A Novel Haptic Device With Force Feedback and Closed-Loop Torque Control for Endoscopic Procedure

In robot-assisted endoscopic procedures, the surgeon steers haptic devices to perform delicate and interactive surgical tasks on soft tissue. This instrument of the haptic device can measure the surgeon’s hand motion information and send motion commands to the remote flexible manipulators. It is also required to render accurate force feedback to the surgeon. However, the lack of force feedback and closed loop torque control in most haptic devices poses a challenge. There is also a mismatch in the degree-of-freedom (DOF) between the haptic device and the flexible manipulator. To resolve these issues, we have developed a haptic device with force feedback and accurate torque output, which has 5-DOFs for recording hand translation, pitch, yaw, roll, and gripping motion displacements. The pneumatic actuator was used for real-time force feedback, which can respond promptly within 180 ms and deliver a torque of 300 Nmm. The torque measurement system was incorporated into the pneumatic actuator to detect its actual output torque. The fuzzy PID method was adopted to construct the closed loop control system, realizing enhancements of 77.5% and 59.1% in torque accuracy and response time, respectively. Utilizing the force feedback leader-follower control strategy, the haptic device can effectively regulate the flexible manipulator and render the feedback force to the surgeon. The haptic device’s performance was also evaluated in both <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ex-vivo</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in-vivo</i> animal trials, demonstrating its feasibility for endoscopic procedures.