Development of a Sensor Concept for the Measurement of Tissue Interaction Forces in Minimally Invasive Robotic Surgery

Abstract

This thesis describes the development of a sensor concept for sensing tissue interaction forces in minimally invasive surgery. An overview of force sensing principles, force feedback instruments, and the requirements for force sensors in minimally invasive robotic surgery is provided based on current state of the art. Moreover, current commercially available miniature force/torque sensors are assessed for compliance with the defined requirements for integration into the minimally invasive robotic instrument MICA developed at the German Aerospace Center (DLR). A field study is performed regarding the validity of partial force feedback. The study shows that the most sensible solution is represented by the feedback of the end-effector actuation force. Former research on the MICA instrument shows that the actuation of the end-effector influences the tissue interaction force measurement. Therefore, a test bench is developed to examine the influences of the instrument actuation on a force sensor placed between the wrist of the instrument and the end-effector. A mathematical model describing the force correlations in the test bench is defined and verified by experiments. Initial results indicate the required improvements needed for the test bench and experiment design, which are implemented in a final test plan. This thesis concludes with a concept presentation for the integration of a commercially available force sensor with the MICA instrument, providing a compensation solution for the influences of the end-effector actuation.