It is pretty obvious that people are spending a lot of time into the chassis, wheels, motors and even kickers. Well this thread is to bring attention to the lifting portion of the robot. I realize that a lot of people havent started that part yet, and i also realize that others have it made. Leave ideas, pictures, plans, problems, and everything you can think of about a device in order to lift the robot at the end of the competition. Thanks a lot.
So far we have a Harbor Freight winch coupled to a AM 3 stage GEM transmission with a CIM that can seams like it is strong enough lift a small car 
Eventually we will make a custom winch with the GEM but if we run out of time at least we have something.
I like it. I was thinking about using the 5th CIM with stacked GEMs for extra torque and it doesn’t sound like such a bad idea.
I’ve got nothing else to show, other than that I’ve been inspired by the Pink team and the Poofs. I really have no idea how to do this. :3
don’t need the torque so much as you need to slow it down
We had the shooter concept in 2 days. The chassis in 4. Just today we had a major breakthrough on a simple way to hang and we’re cadding it to check feasibility. We’ve spent time in every meeting so far discussing hanging.
I believe the difficulty hanging is disproportionate to the returns. Consider that if you didn’t hang for those 20 seconds, you could probably get 1 more ball in the goal, rendering the hanging only really worth 1 point. Consider if non of your bots could hang, you could potential score 2 or 3 balls in that 20 seconds. Perhaps matches will be decided by a couple points, but this is NOTHING like 2007 where a single bot with a good ramp system could win 80% of it’s seeding matches just by virtue of having those ramps.
Finally, the difficultly of suspending means that I doubt very many matches will see robots suspended. Even if they do manage to suspend, that extra 1 point probably won’t be all that important: I certainly would not make it a design priority.
I look forward to someone building a bot specifically for the finale - there are ways to do it (twin ramps, lifting the other 2 robots on your team, etc). That bot could be a very valuable asset, but I don’t think it’s a game breaker like a good ramp bot was in '07.
We are going for 3-5 seconds for BOTH cable attachment to tower bar using a latex tubing snap bar, and then fast elevation of our bot with pneumatic cable tensioning speed, having saved all of our air for the end game ( our kicker is a winder that stores bungee tension & releases at any point during the wind up for variable kick power). If you can’t make this happen quickly there is little time left to help partners get off the floor. Yeah, the two points is marginal, but 5 or 8 starts looking worth it.
The initial pneumatic pull up will be supplemented by having more winder pulling available at a stronger than pneumatic force levels from our same kick winder mechanism. So, if partners can get hooked on to our deployed hanging Kevlar cables, even with a mere static hook at top of their frame, we can still hoist them up off ground using our kick winder drive pulling at 250+ pounds of lift. Heck, we will even loan them a hook to mount on their frame before the match begins!
-RRLedford
5 seconds to attach and lift would make it worth doing. 20 seconds…not so much.
Right now the plan is no winch, no cables… you will elevate us, and we will suspend you.
With a bit of credit to 1114’s rack’n’roll design, we’re looking at ramps.
It’s still in the design stage, however, and if it doesn’t pan out, well… winches work, too.
Jason
I couldn’t agree more.
Has anyone considered a compound pulley system to lift their robot?
This would be considerably easier to build than a large gearbox, could potentially be lighter, and would result in less mechanical strain on the gears and axels.
It would be beneficial for teams to examine alternate lifting methods. Why is everyone so focused on hanging from the horizontal bar, when there are four vertical bars that would work just as well with a smaller, simpler mechanism?
I don’t see the smaller, simpler mechanism I could employ to hang from the horizontal bars. I’ve thought about it and anything that comes to mind isn’t easy to detach. Vertical hooks just slide over the bar and pull up.
Would have to agree with Chris here. You can’t really get much simpler then up, over, and pull.
Unless you could magically lift yourself up with a bag of air? :yikes:
-RC
Add in the mechanism to get the hook up there, and you’ll see where my concept of complexity comes from. I’ve been working on a design that literally has two hinges, and can hang the robot.
Edit: Bag of air?! Heck yes!
Tension elements are the best approach for elevating, being lightest and strongest. Yes, you still need an arm to hook cable onto horizontal bar, but 1000 lb kevlar is light, and bar can be reached with the arc of a single arm rotation. Multiple long stroke air cylinders spreading pulleys apart in a compound array can give rapid cable tensioning lift to the required height, especially if you don’t deplete your air reserves doing a pneumatic kicker.
-RRLedford
After considering all situations that could happen in the last 20-30 seconds when handing will be attempted i came to the conclusion that it is best if 2 robots hang and one continues to score. This is simply because there will be potentially ungarded goals and more then likely 2+ balls in the scoring end, or a ton in the middle. If you have a good kicker it may be best to score even if you could hang. 2 teamates can easily hang off of the tower, any more and you have to hang off eachother. I think this will be a challenge and not all teams will be able to do this quickly. So if two teams hang off the tower and the third scores the team will have 4+(i would guess anywhere from 2-5 points) The other team will have from 6-8 if there whole team hangs. If 2 of the opposing team hangs then its even. If you run through all the senarios and make some assumptions you will see what i am saying. I think, but i may be wrong, that scoring with no deffender will be easy in the last 20-30 seconds (depending on when the enemy has to start hanging) and therfore it will be benifical to build the best kicker you can because if teams realize this they will want you.
Of course if no one builds a hanging bot then this doesn’t matter.
My team is focusing on our kicker now and if we finish with time left we will build a hanging mechanism. This will give us time to practce while we build the hanging mechanism and then attach it on in the end if we decide to. I think this strategy will be great because we will then have a ton of driving practice, and the ability to do any task.
We’ve looked into a system much like this; the trouble we’re having is limiting degrees of freedom while elevating.
Here is an idea that our team came up with that we believe would work and is outside the norm of lifting a robot that others may not think of. I was extremely proud of all of the ideas that the students generated this year for lifting. Besides this idea, they also came up with a great idea for lifting using the vertical bars. For the record, we are not using either idea. We are using the KISS method (Keep It Simple Students) and believe that we will have a lifting robot that can do the job quickly, efficiently and is simple.
I include this diagram within the spirit of Gracious Professionalism
Lift Concept.doc (648 KB)
Lift Concept.doc (648 KB)
Neat idea! did anyone calculate the load on the winch? that low angle will make it pretty tough.
That is a quite awesome idea.
I hope you guys make it work.