4577C Wallbot Reveal

Okay so last Friday night one of our team members decided to build a wallbot for Sunday’s competition. We spent all of Saturday building it. Due to issues with the lock getting stuck and the drive just being plain awful, it ended up doing poorly, but it’s a good proof of concept if anyone wants to pull ideas from it. The biggest issue was that the center 2 wheels had a really tough time gripping the ground so they slipped a ton. If we’d had another couple days it would have been much better, but that was our last competition of the year and it didn’t qualify for worlds, so I guess that’s it for it :rolleyes:

Vid: https://www.youtube.com/watch?v=tVC5opbJ3CM

What’s the gear ratio on that thing? It looks faster than my 2:1, so I’m guessing 2.4:1 or even 3:1. Can I also get a weight? I’m working on an idea right now for gearing faster, but I’m worried about too much mass causing a problem.

EDIT: Watching that again, you used Pneumatics for the expansion. You didn’t drive it outwards. Never mind.

That’s very impressive for just a day!

I would have loved to see what you could have done if you had some more time.

Nice. Was it really worth it to strafe, turn, then expand?

We used elastic tubing inside the slides to help it open which is why it jerks suddenly in the beginning. The pneumatics are actually just to lock it shut. We do drive outward after it opens about halfway on its own.

It weighed just under 16lbs.

The strafe wheels are direct driven by 393s geared for speed. The forward facing ones were geared a tad faster than that, can’t remember the exact ratio. You should do your own tuning, though; this was such a last minute job :stuck_out_tongue:

The reason we did that was because we were using omni wheels and the horizontal wheels were much more consistent. It was a workaround for the poor performance of the front-facing wheels. That way, once the driver control period started, the driver would manually turn it until it was actually horizontal and then open it.

Oh, I’m not building this design. For a number of reasons. I do want to go faster than a 2:1 ratio for something, though. So it’s either pneumatic accelerators or I gear up. At 16 lbs, you couldn’t do over 2:1 with 4 motors. But if I get my robot light enough, I might be able to gear up.

Wasn’t saying you should make one bolt for bolt; far from it, actually. But I think it’s a good design to build off of.

make it lighter and more motors on the drive

Seems like a great concept, more improvement! :smiley:

Add more weight on your robot, gear your drive to a higher gear ratio possibly?

I am impressed how you built that in just a day…

It was effective at blocking the stash, if you had more time I think your concept could have worked really well. So nice work for one day.:stuck_out_tongue:

I really wasn’t going to get into this. But you’re pushing this as a concept, so now I have to explain why it’s flawed.

Say that, hypothetically, you could deploy this robot during the first 0.1 seconds of Autonomous. The cylinders are locked down entirely, unless you want to open them. I can tell you right now how even a semi-decent alliance could beat it.

Red Robot 1 plays defense on your partner. For the entire match, all he does is push and shove your partner. He doesn’t have to pin your partner, just hit him repeatedly. He has two goals. The primary goal is to stop your partner from scoring in the cylinder. We blocked off an entire trough last year with a 6 motor pushbot. Preventing access to one 8" tube is easy in comparison. His other goal is just to slow down your partner’s ability to move game objects into the end zone.

Red Robot 2 moves game objects into the end zone. He completely ignores the cylinders. Move their objects in, take any objects your partner has introduced out. He’s uninhibited. He has the entire field and all the game objects to use. You aren’t stopping him. Your partner sure isn’t. In 2 minutes, he could easily score all 40 points.

We spent a long, LONG time trying to work out what makes a defensive robot feasible this year. These were the three criteria we came up with.

  1. The robot must be able to block off both cylinders from the opponents. This MUST occur during the Autonomous period, and hopefully it takes place in the first 5 seconds of Autonomous.

  2. The robot must be able to prevent the opponents from playing defense on their partner. Otherwise, we get the scenario I outlined above and you loose.

  3. The robot must be able to prevent the opponents from hanging. We saw a double high-hang posted to the forums earlier today. That’s 40 points. That’s way too much to be an acceptable weakness.

