Hybrid control of master-slave velocity control and admittance control for safe remote surgery

Remote surgery has attracted great interest in recent decades because it has the potential to improve equality of access to health care. However, remote surgery has not been approved in any country, since patient safety cannot be guaranteed. In this paper, we present a hybrid control system for master-slave velocity control and admittance control for safe remote robotic surgery. The proposed controller switches between these two controls adaptively and stably and avoids excessive contact force between the robotic surgical instrument and the patient's organs. Through the proposed scheme, the contact force between the robotic instrument and objects at the slave site can be bounded by a set upper limit regardless of the motion the operator inputs at the master site. The performance of the proposed system was verified analytically. The proposed control scheme was implemented in a robotic surgical system and its performance was verified through simulations and experiments. The results of the simulations and experiments showed that the system autonomously switches stably between master-slave velocity control and admittance control and avoids excessive contact force.