Effect of backlash hysteresis of surgical tool bending joints on task performance in teleoperated flexible endoscopic robot

Abstract

BACKGROUND: The tendon-sheath mechanism provides flexibility but degrades the task performance of the flexible endoscopic robot because of the inherent backlash hysteresis problem. Previous studies have only focused on reducing backlash hysteresis. The goal of this study is to identify the backlash hysteresis criteria of surgical tool bending joints to maintain efficient surgical performance. METHODS: A test platform for a surgical tool has been developed that has initial backlash hysteresis under 5° and can adjust the backlash hysteresis intentionally. Performance variation has been investigated in three bench-top endoscopic tasks in which various backlash hysteresis conditions were intentionally adjusted. RESULTS: A clear drop-off in task performance has been observed when the backlash hysteresis of the bending joints was greater than 10° regardless of the type of task and link length. CONCLUSIONS: The backlash hysteresis of surgical tool bending joints should be reduced to at least 10° to maintain efficient performance in robotic endoscopic surgery.