In this paper an actuator with a new magnetic configuration having a nonmagnetic cylinder (or disc) in a ferrofluid differentially pre-magnetized by permanent magnets is studied by simulation and experiment. This prototype shows superior performance compared to an actuator with basic magnetic configuration. The new actuator exerts a force approximately three times higher than the basic actuator. In addition, the transfer characteristics, current versus displacement and force, have a better linearity.

Keywords: Ferrofluid actuator, Magnetic force, Magnetic fluid