VEXU: Is this legal? Why wouldn't this be an entanglement hazard

My thoughts exactly. Tether robots have been apart of VEX for some time now. Last year is when people really brought some light to it. Having tethered robots are completely legal as long as at the start, they start in the right size dimensions and during the match, the tether isn’t an entanglement hazard.

USC clearly tried to get entangled to get SYNC DQ’d or so, which is a perfectly legal strategy (though I don’t approve of it), but they wasted a whole match doing that instead of trying to just out score them. All honestly, in Semi-final 1, they should have been DQ’d for touching the red tile, at least that’s what I saw in the video.

Instead of saying something is illegal, do some research, check the rules, and do some research again. The rules are vague but VEX is all about thinking outside the box and being creative. Last year OYES surprised everyone with their tethered robot and it was an amazing design that made me have one of those “Duh, of course” moments.

Great work to SYNC though on build a really efficient robot. My team has been planning on doing something similar but you guys have set the standard. I know of at least 3 other VEX U teams doing tethered robots but I’m curious to read your detailed post of your robot in the future.

<SG10> Intentional strategies causing an opponent to violate a rule are not permitted, and will not result in a foul on the opposing alliance. Minor violations of this rule that do not affect the match will result in a warning. Egregious (match affecting) offenses will result in a Disqualification. Teams that receive multiple warnings may also receive a Disqualification at the head referee’s discretion.

<G12> Strategies aimed solely at the destruction, damage, tipping over, or Entanglement of Robots are
not part of the ethos of the VEX Robotics Competition and are not allowed. However, VEX Skyrise is an
interactive game. Some incidental tipping, Entanglement, and damage may occur as a part of normal
game play. If the tipping, Entanglement, or damage is ruled to be intentional or egregious, the offending
team may be disqualified from that Match. Repeated offenses could result in a team being Disqualified
from the remainder of the competition.

Entanglement – A robot is considered to have Entangled an opposing robot if it has grabbed or hooked
the opponent robot.

<G1> When reading and applying the various rules in this document, please remember that common
sense always applies in the VEX Robotics Competition.

It’s not, it violates <SG10>.

This is NOT an automatic DQ. It’s a DQ only if it affects the outcome of the match. If you lose the match, which USC did, then you will only be DQed for <SG9> violations if you have previous warnings and then only at the head ref’s discretion.

Anyway, I don’t think USC touched the red tile in semifinal 1:

The robot that drives in and scores on the skyrise is SYNC’s 15" robot.

This is a stupid question but would a tethered robot like this be legal for high school teams? I remember seeing a tethered robot last year at worlds for high school but what about this year?

For interest the type of tether used by SYNC (and the OYES 2014 one) would not be allowed in FTC. In 2012/13 we used a tethered minibot for Ring It Up but kept the tether suspended above the playing field so it was impossible to drive over plus it was actually usable for a defensive wallbot albeit a little on the light side. We were warned by the world championship field inspectors and referees that if any entanglement occurred they’d be pointing the finger at us. Of note we never entangled.

My opinion is that once part of your robot design can be driven over you’ve forced the opposing alliance into either totally avoiding it or trying to run over it to achieve their game strategy. During autonomous operation there’s every chance driving over the tether is going to cause some navigation issues.

Why OYES/SYNC style tethers shouldn’t be legal? Once again my opinion: Opens the door to creating a robot design which is tethered specifically to disrupt autonomous navigation (and driver to some extent) by essentially leaving a trail of unpredictable obstacles behind it. Leaving detached objects behind is against the rules however these tethers are just a collection of joined objects potentially strewn around the whole field. What happens when there’s one of these on each alliance? They’ll end up in knots literally. Messy…


It would be legal, but nearly impossible to pull off. I struggled making this work with 24" and 12 motors, so I can’t imagine using only 18" and 10 motors. Half of the cube robot hung over the tile on a kick stand and the two robots fit together like a puzzle with overlapping sections.

Well, it depends if you actually intend to score or not :stuck_out_tongue:

I am not planning on tethering and even if i did i wouldn’t use that design because yes i did see how hard it was to fit together while you were practicing and also if the skyrise was not lined up there was no way of fixing it , btw i really liked your 8 drive motor 15 inch bot :stuck_out_tongue:

Correct. I apologize for my wording.

What I was trying to say was that USC could have said that they were trying to score and they got entangled with the tether but their intentions were to get entangled to begin with. It’s all up to how the ref wants to call it.

At the :27 mark in SF 1, it looks like the USC robot was touching the red tile. That’s what I thought the SYNC drivers were looking at during that point. I was wrong about the DQ regarding that rule. Thank you for pointing that out.

They were crossing our colored tile around 0:45 in the second Semi Final match but it wasn’t match affecting. That poor ref had his work cut out for him in those matches, he did a really good job with listening to both sides and he took his time making sure he made the right call.

*Cough cough 1471A

Thats ok :stuck_out_tongue: The rules are kinda fuzzy sometimes.

I am not using this robot for matches at worlds but maybe for skills, as I mentioned I think it is strategically flawed. I tested this robot on different drive clearances and anything with at least 1 hole of clearance had no problem driving over it. Robots with little to no ground clearance could not get entangled, but they couldn’t drive over it either. Low drive bases just push it. I have been discussing it a bit and this robot falls into a grey area where it becomes a conditional wallbot. Against opponents who have enough clearance there is no problem, but against robots who can’t get past the tether it becomes an unintentional wallbot and should be treated as one by the refs. I wanted to go into more detail in the reveal thread (maybe later tonight). Anyways, there wasn’t a risk of entanglement but the robot does create a lot of questions.

Oh yeah, don’t forget 1471A: the robot that manage not only to only partially cut off the opponents, but completely enclose their scoring teammate where they cannot do anything. It was a good idea, but I can’t say it worked too well. I actually had a match against it and team 21 (quite a coincidence), and after driving over the expanding “walls” and tethers still managing to score quite a few buckyballs, looked over to see one of the top scoring robots in the world stuck in the corner with nothing to do. Toss Up was definitely not a wall-bot game, just very defensive.

I haven’t seen very many wall/defensive bots that benefit their teammate, but the split-robot idea is viable.

I see. To me, it’s not really a wall-bot since it’s not intended as a defensive mechanism, but I can see what you mean by “conditional wall-bot”. From what I could tell on the videos in the finals, it wasn’t your driving that was the problem, but more that the bot itself raised legality questions. I guess tether-bots just create a really grey area that relies heavily on referee judgment to decide what passes as a legal robot, and that therefore (unless an amendment to the manual is made) can be interpreted differently from referee to referee.

Jason - you don’t like Master & Puppet???
That kind of feels like you have insulted a close friend :smiley:
If you had met this “Claws bot”, (or was it “Claw Bots” ?) you might have a different perspective.

My opinion - disrupting autonomous is a highly desirable thing to do. Autonomous is not a programming skills run. Other robots move, scoring objects move, sometimes even goals move, there is interaction.

For Toss Up game, 99+ % of robots were capable of driving over a 2" high bump. This is a big reason why the flat tether was implemented. For the record, Master & Puppet could not get over the bump :stuck_out_tongue:

Aaron - very impressive robot! I agree that your game strategy should ideally drive your design process, but building this must have been a lot of fun. :slight_smile:


oh yeah that bot

I wouldn’t even call that a bot it’s more of a thing or monstrosity.:rolleyes:

Come see our pits (8086A) in the High School Division at Worlds. :smiley: