View Full Version : [FTC]: Opinion on lifting robots
I was wondering what everyone else thought on the feasibility of lifting robots.
Andrew Lawrence
08-09-2012, 21:51
I think lifting by a few inches would be feasible for any robot. However if they want to lift a robot the full 24 inches (which is something like 120 points), then a dedicated lifter robot who is built for the sole purpose of lifting another robot up 24 inches (and maybe playing some defense) would be the only way I see this as plausible.
So a dedicated lifter bot paired with an awesome scoring robot leads to a pretty high score, if I say so myself. It may be a good idea to make one....
Never had to do anything about a robot lifting another, but like SuperNerd said, it should be fairly possible for all robots.
Of course, you still have to build your robot with this in mind. Our team had a preliminary idea of having our electronics and battery and NXT mounted on a plate that we could move horizontally from front to back of the robot to slightly shift the center of mass to adjust for robots being heavier or lighter.
Honestly though, there's been posts about people analyzing highest theoretical scores, and one said it was 1,720. In that score, 720 was from the weighted rings on the corner goal.
I think the weighted rings are BIG in this game. If you get 5 on, your score is doubled.
ehochstein
08-09-2012, 22:07
Never had to do anything about a robot lifting another, but like SuperNerd said, it should be fairly possible for all robots.
Of course, you still have to build your robot with this in mind. Our team had a preliminary idea of having our electronics and battery and NXT mounted on a plate that we could move horizontally from front to back of the robot to slightly shift the center of mass to adjust for robots being heavier or lighter.
Honestly though, there's been posts about people analyzing highest theoretical scores, and one said it was 1,720. In that score, 720 was from the weighted rings on the corner goal.
I think the weighted rings are BIG in this game. If you get 5 on, your score is doubled.
You need to have a score to be doubled... In which case you need a robot that can not only sort rings, and score them on the corner post but also a robot that can score on the center posts.
In the perfect alliance I see on robot which can lift other robots and sort rings... While the other robot concentrates on the center posts. In the end game one robots lifts the other, it really all depends on how efficiently you can score rings.
You need to have a score to be doubled... In which case you need a robot that can not only sort rings, and score them on the corner post but also a robot that can score on the center posts.
In the perfect alliance I see on robot which can lift other robots and sort rings... While the other robot concentrates on the center posts. In the end game one robots lifts the other, it really all depends on how efficiently you can score rings.
I know you need a score to be doubled.
I really don't see any reason for not having a robot that can't differentiate between the two rings. If you grab it with a small claw that's about the size of a diameter, have a "subclaw" of that claw. Hard to explain in text, but here:
http://i48.tinypic.com/3h552.png
You just have a subclaw within a claw. You grab the rings with the top part of the claw, but the sub claw has a tolerance of 2 oz (this can be made more) and if the rings is heavier it will drop. Easy indicator of the weight and it takes little to no space in an existing claw.
ehochstein
08-09-2012, 22:26
I know you need a score to be doubled.
I really don't see any reason for not having a robot that can't differentiate between the two rings. If you grab it with a small claw that's about the size of a diameter, have a "subclaw" of that claw. Hard to explain in text, but here:
You just have a subclaw within a claw. You grab the rings with the top part of the claw, but the sub claw has a tolerance of 2 oz (this can be made more) and if the rings is heavier it will drop. Easy indicator of the weight and it takes little to no space in an existing claw.
I like the idea! (Although I hope that 2 pound spec is a mistake... I don't think the rings weigh two pounds ;)
I was thinking something very similar to that, in a two minute period are you going to be able to go through every single ring though?? There are 26 per alliance. You would pretty much have to pick a ring up, and set it down if it wasn't weighted. You wouldn't have time to score it.
LeelandS
08-09-2012, 22:35
Lifting robots doesn't seem that hard to me. Well, depending on how high you want to go.
You could go the FRC2007 route, where many teams built a ramp system that leads to a flat top. As long as the angle of the ramp isn't too steep, many robots shouldn't have a problem. With that, I can't imagine it would be hard to get your partner up at least 1" for the bonus. Maybe even a few inches more. I wonder how feasible it would be to create a series of inclines to achieve further height...
That said, if you want to go higher, matters get a little tricky. You could use the ramp system mentioned above, and build in some kind of elevation system (like a scissor lift). Though that could quickly become heavy and complicated if you want the stability to hoist a robot 24" in the air.
The matter certainly requires some thought. From my side of things, the FRC2007 ramp system seems like a simple and effective way of getting the robot. It can also leave room for a team to develop a method of scoring rings. The lifting of robots sounds like a fun end game, and is certainly possible.
