This paper presents an approach to establish the analytical formula for the force acting on a non-magnetic disc plunged into a ferrofluid, due to the effect of a magnetic field gradient generated by the magnetic inductor of the actuator. The expression of the force acting on a magnetizable body placed in a magnetic field was used for the particular conditions imposed by the actuator configuration. The magnetic field distribution in the inductor core and in the ferrofluid was determined and the expressions of the force were obtained in the case of intense and moderate magnetic fields.

Keywords: Magnetic actuator, Ferrofluidic actuator, Magnetic force, Ferrofluidic force, Ferrofluid, Magnetic fluid.