Page 321 - Flexible Robotics in Medicine

Design evolution of a flexible robotic bending end-effector for transluminal explorations 311

‘Stress 5 49:7 MPa:

We, therefore, took 49.7 MPa as theoretical maximum stress at which the device will not
fail. All design verification tests conducted from this point on used this theoretical
maximum as an acceptance criterion for validation purposes.

Using the theoretical θ max as determined before, we can also attempt to generate a
theoretical workspace in which the flexible manipulator operates within the nasopharyngeal
cavity. This workspace can be generated using the equation if we assume the workspace to
be roughly a hemisphere (Fig. 13.25):
2
2
2
2
x 1 y 1 z 5 R ;

sin Nθ max
ð
where R 5 H 1 h 0 Þ 2 ;
sin θ max
2
‘R 5 15:7mm:
However, this is simply a theoretical workspace, so we carried out verification to determine the
true workspace of the device. Using a protractor, we measured the maximum bending angle of

Figure 13.25
Theoretical workspace of the flexible manipulator.