TY - JOUR

T1 - Modeling, calibration, and evaluation of a tendon-actuated planar parallel continuum robot

AU - Nuelle, Kathrin

AU - Sterneck, Tim

AU - Lilge, Sven

AU - Xiong, Dezhu

AU - Burgner-Kahrs, Jessica

AU - Ortmaier, Tobias

N1 - Funding information: Manuscript received February 24, 2020; accepted June 24, 2020. Date of publication July 17, 2020; date of current version July 30, 2020. This letter was recommended for publication by Associate Editor M. Liu and Editor D. Song upon evaluation of the Reviewers’ comments. This work was supported by the German Research Foundation (DFG) under Grants OR 196/35-1 and BU 2935/5-1. (Kathrin Nuelle and Tim Sterneck contributed equally to this work.) (Corresponding author: Kathrin Nuelle.) Kathrin Nuelle, Tim Sterneck, Dezhu Xiong, and Tobias Ortmaier are with the Institute of Mechatronic Systems, Leibniz University Hannover, 30823 Garbsen, Germany (e-mail: kathrin.nuelle@imes.uni-hannover.de; tsterneck@gmx.de; dezhu.xiong@gmail.com; tobias.ortmaier@imes.uni-hannover.de).

PY - 2020/7/17

Y1 - 2020/7/17

N2 - In this work, a novel planar parallel continuum robot (PCR) is introduced, consisting of three kinematic chains that are coupled at a triangular end-effector platform and include tendon-actuated continuum segments. The kinematics of the resulting structure are derived by adapting the descriptions for conventional planar parallel manipulators to include constant curvature bending of the utilized continuous segments. To account for friction and non-linear material effects, a data-driven model is used to relate tendon displacements and curvature of the utilized continuum segments. A calibration of the derived kinematic model is conducted to specifically represent the constructed prototype. This includes the calibration of geometric parameters for each kinematic chain and for the end-effector platform. During evaluation, positioning repeatability of 1.0% in relation to one continuum segment length of the robot, and positioning accuracy of 1.4%, are achieved. These results are comparable to commonly used kineto-static modeling approaches for PCR. The presented model achieves high path accuracies regarding the robot's end-effector pose in an open-loop control scenario.

AB - In this work, a novel planar parallel continuum robot (PCR) is introduced, consisting of three kinematic chains that are coupled at a triangular end-effector platform and include tendon-actuated continuum segments. The kinematics of the resulting structure are derived by adapting the descriptions for conventional planar parallel manipulators to include constant curvature bending of the utilized continuous segments. To account for friction and non-linear material effects, a data-driven model is used to relate tendon displacements and curvature of the utilized continuum segments. A calibration of the derived kinematic model is conducted to specifically represent the constructed prototype. This includes the calibration of geometric parameters for each kinematic chain and for the end-effector platform. During evaluation, positioning repeatability of 1.0% in relation to one continuum segment length of the robot, and positioning accuracy of 1.4%, are achieved. These results are comparable to commonly used kineto-static modeling approaches for PCR. The presented model achieves high path accuracies regarding the robot's end-effector pose in an open-loop control scenario.

KW - calibration and identification

KW - Flexible robots

KW - kinematics

KW - parallel robots

UR - http://www.scopus.com/inward/record.url?scp=85089303726&partnerID=8YFLogxK

U2 - 10.1109/LRA.2020.3010213

DO - 10.1109/LRA.2020.3010213

M3 - Article

AN - SCOPUS:85089303726

VL - 5

SP - 5811

EP - 5818

JO - IEEE Robotics and Automation Letters

JF - IEEE Robotics and Automation Letters

SN - 2377-3766

IS - 4

ER -