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Unread 15-02-2012, 10:56
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juchong juchong is offline
Electrical Engineer
AKA: Juan Chong
FRC #2655 (Flying Platypi)
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Join Date: Aug 2008
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Location: Greensboro, NC
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Re: Extrapolating Direction From Images

From our testing, with the stock kitbot setup and using PWM, it's nearly impossible to have the robot precisely move to a certain position. The slop in the chain, transmission, and the varied power needed to overcome the moment of inertia are all contributing to the robot overshooting in order to attempt to aim.

Our solution: use CAN and encoders on the transmission, tune motor PID on the carpet, and tweak autoaim code. CAN enables us to closely monitor the number of rotations or set a speed at which to track, no matter what resistance the wheels meet (to an extent).

The overshoot that everyone is noticing with the example above is due to the camera being slightly off and the robot trying to precisely correct. This can be improved by using more case structures which vary the motors' power, instead of having a single power at which the robot will track, but it won't solve the problem.
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What I do: Analog Devices iSensor Product Engineer
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