Achieving high-speed smooth motion for stick-slip piezoelectric motors with impact-enhanced driving mode

Abstract Stick-slip piezoelectric motors (SSPEMs) are widely regarded as promising candidates for precision positioning systems due to their compact structures and simple driving modes. However, challenges inherent to conventional SSPEMs, including backward motion and instability, seriously limit the output speed of SSPEMs at high driving frequencies. Inspired by the driving principle of impact inertial piezoelectric motors (IIPEM), this paper proposes an impact-enhanced driving mode that enables SSPEMs with smoother ripple motion and improved driving frequencies compared to conventional driving modes. The proposed driving mode utilizes the parasitic motion of the compliant mechanism (CM) and the inertia of the driving foot to generate larger force to the mover at high driving frequencies, so that the backward motion can be eliminated and the output performance can be improved at high frequency. To validate the proposed driving mode, an SSPEM with modified triangular configured CM (TCCM) is carefully designed by analytical models and finite element simulation. A prototype is then fabricated for validation. Experimental results show that the backward motion is eliminated when the driving frequency exceeds 800 Hz. Comparative results further highlight the advantages of the impact-enhanced driving mode, achieving a maximum driving frequency of 1800 Hz and a peak velocity of 38.19 mm/s. The proposed impact-enhanced driving mode offers a universal and effective solution for SSPEMs with parasitic-motion CMs, significantly improving speed, accuracy, and high-frequency one-step stability.