Speed control of stepper motor using phase locked loop
Speed control of stepper motor using phase locked loop
(OP)
i am trying to control the speed of the stepper motor using phase locked loop, using simulink for the simulation. Want to know if i can use the stepper motor transfer function for this approach of controlling the speed using phase locked loop.





RE: Speed control of stepper motor using phase locked loop
Stepper motors are position (angle) based. Therefore, cannot they be perfectly controlled open loop?
RE: Speed control of stepper motor using phase locked loop
Is the stepper motor really part of the loop? What are the inputs and outputs? It's just that "this approach" you refer to doesn't ring any bells for me and there's certainly not enough information in your post to figure it out. Hopefully that's just my ignorance and others know what you're talking about.
Finally, it actually looks like you're asking about a "stepper motor transfer function". That sounds like a Simulink component to me. You might be better served over in the Simulink forum: http://www.eng-tips.com/threadminder.cfm?pid=576
Judging by the post[1] on the Mathworks site, you've already exhausted the Simulink experts anyway. Maybe it's time to revise your question?
[1] http://www.mathworks.com.au/matlabcentral/answers/...
RE: Speed control of stepper motor using phase locked loop
RE: Speed control of stepper motor using phase locked loop
RE: Speed control of stepper motor using phase locked loop
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RE: Speed control of stepper motor using phase locked loop
RE: Speed control of stepper motor using phase locked loop
RE: Speed control of stepper motor using phase locked loop
Perhaps this is more of an academic exercise to learn about PLLs rather than being a practical application?
RE: Speed control of stepper motor using phase locked loop
The transfer function you're talking about - what is the input and output? Judging by the function, is sounds like you're modelling the motor as an RL circuit, setting voltage as input and current as output? You then stick that in the middle of the PLL, so the input voltage becomes the low-passed error signal and the output current becomes the input to the VCO. What makes you think that will work?
As already suggested, the only way I can think of to actually make this work is to get some feedback from the motor shaft. Hopefully I'm wrong and someone knows what you're trying to do, but it's not looking promising!
RE: Speed control of stepper motor using phase locked loop
RE: Speed control of stepper motor using phase locked loop
http://books.google.com/books/about/The_Phase_Plan...
or maybe
http://books.google.com/books/about/Stepping_Motor...
I.e., you need to model some logic circuit that feeds the PLL oscillator's output to four drivers, which beat on two coils, which beat the crap out of the rotor, which may or may not move the load, which you also have to model, and some kind of encoder attached to the load.
You might want to model a DC motor first; steppers are complicated and weird.
Mike Halloran
Pembroke Pines, FL, USA
RE: Speed control of stepper motor using phase locked loop
Is a PLL even the right solution? PLLs are really intended for steady state behaviors, e.g., matching something to a reference crystal. If there is going to be large variations in the motor speed, a PLL is probably inappropriate and a conventional servo loop is probably more apropos , although you would still need some means of measuring the motor speed.
TTFN

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RE: Speed control of stepper motor using phase locked loop
A typical printer (for exampke) might contain a half dozen stepper motors, and zero PLLs.