Teleoperated control based on virtual fixtures for a redundant surgical system

One of the main limitations of systems for Minimally Invasive Robotic Surgery is the lack of haptic feedback. In this paper, a teleoperated system for robotic surgery is introduced, able to guide the surgeon towards a target anatomy by providing her with force feedback based on Virtual Fixtures (VF). The teleoperated system has a redundant slave robot. A closed-form inverse kinematics is proposed to solve redundancy that is based on an optimization approach in one variable. Four different cost objective functions are proposed in the paper and one is implemented and validated, i.e. the cost function aimed at minimizing the amount of space of the robot in the operative theater during the surgical procedure. The proposed teleoperated architecture has been tested on a teleoperated system composed of a 3-DoFs haptic joystick and a 7-DoFs anthropomorphic manipulator. Experimental tests on 12 volunteer subjects have been carried out. Results demonstrate that a force feedback based on VF provides a statistically significant enhancement of procedure accuracy.