EndoCAT: An EtherCAT-based Articulated Rear View Endoscope for Single Port Surgery

Single port and natural orifice surgeries gain popularity compared to multi-port ones. The main reason is that single port surgeries are less invasive and thus less harmful to the patient than multiport surgeries. However, one of the drawbacks of devices for single port surgery is their limited access to regions proximate to the point of entrance. Moreover, they are strongly limited in choosing (controlling) the end-effector's orientation. Thus, inspecting a point of interest inside the endoscope's workspace from different angles is challenging. To overcome the existing limitations, we propose an EtherCAT-based master-slave robotic system. This master-slave system consists of an articulated endoscope with two work channels that can be manipulated by a force-sensing joystick. The articulated endoscope is capable of realizing a large range of orientations $\pmb{(\pm 220^{\text{o}})}$ throughout the workspace, can turn back, and look upon itself within a radius of 40 mm. The suggested robotic system will be useful in single port interventions such as inspections and treatments of the cardiac sphincter, the fundus in the stomach, or the neck of the bladder. In this paper, we present the design of the endoscope, analyze its kinematics, and present the workspace including the feasible orientations. Finally, the independent tele-operated joint control of the master-slave system EndoCAT is demonstrated in two experiments on a mockup stomach.