This seminar is open to the public. Students in ME 328 and CS/ME 571 are required to attend.
Prof. Katherine Kuchenbecker
Seminar Topic: Tactile Feedback and Skill Analysis in Robotic Surgery
Although commercial robotic surgery systems such as the Intuitive da Vinci are approved for use on human patients, they provide the surgeon with very little touch feedback. Measuring and recreating tool-tissue interaction forces is technically challenging, especially while satisfying the safety and sterility requirements of surgery. My team at Penn has invented and studied two methods for adding tactile feedback to such systems.
The first approach enables the surgeon to feel high-frequency instrument vibrations, which indicate important transitions in manipulation contact state that are often difficult to discern visually. We mount three-axis high-bandwidth accelerometers to the robot arms under the sterile draping; their outputs drive one-axis voice-coil actuators positioned on the surgeon hand controllers. Categorizing the tool vibrations recorded during in vivo animal surgeries showed that 82% of surgical actions caused measurable vibration cues; recordings during live human surgeries also indicate the clinical feasibility of this approach. Other studies have demonstrated that surgeons doing manipulation tasks significantly prefer receiving this additional vibration feedback over the standard configuration of the da Vinci. This feedback significantly improves the surgeon's ability to detect off-camera instrument collisions, potentially improving patient safety. We have also found that experienced robotic surgeons cause significantly smaller tool vibrations than novice surgeons; this unexpected discovery led us to examine the role instrument vibration feedback can play in training residents and in estimating trainee skill.
Our second approach to providing haptic feedback in robotic surgery centers on palpation, where the surgeon examines soft tissue using his or her fingertips. Working with the University of Siena, we mounted a biomimetic fingertip tactile sensor (SynTouch BioTac) to the end of a da Vinci instrument and developed a custom cutaneous display to attach to the corresponding da Vinci master controller. We calibrate the system by placing the BioTac inside the cutaneous display and recording the fingertip deformations and high-frequency vibrations that the sensor feels at a range of actuator configurations that span its workspace. During use, our control algorithm finds the closest fingertip deformation experienced during calibration and drives the cutaneous display to the corresponding actuator outputs. A human-subject experiment with this system demonstrated that fingertip deformation feedback significantly improved the operator's ability to locate a rigid stick embedded in soft simulated tissue.
Katherine J. Kuchenbecker is an Associate Professor in Mechanical Engineering and Applied Mechanics at the University of Pennsylvania. Her research centers on the design and control of haptic interfaces for applications such as robot-assisted surgery, medical simulation, stroke rehabilitation, and personal computing. She has won several awards for her research, including an NSF CAREER Award in 2009 and the IEEE Robotics and Automation Society Academic Early Career Award in 2012. She gave a TEDYouth talk on haptics in 2012, and she received a Penn Lindback Award for Distinguished Teaching in 2014. Before becoming a professor, she completed a postdoctoral fellowship at the Johns Hopkins University, and she earned her Ph.D. in Mechanical Engineering at Stanford University in 2006.