Robot Arm C

[windu34]

I submitted this question some time ago but have not received a reply, so I thought I would ask it here. Would it be permissible for the base to deploy an RC car which would then drive around the board moving pennies so long as either the control or power were to remain on the base and the car were to remain attached by a cable? I can find no rule specifically outlawing this, but it seems to me to be a violation of the spirit of the competition as a flexible tether is hard to interpret as an arm. I strongly suspect that my students are not going to be the only ones looking at this as a possible solution, so I think a FAQ on the subject is in order.

99% sure this would not be legal as the rules seemed to make it quite clear that they wanted to avoid this. The rules mention that the base cannot move during the run or the match will be ended, and I believe this would include an RC car moving along the field, so as soon as the car moved the match would have to be stopped. I remember reading a related clarification last year but don't remember where.

There has been recent debate on this idea. By a single reading of the rules and a literal interpretation, it seems legal that a tethered car would be legal, but it is obviously not the intention of the writers. I agree a FAQ would be helpful

[dragonfruit35]

I submitted this question some time ago but have not received a reply, so I thought I would ask it here. Would it be permissible for the base to deploy an RC car which would then drive around the board moving pennies so long as either the control or power were to remain on the base and the car were to remain attached by a cable? I can find no rule specifically outlawing this, but it seems to me to be a violation of the spirit of the competition as a flexible tether is hard to interpret as an arm. I strongly suspect that my students are not going to be the only ones looking at this as a possible solution, so I think a FAQ on the subject is in order.

This is pretty similar to what happened a few years ago in Robo-Cross- you got extra points for finishing faster. The loophole with this is that you can just have the robot drive into zone D and call "Science". Actually, my partner and I used something similar to this and got 6th place in the state .

However, I feel that this might be disqualified, as windu said, because this is definitely not the intention of the rule, given that the name of the event is Robot Arm. Also, in Robo-Cross, at least using the loophole couldn't get you as many points as actually doing it the traditional way. In this case, I feel like using a car would provide an advantage. It doesn't exactly fit the spirit of the problem, although I do think that this definitely merits a clarification.

[Bazinga+]

Also, in Robo-Cross, at least using the loophole couldn't get you as many points as actually doing it the traditional way. In this case, I feel like using a car would provide an advantage. It doesn't exactly fit the spirit of the problem, although I do think that this definitely merits a clarification.

How would a car give an advantage? I think the task is significantly easier than using a fixed base arm rather than a separate car. Perhaps using a car is easier at a lower level for those with less resources available, and the event is meant for that initial challenge to exist.

[windu34]

Also, in Robo-Cross, at least using the loophole couldn't get you as many points as actually doing it the traditional way. In this case, I feel like using a car would provide an advantage. It doesn't exactly fit the spirit of the problem, although I do think that this definitely merits a clarification.

How would a car give an advantage? I think the task is significantly easier than using a fixed base arm rather than a separate car. Perhaps using a car is easier at a lower level for those with less resources available, and the event is meant for that initial challenge to exist.

I agree. At lower levels of competition, it may be possible to do well simply by pushing pennies into the target, but at higher levels when flipping the pennies becomes a must, a car would have a significant disadvantage (if it is even possible to place pennies after flipping them accurately with a car equipped with a shovel or scoop of some kind)

[jander14indoor]

REALLY need to add my UNOFFICIAL notice on this one...

These comments are NOT official and not valid for an appeal!!

In prior years we had this language in para 3: "optional detachable passive Arm end effectors (parts that interact with the Items on the Competition Area)" which made it pretty clear that remote control cars were not allowed (they certainly weren't passive!), and the FAQs supported that position consistently.

This year we were trying to eliminate the detachable end effectors so lost that whole passive language in the rules to hang the past FAQs about cars on.

I HATE using intent to decide these things because too often the people who were involved with writing the rules can't fully agree on the intent the day after the rules are finalized. I'll say that my sense of our collective intent was clearly not to allow something like a tethered car.

Hmm, perhaps we can look at the definition of an arm. Something to the effect of an arm is made of rigid elements connected by joints of some type. If I can find a source... That would take care of all the tethered ideas as a tether is certainly not rigid.

Problem is it would eliminate one type of robot that we didn't mean to, the tower crane concept. Not that I'm sure such a robot would be very successful...

So yeah, keep asking the question on the SOINC site and we'll eventually get a FAQ or Clarification out there.

OH, unless the robot started on the surface of the robot square, it wouldn't be part of the base and shouldn't stop time when it left the square.

