Forbidden region dynamic active constraints for tele-operative surgery

Robotic-assisted minimally invasive surgery has gained greater popularity compared to conventional surgery. However, one of the biggest technical limitations of most commercial tele-operative surgical robots is the lack of haptic feedback, which increases surgeons' mental workload and reduces task safety. This thesis explores potential approaches for addressing this issue. To identify potential avenues for providing haptic guidance to users during tele-operation, a comprehensive review was conducted, narrowing down Active Constraints (AC) as the predominant technical approach in this study. To facilitate algorithm verification in a tele-operation scenario, the first-generation da Vinci Research Kit (dVRK) was employed. Through an extensive review process and a user questionnaire study, major technical constraints of the dVRK were exposed. To address the positioning inaccuracy caused by multiple time-variant factors in the dVRK robot, an on-the-fly calibration framework was then proposed. Both quantitative and qualitative experiments were conducted to verify the effectiveness of the proposed framework, which was then compared with other state-of-the-art methods. To develop an AC pipeline that accounts for eventualities in a real clinical setting, a Forbidden Region Dynamic Active Constraints (FRDAC) framework was then proposed. In vitro trajectory tracking experiments were designed to aid quantitative assessment of the method, including its effectiveness in maintaining task safety, which was confirmed by successfully maintaining a pre-defined safety distance across all trials. Finally, to further examine the proposed FRDAC pipeline in a user-present tele-operation scenario, a pilot user study was conducted. The tracking results demonstrate the effectiveness of the proposed FRDAC pipeline in maintaining a safety distance in a dynamic scenario compared to when no AC was provided to the user. Although the pipeline has proven effectiveness through in vitro experiments, it is acknowledged that certain limitations exist and should be addressed in future studies.