Chief Delphi

Chief Delphi (http://www.chiefdelphi.com/forums/index.php)
-   General Forum (http://www.chiefdelphi.com/forums/forumdisplay.php?f=16)
-   -   Intentionally blocking traffic in Hybrid (http://www.chiefdelphi.com/forums/showthread.php?t=65301)

hipsterjr 01-03-2008 23:26

Re: Impeding in Hybrid
 
Quote:

Originally Posted by TubaMorg (Post 710729)
There's no crying in robotics!

yes, but there is strenuous, drawn out debates between uncompromising professionals. A.K.A: nerd fight:p

Zyik 01-03-2008 23:29

Re: Impeding in Hybrid
 
What if a team is just beginning to develop their autonomous? If they had something that told the robot to go forwards x amount of feet to cross the first line, but somehow came out as x amount of inches, it might be seen as a "defensive autonomous" when it wasn't. If a robot hit them the first time they tested this and they didn't know it did this, should they be given a yellow card?

If they were, that would really discourage teams from attempting to write and autonomous mode in the middle of a regional. Writing code halfway through Friday is a time honored tradition, and I'd hate to see it go away. :rolleyes:

The point being, until you see the team do this multiple times in a row, don't assume anything.

jgannon 01-03-2008 23:30

Re: Impeding in Hybrid
 
It sounds like there may be some confusion about what actually constitutes an impeding penalty. Please, before complaining any more about this, reread <G40>, and then review a few videos on TBA.

Cory 01-03-2008 23:43

Re: Impeding in Hybrid
 
Quote:

Originally Posted by jgannon (Post 710760)
It sounds like there may be some confusion about what actually constitutes an impeding penalty. Please, before complaining any more about this, reread <G40>, and then review a few videos on TBA.

Actually, I think if you revisit the Q&A answer provided on the second page, you'll see the GDC makes no mention of "IMPEDING" as defined in the rulebook.

They simple say strategies designed to block traffic will not be permitted. In my opinion, this has no relevance whatsoever to <G40> furthermore <G40> applies only to teleoperated mode, not hybrid.

They do specifically mention that "The purpose of these modifications is not to permit the intentional blocking of the Track during Hybrid Period.", after saying that <G40> does not apply.

Jack Jones 02-03-2008 00:55

Re: Impeding in Hybrid
 
Quote:

Originally Posted by Zyik (Post 710759)
What if a team is just beginning to develop their autonomous? If they had something that told the robot to go forwards x amount of feet to cross the first line, but somehow came out as x amount of inches, it might be seen as a "defensive autonomous" when it wasn't. If a robot hit them the first time they tested this and they didn't know it did this, should they be given a yellow card?

...

YES! FIRST has been raising the bar and aiming high for some time now. A failure to prepare should have consequences.

Qbranch 02-03-2008 01:33

Re: Impeding in Hybrid
 
I don't think there will be any rule change about the blocking in autonomous. It's kind of obvious when people are doing it on purpose and when they arent, but I just don't think there will be any kind of rule against this.

However, to deal with blocking robots, 1024 is possibly going to hand shifter control over to RALFF (our autonomous driver). In this case, if an obstruction is detected by the forward ultrasonic sensor array, our robot would gently (2 ft/sec) approach a robot which 'accidentally' got in the way, shift in to low gear, and push whatever is in the way out of the way with our 299lb pushing force (sustainable about 5 seconds at this 299lb level).

As usual, as soon as the traffic is cleared, the robot will continue on it's usual course. If for some reason the robot does not slide away from the front of our robot, ours would continue to push the robot at the 2ft/sec speed until the end of the hybrid period.

The thought of doing something like that never occurred even as a thought to our programming team until a certain 'explosive' robot continually blocked our autonomous. Don't take that as me complaining, I understand there is no rule that says you can't, and opposing robots have the same right to win as their opposition does.

See you all at Boilermaker!

-q

EDIT: While the drivetrain can produce 299lbf, I'm not 100% sure what exactly the tires can put to the floor. This has never been tested. Nope, we don't have any supersticky materials or anything.

