title: Shape Tracking of a Dexterous Continuum Manipulator Utilizing Two Large Deflection Shape Sensors.
abstract: Dexterous continuum manipulators (DCMs) can largely increase the reachable region and steerability for minimally and less invasive surgery. Many such procedures require the DCM to be capable of producing large deflections. The real-time control of the DCM shape requires sensors that accurately detect and report large deflections. We propose a novel, large deflection, shape sensor to track the shape of a 35 mm DCM designed for a less invasive treatment of osteolysis. Two shape sensors, each with three fiber Bragg grating sensing nodes is embedded within the DCM, and the sensors' distal ends fixed to the DCM. The DCM centerline is computed using the centerlines of each sensor curve. An experimental platform was built and different groups of experiments were carried out, including free bending and three cases of bending with obstacles. For each experiment, the DCM drive cable was pulled with a precise linear slide stage, the DCM centerline was calculated, and a 2D camera image was captured for verification. The reconstructed shape created with the shape sensors is compared with the ground truth generated by executing a 2D-3D registration between the camera image and 3D DCM model. Results show that the distal tip tracking accuracy is 0.40 ± 0.30 mm for the free bending and 0.61 ± 0.15 mm, 0.93 ± 0.05 mm and 0.23 ± 0.10 mm for three cases of bending with obstacles. The data suggest FBG arrays can accurately characterize the shape of large-deflection DCMs.
authors.affiliation: State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 100080, China, and also with the Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218 USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
authors.affiliation: Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218 USA.
authors.forename: Amirhossein
authors.initials: A
authors.lastname: Farvardin
authors.affiliation: Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218 USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Grupp
authors.affiliation: Applied Physics Laboratory, Johns Hopkins University, Baltimore, MD 21218 USA.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Murphy
authors.affiliation: Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218 USA.
authors.forename: Russell H
authors.initials: RH
authors.lastname: Taylor
authors.affiliation: Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218 USA.
authors.forename: Iulian
authors.initials: I
authors.lastname: Iordachita
authors.affiliation: Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218 USA, and also with the Applied Physics Laboratory, Johns Hopkins University, Baltimore, MD 21218 USA.
authors.forename: Mehran
authors.initials: M
authors.lastname: Armand
keywords: Fiber Bragg grating; dexterous continuum manipulator; large curvature; obstacle; shape tracking