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our team used the FIRST yaw rate sensor, integrated the signal by adding it to a register that was initialized to 32,000 - as long as your robot does not turn faster than the max rate of the sensor, it was very accurate for us.
For this year, if we need to do some sort of naviagation again, we are planning to design a distance and speed sensor. the simply approach is to put white paint marks on the side of a wheel and count them with an optical sensor.
there are two problems with this approach. the wheel might be slipping and you cant be sure which way the wheel is turning (someone might be pushing you backwards while your robot is commanded to go forwards - and there is no way to tell just by counting the marks on the wheel - the optical sensor only sees: On - off ----on ---off)
an easy way to get by the slipping wheel (drive motor is causing the wheel to spin) is to use a nondriven wheel - like they do at car testing labs -you see them on TV sometime, with the bicycle wheel attached behind the car)
to solve the fowards or backwards problem - one way is to use two sensors and wider marks on the wheel - then you can tell which dirction you are going by which sensor changes state first.
then by counting (integrating) the marks you get distance, and by measureing the time between marks you get speed.
BTW - there will probabally be some kind of auton mode requirement this year, but dont assume it will be auton navigation - they could require us to do somehthing like having the driver control the robot position, but the robot does something else by itself at the same time.
Last edited by KenWittlief : 15-11-2003 at 08:52.
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