The first full sized, double trough blocker? :D

Last year in 6 weeks we built a 6 foot scoring wallbot for worlds with an 8 motor mecanum drive and a rubber band powered chain bar arm extension. We figured we would continue the tradition and make a “mathematical advantage” defensive bot this year.

So we’ve been working on this all season.

We’ve created a robot capable of expanding to 12 feet long, lifting two arms and expanding two scissor expansions, covering the opponents troughs and defending one of our own, and braking its wheels within 4 seconds of the autonomous period.

Don’t make us think about the 1000+ man hours that have went into the building and tweaking of this robot. It hurts to remember the amount of work this thing required!

6 motor drive - 1:3 for speed
two 1 motor 1:5 lifts
6 pistons - two pulling a pneumatic pin releasing a 6 foot linear slide expansion. two braking the chain drives, making us literally unpushable by just about anyone. two releasing the scissor expansions that cover the troughs.
about 9000 rubber bands

High goal blocker is coming with our last two motors. The far expansion needs some strengthening. But everything is coming along. This robot is dangerous :3

What do you guys think?

P.S. - we know the right side trough cap doesn’t work too well in the video - we’re working on it! It’s worked a few times just as good as the left :slight_smile:

This is an epic win. expect one thing, why would you block both of your alliance troughs as well (with the sliders near the ground)?

Most robots can drive under them. Especially the ones in the middle. And robots can easily score behind the trough caps into our color goal.

How many sliders does this use? Also how does the piston break work?


I am totally impressed. That thing is just plain awesome. I really thought it couldn’t be done.

People will no doubt post their assessments of weaknesses they see in the design, or questions about how rules affect this strategy, but here’s hoping they have the courtesy to start their posts by admiring a job well done.

That rocks!


18 total linear slides I believe. The robot weighs like 40 pounds >.> Piston break just shoves an axle into the chain drive on each side, and we’ve been unable to break the chain with this no matter what we do.

And thanks for the admirations guys!

Oh thats pretty cool, and it can’t be 9000 rubber bands, that would cost so much money.

Okay sorry it might be only 8,999. :wink:

I’m pretty sure various expletives are going through peoples’ minds right now :smiley:

Here’s another video from a better angle:

Wow!! Jaw still hanging open.

That’s pretty imba.

However, I wonder what’s gonna happen if you guys match up with a robot which is 1:5 for torque.

and can your robot function well if an opponent trying to pass the trough at the very first moment of a match?

We think that the brakes will be able to handle a robot geared 1:5. You can’t see them very well in the pictures, but the basically shove a pin into the chain which completely stops the wheel from moving. It would be a tough call, but we should be able to handle it.

That’s one of the things we have to work on. Speed is vital to our strategy, so we geared our drive 3:1, and are continually working to make our autonomous take less time.

Doing this during autonomous mode is worth applauding.
I can see that you were able to combine the speed and power needed for this design.
I like how the cappers themselves expand with scissors that is an interesting way of accomplishing that.
Have you tested for the maximum damage you because people will come up with strategies against it and that could involve pushing.

That’s both terrifying and awesome at the same time lol, it should definitely introduce some new strategies!

Nice work though, looks like you have this thing pretty well perfected!


What are you going to do if a faster robot makes it between you and the trough post on your side of the field, effectively forcing you into pinning them?

I absolutely disagree. If the robot is driven by anybody with opposable thumbs they would certainly be able to drive the robot in a manner that would fit within the boundaries of the VEX rulebook. Assuming the driver lifts the trough covers to no longer be considered “wrapped” (or even better, lengthen the arms that carry the cover). As for latching onto the center post, maybe I am just totally overlooking this mechanism that latches on, but I do not see it. To solve the problem of being in constant contact with the post the solution is simple: back the robot up an inch in driver control. If the robot stayed totally stationary from where it was shown in this video, then yes, disqualification is warranted. However, if this robot had a driver with any knowledge of the rulebook, it should not receive a disqualification in any match it plays.

Open to responses,


Here is why this robot right now is highly illegal.

If you look at the right side of the picture, the Scissor extends past the center post. The nature of their mechanism is what make it illegal.

Now before I explain I need to touch on the basic concept of this robot, and why I think its latching at all points.

From what it appears all the blockers are on an arm, this is what allows it to get over top of the trough. Now on the left side of the picture I attached you can see it is just sitting there, but there is one key difference that makes it what I think is illegal at this point. The scissor mechanism used to expand it goes past the black dividers of the trough. This shows an attempt to hold itself in place, However the saving grace of this part of the robot is that the blockers themselves are on an arm. This allows them to pull back at any point their robot is interfered with. Making this part legal if they were to take the blocker off any time another robot touched them.

Now for the otherside, the Scissor mechanism is clearly a passive mechanism there is not bringing it back in once its expanded. (This is where the picture comes in) It is also on the same arm is on the left side, however once expanded the physical part of the arm is then further than the High Goal Post. The fact that this arm is non-retractable make its a clear attempt at latching to the field and staying there (even if it was not the teams intention) You might argue its on the same arm that the other one was, however it cant be retracted because of the central post. Thus making the robot actively latched to the field.

This is how I see it, I will be posting a Q&A later tonight.

  • Andrew

I would still disagree. A simple raising of the arms attached to the blockers during driver control would surely fix your conceptions of the illegality of this robot. Raising the arms so that it is (a) above the black trough divider, therefore in no way would the robot possibly be seen as using that piece as support, and (b) it would no longer be curled around the trough and would be no different than a more standard robot hovering its intake over the trough…make sense?

Look at the High Goal Post.