The flexible caterpillar based robotic colonoscope actuated by an external motor through a flexible shaft

Previously developed robotic colonoscopes have difficulties in performing diagnostic procedures since they should be performed by experienced endoscopists to control the device efficiently. In the previous study, therefore, we presented a robotic colonoscope adopting an electric motor in the body to rotate elastic caterpillars. However, the installed small motor, due to the limitation of the robot size, limited velocity and thrust force. In addition, the electrical short can occur when it is operated in the watery lumen of a pig colon. Therefore, in this paper, we present a robotic colonoscope based on elastic caterpillars which are activated by an external motor through a flexible shaft. Since it uses a high power motor, it enables faster self-locomotion in the colon and to prevent short circuits. First of all, we investigated the velocity of the robot according to thrust force and torque from the flexible shaft generated by the motor which influences the robot performance. In preliminary tests, the robot performance was tested in various radii of the acrylic pipes and a latex tube. After obtaining promising results in the artificial colon, we carried out the ex-vivo test by using an excised pig colon. Conclusively, the robot showed the reliable locomotion performance of about 2.58 cm/s without causing any mucosal injury of the colon.