Page 381 - Flexible Robotics in Medicine

374 Chapter 16

Figure 16.12
Location of servo motor after rotation by a stepper motor.

another direction, ensuring that the camera is able to view the entire nasopharynx region
effectively.

There are five components that are associated with the rotation mechanism, namely the tip,
the sheath, two stainless steel wires, the motor wheel, and the stepper motor. The motor
wheel serves as a platform for the servo motor to couple with the stepper motor. The motor
wheel is screwed to the shaft of the stepper motor so that the wheel will rotate with the
shaft while rotating the servo motor along at the same time. Fig. 16.12 shows that the servo
motor has been rotated 180 degrees by the stepper motor.

16.3 Design verification

Design verification is to confirm that the design outputs fulfill the design input requirements.
Mechanical tests are conducted to determine the failure of the materials under different
conditions such that the device is safe enough under various load conditions.

16.3.1 Deflection

In order to ensure the safety of the device when it is operating, the stability of the device is
taken into consideration. Thus the deflection of P.A.T.S is measured to determine the
stability during the maneuvering process. Since the sheath is made of TangoBlack, which is
a rubber-like material, the sheath tends to bend when force is exerted on it. As shown in
Fig. 16.13, there is a deviation of 10 degrees up and down about the neutral axis of the
sheath of P.A.T.S. The diameter of human adult nasal passageway is about 7 8 mm , thus