Robot climbing times

FIRST General Forum
#64

I can envision a pretty darn fast mechanism for this, but you’d be dedicating your robot to a super-fast climb. Here’s my thinking:

Common Sense Climbing: Most of us are thinking of a climber that has a moving grabber and a stationary grabber. Moving grabber latches on, pulls you up till you engage the stationary grabber. Then you extend the moving grabber, latch on again, and repeat till you get to the top. Doing all of that rapidly enough for a 4 second lift seems difficult. Plus is that this is (relatively) uncomplicated and light.

Superfast Climbing: You’ve dedicated your robot to climbing, so your climbing mechanism can be as heavy, bulky, and power hungry as necessary. So you make a climbing system with three different moving grabbers. Drive up to the pyramid, first grabber latches on and starts lifting. When it’s done, your second grabber is perfectly positioned to latch on and start lifting, so it keeps pulling you up with very little pause. Ditto the third grabber. So you get nearly continuous lifting at the cost of building three moving grabbers instead of one. And powering them of course. My specific implementation of this would be a corner climber with three pairs of telescoping poles with spring loaded hooks to grab the rungs. You’d want some kind of shock on the idler wheel that’s running up the pole, of course. And even then it’d be a pretty wild ride going up the corner that fast…

#65

From a rappelling exercise I did a long, long time ago, I know that you can rappel down a knotted rope without losing speed and without falling off when you hit the knot, using a rotating zip-climber that mechanically rotates itself around the knot without allowing a cantilever on the part of the climber.

Such a device is feasible for an FRC robot on the corner post – clamp it on and power it, and then just drive up! (You’d go to half power over the knuckles – compensated by momentum but detracted by gravity – but full power elsewhere).

What it isn’t is possible for 1551 to properly develop and test over a six-week period. :wink:

#66

Three hanging and dumping specialized bots on an alliance could easily get 120+ points. 3 hangs, 90 point total, 6 pyramid dumps, 30 more, auto dumps, up to 8 more, and then any dumps for 1 point goals from autonomous to hanging. Easily 120+pts, depends on if one bot can easily do all pyramid discs, while other 2 spam 1 point dumps.

#67

Your math works, but I find this to be perhaps the most interesting use of the word “easily” I have ever seen. :wink: I wonder if you mightn’t have confused it with “IRI”.

Joking aside though, in most any situation where you could get 3 such robots on the same alliance [barring a very weird qual schedule], you are quite likely to be up against some beastly shooters + 10-20pt (maybe 30) hangers yourself. They’d give the hanging alliance a run for its money, particularly given the time they’d have unrestricted and the defense you can lay down against dumpers. In fact, with the strategy you just laid out, you’d be lucky to execute fully at all. My #1 priority would likely be keeping that colored-disk loaded bot away from their pyramid, and anyone running around loading and dumping before they hang will be in for some very tough driving. Their might be fouls involved (maybe even a technical), but even a 20pt technical is worth it if it prevents a 30-50pt hang. Nothing’s ever as easy as it sounds.

#68

I hate to spill the beans on this design, but since we almost certainly won’t be using it, I might as well.

Minibot up the diagonal of the pyramid. This was the first thing that entered my head when I saw the challenge. Use a large pneumatic wheel to get over the crossbars, or an innovative wheel arrangement. Put two levels of idlers behind the pole, and be able to switch them over the crossbar quickly. You would clip onto the pole with your idlers, and just drive the pnumatic wheel up, and when you got to the crossbar, unclip your first idler, and after you’ve driven high enough to get over the bar, reclip it.

I think this is the only design that could get up in the under 10 range. Kevin, I don’t think three arms is the way to go, or even possible for all but the best teams (who wouldn’t want to go all out on it in favor of a shooter anyway).

If this such a good design, why aren’t we going with it? Because it would be really hard to package with our shooter, and because climbing fast isn’t all that important anyway.

#69

I’m not proposing that as a sensible solution. Just as a method of ascending pretty much as quickly as possible.

Also, I’m having difficulty picturing your proposed solution. Specifically how you get the idler out of the way of the crossbar. If the idler is behind the crossbar, you’d have to move it outwards to disengage the pole, then sideways to clear the bar. Unless an idler is actually two idlers that come in from opposite sides and wrap around the pipe to keep you from sliding off sideways or something.

#70

This might be treading on thin ice. Depending on how you plan on “preventing” their hang, the judges might automatically award the 30 points anyway and give you a technical foul.

#71

Interfering with Andy’s strategy has almost nothing to do with directly preventing their hang. With three 30-point hangers running around the field trying to pick up colored disks and feed/dump, there would be plenty of opportunity for ‘forced preoccupation’ without putting a defender anywhere near their pyramid itself. (The only technical on the horizon would be a last-minute long pin.) If you’re actually that good at 50pt climbs, you’re going to have your hands full of people getting in your way any time you stray from the pyramid.