Matt H. 02-03-2008 01:41

Re: Impeding in Hybrid
 
I am of the firm belief that if impeding is allowed then high speed (autonomous) ramming should also be allowed. The IR is simply to flakey to ensure consistent commands and it would take an amazing team to program a robot which reliably avoids other robots. If impeding is allowed and ramming is not allowed autonomous will be limited to two line crosses and one trackball down for fear of penalties. The two rules go hand in hand--either both should be allowed or neither should be allowed.

Cory 02-03-2008 01:48

Re: Impeding in Hybrid
 
Quote:

Originally Posted by Qbranch (Post 710838)
n this case, if an obstruction is detected by the forward ultrasonic sensor array, our robot would gently (2 ft/sec) approach a robot which 'accidentally' got in the way, shift in to low gear, and push whatever is in the way out of the way with our 299lb pushing force (sustainable about 5 seconds at this 299lb level).

299 lbs?? :ahh: that'd be a coefficient of friction of 2.006 (which certainly is not possible) assuming a maximum weight of 120 lbs plus 14 for the battery, plus 15 for the bumpers.

Qbranch 02-03-2008 01:48

Re: Impeding in Hybrid
 
Quote:

Originally Posted by Matt H. (Post 710843)
I am of the firm belief that if impeding is allowed then high speed (autonomous) ramming should also be allowed. The IR is simply to flakey to ensure consistent commands and it would take an amazing team to program a robot which reliably avoids other robots. If impeding is allowed and ramming is not allowed autonomous will be limited to two line crosses and one trackball down for fear of penalties. The two rules go hand in hand--either both should be allowed or neither should be allowed.

Perhaps instead a required distance of movement in autonomous? Maybe something like "robot must be touching rear wall or must move outside of it's alliance's homestretch starting box (make a tape line box going from the end of the lane divider to the wall of the field)"

Really, even though it doesn't make me happy when i see our robot defensive autonomoused (it's so much fun to watch when it isn't!) by the way the rules lie right now, it can happen. So, instead of begging for a rule change, we'll hope for one, but as with most things in engineering, there's almost always another way to solve a problem. (i.e. what I mentioned above).

-q

Matt H. 02-03-2008 01:58

Re: Impeding in Hybrid
 
I like your above solution to the problem and as we have a spare ultrasonic it might be worth a try.

A note to the person who said such a pushing force was impossible I don't believe that it is. http://www.engineershandbook.com/Tab...efficients.htm
lists the coefficient of friction of rubber on solids as being 1-4. That is for a smooth rubber strip on a smooth solid. A coefficient of friction of 2 on carpet is highly possible.

Vikesrock 02-03-2008 02:03

Re: Impeding in Hybrid
 
Quote:

Originally Posted by Matt H. (Post 710851)
I like your above solution to the problem and as we have a spare ultrasonic it might be worth a try.

A note to the person who said such a pushing force was impossible I don't believe that it is. http://www.engineershandbook.com/Tab...efficients.htm
lists the coefficient of friction of rubber on solids as being 1-4. That is for a smooth rubber strip on a smooth solid. A coefficient of friction of 2 on carpet is highly possible.

They are using 2 pairs of IFI traction tread (I would guess the wheels as well but we all know what happens with assumptions) and Andymark omnis (1 pair offset per side) in the front. The CoF of these wheels has been measured on carpet of the type used in FRC competitions and it is much closer to 1 than 2

Travis Hoffman 02-03-2008 02:03

Re: Impeding in Hybrid
 
Quote:

Originally Posted by AdamHeard (Post 710433)
Okay, based on update 2 and 5, I see that no mention of impeding exists in hybrid mode.

Still, I don't like that high speed ramming is called, when it is clearly an unintentional act, and impeding is. Also, I will be very upset to see any team get called for ramming in hybrid after they hit a robot that drove 3 feet to impede traffic in hybrid (that would not be illegal, as the 3 foot drive is attempting to get hit, and you can't draw penalties). It's a shady strategy overall.

I understand it is legal per the rules now, I'm just venting.

Vent away, sir. I can understand your contention about waiving high speed ramming for hitting those who obviously intend to get hit. Waiving it for ramming/tipping robots numerous line crossings down your path that are stopped on the field because their auton is over, or they just happen to be jammed into a wall, or they never moved in the first place, is another story, IMHO.

