Chief Delphi - Best defensive strategies

Quote:

Originally Posted by O'Sancheski (Post 1087761)

This is a debatable statement. Not all defense is stopping the opponent from scoring. Defense can be stopping the opposing alliance from scoring, but it also can be getting in the way and making it harder for them to score. If you can't block the opposing robot from scoring, at least make it earn the points that it is about to attempt. Ive seen even the best drive teams stumble when their strategy of easy scoring didn't work. This topic was brought up in the thread where it talked about mecanum wheels and defense. http://www.chiefdelphi.com/forums/showthread.php?t=91401&page=4&highlight=mecanum+wh eels+defense

Getting in the way and making it harder to score IS stopping the opponent from scoring. By doing this they score less then they otherwise would. This type of defense would fall under the "During" which I have requoted and bolded for your convinence below.

Quote:

Originally Posted by BJC (Post 1087751)

Playing Defense is the act of preventing the other team from scoring.

As such it can be used before, during, and even after the scoring process of the opponent.

Before: Tube starving this year. Taking a tube the other team was trying to pick up. Pushing tubes into the lane so the opponents can't get to them. ect.

During: Activly attempting to stop them from actually scoring points. T-boning, zone defense, ramming ect all fall under this. This is probably what most people think of as defense.

After: generally descoring, or the act of taking their points away. FIRST has been trying to get rid of this type of defense in recent games. Often times it is illegal to descore. However, it is arguably the most effective method of defense because it (usually) involves the most reward for the least work. Example: this year knocking off a logo piece on the top row at the end of the game would have been more effective then playing robot on robot defense the entire match. (of course that's why it was illegal.)

When considering defense one must look at the "net value" of the defense. Basically, this amounts to if your robot can more positively impact the score by stopping the opponent from scoring rather then by scoring themselves.

Ex: Red scored 20 and Blue scored 17 with all robots attemping to score. In the next match Blue places its weakest robot which only contributed 2 points in the previous match on Red's strongest scorer which scored 10 of the points in the previous match. In this match all of the other robots contributed similarly except the weakest Blue robot which scored no points (-2 because it did not score the two points it normally does) However, the strong Red robot was only able to score 4 points as a result of Blue's defense (+6 for the Blue alliance because Red scored 6 points less then it otherwise would have been able to.) This resulted in a match 20-6=14 to 17-2=15 Now the Blue team wins as a result of smart defense.

I hope this kind of shows how defense can be a smart play. A very important note with defense is that when your alliance is deciding how to play you must make sure you maintain your offensive power. Basically in order to make defense effective, your alliance still must put up points. On the same note, if the defense being played is ineffective, then you are putting your self in a loosing situation.

Ex: Using the same example above, if the weaker Blue robot can only hold the strong Red robot to scoring 8 points instead of ten (+2 for Blue's defense and -2 for lack of offense) there is a net gain of 0 points and the defense was unwarrented. Using a different deffensive method, the weak blue robot now pushes all tubes on the opponents side of the field into the lanes. This affects all three of the opponent's robots negitively. Lets say strong Red was fast and still able to put up 8/10 points. However, the other two Red robots were less able to cope and put up only a combined 6/10. This results in Blue's -2 for lack of offense. However, Red scored only 8+6=12 out of 20. 6 less then they normally would (+6 for Blue). Now the score is 20-6=14 to 17-2=15 again a win for Blue using smart Defense.

In conclusion, Defense (and Offense) are all about maximizing your "net score." Because of this, finding effective ways to defend using minimal effort while still recieving results is key to success in any FRC match.

This is a really interesting topic, defense is definatly more then just hitting people.
Regards, Bryan

Edit: 469's 2010 robot played "Before" defense. preventing the opponents from being able to aquire game objects in order to score them. However, they were able to do this while also scoring at the same time. Because of this their "net score" was doubly effected. Not only were they scoring 10+ a game but they were recycling 3+ balls that the other team couldn't score with and usually drawing a defender to play "ping pong" which was a another loss of points for the opposing alliance.