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Unread 26-09-2016, 07:22
adciv adciv is offline
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Re: Tuning PID Constants Over a Range

Quote:
Originally Posted by botster View Post
For example we can tune gyroTurn(5) to turn 5 degrees, but those constants don't work for gyroTurn(25). Are we doing something wrong? or are we supposed to create different sets of constants for ranges of the angle?
You aren't doing something wrong, its physics at work. Due to static friction small angle are hard while larger angles are easy. Somewhere between 5 and 10 degrees you change between the two. Basically, in order to start turning, your drive motors need to be above a certain value in order to overcome static friction. At that point, you're then only subject to dynamic friction. We typically tune our PIDs for large turning values and then if we need to make a small turn, turn away and then towards the desired angle.

This year, we ended up having different turning/yaw control PID values based on if we were moving forward or not.
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