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The new FAQ unfortunately reaches much farther than permanent magnets. I use one gripper with a motor(that is wired to my base) to pick up one type of object and once all of that object is picked up, drop that gripper in the arm square and use a different one to score other objects. With the new faq, this strategy is for some reason illegal, even though my arm is not detaching from the base, and nothing resides in an area outside of the arm square.

JBoyd-NY wrote:I was proposing a hypothetical. If it's impossible to design a robot arm without having it attached to a base, then why do the rules refer to the base as optional?

There are several scenarios that came up at nationals last year in which the base was an unexpected "base" that was removable (specifically, a team essentially attached an arm to a roving bot, like a sumo bot, that only pivoted on top of a piece of sheetwood.)

JBoyd-NY wrote:And I disagree that calling Time before you have completed the tasks is not a penalty, especially if the items that are held by the part of the arm that is being detached are not counted - you lose those points and the chance to put any other items in the goal boxes, and I would certainly call that a penalty.

And I disagree that not awarding points is a penalty, it's just not receiving something (so, a net of 0.) A penalty is removing something (a net negative.) However, that is just semantics and is irrelevant.

wlsguy wrote:And.... to make things even more confusing....
just thinking....

What if my permanent magnets were tethered to the arm (not the base) around the shoulder joint by strings. I would call them little "arms" on my documentation to prevent them from being part of the base.

When I drop them they are:

A) still attached
B) allowed to touch both the surface of the field, the objects, and the containers.

I think this would be legal but would likely be declared in "violation of the Spirit of Competition".
But this would be incorrect because the whole idea of disallowing permanent magnets is wrong because "2.Unless otherwise stated, it is generally understood that if writing utensils, notes, resources, calculators, actions, etc., are not excluded, then they are permitted unless they violate the spirit of the problem". The problem in this case is to build a robot arm that moves objects into containers.

Now this is an extremely interesting idea and I suspect a FAQ would be posted on it if several people asked questions about it....

blazer wrote: The new FAQ unfortunately reaches much farther than permanent magnets. I use one gripper with a motor(that is wired to my base) to pick up one type of object and once all of that object is picked up, drop that gripper in the arm square and use a different one to score other objects. With the new faq, this strategy is for some reason illegal, even though my arm is not detaching from the base, and nothing resides in an area outside of the arm square.

But is it detached? If it is still tethered to the base, it might not be considered detached. NOTE: I do NOT know the answer to that question and this should be in no way considered an official clarification or even a hint at one. I am simply saying that this idea hasn't really been considered too much before (no one has asked about it...) and is something that will have to be discussed.


Fundamentally, I think the issue here is the definition of the tools/detachable objects/magnets/whatever you want to call them. Are the tools part of the base, arm(s) or control box? These are the only allowed components listed at the beginning of rule 3. If they are part of the "base" the the "permanently attached" phrase in rule 3 becomes highly relavent. If they are part of the "arm," rule 6.c.vii becomes relavent. If they are part of the "control box," then rule 6.c.vi will become critical (as well as the spirit of the problem.) I'm not saying the rules are perfect (they clearly are not and this will be addressed next year) but to me, the FAQ appears to follow the letter of the written rules very closely.

chalker7 wrote:Fundamentally, I think the issue here is the definition of the tools/detachable objects/magnets/whatever you want to call them. Are the tools part of the base, arm(s) or control box? These are the only allowed components listed at the beginning of rule 3. If they are part of the "base" the the "permanently attached" phrase in rule 3 becomes highly relavent. If they are part of the "arm," rule 6.c.vii becomes relavent. If they are part of the "control box," then rule 6.c.vi will become critical (as well as the spirit of the problem.) I'm not saying the rules are perfect (they clearly are not and this will be addressed next year) but to me, the FAQ appears to follow the letter of the written rules very closely.

So, another interesting question arises: If Blazer starts with his two grippers as part of his Base, then picks up the first one, grabs and deposits all the items he wants to with that one, places that gripper back in/on the Base and then picks up the second gripper, has he violated the "time stops when any part of the arm becomes detached"? If his grippers are designated in the documents as part of the Base, is he allowed to pick up parts of the base, use them, then put them back? In other words, if a part starts as a piece of the Base, does it become a part of the Arm if the Arm picks it up, or is it still a part of the Base and can therefore be placed back on the base without Time being called? (Technically, as long as the gripper is either on/in the base or attached to the arm, then it is permanently attached to the arm. When Blazer places the gripper back on the Base, he just has to make sure it is in contact with the Base before releasing it from the arm so that there is no time when the gripper is not attached to either the arm or the base.)

Just wanted to chime in on a couple things (which may or may not add fuel to this fire;)

Rule 6.c.iv. says time stops when any end effector is moved by anything besides stored energy in the device. When you drop a magnet or something else on the end of the arm, whether it is tethered by a string or not, it's going to be moved downwards by gravity, not energy stored in the device. (start arguments about crane designs in 3... 2... 1.....

In industrial robots with interchangeable end effectors, each end effector has a specially designed 'pocket' or 'holder' that it is placed in when not being used... they don't simply 'drop' them anywhere. My opinion is that placing an end effector back into a pocket or holder (that is part of the design of the device) means it is still 'attached' to the device.

Regarding FAQ's 'changing the rules' versus Clarifications, there isn't a clear cut division there. In general we issue clarifications only when we explicitly need to change specific words in the rules (either we need to remove some or add some). Clarifications are few and far between. FAQs are generally used to help explain the 'spirit of the problem' as we intended it or to provide more information than we could fit in the rules.

