Re: PWM control with encoder regulation

Thanks for the quick help guys.

Just to clarify, this doesn't need to be a precise application - at
all. If the speed is within 20% that is fine. Repeatability is more
important, that is, if it is 20% off, I need it to be within, say, 5%
of being 20% off every time (if that makes sense).

Secondly, I already have a PWM signal available that I can control (or
filter to a rough DAC to input to a chip). I said the 0-5V speed input
because I figured it to be more likely that a chip would have an analog
input of 0-5V than have a filter on board for the PWM signal already,
and I could just filter it myself.

Hopefully I'm not way off base, but the reason I am even doing this at
all (using feedback) is to allow the motor to have more torque as very
low speeds (low speed = low voltage = less torque). I am hoping (and
almost certain) that this type of feedback control will effectively
increase voltage (by increasing pwm) such that the motor will receive
enough voltage to suit my torque needs under a variety of speeds
including very slow. At very slow speeds with a large load, the speed
would slow down to the point of "stalling," where a small increase in
voltage (pwm signal decided by PID and the chip I need) could increase
the voltage just enough to spin at the speed I desire. The problem now
is that at 50% + there is enough torque, but as the duty cycle gets
lower, there is much less torque output.

.

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