Hello;

I am looking for a way to do some control of a DC motor. I have looked around the net for possible solutions, ie. a PID feedback control.

It seems that many of the solutions use chopper to measure speed and use that in the feedback. I have also seen motor control ICs that have current sensing integrate in them. Could this somehow be used to provide station keeping? Or perhaps speed control even? (I need on/off[with brake, and station keep]).

Are there any books or websites that might provide me with more useful info? (more on the practical side, ie. circuits, etc would be optimal).

Thanks,
-mike

 

Mike,

The easiest way I think is to incorporate
a brake with your dc brushed motor. Brakes are powered [24Vdc typical] to release the motor shaft and binds the motor shaft when power is removed. This is typically used in the semiconductor robotic wafer handling equipment.

I believe that you can get these brakes with different holding force.

If you are using a brushless dc motor, braking or stopping can be accomplished by shorting together the three phase windings of the motor to the return.
Good luck.

Oly Jeon-Chapman
Magmotor
508=929-1400

 

Your question poses more questions, which will make answering you difficult.

First of, however, how large is the DC Machine in question? Is it fractional, or are we talking several horsepower? Voltages, and Currents required to run the DC Machine are also necessary.

In general, it's no biggie, and I do not agree with the gentleman who suggested using a brake, since you give me the impression that the DC Machine has to be live: I.E., the Machine is used in a Positioning Application.

I can't be as accurate and thorough as I would prefer because of the lack of information, but a stand-alone PID Loop won't, in itself, "cut" it. Rather, you need a Drive Controller capable of 4-quadrant operation: I.E., able to motor and regenerate in both the "fwd" and "rev" direction.

Write back -------- I have no doubt that I can assist you.


Kind regards,


NJB