Here's to hoping we don't see any 24" topples...
I like the idea! (Although I hope that 2 pound spec is a mistake... I don't think the rings weigh two pounds ;)
I was thinking something very similar to that, in a two minute period are you going to be able to go through every single ring though?? There are 26 per alliance. You would pretty much have to pick a ring up, and set it down if it wasn't weighted. You wouldn't have time to score it.
Yeah, that's true.
I'm just throwing around ideas for now but I like this as a way to sort rings because it's quick and embedded in the actual claw.
To be honest, I was really looking toward having a claw capable of picking up multiple rings. Like either 2 or 3. In this case, you obviously have to adjust the tolerance to say, 6 oz.
But at this point its a matter of being able to take one off at a time.
Lots of things to think about, but it's a very viable idea. Physics behind it is simple enough too.
http://i45.tinypic.com/j9n01y.jpg
kiasam111
08-09-2012, 22:49
Check this out: http://www.youtube.com/watch?v=wvmyemana30
A combination of that and the crazy lifting mechanisms that we saw in Bowled Over could be a fantastic combination!
Ooh, does stacking count as lifting?
Optimized lifting means having a robot get up on top of your robot. That is 18 inches without any lifting and then make up the last 6 inches with air cylinders or maybe some other sort of "Stinger"
LeelandS
08-09-2012, 23:03
Ooh, does stacking count as lifting?
From Game Manual 1.3.4 End Game
"In order to earn the Lifting Bonus, the lifted Robot must be fully supported by the Alliance partner’s Robot and not by any other game object (i.e. 100% of the weight of a robot must be supported by the Alliance partner’s Robot)."
Therefore, it seems to me that, as long as one robot is COMPLETELY supported by another, it counts as being lifted for the bonus.
Optimized lifting means having a robot get up on top of your robot. That is 18 inches without any lifting and then make up the last 6 inches with air cylinders or maybe some other sort of "Stinger"
The challenge then is, how do you get a robot up 18"? A ramp of some sort for that purpose would be quite steep.
From Game Manual 1.3.4 End Game
"In order to earn the Lifting Bonus, the lifted Robot must be fully supported by the Alliance partner’s Robot and not by any other game object (i.e. 100% of the weight of a robot must be supported by the Alliance partner’s Robot)."
Therefore, it seems to me that, as long as one robot is COMPLETELY supported by another, it counts as being lifted for the bonus.
The challenge then is, how do you get a robot up 18"? A ramp of some sort for that purpose would be quite steep.
Not if you make it long.
Technically if you had some sort of sheet of metal at the top of your robot that folds out into a ramp, and you're serious about being a ramp bot, you should have some kind of way to expand the ramp to be longer to not make it a steep adventure.
LeelandS
09-09-2012, 00:04
That's plausible. If that's the plan, instead of one sheet that flips down to make a ramp, you could have two sheets that flip down to make one continuous ramp. As long as they can be locked in place to prevent them collapsing, that's definitely possible.
That would be quite a sight. A "Super ramp" that flips down so an alliance partner can climb on top. That would be one monster of a climb.
The challenge then is, how do you get a robot up 18"? A ramp of some sort for that purpose would be quite steep.
My idea is to make a 4 stage mechanism that starts at a lower point emits a more shallower ramp. that has a place to secure the alliance bot and then the ramp retracts back in a lot like a flatbed tow truck and then brings the main platform up to 18 in and then the bot up the last 6.
That's plausible. If that's the plan, instead of one sheet that flips down to make a ramp, you could have two sheets that flip down to make one continuous ramp. As long as they can be locked in place to prevent them collapsing, that's definitely possible.
That would be quite a sight. A "Super ramp" that flips down so an alliance partner can climb on top. That would be one monster of a climb.
Yup, pretty much.
Another design that came across my mind was kind of like a forklift type design where you have a forklift that can get from the floor to the very top of the robot. Attached to the carriage of the forklift is simply an 18x18 sheet of strong metal. It's in vertical position when game starts, but then at end game, this 18x18 metal is expanded; its basically now flat with the floor.
A robot can then get on the metal sheet, and the forklift of the lifting bot can raise the robot & the metal sheet to the top of the bot, and then viola.
Yup, pretty much.
Another design that came across my mind was kind of like a forklift type design where you have a forklift that can get from the floor to the very top of the robot. Attached to the carriage of the forklift is simply an 18x18 sheet of strong metal. It's in vertical position when game starts, but then at end game, this 18x18 metal is expanded; its basically now flat with the floor.
