Precise stepping control of a piezoelectric traveling wave micromotor through embedded in-situ detection

Abstract

Piezoelectric actuators are well known for their high precision, and are promising for applications in microrobotics, drug delivery and nanopositioning. However, a piezoelectric traveling wave ultrasonic micromotor is very hard to control due to the frictional drive principle. This work introduces a closed-loop control strategy for a micromotor. An integrating on-chip structure with a piezoelectric stator and sensor alignment is firstly achieved within a 5 × 5 mm2 area, which provides in-situ detection during rotation. With the help of real-time detection and control, a high angular resolution of 0.3° is realized for the micromotor.