[SOLVED] Linear Actuator for Tuning Resonant Cavity

[kthackst]

I am working on a way to tune the coupling of a large resonant cavity. In order to do this, we would like to physically adjust the probe length going into our cavity. Being an electromagnetics guy, I'm not really sure where to start with the hardware and would love any advice.

My first thought was to find an electrical linear actuator that would fit my needs. I need to tune over only a small range (3 in would be lovely). I would like this to be able to adjust as quickly as possible, preferably >2 in/s. Moreover, I am only moving a small copper wire; I don't need the motor to pull or push any considerable weight. But everything I find online seems to be for high force applications and overkill for my project.

Can anyone recommend a low force, high speed, economical, electrical linear actuator with a range of a few inches?

 

[BradtheRad]

A servo is probably ideal for what you want. It moves rapidly. Its position can be controlled. By adding an extension arm you can get the range of movement you want.

It has 3 wires. Two for supply, the third for positioning. A normal control method is to apply DC pulses which vary in length between 1 and 2 mSec.

 

[Warpspeed]

Two inches per second is pretty fast, as Brad says, a servo system would be most appropriate.

But if you want simplicity, and microprocessor control, a linear actuator using a stepper motor and built in lead screw may be better, but the speed may be a challenge.

 

[kthackst]

Thank you for your help, I will search for servos!

 

[Warpspeed]

There are now some pretty sophisticated and low cost servos used for radio controlled models and robotics.
They can move at lightning speed with high force and have very accurate positioning.