I believe this was meant to be in the general forum as a discussion, as there doesn’t seem to be any question there. As for tether bots/wall bots, I think it is to over complicated. In addition, I feel it would be hard to effectively build both a wall bot that somehow extends at least 5 feet in the air and spans 12 feet, as well as build a catapult capable of launching stars over your own wall.
The only possible good combo I could think of would be to have one part of the robot sitting at the fence with a simple conveyor to drop over, and the second part being a fast and maneuverable mini base with “catch” and manipulate controls. Even then, you’d only be able to grab 2-3 stars at a time, and then you’d always have to return to your “home” to score points, all of which could easily be blocked. Plus, you would almost guaranteed not be able to hang, unless you had a “reattach” function that would be considerably difficult.
Overall, I agree with @Mystical Pie - no need for wall bots/tether bots this year.
Not to mention that you’d be splitting your motor distribution across two distinct “sub-bots.” With a cap of 12 motors in this game (10 with pneumatics), they’re a precious commodity. I know there was a tether bot in Skyrise that worked quite well for its kind (if you don’t know what that tether-bot is, go look at robotc.net), but this year’s game, in my view, requires an additional layer of complexity for the robots to be successful on the world level. I don’t think a tether bot can be up to the task.
I really dont think I will enjoy having an alliance that is a wall-tether bot…
It is a confined space this year. The tether cable that joins the 2 robots together will be hindering the movement of the alliance robot.
So please… do tether-bot please…
And really… think i can easily have a fast scorer and play good defence at the same time.
I had the same idea! And it would reck everyone all day everyday if i can make a 1 way wall… Unfortunately @Aponthis (one of the masters of wallbots) said it was next to impossible to fit A wallbot within 18x18 (127’s previous wallbots didn’t need a wall, just the scissor part connecting them) so getting the next to impossible wallbot and an additional tetherbot fitting is going to be flipping difficult. Although the motors do work out okay (not too good though)… 2 wheel drive for each side of the wall, 1 linear slide to raise the wall on either side, 4 wheel drive for the tetherbot, and a 2 motor catapult for the tetherbot =12 motors if the one way wall and the fitting worked perfectly, it would be awesome but I don’t think those will work out…
I wouldn’t say I am a master of wallbots. But having seen a couple effective (yet smaller than those called for this year) wallbots in action, it’s definitely not possible to block the whole fence to a height of up to 5 feet, especially while having one-way flaps.
I think a wallbot is definitely possible up to 5 feet (2 motor drive + 2 motor 2 stage linear lift, x2), but it would require using a net rather than a solid wall.
I don’t think it will be practical and I don’t think you will see one in our region
We’ll probably prototype one over the summer, but I doubt it can stand a human throwing a cube at it. If it can, I’ll try to convince our B team to take it to competition.
wallbot is definitely possible…
but still - please… no tether bot please…
Here is another sack attack wallbot video:
You can only sympathize with the team who spent considerable amount of time building the robot and then all they could do is just to stand there, unable to do anything, while the opposing alliance scores away.
I think everybody understands that defending 12x2 sq ft area above the fence is hard, while it could be easily defeated by a high-trowing catapult or a pushbot forcing stars under the fence. However, everyone would be thrilled to see an actual wallbot this season.
Lets assume, for a moment, that there is no high-throwing catapults and the only opponents are the pushbots and the dumpers. One way to implement the wall would be to deploy two or three stationary posts that will be inclined into opponent’s territory over the fence:
You may not even need to have full net between the posts - just a few horizontal strings might be all it takes to mess with the opposing dumpers. Each post could be passive hardware only (about 6 c-channels, no wheels) with rubber bands that raise it up when deployed (for example, released by pneumatics). You could also have another string few inches from the floor to make it harder for pushbots to do their pushing.
Let say you manage to perfectly deploy the wall every time and then the rest of your robot (with 10 motors and connected to the wall via string tether) could drive around and even have high-throwing catapult for scoring. This is the best case scenario, but there would still be many problems.
First of all, your opponents will quickly figure out the strategy to push your wall out of place. Even if you put 10 lbs of the metal into each base of your posts, to prevent if from being pushed or overturned, the dumpers should still be able to sag your net, having 6 ft spans, with minimal efforts.
