Design and Performance Investigation of the Microanastomosis Surgical Robot Based on the Novel Dual-Triangular RCM Mechanism

The manual microanastomosis poses significant challenges for surgeons who face inherent limitations in terms of physiological tremor and dexterity constraints. It requires precise repair and reconstruction of small-caliber tissues (0.3-3mm), including vessels, nerves, and lymphatic structures. This study presents a specialized robotic system for microanastomosis based on a 7-degree-of-freedom (DOF) position-orientation decoupled configuration. The system integrates a 3-DOF linear stage for positioning with a novel 3-DOF dual-triangular remote center of motion (RCM) mechanism for orientation control, and a 1-DOF two-finger mimicking end-effector is incorporated to facilitate rapid interchange and precise actuation of different microsurgical instruments. Positioning accuracy was improved through kinematic parameters calibration and RCM point deviation compensation using the linear stage. Experimental results validate the prototype performance in the X-Z plane and Y-Z plane, demonstrating repeatability of 1216μm and 1217μm, respectively, and absolute positioning accuracy of 56115μm and 83135μm. In master-slave control mode, motion accuracy ranges from 14-25μm with a motion scaling ratio between 5x and 20x. Additionally, needle threading and stamen stripping experiments were conducted to validate the robot's feasibility for microanastomosis surgery.