LAUSR

An actuator for microposition adjustment and vibration isolation using the controlled ferrofluid is reported in this letter. The proposed actuator levitates on the ferrofluid which is affected by the combined dynamic magnetic field which is formed by coupling a permanent magnetic field with a controlled electromagnetic field. A controlled electromagnetic field is superposed on the permanent magnetic field in order to change the shape of the ferrofluid to ultimately move the actuator. The experimental results indicate that the proposed actuator can adjust the position with high accuracy and has a good dynamic performance. The proposed actuator can bear over 2 N loads, and the positioning accuracy is within 0.1 μm. The stroke of the actuator is about of ±30 μm with no load, and the stroke increases to ±75 μm at 2 N load. Its dynamic band with –3 dB amplitude attenuation and –90° phase is over 40 Hz. In addition, the displacement has a very good linear relationship with the input current. The results also de...