title: Tendon-driven continuum robot for neuroendoscopy: validation of extended kinematic mapping for hysteresis operation.
abstract: OBJECTIVE
  The hysteresis operation is an outstanding issue in tendon-driven actuation--which is used in robot-assisted surgery--as it is incompatible with kinematic mapping for control and trajectory planning. Here, a new tendon-driven continuum robot, designed to fit existing neuroendoscopes, is presented with kinematic mapping for hysteresis operation.
  
  
  METHODS
  With attention to tension in tendons as a salient factor of the hysteresis operation, extended forward kinematic mapping (FKM) has been developed. In the experiment, the significance of every component in the robot for the hysteresis operation has been investigated. Moreover, the prediction accuracy of postures by the extended FKM has been determined experimentally and compared with piecewise constant curvature assumption.
  
  
  RESULTS
  The tendons were the most predominant factor affecting the hysteresis operation of the robot. The extended FKM including friction in tendons predicted the postures in the hysteresis operation with improved accuracy (2.89 and 3.87 mm for the single and the antagonistic-tendons layouts, respectively). The measured accuracy was within the target value of 5 mm for planning of neuroendoscopic resection of intraventricle tumors.
  
  
  CONCLUSIONS
  The friction in tendons was the most predominant factor for the hysteresis operation in the robot. The extended FKM including this factor can improve prediction accuracy of the postures in the hysteresis operation. The trajectory of the new robot can be planned within target value for the neuroendoscopic procedure by using the extended FKM.
authors.affiliation: National Center for Image Guided Therapy, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.|Healthcare Optics Research Laboratory, Canon U.S.A., Inc., Cambridge, MA, USA.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Kato
authors.affiliation: Mechanics R&D Center, Canon Inc., Tokyo, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Okumura
authors.affiliation: Mechanics R&D Center, Canon Inc., Tokyo, Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Kose
authors.affiliation: Mechanics R&D Center, Canon Inc., Tokyo, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Takagi
authors.affiliation: National Center for Image Guided Therapy, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA. hata@bwh.harvard.edu.|Department of Radiology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA. hata@bwh.harvard.edu.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Hata
mesh_terms: D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D055595:Mechanical Phenomena; D044583:Neuroendoscopy / Q000379:methods*; D015203:Reproducibility of Results; D012371:Robotics / Q000295:instrumentation*
keywords: Continuum robot; Neuroendoscopy; Robot control; Robot kinematics; Tendon-driven robot