Team Update #18

[MagiChau]

West Michigan from what I know found no problem with Team Update 18. From what I remember all minibots that went up scored.

[Kpchem]

Update from Seattle Cascade:

Today there were no false positives in 64 matches on the Seattle Cascade field. If I remember correctly, there were two instances where a minibot successfully reached the top of the tower, but did not trigger the sensors. In both instances, the referees followed the latest Team Update and did not score it. Both of those minibots scored at other times throughout the regional.

[Grim Tuesday]

In my opinion, this is illegal per the rules mentioned above. The hostbot is providing a track that is pushing the minibot up vertically.

But the power is coming from the minibot. I therefore believe that it is legal. This would be an interesting topic in the "You make the call" section.

[Chris is me]

In my opinion, this is illegal per the rules mentioned above. The hostbot is providing a track that is pushing the minibot up vertically.

I've never thought of it that way, but I can't argue with that...

Sucks to be 190 and 233 I guess.

[Karthik]

I've never thought of it that way, but I can't argue with that...

Sucks to be 190 and 233 I guess.



Be careful to paint both teams with the same brush stroke. Mark made a specific description of 190's deployment which made Paul think it's illegal, namely the creation of potential energy by the downward movement along the track. From my understanding, Pink's ramp only goes upward, meaning the track (and thus the hostbot) would not be contributing any energy.

[Chris is me]

Be careful to paint both teams with the same brush stroke. Mark made a specific description of 190's deployment which made Paul think it's illegal, namely the creation of potential energy by the downward movement along the track. From my understanding, Pink's ramp only goes upward, meaning the track (and thus the hostbot) would not be contributing any energy.

Good point.

For what it's worth, 190's track begins horizontally like 233's track - the minibot is the sole source of energy.

One could make an argument that the robot converts the horizonal motion of the minibot into vertical motion, but that's a bit of a shaky justification.

[Chris Hibner]

An update from Detroit:

All of our minibot runs triggered the tower. Everyone that I saw triggered the tower except one:308's minibot failed to trigger once and it cost them the match. I'm not sure if it hit the bolts, but it hit the plate with more than adequate force. They have a very reliable minibot that triggered every other time they ran it.

I think I may have saw one false trigger, but I can't confirm.

[Chris Hibner]

Good point.

For what it's worth, 190's track begins horizontally like 233's track - the minibot is the sole source of energy.

One could make an argument that the robot converts the horizonal motion of the minibot into vertical motion, but that's a bit of a shaky justification.

I would say that if the track is horizontal and fully below the deployment line it is legal. However, if it starts above the deployment line, uses gravity to gain momentum, then deploys below the line, I would say it is illegal because it used potential energy to impart vertical motion.

[Ian Curtis]

Be careful to paint both teams with the same brush stroke. Mark made a specific description of 190's deployment which made Paul think it's illegal, namely the creation of potential energy by the downward movement along the track. From my understanding, Pink's ramp only goes upward, meaning the track (and thus the hostbot) would not be contributing any energy.

As a devil's advocate, I'm still not sure even that is legal. <G19> specifically says "...solely through electric energy provided after the start of DEPLOYMENT by the permitted..." As the 190 design has the robot accelerating through electrical energy prior to deployment (crossing the plane of the base) I could see the argument that they are storing "non-incidental" kinetic energy in their minibot. Probably the only way to get the real answer is the Q&A. Does 233 start their minibot within the base? I'm pretty sure 190's did not.

It wouldn't be an FRC game if 190 didn't do something that CD could argue the legality of for entirely too many posts!

[jspatz1]

But how much did your minibot weigh during this test, which found this diameter to be optimal?

In this case, 2 lb. 9 oz.

[boomergeek]

I would say that if the track is horizontal and fully below the deployment line it is legal. However, if it starts above the deployment line, uses gravity to gain momentum, then deploys below the line, I would say it is illegal because it used potential energy to impart vertical motion.

I see it slightly differently:
The track PRIOR to the DEPLOYMENT cylinder needs to be horizontal (or upward) and should not be longer than the length of the minibot (plus a grace distance of couple inches). Long horizontal tracks spanning the HOSTBOT would violate <G19>.

The shape of the ramp within the deployment cylinder can be any shape because the shape does not create additional energy.

If a team uses a ramp, the HOSTBOT must remain perfectly stationary while the MINIBOT is moving on the RAMP, otherwise it is not clear if the HOSTBOT is adding energy to the MINIBOT.

[jspatz1]

Seems to me that "...solely through electric energy provided after the start of DEPLOYMENT..." is pretty darn unequivical. No other form of propulsion energy can be used, even if it is the robot's own potential energy. Just because acceleration from gravity is free does not mean it is allowed. This would certainly qualify as energy other than electric energy, and if I understand the description, would also be partially gained before deployment (before crossing the cylinder of the platform.) This is one of those cases where you are just going to have to live with the "spirit of the rule."

[kstl99]

Anyone know of a video for the 190 or 233 deployment system in action?

[jspatz1]

The shape of the ramp within the deployment cylinder can be any shape because the shape does not create additional energy.

If the ramp shape causes a net elevation drop in the minibot before it reaches the pole, then additional energy other than "electrical energy from the motors" (in this case the minibot's own potential energy due to gravity) has indeed been imparted on the minibot.

[MrForbes]

I haven't heard of any problems at AZ. Our minibot did not trigger the second time we deployed...but we did find our charger, and we think it will make it further up the pole next time.

[boomergeek]

If the ramp shape causes a net elevation drop in the minibot before it reaches the pole, then additional energy other than "electrical energy from the motors" (in this case the minibot's own potential energy due to gravity) has indeed been imparted on the minibot.

