A Differential Friction Driving Piezoelectric Stepping Robot for 3-DOF Planar Micromanipulation

Miniature piezoelectric robots exhibit significant potential in high-precision actuation applications; however, their inherent structural complexity often limits their widespread adoption in the miniature robotics field. To address this limitation and develop a miniature robot characterized by high precision, 3-DOF, structural simplicity, and low driving requirements, this paper proposes a piezoelectric stepping robot based on a novel differential friction principle. This differential friction piezoelectric stepping robot effectively leverages the friction differential principle to achieve high-precision actuation while maintaining structural simplicity. Its 3-leg driving configuration provides excellent motion stability and enables 3-DOF planar motion (translational and rotational). Experimental results demonstrate that the robot (dimensions: 44.5 mm x 50.3 mm x 16mm) achieved a translational resolution of 6.97 nm and a maximum speed of 339.35 $\mu $ m/s, along with a rotational resolution of 2.82 $\mu$ rad and a maximum speed of 4.31 mrad/s. The robot also demonstrated an excellent maximum payload-to-weight ratio of 64.52. Furthermore, the robot successfully performed precision alignment of a 200 $\mu $ m diameter optical fiber. Its advantages such as simple structure and few driving units enhance its potential for practical applications and provide a promising approach for developing high-performance micro-robotic systems. Note to Practitioners—This paper is driven by the practical need for a miniature robotic positioner that is simple in design, easy to control, yet capable of delivering high-precision, multi-degree-of-freedom motion with significant load-carrying capacity. Such robots are essential for applications ranging from semiconductor probing and optical device alignment to in-situ sample manipulation inside scientific instruments. We present a novel 3-DOF planar stepping robot that achieves these goals using a unique “differential friction” principle, requiring only three simple piezoelectric actuators. This design significantly reduces the structural complexity and the number of driving channels compared to traditional multi-DOF micro-robots. The experimental results validate its practical utility: the robot demonstrates nanometer-level positioning resolution (6.97 nm linear, 2.82 $\mu $ rad rotational) and a remarkable payload-to-weight ratio of over 64. We have successfully demonstrated its capability in a challenging fiber optic alignment task, showcasing its ability to perform fine translational and rotational adjustments. For practitioners looking to build or integrate a compact and robust micro-positioning system, this work offers a complete blueprint—from the operating principle and design model to demonstrated performance. The inherent simplicity of the robot makes it a promising platform for developing next-generation automated micromanipulation systems for both research laboratories and industrial settings.