Virtual Tendon-Based Inverse Kinematics of Tendon-Driven Flexible Continuum Manipulators

Tendon-driven Flexible Continuum Manipulators (FCMs) have proven their potential usability in confined and unstructured environments where rigid-link manipulators under-perform. However, inverse kinematics remains a challenge. This paper presents a new approach that relates the manipulator's workspace to the actuation space. In this approach, a virtual actuation space is defined, comprising a virtual tendon and the bending plane of the manipulator. The change in lengths of the actuating tendons that cause the bending is mapped to the change in the length of a single virtual tendon. An example of a tip-actuated three-tendon FCM provides a detailed description of the forward and inverse kinematics and experimental validations. The experimental results show a reasonable match between the commands and estimates. This approach reduces the order of the actuation space from three tendons to one tendon for the example system, thus, providing a simpler method for designing and controlling FCMs with multiple sections.