...move up the POST solely through electric energy provided after the start of DEPLOYMENT by the permitted, unaltered battery and converted to mechanical energy by the permitted unaltered motors...

As long as gravitational potential lost plus gravitational potential gained is zero or negative below the deployment line- it provides NO ENERGY "to move up the POST". All energy is coming from the batteries/motors- but the allowed advantage for the rampbot is that its battery/motors energy expended as soon as it crosses into the deployment cylinder can be transferred through any shape ramp into vertical motion up the pole.

[R1ffSurf3r]

Does 233 start their minibot within the base?

yes

[jspatz1]

...move up the POST solely through electric energy provided after the start of DEPLOYMENT by the permitted, unaltered battery and converted to mechanical energy by the permitted unaltered motors...

As long as gravitational potential lost plus gravitational potential gained is zero or negative below the deployment line- it provides NO ENERGY "to move up the POST". All energy is coming from the batteries/motors- but the allowed advantage for the rampbot is that its battery/motors energy expended as soon as it crosses into the deployment cylinder can be transferred through any shape ramp into vertical motion up the pole.

I envisioned from some of the descriptions a ramp with a net downward slope that allowed the bot to gain momentum from elevation change. If instead you are saying that the minibot gains momentum between the deployment cylinder and the pole by simply using its own motors to get a "head start" and then the track directs this momentum upward, then I would say that is legal, and a clever idea.

[Al Skierkiewicz]

Peachtree update:
It looks like, for peachtree at least, all this worry was for naught.:)

Seems I have heard that somewhere before...

As for the 190 design, if the curved pipe does not contact the tower above the 18" mark there is no violation there. The minibot is using the electric energy stored in it's legal battery to drive so no violation there. The GDC has ruled that the motors on the minibot can be running prior to deployment so there is no violation there. However, G19 may apply if it can be proven that gravity is actually adding to the minibot's ability to climb the pole. I cannot see that a downward movement on a pipe adds anything to the upward motion of the minibot. What goes down does have to come back up afterall.
<G19> MINIBOTS must remain completely autonomous and move up the POST solely through electric energy provided after the start of DEPLOYMENT by the permitted, unaltered battery and converted to mechanical energy by the permitted unaltered motors (and associated, appropriate circuitry). Violation: The TOWER on which the MINIBOT is DEPLOYED is disabled. If the MINIBOT is DEPLOYED on something other than a TOWER, then the ALLIANCE’S TOWER upon which the highest RACE SCORE was earned will be discounted.

<G19> means that HOSTBOTS are not allowed to launch the MINIBOT up the pole at the TARGET, or otherwise contribute to the vertical movement of the MINIBOT. Energy for vertical movement may not be stored in the MINIBOT before DEPLOYMENT (except that which is contained within the battery and excluding incidental kinetic energy stored in the motors or wheels, but NOT, for example, in a flywheel).

[Ether]

I cannot see that a downward movement on a pipe adds anything to the upward motion of the minibot.

It could if implemented well.

If the minibot on the host is higher than the deployment line on the tower pole then in theory the difference in height is potential energy that gets converted into kinetic.

It all depends on whether the friction loss traveling the curve pipe is greater than the KE gain due to the added PE.

[boomergeek]

It could if implemented well.

If the minibot on the host is higher than the deployment line on the tower pole then in theory the difference in height is potential energy that gets converted into kinetic.

It all depends on whether the friction loss traveling the curve pipe is greater than the KE gain due to the added PE.




I think, in the context of the rule, it's irrelevant whether the the ramp on the hostbot starts above or below the deployment line. If the minbot loses gravitational potential on its run up to crossing into the cylinder of deployment, and the minibot design converts horizontal into vertical motion, then my read is it is in violation of <G19>.

I would imagine that most design have the ramp start BEHIND the deployment cylinder in order to get everything lined up prior to the 10 second mark: I think such designs would need to be completely horizontal or uphill prior to crossing into the cylinder in order to stay within the confines of <G19>

Are there any pictures or videos available of the various ramp bots?

[Ether]

I think, in the context of the rule, it's irrelevant whether the the ramp on the hostbot starts above or below the deployment line.

You misunderstood the point I was making, which was simply that if the minibot starts at a point on the hostbot above the height of the deployment line on the tower pole, then the conversion of this stored potential energy into kinetic during the downward movement on the hostbot track could in theory add to the upward motion of the minibot on the pole. I wasn't suggesting this was legal or suggesting it as a design strategy.

[Al Skierkiewicz]

OK Ether, you run the numbers and give us a report on how high that pipe inside the robot has to be before there is a payback for the added weight, length of travel and increase in speed that makes a difference in the time it takes to get to the top. Make sure you include data on how long it takes for the minibot to cross the plane of the tower base as it begins it's downward travel and how long it takes from that point to actually hitting the top.

[boomergeek]

You misunderstood the point I was making, which was simply that if the minibot starts at a point on the hostbot above the height of the deployment line on the tower pole, then the conversion of this stored potential energy into kinetic during the downward movement on the hostbot track could in theory add to the upward motion of the minibot on the pole. I wasn't suggesting this was legal or suggesting it as a design strategy.



My mistake, my apologies: I was assuming you wanted to focus on physics within the confines of the rules as opposed to broadening the scope of the discussion outside the game.

A legal ramp can work a bit like the blocks in a runners race, allowing the motors to get to the range of most work within the power curve, faster.
Does that speed to the best part of the motor curve exceed the extra work needed to cover a longer path? Probably too complicated to be discoverable by mathematical analysis of easily measured parameters.
Testing it directly would be the only realistic way to know.

Assuming a single speed transmission, I would guess that one can compute a drop angle and distance that optimized the time to the best part of the motor curve- at that point, I don't think there is an advantage of continued downward trajectory. In a sub 2 second race, getting to optimum portions of the motor curve faster (let's guess 1/10th of a second) might have measurable advantages at the finish line.

