An Ultradurable Piezoelectric Inertia Actuator via Wear-Adaptive Mechanism

Piezoelectric inertial actuators (PIAs) enable cross-scale motion ranging from nanometers to millimeters with simple and compact structures. However, friction and wear issues limit their service life and reliability. This work proposes a cascaded magnet piezoelectric inertial actuator (CM-PIA) for durable service via a wear-adaptive mechanism. Additionally, the displacement vibration characteristic in PIAs, typically considered a defect, has been positively utilized for the first time. Through friction experiments, we demonstrated the CM-PIA's advantages in wear adaptability, modular interchangeability, and assembly adaptiveness. The actuator operated over 190 km with 2.5 μm wear and showed a 16% frictional force reduction with 4 mm wear, theoretically enabling operation for 300 000 km and enhancing the travel life by three orders of magnitude. The replacement cost for the modular magnetic actuated foot is only 4 cents, and it exhibits stable friction over an extended stroke of 400 mm. Employing three degrees of freedom (DOF) integration, we have applied the CM-PIA, which possesses a stroke up to 18 mm and a test resolution was 4 nm, in minimally invasive cellular manipulation utilizing displacement vibration by a singular core for the first time.