JBoyd-NY wrote: So, another interesting question arises: If Blazer starts with his two grippers as part of his Base, then picks up the first one, grabs and deposits all the items he wants to with that one, places that gripper back in/on the Base and then picks up the second gripper, has he violated the "time stops when any part of the arm becomes detached"? If his grippers are designated in the documents as part of the Base, is he allowed to pick up parts of the base, use them, then put them back? In other words, if a part starts as a piece of the Base, does it become a part of the Arm if the Arm picks it up, or is it still a part of the Base and can therefore be placed back on the base without Time being called? (Technically, as long as the gripper is either on/in the base or attached to the arm, then it is permanently attached to the arm. When Blazer places the gripper back on the Base, he just has to make sure it is in contact with the Base before releasing it from the arm so that there is no time when the gripper is not attached to either the arm or the base.)

That brings up another question. Rule 6.c.v. states that time stops when any part of the device touching the arm square leaves the square. Does that mean part of the base not in contact with the arm square can not only leave the square, but also touch the competition surface without time ending? Also, does it mean an arm could not start in contact with the square, because time would stop if it leaves the square?

EDIT- About chalker's pocket: could the pocket be in the arm square, as part of the base? Could the wire going from the pocket to the gripper touch the surface outside of the square without time stopping?

blazer wrote:That brings up another question. Rule 6.c.v. states that time stops when any part of the device touching the arm square leaves the square. Does that mean part of the base not in contact with the arm square can not only leave the square, but also touch the competition surface without time ending? Also, does it mean an arm could not start in contact with the square, because time would stop if it leaves the square?

The arm could not be considered the base so I don't think it matters if the arm is touching the arm square. I would think that something (not to include the arm) that was on an optional base, thus not touching the arm square would be able to touch the competition area. Let's just home I have all my screws tight so one does not pop out and cause the time to stop.

chalker wrote:Just wanted to chime in on a couple things (which may or may not add fuel to this fire;)

Rule 6.c.iv. says time stops when any end effector is moved by anything besides stored energy in the device. When you drop a magnet or something else on the end of the arm, whether it is tethered by a string or not, it's going to be moved downwards by gravity, not energy stored in the device. (start arguments about crane designs in 3... 2... 1.....

i'd just like to mention that the energy is stored in the device in the form of gravitational potential energy. gravity isn't increasing the overall energy of the arm at all, the potential energy from gravity is just being converted into kinetic energy. also the conversion of gravitational potential energy is going to occur whenever any point of the arm changes altitude at all. sooo if gravitational potential energy were against the rules to use, not a single robot would be able to score because they wouldn't be able to move downward

28 wrote:

chalker wrote:Just wanted to chime in on a couple things (which may or may not add fuel to this fire;)

Rule 6.c.iv. says time stops when any end effector is moved by anything besides stored energy in the device. When you drop a magnet or something else on the end of the arm, whether it is tethered by a string or not, it's going to be moved downwards by gravity, not energy stored in the device. (start arguments about crane designs in 3... 2... 1.....

i'd just like to mention that the energy is stored in the device in the form of gravitational potential energy. gravity isn't increasing the overall energy of the arm at all, the potential energy from gravity is just being converted into kinetic energy. also the conversion of gravitational potential energy is going to occur whenever any point of the arm changes altitude at all. sooo if gravitational potential energy were against the rules to use, not a single robot would be able to score because they wouldn't be able to move downward

I see what you're saying, but again it's the "spirit of the problem", gravity is not a power that is controlled by the arm
And most arms are not going to need gravity to move, the motors(at least if it uses servos) will move the arm both up and down, essentially they would work just fine in 0G

harryk wrote:

28 wrote:

chalker wrote:Just wanted to chime in on a couple things (which may or may not add fuel to this fire;)

Rule 6.c.iv. says time stops when any end effector is moved by anything besides stored energy in the device. When you drop a magnet or something else on the end of the arm, whether it is tethered by a string or not, it's going to be moved downwards by gravity, not energy stored in the device. (start arguments about crane designs in 3... 2... 1.....

i'd just like to mention that the energy is stored in the device in the form of gravitational potential energy. gravity isn't increasing the overall energy of the arm at all, the potential energy from gravity is just being converted into kinetic energy. also the conversion of gravitational potential energy is going to occur whenever any point of the arm changes altitude at all. sooo if gravitational potential energy were against the rules to use, not a single robot would be able to score because they wouldn't be able to move downward

I see what you're saying, but again it's the "spirit of the problem", gravity is not a power that is controlled by the arm
And most arms are not going to need gravity to move, the motors(at least if it uses servos) will move the arm both up and down, essentially they would work just fine in 0G

Yes
but, gravity is "activated" and deactivated by the arm (it picks something up and lets it go to "activate" gravity)
Without this definition NOTHING could be picked up because if you didn't set everything down completely and let any item drop, it was acted on by an outside force and would not be permitted.

In any case, the rules state "competitiors" may not input energy. Gravity is not the same as "competitiors".

I think this is a good discussion for changes and clarifications to next year's rules.

What's really happening is the motors in the arm are controlling the flow of energy. When the motors are moving up, they are converting the electrical energy that is put into them into gravitational potential energy. When the arm is being moved downward, the motors are just controlling the transfer of gravitational potential energy into kinetic energy- making the arm move slower than gravity would move it.

so if the arm picks up an object and lifts it up, it is using its electrical energy to increase the gravitational potential energy. dropping the object would only be releasing the energy that originated from the power source of the robot. 3.c states that "competitors must not impart energy directly into the arms (ie all end effector movements must be powered by stored energy in the device components)" they do not say what form the energy has to be in, ie chemical or elastic