Re: pic: Simple hook delivery system

Amazing mechanism! Especially for something done over the course of a competition! Is that a shaft collar being used to attach the fiberglass on to the hook? Also, I'm not a hundred percent sure about this but, one of our mentors said that fiberglass was not legal for use, as it shatters if it breaks and can cause splinters if not handled correctly.

04-04-2016 00:14

pilleya

Re: pic: Simple hook delivery system

There are quite a few teams that haven't utilised pneumatics this year, a Servo-motor actuation system could be used as a replacement for pneumatics

04-04-2016 00:17

MrForbes

Re: pic: Simple hook delivery system

heh....if fiberglass were illegal, then a whole bunch of 842's past robots would be illegal! since they had fiberglass chassis



I'm sad I don't get to see it live in action. I guess we need to win so we can go to Champs so I can see it work!

04-04-2016 00:25

JohnFogarty

Re: pic: Simple hook delivery system

I'm confused. How does your hook stay open till it clamps on? I know how the 118 style one works, but this one seems fundamentally different.

04-04-2016 00:27

s_forbes

Re: pic: Simple hook delivery system

We had a few missed shots (some due to not being able to align correctly, since our bumpers can interfere with alliance partner bumpers when we're all on the batter, and some due to week shots because we didn't load it properly). The climbing rope tends to yank the grappler straight back at the robot, and it doesn't stray far from our frame perimeter. As far as I know we never received a penalty for exceeding the 15" on a missed shot during the Vegas regional.

The best picture I have of the latex is in the image in the first post. On the grappler itself, the latex is looped in a way that keeps the grappler open, but as soon as it hits the pole the claws snap over center and the latex clamps them together.

Our gearbox was a toughbox nano with a 1/2" ratcheting wrench zip tied to the side: http://i.imgur.com/YwcDhV6.jpg

The 1/2" output shaft acts as the spool for the rope.

Great minds must think alike! We built a second one during the Vegas regional for cheese caking purposes and bagged it with the robot.

The large shaft collar acts as a clamp to hold the 1/2" hex shaft onto the fiberglass rod. Generally fiberglass material has not been ruled as dangerous by inspectors, especially rods like the ones we used. Teams have been using them for years.

04-04-2016 00:29

Kevin Sevcik

Re: pic: Simple hook delivery system

Open is easy, You can look at it and tell it's an over-center mechanism. The back piece of latex tube would clearly hold it open under tension. I'm more curious about what moves the two halves far enough forward to break-over and snap shut. Is it just inertia when the middle hits the bar?

04-04-2016 00:32

s_forbes

Re: pic: Simple hook delivery system

Yep!

Even if it doesn't hit a bar, the inertia of the two hooks makes them go over center when the grappler reaches the end of the rope.

04-04-2016 01:03

Boltman

Re: pic: Simple hook delivery system

Very cool.

What happens when it misses does it ever have the potential to go outside 15"?

How do you aim it?

04-04-2016 07:52

joeojazz

Re: pic: Simple hook delivery system

How did you use the rubber band like a crossbow if it was inside of the pneumatic cylinder. Also could you fit under the low bar with it?

04-04-2016 08:09

connoc1

Re: pic: Simple hook delivery system

What I believe they did was use that red stick thing to push back an elastic band (probably surgical tubing), and then used the pneumatic cylinder to hold back the elastic band and keep it there until it was quickly released by actuating the cylinder.

04-04-2016 09:49

Chris is me

Re: pic: Simple hook delivery system

I strongly suspect you haven't tried to add a hanging mechanism to a robot that wasn't designed for one within a 6 hour window before! It's quite difficult. Getting the hook onto the bar is the easy part. Dropping in a winch, ensuring that winch either pulls from the robot's CG or from multiple points on the robot, keeping the robot level on its way up, and programming make this a nontrivial task. I'm sure it'll be done once or twice, but this won't be commonplace, particularly for short robots.

The other reason this won't be seen that often is that your second pick this year actually is really valuable and needs to play the game well, whereas in 2015 you could pick a robot that was a lot worse at playing the game in exchange for a robot that is easy to cheesecake.

04-04-2016 11:29

TheOtherGuy

Re: pic: Simple hook delivery system

The winch, I think, is the easy part: http://www.gearwrench.com/MagentoSha..._FRNT_MAIN.jpg

I agree that the longest part of the cheesecaking process would be locating it on the robot to align with the CG, though.

