A Cross‑Scale Bioinspired Friction‑differential Stepping Positioning Platform Driven by Piezoelectric Bimorph Benders

While piezoelectric positioning platforms show significant potential in micro/nano actuation, their widespread adoption is often limited by inherent structural complexity. To address this, we proposed a cross-scale friction-differential stepping platform driven by only two piezoelectric bimorph benders. Utilizing a specially designed T-shaped structure, the platform achieved both linear and rotational motion through an innovative friction-differential principle. Following theoretical and dynamic simulation analyses, a prototype was fabricated. Experimental results demonstrate stable performance and high repeatability. For linear motion, the resolution was 2.853 µm; at 150 V (no load), the maximum speed reached 3.306 mm/s (30 Hz), with a return deviation of 348.718 µm (1 Hz). For rotational motion, the resolution was 0.063 mrad; the peak angular velocity attained 136.551 mrad/s (15 Hz), with a return deviation of 7.598 mrad. Furthermore, the platform exhibited a maximum payload-to-weight ratio of 63.49. This design offers a simple, redundancy-free 2-DOF solution, significantly reducing structural complexity compared to traditional platforms.