Attaching the negatively-connotated words "shady" and "blatant" to any hybrid blocking strategy is going a bit far.

NO alliance is OBLIGATED to give ANY team a huge advantage in hybrid just because their robot is "cool" and can cross 48,000 lines in auton.

Blocking in hybrid is a smart, effective, legal (??....sigh), and SIMPLE strategy. I do believe you should only employ one bot for this effort (1504 did it expertly), as blocking the entire lane seems to bring the bump to pass rule into question. If there's a lane for the oncoming robots to move around the blocking robot, they have no beef.

There is nothing wrong with simple - I feel people tend to glorify the complex and put it up on a pedestal a bit too emphatically sometimes, at the expense of the more "boring" strategies. There is a place for both in FIRST.

And if the uber-hybrid bots don't like being blocked, they are welcome to use their programming expertise to add some collision avoidance code and move around the obstacle. Use it as an opportunity to "wow" people even more with your adept engineering skillz.

Qbranch and 1024 already outlined a constructive way to respond to this new challenge with additional strategic programming. I see this as yet another instance of "raising the bar". Quite literally getting a "free pass" does not accomplish this objective nearly as effectively.

DARPA Grand Challenge planners don't dilute the accomplishments of event participants by telling big rocks and obstacles to get out of the way of an oncoming autonomous vehicle (there's a funny thought). It's fairly safe to say we are amazed at the way that event "raises the bar" - why can FIRST not employ and permit similar tactics in their challenge design - the addition of defense simply adds "unexpected" disturbances for which robots must compensate.

Matt H. 02-03-2008 02:06

Re: Impeding in Hybrid
 
Ah I made the mistake of not actually viewing their robot before posting. As IFI wheels have a coefficient of friction of 1.2-1.3 their pushing power may be lower than the posted figure. However teams have also designed their robots in creative ways such that when pushed from the front a fraction of the force is transmitted to their rear wheels placing much more weight on them and allowing for stronger pushing. (6 wheel drive with lowered centered wheel can achieve this effect).

Matt H. 02-03-2008 02:09

Re: Impeding in Hybrid
 
Travis I would agree with most of what you are saying however the issue becomes more prominent when the team with the autonomous is penalized for "ramming" a blocking opponent as has happened already. I will stand by my earlier statement that if impeding is allowed then ramming must also be allowed. If a bot chooses to block then it is knowing putting itself into harms way.

Daniel Bathgate 02-03-2008 02:15

Re: Impeding in Hybrid
 
Quote:

Originally Posted by Zyik (Post 710759)
What if a team is just beginning to develop their autonomous? If they had something that told the robot to go forwards x amount of feet to cross the first line, but somehow came out as x amount of inches, it might be seen as a "defensive autonomous" when it wasn't. If a robot hit them the first time they tested this and they didn't know it did this, should they be given a yellow card?

If they were, that would really discourage teams from attempting to write and autonomous mode in the middle of a regional. Writing code halfway through Friday is a time honored tradition, and I'd hate to see it go away. :rolleyes:

The point being, until you see the team do this multiple times in a row, don't assume anything.

Good point. Last year, our Friday written rookie autonomous was supposed to drive to the center of the field and stop to prepare for playing defense. The first time we ran it, our robot drove clear across the field and rammed an opposing robot because I guessed a time wrong. Getting a yellow card wouldn't have made me very happy.

Quote:

Originally Posted by Jack Jones (Post 710822)
YES! FIRST has been raising the bar and aiming high for some time now. A failure to prepare should have consequences.

No! Why would you want to discourage rookies that had a hard enough time getting a working robot in the crate on time (and everyone else, for that matter) from trying something simple but effective? The line violations in autonomous are discouragement enough from trying as it is. Wouldn't you prefer your alliance partners go for those 4 points?

and...
Quote:

Originally Posted by Drwurm (Post 710718)
As soon as the robot makes a turn, your IR board becomes somewhat useless.

Not if you have an omni drive like us! :D


All times are GMT -5. The time now is 15:49.

Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi