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Unread 07-08-2012, 17:50
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Re: Are we still using only 256 unique PWM steps?

Quote:
Originally Posted by Michael Hill View Post
The reason I mentioned that it would be nicer to have more resolution is well...put it this way. This year, the majority of teams (including 3138), had shooter wheels with a speed controller. If your max speed (that is full voltage to the motors/128 counts) is 4000 RPM, which is easily attainable, the finest you can change your motor speed by is ~30 RPM, which can be a heck of a difference.
If:

a) your wheel has sufficient moment of inertia, and

b) you are reading the wheel speed sensor, computing your control algorithm, and outputting a new motor command fast enough,

... then you are not limited by the resolution of the motor command.

In fact, you can get very accurate and stable motor speed with only 1-bit resolution of the command (ie ON or OFF), as described here.


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