Impact-Based Amplification and Frequency Down-Conversion of Piezoelectric Actuation for Small Robotics

Abstract

This paper explores a concept for dynamic amplification of piezoelectric actuator motion using repeated impacts between the active transducer and a compliant amplification mechanism. The design shows good performance in amplifying vibration of a lead–zirconate–titanate (PZT) bimorph while down-converting the output frequency of motion from more than 150 Hz to less than 20 Hz. A simple dynamic model is used to identify the conceptual opportunities for impact-based amplification of PZT displacement. Experimental results are gathered from a prototype system with dimensions 55 mm × 22 mm × 1 mm. PZT displacement is amplified by a factor of more than 100 with near-periodic output oscillations at select input frequencies. Implications for leveraging the low-frequency output oscillations in small mobile robots are briefly discussed.