Design, kinematic modeling, and experimental testing of a modular minimally invasive robot for pituitary surgery

To address the constraints of narrow surgical corridors and limited workspace in pituitary tumor procedures, this paper presents a compact and modular minimally invasive surgical robot. The system adopts a master–slave architecture in which all degrees of freedom are controlled via a remote operating platform. Three 5 mm end effectors are coordinated through a 12 mm diameter channel, enabling localized collaborative manipulation while minimizing tissue interference. The robot comprises an integrated lifting–rotating platform, one endoscope module, and two surgical modules arranged vertically in a staggered configuration. Each surgical module provides five degrees of freedom—vertical translation, axial rotation, lateral oscillation, pitch, and grasping—through a cable-driven ball-joint mechanism to achieve high dexterity within confined spaces. The endoscope module offers vertical translation and axial rotation for intraoperative visualization. The lifting–rotating platform synchronizes axial and vertical motions of all modules to ensure coordinated operation and flexible instrument repositioning. Structural design and kinematic modeling are presented, followed by prototype development and experimental validation. Performance tests, including positioning accuracy and cooperative manipulation, demonstrate high precision and operational flexibility, confirming the feasibility of the proposed system for minimally invasive pituitary surgery.