Dc motor direction control using pid

[tehmaas hasan]

Greetings Friends

My aim is to make pid controller for a 6 volt dc motor to control its direction.
When we move pot to one direction it moves in one direction and when we rotate the pot to other side the motor first slow down then moves in other direction.

I want to perform this project by op-amps.

also tell how the same task can be accomplished using micro controller pic16f877.

Hoping for excellent conversation.
Thanks

 

[kripacharya]

using just opamps is tricky. to reverse direction of a dc motor you have to reverse the polarity while providing it with enough voltage/ current for the desired speed.

with a PIc it is much simpler.
here is one simple functional description :

connect the pot between +5 and Gnd. Feed the wiper to an ADC input and read off the voltage in the PIC.

configure a timer to generate a PWM signal which is proportional to |Vadc - 2.5|
configure another pin output of the PIC which is high or low (direction) depending on whether Vadc is higher or lower than 2.5v.

connect the PWM output to a full-bridge driver circuit ENA pin.You could use a chip like the L298 or L293 (dep on motor size).
connect the 'direction' to the IN pins.