Chen, Yu-AnYu-AnChenChen, Ta-ChingTa-ChingChenYU-HSIU LEE2026-01-082026-01-082025-07-0124058971https://www.scopus.com/record/display.uri?eid=2-s2.0-105023058733&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/735155Ophthalmic surgeries demand extraordinary precision due to the delicate anatomy of the eye, where even minor inaccuracies can lead to severe consequences. This paper presents Hybrid Parallel-Serial Tool Exchange Robot for Ophthalmic Precision Surgery II (HYPEROPS-II), an enhanced version of the HYPEROPS-I robotic system, designed specifically for retinal surgeries, incorporating a variable remote center of motion (RCM). Key improvements include reinforcement of its hybrid parallel-serial manipulator (HPSM), a more compact and precise tool cartridge, and a redesigned tool exchange mechanism inspired by hydraulic quick couplings and collet chucks. The forward kinematics, footprint, and workspace of the enhanced system are analyzed, revealing a 13.4% reduction in volume and a 50% increase in effective workspace compared to its predecessor. A full-scale prototype was fabricated and tested, successfully demonstrating its degrees of freedom, non-brackdrivable characteristics, stability under extreme configurations and improved tool exchange performance. Despite the promising results, minor issues such as worm gear backlash, were identified, highlighting areas for further refinement.truemechanical designOphthalmic surgeryremote center of motionconference paper10.1016/j.ifacol.2025.10.1932-s2.0-105023058733