Page 70 - Flexible Robotics in Medicine
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54 Chapter 3
Figure 3.6
Stress strain curve for polyurethane and TangoBlack-VeroClear composite.
fractures or damage/tear can be seen on the specimen. The force-deflection graph and
midspan bending moment versus midspan curvature plots can be obtained to measure
bending flexibility. The fixed span length permits force versus deflection comparisons to be
made independently of the specimen length. This is useful for comparing the flexibility of
the diamond-cut endoscope with varying diameters or structural designs.
3.4.2 Functionality test
3.4.2.1 Bending capability test
In order to determine the bending angle, the endoscope is placed at the 90-degree mark just
above the protractor. By manipulating the cables controlling the bending directions of the
endoscope, we will be able to measure the bending angle directly from the protractor, as
shown in (Fig. 3.8). With the diamond-cuts design, the endoscope can achieve a bending
angle of 90 degrees. With the motorization of the control system and proper material
selection and fabrication, we foresee the possibility of achieving a bending angle more
significant than 90 degrees in subsequent prototype fabrications.
3.4.2.2 The functionality of the mechanical zooming segment
As shown in the diagrams (A) and (B), the endoscope is able to retract its camera to avoid
an obstacle (Fig. 3.9). Diagrams (C) and (D) depict the collision and displacement of the
