Page 322 - Flexible Robotics in Medicine
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312 Chapter 13
Figure 13.26
Actual flexible manipulator workspace.
the prototype and used this maximum bending angle to formulate the actual workspace for the
flexible manipulator. The relevant images are shown in Figs. 13.24 and 13.25.
The maximum bending angle calculated was 76 degrees, which fell slightly short of design
acceptance criterion 3, which states that BEE should achieve a 360-degree observation field with an
arc of more than 90 degrees. As can be seen from the actual workspace visualization in Fig. 13.26,
the prototype failed to achieve a fully hemispherical workspace as compared with the ideal
workspace. However, we have determined this actual workspace to still be acceptable with regards
to the prototype, as the field-of-view ultimately achieved is sufficient for NPC surveillance and
functions well within the limited confines of the nasopharyngeal cavity.
Finally, we determined the maximum translational speed of the flexible manipulator to be
0.0338 m/s and the maximum rotational speed to be 45.0 degrees/s. This was done by using
the joystick control interface to manipulate the flexible tip and measuring how long it took
for it to traverse 0.104 m (3.01 3.1 seconds and average of 3.07 seconds, for determination
of translational speed) and how long it took to traverse an arc length of 0.042 m (average of
1.69 seconds, for determination of rotational speed). A total of three trials were taken for
each measurement type, and the mean was then taken.
0:042 m
Rotational speed 5 5 0:0249 m=s:
1:69 s
Converting arc length to radian-0:0249 m=s 5 0:777 rad=s:
Converting radian to degrees-0:777 rad=s 5 45:0 degrees=s:
From the results, the BEE performs its thorough surveillance of the nasopharyngeal cavity quickly.
13.6.2 Mechanical analysis of design
As determined in Section 13.6.1, the maximum stress which BEE must endure without
failure was calculated to be 49.7 MPa. This section serves to outline the procedures taken to
