A Square-Ring 2-DOF Piezoelectric Mobile Robot for Microscopic Image Stitching

Precision planar scanning and microscopic imaging systems require actuators capable of orthogonal two-degree-of-freedom (2-DOF) motion with cross-scale operating capability, enabling both high-speed long-range translation and sub-micrometer stepping resolution within a compact structure. To meet this demand, this work presents a square-ring piezoelectric mobile robot (SRPR) capable of achieving orthogonal 2-DOF linear motion for precision planar scanning applications. The SRPR features a compact design with dimensions of 40 × 40 × 10.4 mm and a weight of 47 g. It utilizes a square-ring metal frame and piezoelectric ceramics to generate two orthogonal linear motions through the excitation of bending vibration modes. The SRPR demonstrates impressive motion performances, achieving speeds of 255 mm/s and 266 mm/s along the LX and LY directions, respectively, with sub-micrometer step sizes (0.88 µm forward and 0.83 µm backward for LX, and 0.91 µm forward and 0.81 µm backward for LY). The system also successfully integrates into a real-time microscopic image stitching platform, where it is capable of high-quality stitching over large areas, improving the field of view (FOV) and resolution in microscopic imaging. Experimental results validate the high-speed and high-resolution capabilities, showing its potential for applications in biological and materials imaging, micro-manipulation, and large-area scanning tasks.