An impedance control strategy for a hand-held instrument to compensate for physiological motion

Current trends in robotic cardiac surgery presage for allowing physiological motion compensation in beating-heart surgery. However, interacting with fast moving soft organs by means of stiff instruments/robots is challenging. This paper concerns comanipulation with a hand-held instrument, the goal being to allow the surgeon to perform low frequency motions that correspond to the surgical task while a distal part of the instrument actively moves in synchronism with the heart motion in order to guarantee that the contact is maintained. This paper explores the difficulties of implementing low-impedance control on a novel hand-held motion compensation instrument. A force feedback control strategy is proposed and evaluated experimentally on a simulated surgical scene. Taking advantage of the sensory capacities of the prototype presented, a successful modulation of the dynamics of interaction is reached. Conclusive results on the performances of the system and possibilities of future improvements are given.