Decision to make about actuator I am entering a variation of a battlebot competition where each robot must be under 30lb and the goal is to push the opponent off the combat volume. The combat volume is composed of 8 tables which have a small metal lip which prevents any bot from having a clearance less than roughly 1/8in. We have settled on a turtle style design. There will be a shell with 2 wedges which can be raised and lowered with some type of actuator. I am searching for a linear actuator which can push atleast 20lbs of force and has an adjustable stroke. I was thinking about a voice coil or solenoid. Any advice?