PROJECT TITLE :

Steering of Multisegment Continuum Manipulators Using Rigid-Link Modeling and FBG-Based Shape Sensing

ABSTRACT:

Correct closed-loop control of continuum manipulators needs integration of both models that describe their motion and methods to guage manipulator shape. This work presents a model that approximates the continual shape of a continuum manipulator by a serial chain of rigid links, connected by flexible rotational joints. This rigid-link model permits a description of manipulator shape under completely different loading conditions. A kinematic controller, primarily based on the manipulator Jacobian of the proposed rigid-link model, is implemented and realizes trajectory tracking, while using the kinematic redundancy of the manipulator to perform a secondary task of avoiding obstacles. The controller is evaluated on an experimental testbed, consisting of a planar tendon-driven continuum manipulator with 2 bending segments. Fiber Bragg grating (FBG) sensors are used to reconstruct 3-D manipulator form, and is used as feedback for closed-loop control of the manipulator. Manipulator steering is evaluated for two cases: the first case involving steering around a static obstacle and therefore the second case involving steering along a straight path whereas avoiding a moving obstacle. Mean trajectory tracking errors are 0.24 and 0.09 mm with maximum errors of one.thirty seven and zero.52 mm for the first and second cases, respectively. Finally, we demonstrate the chance of FBG sensors to measure interaction forces, whereas simultaneously using them for form sensing.