Automatic Field of View Adjustment of an RCM Constraint-Free Continuum Laparoscopic Robot

Automatic laparoscopic field of view (FOV) adjustment can effectively assist surgeons in minimally invasive surgery (MIS). However, existing work based on rod-shaped laparoscopes is inevitably constrained by the remote center of motion (RCM) during the process of FOV adjustment. The RCM limits laparoscopic movement and makes modeling and control more complex. This paper proposes a novel tendon-driven continuum laparoscope that is not affected by the RCM constraint. Furthermore, an automatic FOV adjustment method is designed for the proposed laparoscope robot, which considers the surgical instrument position and size in the image, as well as eye-hand consistency. Two simulation platforms are developed using MATLAB and Webots to intuitively study and optimize the proposed adjustment method. The convergence time of surgical tool tracking with a complex 3D trajectory is only 1s, the average tracking error after stabilization is about 9.97 pixels, and the maximum eye-hand error is only 0.04°. A first-generation prototype is built to verify the tracking performance of the proposed tendon-driven continuum laparoscope. The experimental results show that the proposed system can perform real-time laparoscopic FOV adjustment without being constrained by the RCM.