Robotic-Assisted Technology for Medical Training Purposes - Biomechatronics in Medicine and Healthcare - page 176

Figure 12.7 Detail of the mechanism of the Airway Training System: A wire driving
mechanism has been designed to reproduce different kinds of airway difficulties (Noh, Solis,
et al ., 2009). For color reference, see page 220.

at first, the proposed systems should reproduce the physiology and anatomy of the
organs involved during the airway management. The second principle is that the
proposed airway training system should be capable of reproducing various cases
of difficult airway. Finally, an accurate positioning control should be implemented
to simulate as much as possible the task conditions.
As a result of our research, the proposed system is composed of twelve
active and one passive degree of freedom ( Figure 12.7 ). Such actuation system
has been designed to control the position of sixteen wire driving mechanism
that reproduces the airway difficulties (i.e. mandible dental protusion, restricted
opening mouth, etc.). In particular, the wire driving mechanisms was designed
to control the motion of the following muscles: pterygoideus lateralis, masseter,
genioglossus, anterior belly of digastrics, temporalis, styloglossus, and posterior
belly of digastric muscle. In order to reproduce the various cases of difficult
airway, we have designed the artificial organs by considering the range of motion
of human organs. In particular, we reproduced the motion range of the head, neck,
mandible, and hyoid bone as similar as possible to the human. For this purpose,
we have collected information from the medical literature as well as from MRI's
images.
The actuation system is based on a wire drive system to fit into the size of the
human model. The wire drive system consists of the sixteen Teflon coated wires
(low friction coefficient), pulleys and RC servo motors. Basically, the actuation
system controls the motion of the mandible, tongue and oral cavity ( Figure 12.8a ) .
The details of such mechanisms are detailed as follows ( Figure 12.8b ). During the
opening motion of the mouth, with respect with kinetic axis, human have 3-DOFs.
In order to simplify the design, we have implemented 2-DOFs which represent the
rotational motion (

. In order to control the motion of the
mandible, we have attached six wires to the mandible. In addition, three common

θ ) and translational one ( L )