A Novel Low-Power Linear Magnetostrictive Actuator With Local Three-Phase Excitation

Development of a novel low-power linear magnetostrictive actuator is presented in this paper. The magnetostrictive material used here is Terfenol-D, which is an alloy of the formula Tb_0.3Dy_0.7Fe_1.92 . In response to a traveling magnetic field inside the Terfenol-D element, it moves in the opposite direction with a peristaltic motion. The proposed design offers the flexibility to operate the actuator in various configurations including local and conventional three-phase excitation. In this paper, we demonstrate that the power consumption can be reduced significantly by the local excitation approach. A new force-transmission assembly incorporates spring washers to avoid the wear due to the sudden collision of the Terfenol-D element with the force-transmission assembly. The closed-loop control system was implemented using relay control, which resulted in an optimal closed-loop performance. The magnetostrictive motor has demonstrated a 410-N load capacity with a travel range of 45 mm, and the present maximum speed is 9 mm/min. The low speed is due to the local three-phase operation mode, and it could be increased to 60 mm/min by using the conventional three-phase operation. The maximum power consumption by the motor is 95 W.