Development of a Novel 7-DOF Position-Orientation Decoupled Microsurgical Robot with Motorized Instruments for Microvascular Anastomosis

This work introduces a novel compact 7-degree-of-freedom (7-DOF) microsurgical robot with position-orientation decoupling capacity for microvascular anastomosis. The proposed system employs a modular architecture combining a proximal displacement platform for 3D small-stroke translation and a distal compact remote center of motion (RCM) mechanism for wide-range orientation adjustment. This design meets the workspace requirements for microvascular anastomosis, requiring extensive orientation adjustments with minimal positional movement and reducing the system footprint. The parasitic motion reverse self-compensation method has been developed for motorized surgical instruments, effectively reducing operational resistance to improve precision. Theoretical analysis has been performed on both the RCM mechanism and motorized surgical instruments, and kinematics-based parameter optimization and data-driven calibration have been conducted to enhance superior performance. A prototype has been constructed, and its experimental validation demonstrated that the system achieved repeatability of 11.24 ± 2.31 μm (XY) and 12.46 ± 4.48 μm (YZ), and absolute positioning accuracy of 29.80 ± 12.27 μm (XY) and 37.02 ± 19.47 μm (YZ), meeting super-microsurgical requirements. Experiments that include needle-threading and stamen peeling tasks demonstrate the robot's superior dexterity and manipulation capabilities.