Now, here's a coaching point. Yes understand the rules and don't handicap yourself by interpreting them over rigidly or adding what isn't there. Creativity is to be encouraged. However, be careful about pushing the bounds TOO aggressively, being second tiered will most certainly put you at the back of the pack. Until you have clear direction (or are sure it gives you an overwhelming advantage), I'd suggest a parallel strategy in your approach to this (or any) event. One which does not use the car (or any other questionable strategy) and one which clearly complies.

Jeff Anderson
Livonia, MI

A comment on Robocross and finishing faster for points. What you did was NOT a "Loophole". It was a strategy we explicitly considered when writing the rules. That's why you couldn't get the time points without scoring at least one item. And we considered the point value of the items vs the time carefully. We WANTED you to consider the time it took to score points with an object vs the points earned. Now I have to admit we didn't get the balance right, too much bonus for time, not enough points for objects. And many didn't like (or understand) the tradeoff being part of the event (so you won't see that scoring strategy again). But it was not a mistake or loophole.

[jander14indoor]

First, STILL UNOFFICIAL!

Well, finding a reference turned out pretty quick if I'm to believe the internet.

From Wikipedia:
A robotic arm is a type of mechanical arm, usually programmable, with similar functions to a human arm; the arm may be the sum total of the mechanism or may be part of a more complex robot. The links of such a manipulator are connected by joints allowing either rotational motion (such as in an articulated robot) or translational (linear) displacement.[1][2] The links of the manipulator can be considered to form a kinematic chain. The terminus of the kinematic chain of the manipulator is called the end effector and it is analogous to the human hand.

That alone seems to eliminate tethered cars, have to think about tethered passive end effectors, because while connected they probably meet the definition.

From another site (https://www.robots.com/faq/show/what-is-a-robot-arm):
What is a robot arm?
A robot arm is a programmable manipulator. The arm is comprised of segments connected by rotary and linear joints. These joints allow for controlled movements. Tasks that utilize robot arms depend on accuracy and repeatability. These applications typically require repetitive motions.

A little more ambiguous dictionary definition (http://www.collinsdictionary.com/dictio ... /robot-arm):
A robot arm is a type of robot consisting of parts linked together in the same way as those of a human arm, mounted on a stand.
But I think same result, no part of my arm is attached by a tether like feature.

Summary, unofficial, I don't think we'll need to use intent to rule that a tethered car is not allowed. We can rely on definition of Robot Arm.

Jeff Anderson
Livonia, MI

[Flavorflav]

Well, some of those definitions of "robot" would be problematic. Most of the arms we have seen are not programmable, which would make them not robots by the robot.com definition. Wiki's seems workable, though.

I would agree that the tower crane model is not really affected by this discussion. The crane itself is rigid and has at least one joint at the base (assuming it rotates) and so would seem to qualify as an arm. I don't see how it would cease to be an arm if it were to lower an effector on a tether. One of my students is pursuing a variant of this concept, and it honestly never occurred to me that it might be judged illegal. He is also one of the two students who is considering the car strategy as a backup plan.

[laidlawe18]

I know I'm a little late to the party on this discussion, but I have another scenario that I'm curious about.

I posted earlier about using a caster wheel on the end of the arm in order to take load off of the servos. It seemed like the consensus was that that would be okay, as long as the wheel didn't start touching the ground inside the device square. Now I'm curious what you think about a stiff tether connecting some kind of chassis to the device square, where the chassis has no way of moving without the tether moving it. In other words, say there's a telescoping arm, with a penny dispenser on the end that sits on some caster wheels. The only motion that the dispenser gets is from the arm telescoping and rotating at its base. This might not be very "arm"-like, but I don't think it violates any literal rules. It also seems much less likely to invoke a spirit of competition problem because it's still centrally powered and controlled from inside the device square.

[jander14indoor]

Still not official.

I'd think a telescoping element would easily meet the definitions of 'arm' mentioned previously. Rigid elements connected by in this case a translation(linear) joint. If the outer wheel only rolls free, no power, motion from the center joint and in/out through the telescope, I don't see a problem.

As usual, submit a FAQ for an official answer. And you'll probably see some weasel words to the effect that we'd have to inspect it personally at a tournament to be sure we understood what you were asking.

Jeff Anderson
Livonia, MI

[windu34]

Jander,
In regards to the intent of the rules as a whole, was the purpose to encourage autonomous arms? I have been working on upgrading my master slave system from the previous season and many of the new elements favor an autonomous system as opposed to last year when a master-slave system was favorable due to the " B' slot uncertainty