Kinematic model of colonoscope and experimental validation

Minimally invasive surgery represents the future of many types of medical intervention, such as endoscopic surgery. Colonoscopy involves the insertion of a flexible instrument (a colonoscope) into the human colon for the diagnosis and management of diseases of the colon. A colonoscope consists of a control hand unit with valves and a manoeuvrable bend section at the distal end controlled by two knobs at the control hand unit. During colonoscopy, loop formation present challenges. The form of a walking stick at the distal end of the scope plays a major role in loop formation in colonoscopy. Thus, an accurate kinematic model of the relationship between the motion of the distal end and the control unit could help colonoscopists effectively manipulate the motion of the distal end to avoid loop formation. This study uses D-H parameters to model the kinematics of the distal end of a colonoscope and analyzes the kinematic relationship between the motion of the tip of the colonoscope and the angular control at the control hand unit. The position and orientation of the distal end of the scope can be predicted for a given operation at the control unit. The kinematic model is validated by the experiment.