Page 377 - Flexible Robotics in Medicine

370 Chapter 16

Figure 16.5
(A) Ten-millimeter diameter prototype, with a total height of 54 mm, threaded by stainless steel
wires. (B) Tilting of the ring by pulling of the wires. (C) Actual prototype attached with metal
wires.

16.2.3 Orientation actuation components and rationale

16.2.3.1 Tilting mechanism
The tilting mechanism is an essential feature of P.A.T.S. This mechanism allows the
camera to scan through a single plane of the nasopharynx region right in front of
the camera. A larger viewing area can be achieved by coupling the rotation mechanism.
There are four major components that are associated with the tilting mechanism. The
components are the camera holder, the tip, two stainless steel wires, and the servo motor.
The two stainless steel wires are threaded through the sides, then enclosed in the sheath,
and finally threaded through the two holes on the axle of the servo motor.

The tilting mechanism is controlled and powered by servo motor pulling on the two
stainless steel wires that are wounded at both sides of the motor axle (Fig. 16.6). The
axle can be rotated in either direction, clockwise and anticlockwise. When the axle above
the motor is rotated in a clockwise manner, as shown in Fig. 16.7,itwillexert apulling
force on one side of the camera holder, causing it to tilt to one side (Fig. 16.8).
Similarly, rotation in an anticlockwise direction will tilt the camera holder to the opposite
side. Both the wires are in tension when the axle is in a neutral position. However, when
the axle is rotated, one of the wires will loosen while the other wire will tighten, as
shown in Fig. 16.7, ensuring that there is always at least a wire in tension in order to tilt
the camera holder.