Self-sensing feature of the ultrasonic nano-displacement actuator in Metglas/PMN-PT/Metglas magnetoelectric composite

Self-sensing feature allows an actuator to be used as a sensor. Magnetoelectric (ME) composites consist of piezoelectric and magnetostrictive layers. ME composite is a proper candidate for the self-sensing feature in a wireless actuator due to its concurrent magnetic-charge order. In this study, the self-sensing feature of a nano-displacement ME actuator is investigated. The ME structure design, as well as the effect of geometric parameter and resonance frequency on the ME signal, is evaluated using a numerical modeling. The Metglas/PMN-PT/Metglas composite was fabricated as an ME actuator. The displacement measurement was conducted using a laser Doppler. The effect of bias field and excitation frequency on sensitivity, linearity, resolution and signal stability of actuator/sensor feature were evaluated by a magnetoelectric measurement setup. The experimental results revealed that the maximum sensitivity of actuator was achieved at the resonance frequency of about 60.7 kHz. Compared to the ME voltage, the phase angle was more reliable for application in the self-sensing feature. The actuator/sensor sensitivity was estimated at about 5.2 nm/mA and 0.64 mV/mA, respectively. Also, the output range of the sensoric feature was measured at 58–272 mV. The fatigue test revealed that the ME signal at the first resonance frequency was more stable than the second mode. The results also confirmed that the magnetoelectric signal could be promising candidate for the self-sensing feature in the ultrasonic nano-displacement actuator.