Study on giant magnetostrictive material actuator and its resonant frequency

The fast steering mirror (FSM) is a key part to improve the systemic transmitted accuracy in self-adaptive optical system. According to the applications of FSM, the giant magnetostrictive material is used as driving unit to develop the giant magnetostrictive actuator suitable for FSM. The stroke, output displacement and vibrating model of actuator are studied. The giant magnetostrictive TbDyFe alloy is made through zone-melted directional-solidification method with super-high temperature gradient, and has a <112> preferred orientation. At 10 MPa pre-pressure, its saturated magnetostriction gets to 0.175%, and the linear section length exceeds 1.2%. The quasi-static displacement gets to ± 40 μm, The output force is over 1000 N. Using 10 mm diameter TbDyFe alloy rod, the first order natural frequency of the actuator is 97 Hz when bracing 1 kg mass. The above conditions make a good foundation for the research on FSM system.