Gravity compensation of a 2R1T mechanism with remote center of motion for minimally invasive transnasal surgery applications

Abstract This work addresses the gravity balancing of a 2R1T (2 rotations – 1 translation) mechanism with remote center motion. A previously developed solution is modified and applied to prototype, test results are presented. The an endoscope holder for minimally invasive transnasal pituitary gland surgery. In this surgery, inserted through nostril patient natural path gland. During it vital manipulator be statically balanced so that in case motor failure, protected against any harmful motion endoscope. Additionally, static takes gravitational load from actuators hence facilitates control mechanism. 2URRR-URR type parallel three legs. payload mass distributed legs on sides. By using counter-masses two links each leg, leg lumped proximal link which simplifies problem degree-of-freedom inverted pendulum. via springs. Dynamic simulations indicate when balanced, generated actuator torques reduced by 93.5%. Finally, implemented prototype manipulator. tests within its task space disconnected. When connected, torque requirements decrease about 37.8% balancing.