Haptic interface hardware system for endoscopy training

Abstract

This thesis develops a new haptic interface hardware system which is suitable for implementing the characteristics of endoscopy training. Endoscopic haptic devices with 4 DOF and 3 DOF are developed and the haptic interface system including the haptic device, the motor driver, the host computer with a control board, and Graphic User Interface (GUI) is implemented. The 3 DOF haptic device is designed with one prismatic joint and two revolute joints to provide endoscopic motions. The 4 DOF haptic device that improves defects of the 3 DOF haptic device and implements even roll motion of endoscopy is developed. Motor torques are transmitted using wire-driven mechanism which provides large torques and back drivability. Kinematics, inverse kinematics, and Jacobian matrix are derived. The central axes of each DOF are designed to intersect at one point, and this makes the equations of kinematics and inverse kinematics simple. Performance indexes such as continuous and maximum exertable force and torques, workspace, sensitivity, and inertia of each joint are measured. Frequency response tests such as bandwidth and phase are performed. Experiments to measure bandwidth of the 3 DOF PHANToM are performed to compare developed devices with commercial ones.