PID tuning and development of algorithm for BLDC motor

[sudheervemana]

Hi all,

I am working on positional control of an BLDC motor ,i am
using TIDSP as an controller and I want to follow the ZN ultimate
sensitivity method in developing the PID algorithm ,First i would like
to go for the proportional controller alone for my system to know the
proportional gain
and the ultimate period ,later with the help of the gain and period ,i
will calculate the Kp,Ki and Kd values.Is this the right way to
develop the PID algorithm for my system. Please clear me one
thing,when i am setting the
target position to some 1000 counts,At first from the encoder feed
back i will notice that the motor shaft has rotated to some position
say 400,here the error is 600 ,again i will send this error to my
proportional controller from there to the actuator to move the rotor
to the desired set point,finally i will notice at some point with the
sustained oscillations ,i will calculate the tuning constants and
finally i will implement the PID controller .
here when i am implementing the P controller alone,i need to set some
gain and i need to increase this gain to the desired set point,what is
the intial value for the proportional gain 'K' and at what rate i need
to increment
this again to see the sustained oscillation .Please also clear me how
to draw the waveform regarding the position versus time. Please give
me your valuable suggestions to implement the pid algorithm for my
application.

thanks in advance,

With regards,
Sudheervemana.

 

[Spehro Pefhany]

Hi all,

I am working on positional control of an BLDC motor ,i am
using TIDSP as an controller and I want to follow the ZN ultimate
sensitivity method in developing the PID algorithm ,First i would like
to go for the proportional controller alone for my system to know the
proportional gain
and the ultimate period ,later with the help of the gain and period ,i
will calculate the Kp,Ki and Kd values.Is this the right way to
develop the PID algorithm for my system.

It's *one* way, and the calculations go different ways depending on
the nature of your algorithm and depending on the model of the plant
you are using. The suitability of the parameters, of course, depends
on how well the model used in the calculation of "optimal" (in some
way) control parameters from Tu and K matches the actual plant.

Please clear me one
thing,when i am setting the
target position to some 1000 counts,At first from the encoder feed
back i will notice that the motor shaft has rotated to some position
say 400,here the error is 600 ,again i will send this error to my
proportional controller from there to the actuator to move the rotor
to the desired set point,finally i will notice at some point with the
sustained oscillations ,i will calculate the tuning constants and
finally i will implement the PID controller .
here when i am implementing the P controller alone,i need to set some
gain and i need to increase this gain to the desired set point,what is
the intial value for the proportional gain 'K' and at what rate i need
to increment
this again to see the sustained oscillation.

That's all system dependent. You should be able to better than
ball-park it from the system dynamics.

Best regards,
Spehro Pefhany