Abstract: A giant magnetostrictive microdisplacement actuator which has the function of sensing its displacement and which uses a new type of functional materials (giant magnetostrictive materials) as its microdisplacement device has been developed. A microdisplacement closed-loop control system is also built. A kind of circular membrane flexible structure with high distinguishability, zero friction, and integrated sensing-transferring-displacement capability, is proposed to be used as a mechanism to transfer and sense the actuator's microdisplacement. The analysis formulas and the distribution curves of deflection and variance ratio of strain are obtained by using circular plate bending theory. On basis of this, the distribution of the sensors that sense the actuator's displacement is obtained, and the actuator's displacement-sensing function is realized. At the same time, experimental studies on the actuator and its microdisplacement closed-loop control system are carried out. The results show that the sensitivity of the actuator and the precision of the system's closed-loop control are improved.

Key words: giant magnetostriction, sensing, flexible structure, microdisplacement actuator