Development Of A Novel Colonoscope Force And Torque Sensor

Colonoscopy is an effective and minimally invasive method for inspection, diagnosis and treatment of colon diseases, and it is widely used now. However, there is still about10%failure rate with this technology, and two most important failures are perforation and looping. To overcome these failures, the key is to get the information of force between the distal end (tip for short) and colon and the position (including orientation) of the tip during the operation. One of the solutions is to have a sensor mounted on the tube of the colonoscope, which measures both pushing force and twisting torque produced by medical doctor (MD) and this information is then used to infer the aforementioned force information and position information of the tip. Such a sensor is called colonoscope force/torque sensor (CFTS). However, the CFTS today still has many to be desired, e.g. bulky, difficulty to operate, and more components.The research reported in this thesis aimed to develop a novel CFTS with the characteristics of high agility, ease with operation, and simplicity with fewer components. There are three specific objectives defined for this research, namely (1) to make a rational analysis of the existing design using the Axiomatic Design Theory (ADT);(2) to propose new design principles and corresponding structures including the circuit, then through calibration experiment, calculate each static performance index of the desined CFTS;(3) to integrate the CFTS developed in this research and colonoscope to demonstrate the effectiveness of the developed CFTS.The main results of this study are including:(1) A sensing system based on resistance strain principle has been designed and a seires of static performance index such as linearity, sensitivity, resolution, accuracy and rate of static coupling have been calculated. The results show that the sensor system is superior to the existing similar sensor system;(2) A novel structure of CFTS has been proposed and it has the following advantages:small in size, light in weight, simple and easy to operate;(3) The prototype has been manufactured and it’s effectiveness and operability have been proved.This research has made contribution to the field of sensor especially with the so called machine wearable sensor without intrusiveness and to the field of colonoscopy technology with a safer operation which is highly expected.