In such cases, front wheel drive can have a significant advantage!

[Ether]

OK guys, I'll give it one more shot. Al made the statement "I cannot see that a downward movement on a pipe adds anything to the upward motion of the minibot". I was simply stating that it can*. I don't know whether or not it's legal, and I don't think it's the best strategy to pursue (for a number of reasons).



* It's not about the robot. It's about science, technology, engineering, and mathematics.

[boomergeek]

For what it's worth, the slowed down version of our non-ramp minibot climbing a slightly shortened pole in about 1.5 seconds shows it accelerating significantly through at least the first second. I'd extrapolate that it is not reaching the "most work" portion of the motor curve within the first half second. (I.e., a significant portion of the race time).
Probably time to lessen the diameter of the wheels.

http://www.youtube.com/watch?v=KLZCNbcNopU

Sure wish we still had license access to Dartfish video analysis software...
(It's a physics rockstar)

[jspatz1]

OK guys, I'll give it one more shot. Al made the statement "I cannot see that a downward movement on a pipe adds anything to the upward motion of the minibot". I was simply stating that it can*. I don't know whether or not it's legal, and I don't think it's the best strategy to pursue (for a number of reasons).



* It's not about the robot. It's about science, technology, engineering, and mathematics.



Of course it can. Imagine a car with no motor gaining speed coasting down a steep hill. As it reaches the bottom, it begins a race with a car with a motor that was standing still, and they race up the next smaller hill. The car with no motor can win with initial velocity and energy gained from the first hill.

[Ether]

For physics and/or math students who may be interested, I just posted a short write-up showing how to setup and solve the differential equation for the MINIBOT accelerating from a dead stop up the pole. An analytical solution is given so you can just plug numbers in using a calculator (if you have the patience), or better yet a spreadsheet.

The model ignores friction, which may be a significant factor, but the physics (and math) is nonetheless interesting and useful for gaining insight and rough approximation.

http://www.chiefdelphi.com/media/papers/2470

[nikeairmancurry]

First instances of this came up... At West Michigan District, 67 clearly made it up the tower probably second of the four and didnt set of the light, and where not given any points... Didnt effect match results...

[Francis-134]

As a member of team 190, and having built the robot, the ramp does not go downward, but slopes upward. The motors turn on only after the 10 second mark. The entire system is below the deployment line.

[Matt Krass]

So, it seems like my hunch may have been wrong, it seems like the system is working much better now. I'm excited about this, but I'd still like more information. At the very least, it would be nice to know if all the discussion in this thread is valid, and I think it could be a great learning experience to show students how to design to a full specification. Plus, I personally think it's pretty impressive how two groups can collaborate with just specifications and at the end of the day their two separate solutions, developed in complete isolation, work together because they followed the agreed upon design specification.

Good luck teams, lets hope things continue to work well,
Matt

[Vikesrock]

I didn't get to watch a ton of matches at Peachtree this weekend, but every minibot I saw that looked like it should have triggered the pole did so.

[Navid Shafa]

Someone in another thread on Chief commented that the towers are now looking for a triggered sensor for a certain amount of time to be sure it wasn't just a jostle from a robot.

Whatever the circuitry I am 100% confident that there were multiple (greater than 10) instances at San Diego where minibots compressed the platform upwards into the sensors without the tower actually triggering.

We just had a match yesterday where we launched our slower mini-bot (1.7 seconds). It clearly hit the top, but it apparently didn't trigger...

It was frustrating for that match to swing that way, it makes me empathetic for all of the teams who have these kinds of rulings which are out of their hands.

[bduddy]

At St. Louis, one tower was hit twice with no response; they determined it was defective, switched it out, and fixed the previous scores. There were one or two other incidences of towers not registering hits, but they were borderline in terms of the amount of force applied. Overall the system seems to work OK.

[Lil' Lavery]

I didn't really watch many webcasting this weekend, but from the bit of Bayou I saw, the referees were still using their judgement to call the minibot races. There were many false positives, though I only recall one instance of a minibot not triggering at the top.

[JB987]

I didn't really watch many webcasting this weekend, but from the bit of Bayou I saw, the referees were still using their judgement to call the minibot races. There were many false positives, though I only recall one instance of a minibot not triggering at the top.

So...local refs under the direction of local head refs disregard the update and deal with the reality of imperfect triggers? Let's hear it for common sense!

[AdamHeard]

So...local refs under the direction of local head refs disregard the update and deal with the reality of imperfect triggers? Let's hear it for common sense!

I love it!

[MrForbes]

Why bother having rules?

[Michael Corsetto]

So...local refs under the direction of local head refs disregard the update and deal with the reality of imperfect triggers? Let's hear it for common sense!

Wish they followed this path at Sacramento, we clearly hit the top with 1868's minibot (1.2 second climb) in our last finals match and the tower didn't trigger. Didn't change the match results, but I'm trying to imagine the outrage when a tower doesn't trigger on Einstein...

[billbo911]

Wish they followed this path at Sacramento, we clearly hit the top with 1868's minibot (1.2 second climb) in our last finals match and the tower didn't trigger. Didn't change the match results, but I'm trying to imagine the outrage when a tower doesn't trigger on Einstein...

This is interesting as I never saw a single time at Sacramento where the towers missed a trigger. Now I must admit, I always focussed my attention on our minibot, so I might have missed yours. Ours is a bit of a tugboat, but it always triggers the tower, and even won several races.

By the way, you guys did a great job in Sacramento and deserved the win. Congratulations!

