Design and Control of a Robotic System with Redundant Degrees of Freedom for Surgical Assistants

Robot-assisted surgery is a rapidly growing area of modern medicine. However, there are no robotic systems that support surgical assistants in their tasks. Currently, they have to work directly next to the surgical robot on the patient, which is ergonomically problematic and carries a risk of collision. This work presents a dual-arm surgical assistant robotic system with up to 13 degrees of freedom (DOFs) that can be controlled by the surgical assistant. The redundant DOFs allow evasive maneuvers to avoid collisions with the primary surgical robot. For teleoperation, a twist-based control is implemented to transfer the movements of the surgical assistant to the instruments on the robotic arms, while maintaining the remote center of motion (RCM) constraint required for laparoscopic surgery. Collision avoidance is achieved by model predictive control (MPC)-based calculation of the avoidance motion. A digital twin of the operating room fuses data from the assistive robotic system, the primary surgery robot, and an optical tracking system. The effectiveness of the collision avoidance is demonstrated in simulations. In real-world experiments, the control via the surgical console is evaluated and it is shown that an average RCM deviation of less than 2.5 mm can be achieved.