Enhancement of Force Feedback in Teleoperated Surgery

Providing the surgeon with force information from interactions can potentially restore the feeling of presence at the operation site. Nevertheless, despite the advantages of force feedback in teleoperated surgery, many surgical teleoperation systems lack this feature. This thesis presents novel approaches for providing force feedback that may increase the safety of surgical procedures. This thesis proposes and experimentally validates an adaptive force reflecting method for teleoperations involving stiff tissues. The proposed method estimates the parameters of the Kelvin-Voigt model of the tissue in real-time, and adaptively scales and feeds back the interaction force to the surgeon to ensure stable contact at every moment. The proposed adaptive force reflecting method can be added to existing teleoperation systems with no force feedback mechanism, and thus provide some degree of force feedback to the surgeon. The humanâ s discrimination ability is generally degraded for low-intensity stimuli; consequently, in micro-surgery excessive forces may be applied by the surgeon in order to discriminate between different tissues, and this could result in damaging delicate tissue structures. This thesis studies the discrimination ability of the human at low-intensity forces through estimating just noticeable differences (JNDs). The relationship between estimated JNDs and reference forces was then mathematically modeled. This model is employed in the design of a force feedback strategy and teleoperation control architecture that augments the force feedback based on human discrimination ability. The experimental results indicate that augmented force feedback compared to traditional force feedback significantly reduces the average applied forces to the phantom tissue, and the number of errors a subject made in discriminating between phantom tissues.Ph.D