Miniature traveling wave piezoelectric actuator for 2D/3D non-destructive ultrasound testing

Conventional positioning systems for non-destructive testing (NDT) are often bulky, inaccurate, and constrained in motion range, making them unsuitable for inspecting small, intricate components like chips or for long-distance scans. To overcome these limitations, we propose a novel miniature traveling-wave piezoelectric actuator with high positioning performance. The actuator features a simple cross-shaped structure, driven by dual piezoelectric elements to generate a traveling wave. Characterization demonstrates a no-load speed of 350 mm/s, a load capacity (>50 g) exceeding seven times its own weight, excellent linearity (close to 1), repeatability (>90%), unlimited stroke, and high motion resolution (0.023 mm). When integrated with an ultrasonic NDT probe, the system successfully performed both 2D and 3D scanning tasks, overcoming the constraints of conventional systems. This work extends the application of piezoelectric actuators to NDT and provides a viable pathway toward miniaturized, high-performance inspection systems.