Automation of Intraoperative Tool Changing for Robot-Assisted Laparoscopic Surgery.

Intraoperative tool change is a time-consuming and labor-intensive task for robot-assisted laparoscopic surgery. Serial multi-DOF manipulators are potential devices for realizing automatic intraoperative tool changes because of the layout flexibility and motion range, and multi-DOF makes it feasible for the manipulator to access and fetch the surgical tools by itself. However, the direction of the trocar may change because of the soft abdomen, and the lack of a fixed RCM makes it difficult for manipulators to reinsert a new surgical tool through the trocar. This study proposes a system prototype using a 7-DOF manipulator to automatically conduct the intraoperative tool-changing task. The newly designed surgical tool docking station facilitates surgical tool coupling/decoupling by rotating the manipulator's end effector once. The proposed trocar recognition method with position error compensation is reliable for aligning a new surgical tool to the trocar port, even when the direction of the trocar is changed. The experimental results confirms that the manipulator can accomplish an intraoperative tool changing task without additional assistance or correction from the human.