Robot Arm C

[harryk]

What is your definition of "used"? like if the shoulder joint of the arm didn't move then the point wouldn't be scored? I know this isn't the place for official clarifications blah blah blah

I think it means that the end effector used to hold the ping pong ball that you are lifting must have been used previously to move another item to score points

[Jdogg]

What is your definition of "used"? like if the shoulder joint of the arm didn't move then the point wouldn't be scored? I know this isn't the place for official clarifications blah blah blah

I think it means that the end effector used to hold the ping pong ball that you are lifting must have been used previously to move another item to score points

I disagree.. i believe that it is a combination of everything that is used to raise the pingpong ball. So for a traditional arm the shoulder and the elbow joints. Plus the end effector because it's holding the pingpong ball. Technically the end effector wouldn't do the lifting though, it would only hold it. This does get rid of almost anything, but having a arm that long and extends.

[jander14indoor]

This is where I suspect the bulk of the clarifications and creative thinking to be for the bonus.

I can think of a lot of possible answers, but I'm not sure I can define it any better than in the rules.

I'll say that I don't think the lift mechanism equals the arm and end effector. But it certainly has to incorporate some part of those things to score the bonus.

The devil IS going to be in the details on this.

Jeff Anderson
Livonia, MI

[chalker]

I disagree.. i believe that it is a combination of everything that is used to raise the pingpong ball. So for a traditional arm the shoulder and the elbow joints. Plus the end effector because it's holding the pingpong ball. Technically the end effector wouldn't do the lifting though, it would only hold it. This does get rid of almost anything, but having a arm that long and extends.

The intent of that rule was to ensure people don't essentially design 2 independent systems optimized for their specific tasks (one to move the objects into the goals, and one to lift a ball as high as possible). We want you to have a more generalized solution, without being too limiting. Hopefully the wording we chose accurately reflects that intent and will be appropriately interpreted by competitors and judges alike.

[Jdogg]

I disagree.. i believe that it is a combination of everything that is used to raise the pingpong ball. So for a traditional arm the shoulder and the elbow joints. Plus the end effector because it's holding the pingpong ball. Technically the end effector wouldn't do the lifting though, it would only hold it. This does get rid of almost anything, but having a arm that long and extends.

The intent of that rule was to ensure people don't essentially design 2 independent systems optimized for their specific tasks (one to move the objects into the goals, and one to lift a ball as high as possible). We want you to have a more generalized solution, without being too limiting. Hopefully the wording we chose accurately reflects that intent and will be appropriately interpreted by competitors and judges alike.

I agree with that, i believe that clarifies things a lot. But say you had two devices that although one is specialized to do the lifting task but still was used to do some of the tasks and one did a majority of the moving objects into goals. Like having a large robot arm that can maybe get 2 or more meters when fully extended and the other might only get 1 meter when fully extended upward. I feel like if that other "arm" scored at least one point, the end effector and the joints both were "used" to score at least 1 point then it would be deemed legal. Right? I feel like the intended purpose of the rules was to make sure everything on the arm that is "used" for the height task has to have been "used" to score at least 1 point. So the joints and end effector that is used to hold the pingpong ball has to have previously been used to score a point. Because looking at the way the rules are written now, only the joints of the arm technically have to have been used to score a point. Because the end effector actually does none of the "lifting" of the ping pong ball, it only holds it. I feel like a good way to fix the problem would to say that the motors (actuators, blah blah blah) used to raise the pingpong ball or hold the ping pong ball must have been necessary in the scoring of at least 1 point. Such that if that motor was not there and was not used (raising or lowing the arm at the shoulder) the point would have never been scored. But this is just my opinion... Do you think that this is good interpretation Chalker? knowing that this is not the place for official rule clarifications blah blah blah

[jander14indoor]

OK, this is why we give that warning about clarifications. You've asked a specific example and done it in such a way that it implies a larger ruling.

We don't want to mislead folks by answering too directly. Unless its something blatant, like no, golf balls may not be substituted for ping pong balls.

