Comparing Human Haptic Perception and Robotic Force/Torque Sensing in a Simulated Surgical Palpation Task

In minimally invasive surgery (MIS), the reliable detection of hard inclusions in soft tissue is crucial for the success of the intervention. In robot-assisted surgery (RAS) however, limited technologies are available for intracorporeal tissue stiffness assessment due to the lack of force and tactile feedback from the robot tool tip. This paper investigates both, human haptic perception and robotic F/T sensing in similar experimental setups to draw conclusions about the usage of a haptic sensor for teleoperation in RAS. We use a novel 6-axis F/T sensor compact enough to be moved through trocars during RAS interventions and experimentally analyze its performance in a simulated robotic palpation task. Furthermore, we carry out a comprehensive user study $(n=30)$ and collect fingertip interaction data to investigate human haptic perception. Results show, that both approaches detect larger bead diameters of 19 mm and 15 mm with high precision and show similar accuracy rates. With regards to interaction forces, subjects on average apply more than 10 times the amount of normal force $(F_{z}=28.8\pm 4.9\mathrm{N})$ , which leads to higher accuracy particularly for smaller embedded nodules. The robotic sensing technique, on the contrary, offers distinct advantages by providing more gentle treatments and reducing the risk of tissue damage.