title: Sensorless Force Sensing for Minimally Invasive Surgery.
abstract: Robotic minimally invasive surgery (R-MIS) has achieved success in various procedures; however, the lack of haptic feedback is considered by some to be a limiting factor. The typical method to acquire tool-tissue reaction forces is attaching force sensors on surgical tools, but this complicates sterilization and makes the tool bulky. This paper explores the feasibility of using motor current to estimate tool-tissue forces and demonstrates acceptable results in terms of time delay and accuracy. This sensorless force estimation method sheds new light on the possibility of equipping existing robotic surgical systems with haptic interfaces that require no sensors and are compatible with existing sterilization methods.
authors.affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68508 e-mail:  baoliang.zhao2@gmail.com.
authors.forename: Baoliang
authors.initials: B
authors.lastname: Zhao
authors.affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68508 e-mail:  cnelson5@unl.edu.
authors.forename: Carl A
authors.initials: CA
authors.lastname: Nelson
keywords: force feedback; robotic minimally invasive surgery; sensorless force estimation