An asynchronous dual-foot inertial piezoelectric actuator with strong magnetic compatibility

Abstract

To address the limitations in actuator selection within strong magnetic environments, this study introduces a novel inertial piezoelectric actuator with asynchronous dual-foot motion, which meets the need for high-precision actuation in strong magnetic field environments. The design principle is to use two driving feet that generate elliptical motion in an alternating method to achieve continuous linear motion of the actuator. This approach enhances load capacity, speed, and stepping characteristics. The design allows for better control of backward motion without modifying the driving waveform, thus improving the actuator's speed and ensuring consistent performance in both directions. A finite element model of the proposed actuator stator is developed and analyzed using commercial software to optimize its dimensional parameters. A prototype is fabricated, and experimental investigations are carried out. The results indicate that the dual asynchronous driving method significantly increases the speed of the actuator and the consistency of the motion by improving stepping characteristics. The prototype reached a maximum speed of 8.98 mm/s, supported a maximum load of 4.5 N, and achieved a displacement resolution of 19 nm. Finally, the strong magnetic field environmental test and MRI image quality test were conducted, and experimental results confirmed that the actuator has superior magnetic compatibility, highlighting its potential for precision applications in challenging environments. This research proposes new methods to enhance the retraction characteristics and output performance of inertial actuators, with their excellent magnetic field compatibility anticipated to be applied in future MRI-compatible injectors, puncture devices, or other actuating mechanisms.