Hybrid Rate—Admittance Control With Force Reflection for Safe Teleoperated Surgery

Teleoperated surgical systems have great potential to improve the performance of surgeons, and their use has spread worldwide in recent years. However, there are some issues that need to be resolved to make robotic surgery more reliable. For instance, the safety of current teleoperated surgical systems is dependent on the performance of the human operator, but human operators can sometimes commit errors. Therefore, a mechanism to ensure the safety of teleoperated surgery should be developed. This paper presents a hybrid system for rate control and admittance control for use in bilateral teleoperation. The proposed control system autonomously avoids excessive contact forces by switching between the rate control mode and the admittance control mode in a stable manner. The stability of the proposed control scheme was analyzed, and the system was found to be able to keep the contact force within an acceptable range. The performance of the proposed control scheme was verified through simulations and experiments. The results of the experiments and simulations showed that the proposed control scheme makes it possible to avoid excessive contact force in a stable manner.