A robot can then get on the metal sheet, and the forklift of the lifting bot can raise the robot & the metal sheet to the top of the bot, and then viola.
How do you counter weight the other bot.
My personal opinion is that lifting your partner using some sort of ramp at the end game is a great way to make a bunch of points in a short amount of time. However, I would hate to really completely on the lifting bonus for points as you would be relying on your partner. If for any reason your partner couldn't go up your ramp your entire design would be useless.
LeelandS
09-09-2012, 09:45
Yup, pretty much.
Another design that came across my mind was kind of like a forklift type design where you have a forklift that can get from the floor to the very top of the robot. Attached to the carriage of the forklift is simply an 18x18 sheet of strong metal. It's in vertical position when game starts, but then at end game, this 18x18 metal is expanded; its basically now flat with the floor.
A robot can then get on the metal sheet, and the forklift of the lifting bot can raise the robot & the metal sheet to the top of the bot, and then viola.
If you were to do this, there would be two things I would make sure you push on the design (and I'm sure you've already considered them, but there's no harm repeating them on the forum).
First, and most obvious, that forklift needs to be extremely sturdy and strong. It needs to support a robot up 24". Not only does it need to actually be able to LIFT the robot up, it needs to be able to HOLD the robot up, even after power is cut to the field, since points aren't totaled until all parts come to rest. So that forklift needs to be strong enough to lift, sturdy enough to hold the robot, and able to lock itself at the top (or any place from bottom to top).
Secondly, were you to design a forklift, I would try to make it more like an elevator. Forklifts generally lift things that don't really move (wood, metal, etc), but this is lifting a robot. A robot that, probably, has wheels. Therefore, it can roll. And I would be terrified if, for whatever reason, the robot going up started to roll, and then plummeted. So I would build it more like an elevator. Have the place to drive on, and 3 "walls" extending from the plate to prevent robots from rolling off. Maybe even design a door to cover that last opening. Alternatively, you could design your forklift to be less that 18", and have it lift a robot up from between their wheels (assuming they have a large enough gap in the center of their drive base), thus preventing them from rolling and taking the robot with them. Though this seems like a design that would be able to support a lesser number of robots.
Remember that there's only a 5 point bonus for each inch. So 18" would only give you 85 points after the first 30 points for one inch. And imagine how much space on a robot a lifting mechanism or ramp would take up. Plus there's only 30 seconds (End Game) to complete the lift.
I think it's more efficient to go for one inch with a simple mechanism. But hey, I wouldn't have thought teams would go 10'+ in the air last year, so who knows!
Remember that there's only a 5 point bonus for each inch. So 18" would only give you 85 points after the first 30 points for one inch. And imagine how much space on a robot a lifting mechanism or ramp would take up. Plus there's only 30 seconds (End Game) to complete the lift.
I think it's more efficient to go for one inch with a simple mechanism. But hey, I wouldn't have thought teams would go 10'+ in the air last year, so who knows!
I agree. The max number of points period for a sole lifting bot is 145 and as calculated on another thread yesterday the max points are 1071 so your not gonna score enough. sure you could de-score mat rings and block opponents but you still wont score enough points and especially if its two defensive bots in a match.
ehochstein
09-09-2012, 12:15
I agree. The max number of points period for a sole lifting bot is 145 and as calculated on another thread yesterday the max points are 1071 so your not gonna score enough. sure you could de-score mat rings and block opponents but you still wont score enough points and especially if its two defensive bots in a match.
The first point total was calculated wrong the actual total number of points is 1,727. Only 145 max from lifting a robot.
For a grand total of...1,727 Points
Yeah, that's true.
To be honest, I was really looking toward having a claw capable of picking up multiple rings. Like either 2 or 3. In this case, you obviously have to adjust the tolerance to say, 6 oz.
FYI - Let's make that 2 rings max :P
<GR2>Robots may Possess no more than two (2) Rings at any time. If a Robot is Possessing more than
2 Rings, the Alliance will be penalized ten (10) points per Ring plus an additional 10 points for
each 5 second interval that this situation continues. Rings will not be legally Scored while a Robot
Possesses more than two (2) Rings (i.e. the extra Ring will not count).
Andrew Remmers
09-09-2012, 15:58
I think lifting will be a fun part of the game, but I don't think minimizing movement from a mechanism is the way to go about it to get to 2 feet from 18 inches.
