Simultaneous Physiological Motion Cancellation and Depth Adaptation in Flexible Endoscopy

Flexible endoscopes are used in many diagnostic exams and surgical procedures in gastroenterology as well as in natural orifice transluminal endoscopic surgery. In order to assist the surgeon during these difficult procedures, physiological motion cancellation has been successfully applied on a robotized endoscope. However, the stability and performance of the classical controllers were ensured only on a small working area, thus preventing the surgeon to manually move the endoscope during motion rejection. In this paper, we propose original methods to improve the physiological motion rejection while taking into account manual depth changes performed by the surgeon. For this purpose, an adaptive repetitive controller based on depth estimation is proposed. The validity of the approach is demonstrated in in vitro experiments.