Page 296 - Flexible Robotics in Medicine

286 Chapter 12

However, one primary concern is the difficulty in expecting the shape of the multiple-
section flexible manipulators, without advanced control algorithms. Various trials were
conducted to achieve the required shape to reach the expected location defined in the
Fig. 12.14, which illustrates the cadaveric environment, where the manipulator has to go
thorugh the oral cavity to reach the desired site.

12.5 Discussion

12.5.1 Comparison with existing flexible manipulator platforms

The workspace of the designed flexible manipulator platform is calculated using the length
and the number of bending sections, as presented in this chapter. The workspace of the
flexible manipulator in this chapter is comparable to existing designs despite having only
two bending sections. For example, the workspace required by the highly versatile single-
port system platform is 10 by 10 by 6 cm [7] as compared to the proposed design with the
workspace of 12 by 12 by 12 cm. However, it is essential to note that the workspace
concerned is only the bending of the flexible manipulator and not the translational
workspace.

Secondly, based on the manipulation of the shapes conducted in the analysis, the ability of
the flexible manipulator to carry its own weight is comparable to that of the modular two
bending segment endoscope designed by Chen, Liang, and Hunter [8]. Both the flexible
manipulator platform and the one designed by Chen, Liang, and Hunter exhibit a strong
linear relationship in their measured angle versus desired angle plots for a two-section
bending flexible manipulator system.

12.5.2 Biocompatible materials

Since this chapter is aiming to develop a preliminary robotic surgical platform, in the long
run, it is essential to keep in mind that the fabrication of the flexible arm must be fabricated
from biocompatible materials eventually. Possible materials that could be used for 3D
printing the flexible manipulator arms are MED610 or polylactic acid [3f]. These materials
are suitable for the fabrication of the flexible arm.

12.5.3 Precision positioning

From the experiments conducted, it can be suspected that there is a degree of positioning
error of the tendon-driven flexible arm that could be multiplied at the distal end due to the
displacement amplification at the distal end from the proximal end. This might result in an
amplification of the velocity, creating a leverage effect [9].