SUMMARY

Flexible endoscopy has proven to be a powerful diagnostic and therapeutic procedure over several decades. Currently manipulating endoscopes for diagnostic and therapeutic procedures are difficult since the surgeons manually aim the distal end (with a CCD camera is attached), while advancing the endoscope and inspecting interior of cavities on a monitor. During therapeutic endoscopy the surgeon maintains the tip of the endoscope to be at a specific location and manipulates endoscopic tools at the distal end. Involuntary movement of the patient or unintended bodily motion can result in undesirable movement of the endoscope tip. The surgeon must carefully reposition and reorient the endoscope tip before resuming the task. Relocating the endoscope tip can be difficult and time-consuming for the surgeon. More importantly, the disrupted procedure results in a longer operation time and higher complication risks, especially if a biopsy or cautery is conducted with unintended perforation or cutting of tissues possible. Robotic control for the articulated tip section of the endoscope will be studied in this research. The articulated section will be modeled using a serial robot model with the basic Denavit-Hartenberg parameters. The articulated portion is a snake-like or hyper-redundant manipulator with only two controllable degrees-of-freedom at the tip (up-down or left-right directions). The control of this section turns to be a difficult and complicated problem due to the nonlinear characteristic of the friction between the actuating cables and their guide holes. Moreover, hysteresis in the cable system introduces significant nonlinearities into control of the tip and an accurate model of the articulated tip is difficult to obtain. It is proposed to use magnetic tracking sensors in addition to the camera system for effective control. Possible control schemes include position-based, image-based, and uncalibrated visual servoing.