A 2-DOF thin-plate piezoelectric actuator using traveling-wave and radial-bending hybrid vibration modes for multispectral imaging

To address the integration requirements of multispectral imaging for a miniaturized multi-degree-of-freedom (DOF) actuator, this study proposes a 2-DOF thin-plate piezoelectric actuator (TPPA). A proposed multiplexed excitation strategy for spatially arranged piezoelectric ceramics independently excites circumferential traveling waves and radial-bending hybrid modes in a thin-plate stator, enabling decoupled rotary and linear motions. The finite element method is utilized to analyze the driving trajectories by adjusting geometric parameters. Subsequently, a prototype measuring 34 × 34 × 6 mm 3 with a mass of 7.2 g was fabricated. Vibration characterization tests confirmed the successful modal excitation and design feasibility. Experimental results indicate that the maximum linear and rotary speeds, output force, and torque reach 148.3 mm/s, 223.8 RPM, 196 mN, and 0.644 mN·m, respectively, alongside displacement resolutions of 0.24 μm and 19.64 μrad in burst mode. Furthermore, integrating the TPPA into a filtering-focusing mechanism successfully demonstrated spectral channel switching and chromatic focal shift compensation. Focused imaging tests across four spectral bands confirmed the practical capability of the mechanism, proving that decoupled 2-DOF control significantly improves multispectral imaging quality. This study provides a compact actuation solution for the integration of multispectral imaging mechanisms.