Quote:
Originally Posted by Swampdude
I think defense is being underrated due to that fact that this scoring object is not big. 1 bot can block 3 legs just by going back and forth a couple feet, 2 could be blocked by never even moving. And if they choose to do this on the opponents side, they will be forced to come around and score on the opposite side of the field, which is being occupied by opposing scorers - and much harder to see what you're doing. The dynamics of this scoring object should be experimented with using live bot defense. Which is what we did. its possible to overreach a defender on the lower 2 levels but the high reachers will need to get in close to score, and may be able to push thier way in. But defense can also be played in keeping the oposing team from picking up the ringers in the first place.
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I think you're undervaluing the importance of being able to reach over a defending bot.
In the following example, I'm going to lay out a few assumptions to make the problem simpler. The scoring bot is a 37"x27" bot, with an un-turreted arm projecting from the 37" dimension. The arm is 4" thick, is 83" long (center of rotation 3" from the rear of the robot) and therefor projects 49" when parallel to the ground from the front of the robot to the front of the end effector (about .3" from the maximum allowed value in this problem, using the hypotenuse 101.823" hypotenuse of the 72"x72" size allowment). The arm has a shoulder joint (and point of rotation) 45" off of the ground. The arm is designed to score the tubes parallel to the ground, and has a wrist joint to keep them parallel through-out the rotation of the arm. The end effector uses one of the sides of the tube to manipulate it, projecting the rest of the tube forward from the end of the end effector.
Now, we plug all these fancy numbers into a calculator, and figure out how far the robot can be away from the rack to score on each level, and we get these numbers back.
Low spider- 61.388"
Middle spider- 58.473"
Top spider- 36.868"
(For more info on how I calculated these number, please consult the illustration below demonstrating the example for the Top Spider, including clearance height for the entire spider foot, stinger, and bottom half of tube)
http://img.photobucket.com/albums/v1...titled-1-2.jpg
Beyond that, all of those reach numbers could be even greater if the robot had a higher point of rotation, and/or a turreted arm (allowing for a longer reach from the frame while remaining in the 72" x 72" size limitation). Given the same arm and base constraints (4" thick arm, 27"x37" base, with the center of rotation 3" away from the end of the 37" dimension) the "holy grail" arm design (360º turret, with a point of rotation at the height of the top spider) you could in fact score from ≈76" away without violating the 72"x72" rule. Note, this the first design not an easy design either (especially making an 83" long arm fit in the 48" starting height), and would probably either require a multi-jointed arm and/or a telescopic arm. But this shows that a 48" robot, with an un-turreted arm can score over the short dimension of a defender at all 3 levels of the rack.
Now, granted, it does not mean that these bots are undefendable, far from it. They still may be able to be pushed away, or rotated out of scoring position. Additionally, if the defending bot is tall enough (or has an arm that can extend high enough), they may be able to block the tube from being scored.