I am having a smaller more manageable ramp, and it will lead up to a platform that is at about 8 inches tall this will create a very nice angle to drive up, something most drive trains should be able to handle without much problem. From there it will lift up with a scissor lift powered by a lead screw. That oh did I mention 6 motors will be powering this?
- Andrew
I think lifting will be a fun part of the game, but I don't think minimizing movement from a mechanism is the way to go about it to get to 2 feet from 18 inches.
I am having a smaller more manageable ramp, and it will lead up to a platform that is at about 8 inches tall this will create a very nice angle to drive up, something most drive trains should be able to handle without much problem. From there it will lift up with a scissor lift powered by a lead screw. That oh did I mention 6 motors will be powering this?
- Andrew
Wow that sounds really cool! Can't wait to see something like that in action. Though I'm having trouble imagining how you'd have room for anything else on your robot.
Andrew Remmers
09-09-2012, 17:06
Wow that sounds really cool! Can't wait to see something like that in action. Though I'm having trouble imagining how you'd have room for anything else on your robot.
Well I can't actually compete, so If this bot gets built then it will be pretty cool pet project. You'll see when I post something about it. :D Also I don't use a single Tetrix part.
- Andrew
I am having a smaller more manageable ramp, and it will lead up to a platform that is at about 8 inches tall this will create a very nice angle to drive up, something most drive trains should be able to handle without much problem. From there it will lift up with a scissor lift powered by a lead screw. That oh did I mention 6 motors will be powering this?
- Andrew
I'm sure I don't have to point out the obvious here. But still keep, keep every part of that mechanism well greased with industrial lubricants. ie if the lead screw is shiny then something is wrong. Also the actual scissor mechanism to should have any sort of scrapping marks. But like I said that is the obvious.
For the record, since somebody asked about weight counterbalancing.
Since FTC for some odd reason has no weight limit, you could technically load your bot with whatever you wanted as long as it doesn't violate any other rules.
So just get a heavy block of steel and put it in some safe place on the bot, and it should be good enough for counterbalance (and I mean heavy).
Also, an idea of one of my teammates was to have some kind of linear slide system that extended out the back of your robot with a weight that would also slide out on said linear slide to counter even further.
Because since your pivot point is something like the mid-center of your robot where you're picking up your teammate, the further the weight from this pivot, the higher torque you're getting to counteract the torque from the robots weight.
Add that far distance & weight to your own robots weight, and it should provide more than enough torque to counter-act the other robots weight.
There's actually another thing I wanted to bring up.
I've talked to quite a few FTC teams planning on, like, a "claw" design for grabbing rings.
I'm sure some of you are aware of this, but I wanted to bring it up just in case.
Since the dispensers are something like 1 foot of PVC with rings on it, and you have a claw on the front of your robot, you either will only be able to reach the first 2 or 3 rings if the claw is basic.
In order to reach the rings deeper on the dispenser, we'd have to get creative. Either a claw that can move horizontally forward to reach them, or a claw that can grab the rings from the the dispenser on the side and somehow pull them to the front of the PVC and get them off - either way there's engineering to look at.
Another thing is I haven't taken too detailed a look at the schematics for the field, but on this note I'm assuming the dispenser height is something like 14", or < 18" at most, because that would prevent the robot from getting to the further end of the PVC due to the robot being the same height.
Thoughts?
Andrew Remmers
09-09-2012, 23:24
There's actually another thing I wanted to bring up.
I've talked to quite a few FTC teams planning on, like, a "claw" design for grabbing rings.
I'm sure some of you are aware of this, but I wanted to bring it up just in case.
Since the dispensers are something like 1 foot of PVC with rings on it, and you have a claw on the front of your robot, you either will only be able to reach the first 2 or 3 rings if the claw is basic.
In order to reach the rings deeper on the dispenser, we'd have to get creative. Either a claw that can move horizontally forward to reach them, or a claw that can grab the rings from the the dispenser on the side and somehow pull them to the front of the PVC and get them off - either way there's engineering to look at.
Thoughts?
It's going to be interesting, I think a lot of teams will have something that changes orientation. I'm working on something now that doesn't have to but we will see how it goes.
Another thing is I haven't taken too detailed a look at the schematics for the field, but on this note I'm assuming the dispenser height is something like 14", or < 18" at most, because that would prevent the robot from getting to the further end of the PVC due to the robot being the same height.