[Tristan Lall]

So, what's the objective of the minibot race, anyway? To trigger the tower first, or to reach the top first?*So...local refs under the direction of local head refs disregard the update and deal with the reality of imperfect triggers? Let's hear it for common sense!I know what the rules say, and that isn't it.

If the object of the race was to get there first, then sure, the referees would be totally right to award the race to the first minibot to arrive, irrespective of what the sensor did. But by defining the race in terms of the sensor, and then making an update to emphasize that point, FIRST has explicitly included the mechanical and electrical characteristics of the tower in the problem of winning the race.

Judging it based on sight—but only when the tower fails to trigger on what appeared to be a sufficient impact—fails to distinguish true negatives from false negatives. (Are the referees making the calls fully aware of the possibility and likelihood of a true negative?)

Incidentally, one could argue that the likelihood of a true negative is remote enough that they can all be disregarded—but I haven't seen that earnestly proposed, and frankly, if FIRST wanted that to be the case, they shouldn't have gone to all the effort to define the race in terms of the sensor. By taking pains to define it as they have, I think their thought process was that by removing human judgment from the outcome, they would have a lower rate of false outcomes than otherwise—but to achieve that accuracy, they had to make the sensor response a factor in the definition.

As for the "common sense" argument, I think our preconceptions about how a race is decided colour our opinions. It may well have been a better idea to conform to those expectations instead of crafting a rule that is slightly more complicated—but the rules are supposed to be the same for everyone, and by trying to correct this on a sporadic and unsystematic basis, I'm concerned that we're letting one element of equity infringe on another.

*Hints: <G67> and the definitions of trigger and minibot race. Why would they write that, but intend something else?

[Adam Freeman]

We have a decently fast minibot (~1.5 sec climb rate). It was 14/15 triggering the target at West Michigan. It triggered the sensors on all (4) towers throughout the weekend.

In SF1-1 we launched the minibot on the Red left side tower, it "won" the race but did not trigger the sensor. We were told that the ref saw that it hit first, but since we had won the match any way they were going to "trust the field".

I was not concerned about getting the actual score corrected, but more so about the next matches and how things would be scored if it didn't register again. We were told that the refs have the power to over rule the sensors if needed...but we were not specifically told that they would manually score our minibot if it didn't register again.

Our minibot never went up that tower again, but 2054's registered every time on that side.

This tower had the light knocked off it at one point on Friday and had not registered a couple other minibots at other times on Saturday.

We have a non-random pattern that our minibot is sufficiently designed to trigger the sensors. The field has a non-random pattern that their sensors are functioning correctly. There is some interaction between the tower and the minibot that in certain instances the variation in their performances line up to produce a false negative.

Is it FIRST, the team, or the refs responsibility to handle the < 5% chance that these variable line up and the sensors don't trigger?

We may attempt to make our minibot robust to this issue, but I am fine with leaving the instances where the match outcome would be effected in the hands of the refs...as long as the benefit of the doubt goes to the team.

[Mike Copioli]

An update from Detroit:

All of our minibot runs triggered the tower. Everyone that I saw triggered the tower except one:308's minibot failed to trigger once and it cost them the match. I'm not sure if it hit the bolts, but it hit the plate with more than adequate force. They have a very reliable minibot that triggered every other time they ran it.

I think I may have saw one false trigger, but I can't confirm.

Chris, I spoke with a team member of 308 after that match. He stated that the tower was disabled due to early deployment. Anyone from 308 can correct me on this if I am wrong.

Our towers triggered every time we successfully deployed at Detroit. Minibot ~2.5lbs or .025 Karthiks at ~ 1.2 - 1.6 seconds.

BTW it was great working with you Chris, I will save my additional comments for the detroit thread.

[jspatz1]

But by defining the race in terms of the sensor, and then making an update to emphasize that point, FIRST has explicitly included the mechanical and electrical characteristics of the tower in the problem of winning the race.

Many feel the problem is they did not also PROVIDE the mechanical and electrical characteristics of the tower. As far as I am aware the length of signal required to register with the FMS is still a mystery.

[MrForbes]

Is it FIRST, the team, or the refs responsibility to handle the < 5% chance that these variable line up and the sensors don't trigger?

We may attempt to make our minibot robust to this issue, but I am fine with leaving the instances where the match outcome would be effected in the hands of the refs...as long as the benefit of the doubt goes to the team.

Which team? the team that failed to TRIGGER the TARGET, or the teams on the opposing alliance?

Come on now....

[Adam Freeman]

Which team? the team that failed to TRIGGER the TARGET, or the teams on the opposing alliance?

Come on now....

I was referring to the team that failed to trigger the target.

I would not want to win a match, District Championship, State Championship, or World Championship because my opposition built a minibot that was faster than mine, beat it up the pole, hit the target with the specified FORCE, but the sensors did not TRIGGER the target.

Especially if their minibot has an approaching 100% success rate and the failed TRIGGER is the result of some interation of unknown variables.

Seems to me checking to see if minibots trigger the target could be part of inspections. If you get the ok at inspections, then it is assumed that the minibot is designed correctly.

The refs would have the ultimate power to either believe or over rule the sensors. If a sensor does not trigger, but the team has passed minibot inspection (including triggering), the refs can determine the winner and assign the points accordingly. If it is too close to call, then the match will be replayed due to a field fault.

Its already bad enough that we spent 6 weeks designing a HOSTBOT that can achieve all the tasks of this game at a very high level, only to have it marginalized by a minibot that every team can build in one day.

[MrForbes]

I would not want to win a match, District Championship, State Championship, or World Championship because my opposition built a minibot that was faster than mine, beat it up the pole, hit the target with the specified FORCE, but the sensors did not TRIGGER the target.


FIELD – .....

FRAME PERIMETER – ....


I don't see an official definition of FORCE in the rules.

