Proof of Concept Implementation of Forbidden Region Dynamic Active Constraints in Minimally Invasive Surgery

Active Constraints (AC), also named as Virtual Fixtures (VF), are a strategy to provide anisotropic haptic guid- ance for surgeons during use so that motions that comply with safety requirements are permitted, while those that breach safety requirements are negated. AC can be helpful also in a teleoperative surgical scenario, in which surgeons operating on the surgeon-side interface are sep- arated from the patient-side, where surgical instruments are held and manipulatd by a robot. One challenging as- pect of incorporating AC into a modern clinical setting is how to efficiently update pre-constructed AC geometries in real time to account for dynamic tissue movement. In this study, we designed a pipeline for implementing Forbidden Region AC (FRAC), where tissue move- ment is constantly captured by a depth-sensing camera. The effectiveness of the pipeline has been confirmed through in vitro trajectory tracking experiments along a deforming aorta phantom. Our experimental results demonstrate the capability of our method to provide timely corrective guidance when a violation of the safety region is detected.