I’m sure there are other people who have looked at the problem, and I welcome your input. If you could do the first two of the three things I described, I think that could be a very solid defensive robot. But doing just one of the three seems like it will be ultimately ineffective.

This is my version of a cautionary tale to anyone thinking “My design isn’t working. I’ll just build this and win.” Don’t. Stick with what you’ve been using all season long and keep improving it. You’ll have much more success.

We built a spring loaded 3:1 drive for our capper last year and it went about 17 feet in three seconds then stopped. That robot weighed 30 pounds so I don’t know how fast a lighter one would go.
Check out this thread for details:

I pretty much came to that same conclusion. The only thing I could debate is the necessity for point 3.

Having the ability to block the stashes and hang is quite unpractical. Getting to one side of the field from the exact opposite side, before your opposing alliance can creates too many factors to predict, and far too many scenarios that your opponent can block.

However, having a wall bot with the ability to score or de-score a few points is more viable. It relieves the strain on your ally. To actually make a system like this, a motor powered turntable, a motor powered claw, a motor to extend the arm, and a couple of motors on an arm with a high gear ratio winch would be sufficient. If the robot could de-score all the opposing large balls and score all of the alliance large balls, a double hang is no longer a threat(ends in a tie). From there, it just roots to an autonomous period and bucky ball scores.

You know, I’m actually in two minds about all this. I don’t want to say too much, and I don’t want to derail Daniel’s thread, but I just want to quickly say what I’m thinking. I know this is not at all ideal for qualifications, but it would be alright for eliminations, particularly at a large event like Worlds when you then have a larger selection of robots to align with.

Wallbot (or defensive) robot goes and does it’s thing. Ally is an 8 motor drive robot (we all know 8 motor drive + pneumatic lift robots exist, we’ve already seen one or two), or a 6 motor drive perhaps with a transmission to get enough torque (I prefer the 8 motor drive option though). Your ally can then come and play defense on my 8 motor drive as much as it likes, but unless it has a drive train to match mine, I’ll push my way to the goals. What can you do? Well, sure, you’ll slow me down. And you can take 6 of my buckyballs (3 per robot), but then that limits your other robot with it’s objective of getting objects to the goal zone.


  1. Your ally has a drive train to match/beat mine
  2. You are another wallbot (well that gets interesting).

But if all goes to plan, I could get 4 buckyballs in the goal (and unless you take all the other 6, I could get more, chances are you’ll only take 3 in your blocking robot, so that’s 7 buckyballs = 35 points), then consider the large balls, and high hanging with a ball. I could get a pretty nice score that way.

If you want to discuss this further, maybe we should make a new thread… note that I haven’t thought about this THAT much, but it’s really the way I see it working.


If the wallbot had the ability to hoard opponent large balls on top of itself, this strategy could be even more effective.

I don’t doubt that at worlds, most of the good teams in the eliminations will be strategically prepared and able to beat a wallbot like this. But, at a smaller regional tournament, many teams have never seen a wallbot before and may not know what to do against it (I can’t speak for other regions but this is the case here in MI). With a good partner, a wallbot could be a very good 3rd robot on an alliance.

Do you think you could show us or explain how you did the latex tubing on the expansion? How does it fit inside the slides?

Could you possibly be called for SG8 if more than 3 Buckyballs get stuck between the connecter and the wall

We definitely thought about that, and our interpretation was that we were not “intentionally pushing or impelling BuckyBall(s) to a desired location or path” nor would we be “intentionally pressing BuckyBall(s) up against a field object.” So, the only way we could get called for SG8 would be if 4 Buckies were somehow accidentally placed on top of our robot and we couldn’t get them off.

In our design, at least, this never happened because the Buckies fell right off the small base with just a quick drive forward or backward, and we never even needed to do that in competition. It was also very difficult to even get a Bucky to touch our robot and the wall at the same time.

I thought about trying to make a Floor Bot. A robot that went into the end zone and covered the entire floor of the end zone. However, I decided that it wasn’t very viable…

thats so hard to do, i mean you have to have metal tiles or like anti slip mat covering the whole thing, I don’t know how you’d collapse 24 square feet into 2.25 square feet, lol.