I would be fine winning a match because my opposition built a minibot that beat ours up the pole, but failed to TRIGGER the TARGET, which is what the rules require it to do. The rules do not make any exceptions.

I guess the thing to do is ask the head ref at our next regional whether they will be calling minibot races based on the rules, or something else.

[Matt Krass]

I'm torn on this one.

On one hand, I believe the intent of the minibot race was to get their first (it's a race after all, it's displayed as such on the scoring metric) and I'm glad to see that refs stepped in when the technology couldn't.

But I'm also frustrated at the refs changing the rules again, while I don't agree with this team update, and I think it's a bad idea, if that's the rule, and that's what every team started working towards, it should be enforced as such. This particular dilemma is precisely why I thought it was a bad idea to throw all their weight behind the system like this, I don't think it's ready yet. Of course, we have no way of knowing if it's ready since we're still working on vague definitions of the 'black magic' actually required to trip the sensor. For all we know it's actually working 100% perfectly, but I suspect that isn't the case.

Matt

[MrForbes]

Of course, we have no way of knowing if it's ready since we're still working on vague definitions of the 'black magic' actually required to trip the sensor. For all we know it's actually working 100% perfectly, but I suspect that isn't the case.

I talked to someone who should know at AZ, and I get the feeling that it is working 100%.

I'm also eagerly awaiting a Q&A response....

[Lil' Lavery]

I don't see an official definition of FORCE in the rules.

I would be fine winning a match because my opposition built a minibot that beat ours up the pole, but failed to TRIGGER the TARGET, which is what the rules require it to do. The rules do not make any exceptions.

I guess the thing to do is ask the head ref at our next regional whether they will be calling minibot races based on the rules, or something else.

Okay, let's just bash at the base of the towers until it triggers. No need to actually race up the pole. So long as we're hitting the pole with our minibot, the minibot is pushing on the tower, which causes the tower to trigger, so it should count.

Fine with me.

I talked to someone who should know at AZ, and I get the feeling that it is working 100%.

I'm also eagerly awaiting a Q&A response....

I can guarantee you from watching the Bayou webcast, it is not working 100%. Not even close.

[Matt Krass]

I talked to someone who should know at AZ, and I get the feeling that it is working 100%.

I'm also eagerly awaiting a Q&A response....

I'm sorry but I don't get the feeling. I definitely think it's a lot better, it's certainly an improvement, but it's not ready for prime time yet in my opinion.

Matt

[Tristan Lall]

Okay, let's just bash at the base of the towers until it triggers. No need to actually race up the pole. So long as we're hitting the pole with our minibot, the minibot is pushing on the tower, which causes the tower to trigger, so it should count.The definition of triggered includes "the act of pushing the bottom disk of the TARGET" as a necessary condition. <G20-B> sees to it that only the minibot does the pushing.

[MrForbes]

I'd like to see a really fast minibot that reverses direction when it returns to the BASE, and goes back up again to make sure the TARGET is TRIGGERED.

:rolleyes:

[Tristan Lall]

I'd like to see a really fast minibot that reverses direction when it returns to the BASE, and goes back up again to make sure the TARGET is TRIGGERED.

:rolleyes:That would be neat: install some sort of ratcheting mechanism that is disengaged for the initial ascent. Once it hits the top, it switches output direction, and then winds up for a fixed number of revolutions of the wheels, and then switches direction again (so that it's headed for the top again). Repeat forever.

[MrForbes]

Its already bad enough that we spent 6 weeks designing a HOSTBOT that can achieve all the tasks of this game at a very high level, only to have it marginalized by a minibot that every team can build in one day.

I'd like to offer another perspective on this....

We have a mediocre HOSTBOT that designed and built itself, without any effort on our part. It can play at the 90th percentile at an "easy" regional.

A couple of times during our matches, our HOSTBOT had a GAME PIECE right there ready to HANG, but the darn PEG dodged out of the way, and the GAME PIECE fell to the floor.

I wonder if we should have received points in that situation?

[Matt Krass]

I'd like to offer another perspective on this....

We have a mediocre HOSTBOT that designed and built itself, without any effort on our part. It can play at the 90th percentile at an "easy" regional.

A couple of times during our matches, our HOSTBOT had a GAME PIECE right there ready to HANG, but the darn PEG dodged out of the way, and the GAME PIECE fell to the floor.

I wonder if we should have received points in that situation?

I think maybe FIRST is starting to make your brain go in to that oatmeal state.... :rolleyes:

Seriously though, I think Adam is right, regardless of how well the minibot sensors work, or not, they're a little overweighted in the competition. I've seen a single minibot beat an entire other alliance scoring for the whole game. Just the minibot score. It's kind of frustrating, but it's probably also a topic for another thread.

Matt

[AdamHeard]

I'd like to offer another perspective on this....

We have a mediocre HOSTBOT that designed and built itself, without any effort on our part. It can play at the 90th percentile at an "easy" regional.

A couple of times during our matches, our HOSTBOT had a GAME PIECE right there ready to HANG, but the darn PEG dodged out of the way, and the GAME PIECE fell to the floor.

I wonder if we should have received points in that situation?

This isn't even close to a fair comparison.

The pegs work, and they are purely mechanical; there is no mystery magic involved.

The towers currently "work", and during week 3 regionals there are some good points of evidence that show they aren't perfect.

[Daniel_LaFleur]

I think maybe FIRST is starting to make your brain go in to that oatmeal state.... :rolleyes:

Seriously though, I think Adam is right, regardless of how well the minibot sensors work, or not, they're a little overweighted in the competition. I've seen a single minibot beat an entire other alliance scoring for the whole game. Just the minibot score. It's kind of frustrating, but it's probably also a topic for another thread.

