Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations pierreick on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Transfer Function of actuator

Status
Not open for further replies.

rollsroyce21

Electrical
Feb 19, 2009
2

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!
 
Replies continue below

Recommended for you

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

 
Status
Not open for further replies.

Part and Inventory Search

Sponsor