04-04-2016 12:51

s_forbes

Re: pic: Simple hook delivery system

We'll already have a motor/winch attached to the cheesecake version at champs. We had a BAG motor with a 90:1 reduction attached to the spare mechanism we made at Vegas and the entire thing (hook+launcher+winch) weighed in at 3.5 lbs. The BAG motor takes about 6-8 seconds to winch up and scale.

Not shown in the original picture is an eye bolt that goes through the end of the launching tube. If the rope for climbing is run through that fixed location near the top of the robot, there aren't issues with CG.

I honestly don't think it takes more than half an hour to install a mechanism like this on a robot and get it to work. It's tough to do at a regional level since all three teams begin playing back to back elimination matches immediately, but at championships you have a bit more time and a 4th robot.

04-04-2016 13:25

FRC_498

Re: pic: Simple hook delivery system

We were watching the Las Vegas Regional this past weekend and were wondering how you did that! Congrats on the win and designing an awesome simple yet effective climber! P.S. we might need to borrow that this weekend at AZ West...:

04-04-2016 22:06

fiona.crush1011

Re: pic: Simple hook delivery system

If you miss, can you retract it back in to use it again?

04-04-2016 22:24

z_beeblebrox

Re: pic: Simple hook delivery system

I don't think they can.

04-04-2016 22:45

s_forbes

Re: pic: Simple hook delivery system

It's a one-shot deal. We have to reload the launching mechanism before each match.

04-04-2016 22:48

IamBuild

Re: pic: Simple hook delivery system

I strongly think climb is within reach for just about everyone (To the point where I'm thinking about designing a "Climb in a box" cheesecake).With only 3.3 ounces I made a launch tube, hook, and rope that has a 95% success rate. It's shot with pneumatics and if you include the motor, winching system, and the solenoid, the whole system can weigh under 3 pounds. If you have any questions about this feel free to ask and I have some pictures of it here: https://docs.google.com/presentation...it?usp=sharing

04-04-2016 23:17

trumpthero786

Re: pic: Simple hook delivery system

Woah. That's awesome. It's like a piston, but the extender is the hook. I like that 95% success rate (don't know what the sample size is, though) but it seems a little surprising with that hook design. I would expect it to fall off easily. Do you have video of you testing it?

Edit: Just read the line "Hook is made to rebound off the slant behind the hook on the tower to then be pulled back and grab on." This seems more feasible for the hook design.

04-04-2016 23:44

IamBuild

Re: pic: Simple hook delivery system

Sample size is out of 40. The idea behind it is the round bar near the base causes it to rotate towards the heavy side (The hook) when getting pulled over. It seems to work nearly 100% of the time if you go slowly. But even when pulled quickly it has a tenancy to bounce off of the tower and center itself onto the bar. The margin of error is pretty big especially when it is shot up close to the wall so even if it hits lower down on the tower it has enough power to ricochet off the slope and over the bar.

06-04-2016 17:05

Kevin_Crossland

Re: pic: Simple hook delivery system

Funny enough this is actually almost identical to my original idea. I'm curious, have you passed inspection with this system yet? Is this mechanism legal, it would appear to conflict with rule R76, specifically
"Do not, for example, paint, file, machine, or abrasively remove any part
of a pneumatic COMPONENT – this would cause the part to become a
prohibited item. Consider pneumatic COMPONENTS sacred."
please let me know if this would be legal, cause I'd love to use a system like this on our own robot

06-04-2016 17:27

JesseK

Re: pic: Simple hook delivery system

It looks like it's a literal air cannon - there are no pneumatic cylinders involved. The fitting isn't modified, it's just attached. Inspection would be easy so long as the housing for the canon isn't PVC, PolyCarb, Fiberglass or other material that is prone to splintering during an extreme failure event.

06-04-2016 18:39

Kevin_Crossland

Re: pic: Simple hook delivery system

the question I guess would be if it classifies as pneumatic component, I figure if worse comes to worse it's a pressure relief with a conveniently placed harpoon

06-04-2016 18:59

joeojazz

Re: pic: Simple hook delivery system

What type of pneumatic cylinder do you use?

06-04-2016 22:57

s_forbes

Re: pic: Simple hook delivery system

Ours just uses the pneumatic cylinder as the latching mechanism to release the crossbow. We just used a 1" or 2" stroke 3/4" bore cylinder. The latex tubing stores all of the energy that fires it up to the bar.

I put the parts into CAD based on memory, since the real mechanism is in the bag. Here's a better angle (click for bigger image):