Matt

Analysis of the game scoring should have happened in week 1 of the build season (if not the 1st day).

... and if your alliance cannot score more than the points of 1 minibot then you'd best be able to stop your opponent from launching said minibot.

On topic: The rules state that it is the order of the sensors being triggered by minibots, not the order of minibots to the top of the pole. Lets focus on what triggers (or doesn't trigger) the sensors rather than blame the system when a minibot doesn't trigger the sensors. Does anyone have factual data on the triggering mechinism and its failure modes?

[TheOtherGuy]

It sure would be nice if we new all the specifics of the towers, but as it stands, there is a rule that says it is triggered when the sensor trips, and not before then. Sure, the towers may have some degree of unreliability, but if the rules are built that way (and this team update suggests FIRST is standing by their towers), then we all have to play the game they designed, whether we like it or not.

I remember a rule in 2008 that caused large amounts of penalties and was seemingly overdone, but it was a rule, and we all followed it.

[Matt Krass]

Analysis of the game scoring should have happened in week 1 of the build season (if not the 1st day).

... and if your alliance cannot score more than the points of 1 minibot then you'd best be able to stop your opponent from launching said minibot.

On topic: The rules state that it is the order of the sensors being triggered by minibots, not the order of minibots to the top of the pole. Lets focus on what triggers (or doesn't trigger) the sensors rather than blame the system when a minibot doesn't trigger the sensors. Does anyone have factual data on the triggering mechinism and its failure modes?

My gripe was with the distribution of the points, just because I'm voicing it now doesn't mean I didn't have a gripe with them in week 1 of build. I don't think it's a question of robot ability, I think it's a question of absurdity, one singular game action should not be able to offset the rest of the game so dramatically, to me that screams unbalanced.

It sure would be nice if we new all the specifics of the towers, but as it stands, there is a rule that says it is triggered when the sensor trips, and not before then. Sure, the towers may have some degree of unreliability, but if the rules are built that way (and this team update suggests FIRST is standing by their towers), then we all have to play the game they designed, whether we like it or not.

I remember a rule in 2008 that caused large amounts of penalties and was seemingly overdone, but it was a rule, and we all followed it.

I agree that the game should be played by the rules, even if I don't particularly like them. I think it's about time that FIRST gave us some concrete data to work with, if they're going to stand by the towers, we have a right to know what they're (the towers) expecting us to do exactly. I'm honestly getting a pretty sour impression from FIRST on this whole situation.

Matt

[Chris Hibner]

I'd like to offer another perspective on this....

We have a mediocre HOSTBOT that designed and built itself, without any effort on our part. It can play at the 90th percentile at an "easy" regional.

A couple of times during our matches, our HOSTBOT had a GAME PIECE right there ready to HANG, but the darn PEG dodged out of the way, and the GAME PIECE fell to the floor.

I wonder if we should have received points in that situation?

You wouldn't get any points, but I'm pretty sure the match would be replayed due to a field malfunction. In fact, that was one of Adam's suggestions.

[mwtidd]

My gripe was with the distribution of the points, just because I'm voicing it now doesn't mean I didn't have a gripe with them in week 1 of build. I don't think it's a question of robot ability, I think it's a question of absurdity, one singular game action should not be able to offset the rest of the game so dramatically, to me that screams unbalanced.

Matt

In qualifications this seems to be true, but as far as Einstein (and many of the finals) goes, the robots will be much more important than the minibots. Teams will need minibots, don't get me wrong, but I don't think they will take home many banners. Minibots are worth at most 50 points, which can be offset by 3 ubertubes and 2 logos. I believe that the game is offset during qualification matches, but creates an incredible dynamic in finals matches.

[AdamHeard]

In qualifications this seems to be true, but as far as Einstein (and many of the finals) goes, the robots will be much more important than the minibots. Teams will need minibots, don't get me wrong, but I don't think they will take home many banners. Minibots are worth at most 50 points, which can be offset by 3 ubertubes and 2 logos. I believe that the game is offset during qualification matches, but creates an incredible dynamic in finals matches.

The minibot score can't be offset at the high level of play, every competent alliance come champs will fill the top and middle rows along with some ubertubes. The sole decider in the win will be the minibots.

[mwtidd]

The minibot score can't be offset at the high level of play, every competent alliance come champs will fill the top and middle rows along with some ubertubes. The sole decider in the win will be the minibots.

I would pick 148 or 1114 with no minibot over the fastest minibot any day.

Both robots put up over an average of 33 pts per match (only robots, excluding minibots)

[AdamHeard]

I would pick 148 or 1114 with no minibot over the fastest minibot any day.

Both robots put up over an average of 33 pts per match (only robots, excluding minibots)

Come champs, every competent alliance in eliminations will be scoring the entire top and middle row. Elite teams, great teams, or even just good teams, it will happen.

[MagiChau]

I'd like to see a really fast minibot that reverses direction when it returns to the BASE, and goes back up again to make sure the TARGET is TRIGGERED.

:rolleyes:

74 already did that. They had a minibot score, then it went down to the base and back up to hit the trigger plate again.

[XaulZan11]

Both robots put up over an average of 33 pts per match (only robots, excluding minibots)

I'm not sure you can say that without watching all of their matches and figuring out how many points they scored on tubes each match and then averaging them. I'm all for using statistics, but they must be reported properly. I'm not sure ERC (or opr) supports that statement.

[mwtidd]

I'm not sure you can say that without watching all of their matches and figuring out how many points they scored on tubes each match and then averaging them. I'm all for using statistics, but they must be reported properly. I'm not sure ERC (or opr) supports that statement.