You can certainly have multiple arms (specifically covered by the rules, so kind of like that golf ball vs ping pong ball example) and they could be specialized. But that's not to say there isn't another very different approach.

Example, you are focusing on an arm with elbow like joints. But I've seen a few very good towercrane solutions to this event. Nothing wrong with those either.

I can think of another approach where the ball was placed on a platform by the arm (that had previously scored a point). The arm might then extend that platform higher, but not ultimately support the ball at the end. I'd see no problem with that. The 'arm' raised the ball as required, but in the end did not support the ball at height (not stated as required, so it should be legal).

Also, the rules say 'part' of the arm, so that implies not all of the arm. Not the 'everything' in your statement.

So, your proposed solution looks OK, but the restrictions you try to add to the rules seem a little over reaching.

Oh, and be VERY careful with 'intended purpose' of the rules. That messes up folks (including ourselves) every year. Yes we had an 'intent' when we wrote the rules. But its not always clear the rules writers all have the SAME 'intent'. Ultimately the bare words in the books are the rules, NOT our intent.

Jeff Anderson
Livonia, MI

[Jdogg]

OK, this is why we give that warning about clarifications. You've asked a specific example and done it in such a way that it implies a larger ruling.

We don't want to mislead folks by answering too directly. Unless its something blatant, like no, golf balls may not be substituted for ping pong balls.

You can certainly have multiple arms (specifically covered by the rules, so kind of like that golf ball vs ping pong ball example) and they could be specialized. But that's not to say there isn't another very different approach.

Example, you are focusing on an arm with elbow like joints. But I've seen a few very good towercrane solutions to this event. Nothing wrong with those either.

I can think of another approach where the ball was placed on a platform by the arm (that had previously scored a point). The arm might then extend that platform higher, but not ultimately support the ball at the end. I'd see no problem with that. The 'arm' raised the ball as required, but in the end did not support the ball at height (not stated as required, so it should be legal).

Also, the rules say 'part' of the arm, so that implies not all of the arm. Not the 'everything' in your statement.

So, your proposed solution looks OK, but the restrictions you try to add to the rules seem a little over reaching.

Oh, and be VERY careful with 'intended purpose' of the rules. That messes up folks (including ourselves) every year. Yes we had an 'intent' when we wrote the rules. But its not always clear the rules writers all have the SAME 'intent'. Ultimately the bare words in the books are the rules, NOT our intent.

Jeff Anderson
Livonia, MI

I gotcha. Though i think your example would still fall under the statement that i suggest above. I personally just feel that by using things like motors as identifies it is easier to distinguish weither a device is legal and the raising of the ping pong should count for a point or weither it shouldn't. so i get what your trying to say.. I don't want to limit other peoples ideas. I love showing up to competitions and seeing designs where i'm just flabbergasted in all the engineering that goes into it. I just would like to get a more clear explanation of what "used" is.

[iwonder]

I think that 'used' would simply mean that if you remove the piece from the arm, the arm could not perform the task.

[chalker]

The intent of that rule was to ensure people don't essentially design 2 independent systems optimized for their specific tasks (one to move the objects into the goals, and one to lift a ball as high as possible). We want you to have a more generalized solution, without being too limiting. Hopefully the wording we chose accurately reflects that intent and will be appropriately interpreted by competitors and judges alike.

Jeff pointed out to me privately that my phrasing of the intent wasn't very good. He suggested the following, which is much more concise:

"My intent was simply to make it hard to raise the ball high as the device had to have SOME other ability."

Of course the standard caveats apply about this not being the official place for clarifications, etc, etc. And as Jeff indicated above we are trying to avoid giving your 'rulings' on specific examples. Rather, we are trying to give you some general guidance as to what we are thinking about, since we'll be some of just a handful of people drafting any responses to FAQs you officially submit.

[chalker7]

I just would like to get a more clear explanation of what "used" is.

You won't get that answer through these forums. Submit an official clarification when the system goes live for this year (which should be relatively soon.)