I am pretty sure that @Dave-Schulpius has with his B9. In one of his videos, he demonstrates the soil sample tool that comes out of the right foot of the B9. It looks to be on a linear actuator.

1:19 or so in this video.

Sorry guys, I have no experience with linear actuators. The soil sampler in this vid is run by a DC motor using a leaved arm to push it through the little door.

I hope you find your answers.

Haven't used a linear actuator myself. Pololu sells them and has a decent write up on how to control them. http://www.pololu.com/product/2337

Recently purchased one from servo city. 10 inch model. very simple device. Positive and negative wire. There are also wires for the built in potentiometer for position feedback but are not needed in order to work. I am controlling mine with a roboclaw 2 x 15 amp motor controller as I really like controlling via serial commands. Simply requires 12 vdc to operate, just reverse polarity to reverse direction.

                                      Chris

Thank you.. I was looking into these to use in place of pneumatics.

I would really like to use a set of LA's on the arms of my B9. However the challenge I've found so far is speed. Their usually pretty slow.

Very true, some can be slow. Mine moves 1/2 inch per second. The units that are rated for less load move quite a bit faster. I think the unit that is capable of 30- 45 lbs moves and 2.5 inches per second. I guess it depends on your application. My original design called for a linear stepper motor. Talk about slow. Complete re-design, and much happier with simple linear actuator.