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Transfer Function of actuator

Transfer Function of actuator

Transfer Function of actuator

(OP)

Hi!!

 I am trying to design a position control system based on an electromagnetic actuator. a PID controller seems like a reasonable choice for me to use but I am having problems trying to derive a transfer function for the actuator before I begin designing the controller
any help would be appreciated
thanks!

RE: Transfer Function of actuator

We need a little more information.  Is the actuator, say, a voice coil driven by a current loop amplifier?

RE: Transfer Function of actuator

(OP)
Yes, sorry about that
Its a SMAC LAL 30-015  moving coil actuator and it is driven by a current loop amplifier.
I am currently trying to measure its performance in terms of robustness. So I am running a MATLAB simulation first of the system and then comparing the results to the actual working model

The amp is a 24v , 5A dc supply
The actuator has a 15mm stroke and peak force of 14.5N

RE: Transfer Function of actuator

So what do you think the basic form of the actuator is?  I would think it would be something like

K*omega^2/(s*(s^2+2*zeta*omega*s+omega^2)

The second order part would represents the mass in the coil and omega should has a very high frequency.  If there isn't much friction then the damping factor, zeta, will be quite low, perhaps 0.1 or smaller.  Let use know what you think.

RE: Transfer Function of actuator

The actuator can be modled as a single pole low pass filter electrically.  You need to know the inductance of the coil to calculate the bandwidth [plus the loop gain of the amplifier].  Or measure it, lock down the actuator, drive the amplifier with a low amplitude square wave and scope the current rise time.

Mechanically, the actuator follows Newton's First Law of Motion, F = M x a

If you want a "Killer" amplifier to drive the actuator, look at a LA-400 amplifier from Varedan Technologies

www.varedan.com  

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