#72

I see a lot of sentences that start with “most teams will be able to…” but I think the sentences mean to read “most *powerhouse *teams will…” or “most teams that are playing in the finals will…” or “Most teams in the eliminations at the world championships will…”

based off of my memories of the 2004 and 2010 games, I believe this thread greatly underestimates the difficulty of climbing and overestimated what truly most teams, meaning more than 50% at any given regional, will be capable of. In 2010 I’d argue less than 50% of teams were able to climb 12" effectively, of the teams that could, at least 50% of them spent a significant amount of time just lining up to do so.

So I’m answering my opinion for the Average team, meaning the median team at any given regional, and the upper 10% powerhouse teams at any given regional. These numbers include time spent aligning, not just climbing.

10 points
The Average Team - 35 second

The Powerhouses - 8 seconds

20 points
The average team - 50% of teams will not climb to the 20 point range. Those that do will spend half the match doing so.

The powerhouses - 30 seconds

30 points -
The average team - Only the ones that build a bot dedicated to only climbing the tower, and spend the entire 2 minutes doing so.

the powerhouses - less than 50% of the powerhouses will *attempt it or **succeed. Average of those that do - ***40 seconds.

***before I get backlash, keep in mind what an average is. Yes some will do it much faster. Others will do it much slower, and many will spend a lot of time attempting it with no avail.

**Robots fall, things come loose and dangle… if a robot makes it to the top tier quickly, but its bumper fabric peels off and dangles 29" off the ground, it is still will only be worth 10 points. For my estimations, this is considered a 10 point climb.

*I believe most powerhouse teams will combine shooting and climbing for their strategy. I am expecting them to spend a long portion scoring many frisbees, then with 30-40 seconds remaining they will have a fast mechanism to get off the ground, and another to pull them above 30".

#73

While I haven’t looked into the specific engineering yet, I was envisioning 4 pneumatic cylinders, two on each side, and actuating at a diagonal. When they would move back, they would both retract from the diagonal, and clear the crossbar.

#74

A single 2" bore (or dual 1.5" bore) pneumatic cylinders can do a 10 point hang (mounted vertically with a hook). This is also a buzzer beater.

This should be;

Almost Every Team - 3 seconds.

The powerhouses - 1 seconds.

Teams, you can 10 point hang; do it :wink:

#75

I agree with you more on level 1 than Barry, I will think it will be a tad more than 3 seconds, but a good average.

#76

Why?

It can be as simple as this;

Drive robot into bar at 30". You have some sort of hard stop to facilitate this.

Actuate the cylinder, this raises the robot and if it’s a double solenoid the motion can all happen after the buzzer.

The above hardstop could even be a sensor automating the process; the driver just rams the pyramid at full speed and can’t miss.

#77

Well I’m taking this as the whole time to line-up and lift. From my years watching FRC end games, many teams will spend the extra 5 seconds to make sure they are 100% locked on. Some will miss a first try and then. I said 3 is a good average, but you will see teams spend 15+ seconds on a 10 point hang.

With your method it is easy to pull off a quick 10 point hang, but not all teams will go that route and will try something innovative.

#78

Let me ask this in a different way. Assuming there are roughly 2,500 teams competing this year:

What will be the average time to both line up and hang of ALL of the top 250 teams? (10%)

Of the teams that are not in the top 10%, being 2,250 teams, what would be the combine average time it takes to align and climb of all of them?

#79

Honestly, a 10 pt hang is just so quick and easy that I’m having difficulty finding a reason anyone not to do it, unless you had 4 discs you knew you were going to make in the last couple seconds. Every team that can hang should bring a “hanging kit” they could install to a partner’s robot in about 15 minutes if a partner robot couldn’t hang (provided they are under the weight limit by enough).

#80

I don’t think anyone is claiming it to be hard to hang from level 1, it’s just the time to do it will vary.

#81

A 10 point hang doesn’t even require an active mechanism. An inverted wedge, a moderately fast drivetrain, and the right center of mass will do the trick.

#82

For teams that can 10 point hang, the average should only be 3-5 seconds. But I don’t think it will be, because asking teams to build a mechanism robust enough to lift a 120 lb robot is still a challenge (not to pick on the design mentioned here too much, but a 1 foot cylinder with a hook being rammed into a pole is a decent lever arm that teams may not have braced all that well). I think a lot of mechanisms will jam, miss, be damaged beyond repair, etc. and that’s ignoring lining up correctly (what if the hook spins and faces the wrong way?). I see the average being more like 20, with at least a third of attempts failing.

I’m taking a pessimistic view here, and I wish 95% of teams could at least 10 point hang because all alliances scoring 30+ a match would make for a really exciting competition. I’ve seen too many 0-0 or 0-2 matches to think it will happen though.

#83

The first thing that will prevent 10-point hangs is, in my guess, robots that are sufficiently tall that very small deviations in their center-of-gravity will torque the robot just enough so that it touches the ground while hanging from the lowest bar.

If the hooking device is directly above the robot’s center of gravity, a hook with either a sufficiently fat pneumatic cylinder or a ratcheting winch should be sufficient for a ten-pointer, and very fast.