Fuzzy based velocity constraints of virtual fixtures in tele-robotic surgery

Velocity control is one of important manipulate methods in terms of tele-operation applications, especially in minimally invasive robotic surgery. The input of the user (doctor) is always with the highest hierarchy in the control loop, however the poor force feedback and limited visual cues may cause inappropriate decision-making. In this paper, a virtual constraint of velocity based on fuzzy logic is presented, by which more proper factors are taken into concern. Firstly, a basic model is generated to demonstrate a general scene of robotic surgery. Then, several factors that may influence the quality and safety of a surgery are identified. After that, a new fuzzy logic rule is created and the outputs of the system provide a virtual constraint to the user in order to prevent penetrations and misoperations. Experimental results show that the proposed virtual velocity constraint is able to accurately limit dangerous operations of the user and protect organs of patients.