Design of Transmission Tubes for Surgical Push-Pull Robots
AUTHORS
ABSTRACT
The performance of concentric push-pull robots
passing through endoscopes is best if their laser-cut transmission
tubes exhibit high axial stiffness, high torsional stiffness, and
low bending stiffness. In this paper we simultaneously consider
all three output stiffness values in the design problem, explicitly
considering axial stiffness, whereas prior work has focused on
the bending/torsional stiffness ratio. We show that it is very
challenging for existing laser-cut patterns to simultaneously
achieve high axial stiffness and low bending stiffness because
these stiffnesses are tightly coupled. To break this coupling and
balance all three stiffness factors independently, we propose
a new laser material removal design approach that leverages
local stiffness asymmetry (EIx ΜΈ= EIy) in discrete bending
segments separated by segments of solid tube. These discrete
asymmetric segments are then rifled down the tube to achieve
global stiffness symmetry. We parameterize the design and
provide a study of the properties through finite-element analysis.
We also consider the effect of interference between the tubes
when the discrete segments are not aligned. Results show that
our discrete asymmetric segment concept can achieve high axial
stiffness and torsional stiffness better than previously suggested
laser patterns while maintaining equally low bending stiffness.
Tags: Conference Papers 2024