Quote:
Originally Posted by bobwrit
A goal. What we did was have the GA that ran the optimization of the NN(weights) be pushing toward being as close to the oppisite alliances trailer as possible. We did that with a combiniation of using the GetRobotAlliance() function and the camera. The problem that the system had was either we either would have to use 2 camera's to get the distance to another teams trailer, or use our accelerometer to find another robot using a bunch of assumptions that were not necesarily true(Using netwon's law of gravitation, assuming the mass of another robot). We couldn't have 2 camera's due to limitations with the cRio, and we couldn't use the accelerometer because of the crowds pull would distort things as well as it wasn't sensitive enough to handle the percision that it would require. So, the system wasn't going to fly at this point, but it could if next year's KoP contains a new cRio with 3 ethernet ports and an new Axis, but I'm doubtful of that.
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I post this as a fun exercise in orders of magnitude, and do not intend it to be a performance in snobbery.
At 1 meter, a 150lbs robot will effect a 4.6 x 10^-10 g acceleration on your robot. The KoP Accelerometer produces 300mV/g, which means that the signal you are reading would be 138
picovolts.
This would require the entire analog system to be good to at least 34 bits before you would get _any_ signal. It would take the cRIO 2.3 minutes to oversample to this level (almost the entire match) if you focused an entire analog module on it. Realistically
, you would want another 6-10 bits so you could tell how far away the other robot is. This would bump the time up to the 1 hour to 4 hour range.
Bear in mind that oversampling more than a couple extra bits isn't really useful, as it requires the noise to be perfectly distributed. Oversampling 30 extra bits is pure fiction. Also, nothing could move during the sampling time.
Lets assume that NI pulls through and donates a 40bit at 100 samples per second A/D next year (These do not exist). Unfortunately, earth's gravity will throw us off a bit. A change in inclination of the accelerometer by more than 10^-10 radians would destroy our reading. Roughly speaking, if a straight stick as long as the earth is wide was attached to the accelerometer, a deflection of more than a millimeter would be unacceptable. For our 6-10 bits extra range, our "earth-stick" could not deflect by more than the width of a human hair.
Edit: When Mars is at its closest to earth, its effect is 10 times that of the robot. At its farthest, its effect is a little less than double that of the other robot.
Edit 2: The moon's effect is ~10,000 times stronger. The sun's effect is ~6,000,000 times stronger. Considering the orbits, it takes 25 seconds for the moon and 90 milliseconds for the sun to change position enough to change the total acceleration vector by one "robot pull" unit.