Also, you would need to persuade judges that your net is not entanglement hazard and that any non-compliant interaction with the fence is the fault of your opponents trying to dislodge you.
Finally, one of the scoring rules will make the benefits of the wall even more iffy. Let say your wall is successful in preventing opponents from dumping stars over it. However, any objects that might be stuck in your net or is touching your robot on the bottom (from the neutral zone) will still be scored against you.
If you must build something big I would go for the wider scoop bucket and the turbo charged omni-drive for both offence and defense:
I agree with @puzzler7 in that a net might be the way to go (if you’re bent on doing a wallbot).
Also @technik3k , I assume that you mean to say that wallbots hurt their own alliance more than the others, correct? From the video, that seemed to be the case.
I agree that there is simply too much room to effectively cover on the field. The only “crazy” strategy that I feel might have the slightest chance of success would be the complete field “blanket”. Instead of building a vertical wall, the hypothetical robot would drive forward, split into two parts that block floor pushbots along each of the sides of the field perimeter, and then extend a huge rolled-up net 8 feet into the air, with some kind of weight at the top. Then, a release of the pneumatic locks (imagine like 4 pistons as locks) and a slight nudge causes this whole net to fall onto the other team’s side at an angle, with the sides of the net resting on the opponent’s field perimeter (only on the top, not grappling) and the weight on the far end serving to ensure the net won’t get pushed up.
This design would basically “smother” the other alliance, and using a mesh-based net would be light and minimal entanglement hazard. The biggest threat I see is the opponent alliance scoring a few stars before the blanket deploys, which could be effectively countered with a small opening in the net that would be extremely awkward for the other alliance to get to, but reasonably simple for your ally. Additionally, the wallbot would essentially steal the opponent’s space and not your own, so there would not be much chance of interference with your partner once the blanket is deployed.
I probably would not advise this strategy in any case because it’s based on far too many assumptions to work out the first time you build it (or second, or third, …), and a lot of refs might have problems with some of the finer rules in the manual. Still, this might be a “black swan” strategy that, if perfected, might upset the game’s balance.
But this (and the robot in the other video posted) covered much smaller areas than would be needed for this year. Even then, they still weren’t very successful. 1471A got pushed around and off the troughs, and all it needed to cover was two troughs, not a whole 12x5 area. It’s impressive what they accomplished but it doesn’t convince me that a larger wall is doable.
And the idea of then having a tetherbot is ludicrous. Building just a wallbot in the starting area is hard enough; impossible, I’d say. An offensive bot as well?..
Just want to highlight that this was done when only 10 motors were allowed.
And sack Attack allowed robots to crossover underneath the trough, whereas this season game will not be legal.
During Skyrise season, there were many teams that said it was not possible or effective to do a wallbot, mainly due to the open space.
8059D did an effective wallbot for the Worlds (just that the seeded teams didn’t dare to take the risk of picking them).
My point is - it is very possible to do a wallbot for this season.
In fact, I do have some ideas on how this can be achieved. But I am not going to do anything or talk about it at the moment.
I don’t think motors are the main issue - it’s how much metal you can fit in an 18 inch cube.
And a wallbot would still have to block the low parts of the fence so stars couldn’t be pushed under
Think the real difficulty lies not in packing all the metal required within the 18" cube, but it is abt how are you going to dos total shutdown but yet allowing your alliance to score
Either way, the problems compound. Having say, a one-way section, adds mechanical complexity.
If you did something like this though one way would be able to launch if they have a catapult, but not the other. Also you can just make a conveyer go over the top of it for dumping
Like meng said, fitting everything isn’t that hard. Unlike 1471A or 127C, there’s no need for the wall to be completely solid. It just needs two solid towers at the ends and a whole bunch of mesh connecting them.
The height isn’t that difficult either. Skyrise lifts were 6’ tall and those had to go up and down. This just has to go up once, so you can use as many rubber bands as needed to lift all that metal.
Only thing that needs to be figured out is how to let your partner score . . .
Do it all during autonomous then proceed to have 1:45 of nothing during driver control.
(kidding…most likely not realistic, but would be great if possible!)