Yeah its close, but on the field at our kickoff it appeared as if you wouldn't be able to do that without some kind of moving system. Its going to be interesting how teams get around this year. Very difficult to play defense. :)
- Andrew
Yeah its close, but on the field at our kickoff it appeared as if you wouldn't be able to do that without some kind of moving system. Its going to be interesting how teams get around this year. Very difficult to play defense. :)
- Andrew
I actually think it'll be real easy to play defense this year. With virtually all points coming from rings on the center pegs, all you have to do is park your robot there and no one can score. All the more reason why an awesome autonomous program is going to be key.
Andrew Remmers
10-09-2012, 12:21
I actually think it'll be real easy to play defense this year. With virtually all points coming from rings on the center pegs, all you have to do is park your robot there and no one can score. All the more reason why an awesome autonomous program is going to be key.
Well coming from Florida where we are doing the new "League System" Playing defense does absolutely nothing for you. Its a pretty good motivation to build something that works and actually try to get into the state championship which is much harder for us this year.
- Andrew
Well coming from Florida where we are doing the new "League System" Playing defense does absolutely nothing for you. Its a pretty good motivation to build something that works and actually try to get into the state championship which is much harder for us this year.
- Andrew
Care to link or explain what the "League System" is?
Andrew Remmers
10-09-2012, 15:58
Care to link or explain what the "League System" is?
Basically Florida is being split up into "Leagues" its basically districts. Each league has set amounts of teams and host competitions At least 3 Competitions. Each Competition has a cap at ~14 teams, but there is something different about them, League competitions are simply scrimmages you play matches all day, no finals, no awards. HOWEVER Team performance is tracked as it is used to then decide who goes to the League Championship, which is basically what we all know as a Qualifier.
From the League Championships hosted around Florida the best teams earn their way into the State Championship. From there we earn into Worlds.
With this system Leagues have to hold at least one "built-it day" (lots of other variations of names).
Teams also compete strictly in their Leagues, However Inter-League play is doable, just means you have to go to multiple competitions outside of your league to get into the league championship.
Its confusing I know, and the only thing I don't like about it is the fact I can't ref every competition in Florida anymore :( But overall the quality/caliber of the teams in the State Championship will be much higher as you can no longer earn your way in from hosting competitions.
Hope that explains it well enough, If I got anything wrong people in a League system are allowed to correct me :)
- Andrew
After what teams did this past year with more restrictive build rules I would say ignore the 24" lift at your own peril.
RRLedford
23-11-2012, 19:18
This tread has died out, and it should not have, so I am reviving it.
We competed in the 1st week of qualifiers here in Illinois a couple weeks ago, where we were the only team to deploy any lifting mechanism. Our system was merely an almost 18 x 18" gravity deployed, fold out ramp that angled downward on deployment and allowed the partner to drive up to a point where their center of weight moving up the platform tipped the angled platform back to horizontal at an elevation of 1.5".
It only gave 30 points, but with the low level of scoring in most matches this would have given a winning score for most matches, where more than one row bonus rarely occurred.
We found that most partners could not make it up our ramp, despite its low angle and wide width. Some were too wide and unable to drive straight, causing their wheel to go off one side. Some were too slow and the ramp tilted too soon (our fault - bad design), hooking their frame or rear wheels before they got up.
In the one match where we had a small footprint partner with good driving skills, we found out how easy it was to defend against our lift. As we deployed the ramp, while our partner was finishing their last ring scoring trip, the opponent merely parked next to the loading edge of the ramp. effectively blocking access.
We had not had time to practice strategy for this situation, and even though we were touched by the defender as we tried to reposition for our partner to have access to the ramp, because we and our partner were not yet in contact at the point where the opponent contacted us, there was no penalty assessed.
So, it became clear that an aggressive lift blocking opponent could easily make bot loading a much less than certain proposition, even with a small bot with good agility. True, they were taking a risk of a big penalty, had we made contact with our partner while the opponent touched us, but it worked for them. Also, our bot could not move very effectively once the platform deployed, so this also was a handicap to overcoming the blocking move.
On top of all these issues, the low scoring of all the matches (only one reached 100 point level) made it clear that using the last 30 seconds to gain multiple row bonuses was a much better way to spend our time.
We have removed our platform and are now concentrating on using the last 30 seconds for getting more scoring trips completed. When one scoring trip placing two single rings can give as much as 190 points (5 row bonuses), a lift that cannot go up at least 20+" is probably not worth implementing.
-Dick Ledford
If a team were using a "forklift/platform type lift that extended more than 18" out from the robot (aside from being tough to lift) how would it work if they were under the other teams robot and their alliance robot and attempted to lift both at the same time. Would that be a penalty and on which team. Just a thought problem one of the teams was contimplating today.
They actually think it could be done.
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