Take Control

[dreamproject]

Hi all,

Does anybody know the link to resources for PID DC motor position control. Is PID a concept like Fuzzy ? or are there ready made PID IC's . I heard PID control can be implemented with op-amp's ?. Is it really that easy ? - low-cost ?. :?

Thanks in advance

 

[Nigel Goodwin]

Hi all,

Does anybody know the link to resources for PID DC motor position control. Is PID a concept like Fuzzy ? or are there ready made PID IC's . I heard PID control can be implemented with op-amp's ?. Is it really that easy ? - low-cost ?. :?

Try doing a google for 'pid control'

 

[stevez]

PID stands for Proportional Integral Derivative - more or less the name we give to three subsets of control methods. Proportional describes the simpest method to implement - the control output is proportional to the difference between the measured value and the setpoint. The greater the difference or error, the greater or lesser the output. Time really isn't a factor. If there is no difference between the measured value and the setpoint then there is no output - or the output doesn't change and stays at some fixed value. The net result is that some systems never actually get to the setpoint value.

Integral control looks at the difference between the measured value and the setpoint over time - and works to correct that difference so that the measured value gets closer to the setpoint.

Derivative control looks at the rate at which the difference is changing. A faster change results in a greater or lesser output.

PID is basically all three of these combined. It is not necessary to employ all three of these at once. P, and PI are common. In the last 20 yrs PID has been easier to implement thanks to modern electronics including microprocessors and microcontrollers.

 

[bmcculla]

You can make a PID with op amps - its really quite easy. Using a microcontroller gives you a bit more flexiblility and is almost as easy. If this is for a hobby project you should just buy a microcontroller and build your own PID controller.

National makes the LM629 if you want a commercial PID controller chip.