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SteveGPage 07-01-2008 22:40

Average Lap Distance
 
We did a number of paper simulations of the average lap distance - laps with very little interference by the other robots, laps where the robot would need to weave around other robots - in an attempt to see what the average distance the robot would need to drive to score a lap. I would love to know what the CD community thinks the average distance per lap would be. Thanks!

SteveGPage 08-01-2008 14:36

Re: Average Lap Distance
 
So far, and it looks like the CD community is fairly consistant in its answers - the average lap distance is 100 - 110 feet. If so, and assuming with acceleration and deceleration - weaving through the crowds - turning, etc ... how many laps can you do in the 2 minute teleoperated period? We figured, using last year's robot, that we could do 10 ft/sec in the straight-aways, or 11 seconds with the calculated distance of the lap - BUT, with the other obstacles and turns, we figured a best guess of 16 seconds per lap, or about 8 laps per match.

How many laps do you think you could do during a match?

Elgin Clock 08-01-2008 15:01

Re: Average Lap Distance
 
I also ran some calculations with this yesterday.

Using the maximum robot size (with bumpers) of ~44" x 34".

Using a CAD calculated elipse with a 870.5" (~72.54') total length shortest travel distance per lap with the best line.

Using your given 10 ft/second robot speed...

The most we can squeeze out of this field in a perfect situation with the maximum sized robot with absolutely no traffic would be:

20 laps in 1:45
(not counting time in Hybrid mode in able to get to "the perfect path")


Good luck with any team who can accomplish this!

I'm guessing a best lap count of about 10-15 will be very rare, and 5-10 will be the norm.

Smaller robots will have a slight advantage as they will be able to manuver around robots & the track a lot quicker, and I see rookies hopefully realizing this and taking advantage of this if they don't want to build an arm for Ball manipulation.

Bongle 08-01-2008 15:05

Re: Average Lap Distance
 
I computed a version of the 'fastest possible lap' yesterday, and found that a lap with semicircles at each end and lines for the straights has length:
2(pi*r + 27 - 2r).
and that your best possible time per lap given radius r and friction coefficient u was:
ttotal(u,r) = 2*pi*r / sqrt(9.8ur) + 4*sqrt( [27-r]/[4.8u] )

Note that there are many assumptions I made in order to get 'ideal' lap
-Robots are points
-Robots are powerful enough that their acceleration is friction-limited

I think if you steered a 13ft radius corner at each end, thus carrying maximum speed out of each corner, a 5-6 second lap might be possible with a robot that dispenses with all other goals except speed. The best possible time for a friction-limited lap with u = 1.3 that does a 13ft corner at each end is 4.1 seconds. You can go much faster if you do a tight corner, but that's only because we're dealing with 1.3g acceleration along the straight.

dlavery 08-01-2008 16:36

Re: Average Lap Distance
 
Quote:

Originally Posted by Elgin Clock (Post 672427)
I
20 laps in 1:45
(not counting time in Hybrid mode in able to get to "the perfect path")

Why 1:45?

Just curious.

-dave

Elgin Clock 08-01-2008 16:53

Re: Average Lap Distance
 
Quote:

Originally Posted by dlavery (Post 672528)
Why 1:45?

Just curious.

-dave

Hahaha! Oops.. :o
As soon as I saw your post Dave I figured there was a reason you asked that.

The explanation is that I was having flashbacks of 2 minute TOTAL time matches from yesteryear, and did my very quick calculations based on that brain hiccup and forgot the Teleoperated period time this year was 2:00 with 15 seconds of Hybrid.. :ahh:

Ok.. so with that said... I'll show my work this time. lol

870.5" long path @ 120" in/sec = ~7.25 second lap time.

120 second match (Teleoperated) / ~7.25 seconds a lap = ~16.5 laps

After 15 seconds of Hybrid time, I would say a perfect line robot at maximum configuration could make in the Teleoperated mode of 2 minutes could make a total of ~16.5 laps.

Aye... my math was way off in that first attempt I guess as well. :(
20 laps was a very generous overestimate I guess.

I'll keep my prediction the same though with my original quote:
Quote:

I'm guessing a best lap count of about 10-15 will be very rare, and 5-10 will be the norm.


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