I think considering both had a double cap, and were both powerhouses on the rack, 33 points as a guesstimate is pretty fair. Also I think I am safe to say what separates 1114 from 148 is their minibot.

that being said I think you are right. I shouldn't have stated that they average that, I should have said that I estimate it. just so everyone know the E in ERC stands for estimated. Sometimes I forget to argue that these numbers are rough estimates. I chose 148 and 1114 specifically because of their reputation right now.

[The Lucas]

At Chesapeake, the only bot I saw touch the plate and not trigger the tower were slow minibots that either didn't exert the required force or ran out of time (I am not sure which was the case).

There was a case in QF 2-1 where our Minibot was the the first to reach the top but the lights on the tower turned off. The rest of the towers lit up with 4 lights, 3 and 2 when the next 3 minibots hit. We still got the 30 pts for first so I guess they looked at the triggers in FMS and the lights just malfunctioned.

[bduddy]

At Chesapeake, the only bot I saw touch the plate and not trigger the tower were slow minibots that either didn't exert the required force or ran out of time (I am not sure which was the case).

There was a case in QF 2-1 where our Minibot was the the first to reach the top but the lights on the tower turned off. The rest of the towers lit up with 4 lights, 3 and 2 when the next 3 minibots hit. We still got the 30 pts for first so I guess they looked at the triggers in FMS and the lights just malfunctioned.If the tower lights turned off (as opposed to continuing to cycle up and down), that means the tower was disabled. Apparently the referees later determined they were incorrect to do so.

EDIT: Or, there was a major malfunction of the tower.

[The Lucas]

If the tower lights turned off (as opposed to continuing to cycle up and down), that means the tower was disabled. Apparently the referees later determined they were incorrect to do so.

Thats what I thought initially but I was told that wasn't the case. I am really not sure.

[TheOtherTaylor]

This is interesting as I never saw a single time at Sacramento where the towers missed a trigger. Now I must admit, I always focussed my attention on our minibot, so I might have missed yours. Ours is a bit of a tugboat, but it always triggers the tower, and even won several races.

By the way, you guys did a great job in Sacramento and deserved the win. Congratulations!

I believe it was the very last elimination match when the minibot didn't trigger the tower. The thing is far too small to hit the bolts, and the switch on the top of the minibot that turns it off takes more force to depress than the limit switches on the tower. (Earlier in the day, we found out that if one of those minibots hit a tower with a hard stop instead of the cushion of the moving ones used in matches, the minibot will actually separate from the tower from the force of impact and go flying. I got a fun little cut on my finger from catching "Marvin" when he decided he wanted to try his hand at flying off the tower.)

Of all the matches that one of the 1868 minibots went up, that was the only time it didn't trigger a tower.

[Lil' Lavery]

The definition of triggered includes "the act of pushing the bottom disk of the TARGET" as a necessary condition. <G20-B> sees to it that only the minibot does the pushing.

Well, if we're getting to that level of lawyering the rules, there's no official definition for PUSH in the rules. There's clearly a force being applied to the bottom disk in order to TRIGGER the sensors on the TOWER. In 7th grade I learned that a force was a PUSH or a PULL. So, by that logic, shoving the bottom of the tower should count.

Or we can use commons sense... :rolleyes:

It sure would be nice if we new all the specifics of the towers, but as it stands, there is a rule that says it is triggered when the sensor trips, and not before then. Sure, the towers may have some degree of unreliability, but if the rules are built that way (and this team update suggests FIRST is standing by their towers), then we all have to play the game they designed, whether we like it or not.

I remember a rule in 2008 that caused large amounts of penalties and was seemingly overdone, but it was a rule, and we all followed it.

The difference in 2008 is that FIRST told us what the lines would be made out of, where they would be located, and how that rule would be officiated from week one. The lines never changed nor malfunctioned during the season. Any penalties incurred because of them was the result of the actions of the teams on the field, not because of mystery forces created by field elements that were never fully explained to teams.

I would pick 148 or 1114 with no minibot over the fastest minibot any day.

Both robots put up over an average of 33 pts per match (only robots, excluding minibots)

You're missing his point. BOTH alliances will have robots like 148 and 1114. While the points scored by 1114 could offset a minibot if the opponent isn't scoring tubes, it's not going to offset the scoring from 148 AND 148's minibot.

There's a definite potential for the tube scores for both alliances to be both incredibly high, and incredibly close. That's where minibots are going to decide matches. It's not going to be a case where those 50 points alone are going to overcome the opponents scoring, but those 25 extra points from getting 1st and 2nd in the minibot race would easily offset the 2 extra tubes the opponent scored more than your alliance did.

[Lil' Lavery]

Your interpretation of the bolts is correct, and that issue has already been brought up. But there are other instances that cannot be explained by hitting the bolts (as certain minibots designs cannot hit the bolts and there have been cases where these minibots didn't trigger the tower).

[Joe Ross]

There were not very many deployed minibots at Arizona. I saw two times the towers didn't trigger. In one case (forgot the team number) the minibot clearly hit the bolts and did not move the plate. In the second case, 842s minibot clearly moved the plate, but it's impossible to say if it moved it the full amount. It did not affect the match result.

[Josh Fox]

If a minibot does stick out far enough from the pole there is definitely potential for it to hit a bolt. That's definitely something teams should take into consideration as something to design around.

This is based on my personal observations of the field.

[Tristan Lall]

The definition of triggered includes "the act of pushing the bottom disk of the TARGET" as a necessary condition. <G20-B> sees to it that only the minibot does the pushing.Well, if we're getting to that level of lawyering the rules, there's no official definition for PUSH in the rules. There's clearly a force being applied to the bottom disk in order to TRIGGER the sensors on the TOWER. In 7th grade I learned that a force was a PUSH or a PULL. So, by that logic, shoving the bottom of the tower should count.In your scenario, bumping the base causes the pole to move, and as the structure sways, the target's guide bolts exert a force on the bottom plate of the target. When the pole springs back, the momentum of the bottom plate trips the sensors. So yes, something pushed on the bottom plate, and so the definition of triggered was satisfied.

