Asymmetric force feedback control framework for teleoperated robot-assisted surgery

Lack of haptic feedback in teleoperated robot-assisted surgery (RAS) is known to be detrimental in many surgical tasks. While performing a class of force sensitive tasks, surgeons commonly use both hands. Oftentimes, one hand is used to exert tension/compression forces, and the other to hold the suture knot or tissue. A novel control framework to accomplish haptic force feedback for two-handed tasks in teleoperated RAS is presented in this paper. The force applied on the surgical environment by the action hand is not transferred back to the same hand, but rather to the other hand. In two-handed tasks that involve an action and a reaction force, this provides an intuitive way of feeling the action. Because the loop in not closed from the slave back to the master of the same hand, it does not have a destabilizing effect. The technique can be easily implemented using a variable-structure controller that combines two PD controllers and a switch. It has been evaluated with an experimental setup consisting of four haptic devices with promising results.