Experimental evaluation of robot-assisted tactile sensing for minimally invasive surgery

The 10 mm incisions used in minimally invasive cancer surgery prevent direct manual palpation of internal organs, making intraoperative tumor localization difficult. A tactile sensing instrument (TSI), that uses a commercially available sensor to measure distributed pressure profiles along the contacting surface, has been developed to facilitate remote tissue palpation. The objective of this research was to assess the feasibility of using the TSI under robotic control to reliably locate underlying tumors. The performance of human and robot manipulation of the TSI to locate tumor phantoms embedded into ex vivo bovine livers was compared. An Augmented Hybrid Impedance Control scheme was implemented on a Mitsubishi PA10-7C robot to perform force/position control during the trials. The results showed that using the TSI under robotic control realized an average 35% decrease in the maximum forces applied, and more than a 50% increase in tumor detection accuracy when compared to manual manipulation of the same instrument. This demonstrates that tumor detection using tactile sensing is highly dependent on the consistent application of forces on the tactile sensing area and that robotic assistance can be of great benefit when trying to localize tumors during minimally invasive surgery.