But where's the minibot? Per <G67>, zero points are awarded, because it wasn't a minibot pushing on the bottom plate that triggered the tower.

Even worse, because something else triggered the tower, the minibot race is over on that tower (per the definition), and no minibots can score. (<G20-B> supports this interpretation.)

[MrForbes]

The Arizona regional used the same field as San Diego.

Chris told me it came from Duluth

:confused:

[Vikesrock]

Chris told me it came from Duluth

:confused:

That also matches the Truck Schedule posted in the Field Supervisor forum. The San Diego field is listed as going to Sacramento this past weekend.

[MrForbes]

Arizona was red

[Joe Ross]

Chris told me it came from Duluth

:confused:

I fixed my post. I knew we were playing with the San Diego field, but not until LA.

[TheOtherGuy]

So, according to team update 19 (http://usfirst.org/uploadedFiles/Robotics_Programs/FRC/Game_and_Season__Info/2011_Assets/Team_Updates/Team_Update_19.pdf), the electrical side of the towers *shouldn't* be an issue, since there is a dedicated module and any press longer than 1ms should trigger. I saw a post a while back mentioning 20ms sampling times, but a few samples at <=5ms should be a short enough time for faster minibots.

Are there any other possible explanations? Everything I've heard and seen about the towers says they should work flawlessly..

[Ether]

So, according to team update 19 (http://usfirst.org/uploadedFiles/Robotics_Programs/FRC/Game_and_Season__Info/2011_Assets/Team_Updates/Team_Update_19.pdf), the electrical side of the towers *shouldn't* be an issue, since there is a dedicated module and any press longer than 1ms should trigger.

The wording is ambiguous and leaves room for doubt. Maybe it means what you said, and maybe not. It doesn't say a signal longer than 1ms will TRIGGER the tower. It says "any input signal longer than the noise buffer is immediately time-stamped and reported back to the central field controller". OK, then what? The central field controller then "processes the received data". What does "processes" mean in this context? Does it require N consecutive positive readings before it TRIGGERS? If so, how many consecutive positive readings?

[TheOtherGuy]

The wording is ambiguous and leaves room for doubt. Maybe it means what you said, and maybe not. It doesn't say a signal longer than 1ms will TRIGGER the tower. It says "any input signal longer than the noise buffer is immediately time-stamped and reported back to the central field controller". OK, then what? The central field controller then "processes the received data". What does "processes" mean in this context? Does it require N consecutive positive readings before it TRIGGERS? If so, how many consecutive positive readings?


That's what I was getting at with the 5ms sampling period, although you're correct, the FMS could require more than 10 or so consecutive positive samples, which may be enough to prevent a fast minibot from activating the tower. A post in Q&A might be the fastest way for clarification on the number of required samples.

It seems like the easiest way to fix the issue though is to slow down your minibot. People are getting all riled up that FIRST didn't explain exactly how the towers work when their minibots are so fast that they look the same to the FMS as a robot bumping the base of the tower :) Some teams are too efficient...

[PayneTrain]

I wonder if FIRST had an oversight with this rule being so strictly enforced. While they are confident the hardware for the minibot towers are solid, the software's registration of the towers are under the swiss-cheese umbrella of the FMS.

I don't mean to take anything away from 75, 2988, or 3143, but in match 46 of the Virginia Regional, the apparent software issue decided the match. Not the hardware on the towers, or the minibots' interactions with the towers, but the towers didn't register anything.

Now, you may be saying, "How do you know that you didn't hit the bolts?" I think it's odd that two minibots didn't trigger in the match, and the head referee did as well, which is why the field was reset after our match. She explained this update that I know all too well, but that doesn't shake the fact that the only failure in the chain was the inconsistent FMS, which has kept me at the Virginia Regional until 8:30 on Saturday before.

TLDR: I understand the rule, but I feel there were some variables unaccounted for. It cost my team a match it shouldn't have lost.

[R1ffSurf3r]

first match of DC regional our minibot didn't register. they "proved" it wasn't the towers themselves by reseting them and shoving up the crew's hook to trigger it manually, with i'm sure plenty more than 5 newtons.

it didn't effect the match but reasserted my worries of more competitive matches at champs being decided by field errror

[PayneTrain]

See, I like to think that by being in 19th after 6 matches (even though with that win we would be 9th or 10th) we would make it into elims.

In 2009 our run ended when an opposing robot ran into the opposing alliances tower with so much force that it knocked out power and communication to the Driver Stations with 20 seconds left. If we had won that match, we would have gone onto finals and, by beating the 1 seed, have a good chance of winning.

The problem I had was that not only was the disconnection of the DS's self-inflicted, but there was no statistical way the other team could have caught up to us. Lunacy had a finite number of points to be scored, which meant that unless our alliance could rack up 40 points in penalties, we would have won.

I get being on the short end of "luck of the draw", and I have to put my faith in our tech every regional, but I get nervous when I have to put faith in the field holding up its end of the bargain.

[FRC4ME]

Just watched an alliance lose the semifinals due to a sensor failure at Virginia.

The frequency with which conditions other than team performance decide winners every year is understandably discouraging. There isn't a year without issues and I really wish FIRST could make the field more reliable. If that's not possible, they could at least give referees the power to override obvious failures, rather than insisting that there is no problem when there obviously is. The field failures are not unfair - they do not discriminate among teams - but they are discouraging to teams.

On a positive note, some parts of FMS seem to be improving. We did not have to replay a single match this year.