Page 415 - Flexible Robotics in Medicine

EndoGoose: a flexible and steerable endoscopic forceps 409

Figure 18.5
The maximum bending angle of the prototype.

the maximum angle; bending will stop when force is still being applied. Using 316 L type
stainless steel gives us an ultimate yield strength of 490 MPa, which will give us a
sufficient strength for the withdrawal of the accessory.

18.3.1 Design review of satisfying design acceptance criteria

To check if we have fulfilled the criteria of the design, Table 18.2 shows a checklist for the
design acceptance criteria. The satisfaction of the design acceptance criteria is based on the
application environment, the ease of operation of the prototype, and the efficiency of the
procedure. The forceps have an external diameter of 3 mm, with one degree of freedom
after extruded from the endoscope, steering from the proximal end using a joystick, and has
the ability to cut the tissue with ease, and the material does not break during the operation
and the retraction. The steering of the proximal end of the endoscope by the operator using
a joystick is resulted in precise movements in the distal end by the forceps due to the
programmed control box. The review of the design criteria is shown in Table 18.2.

Table 18.2: Review of design criteria.

Criteria Fulfilled
Forceps should not have an external diameter of 3 mm to be inserted into the lumen of the Yes
endoscope
Forceps should be able to bend with at least one degree of freedom after being extruded out of Yes
the endoscope
Forceps can be actively steered by the operator from the proximal end Yes
Motion from joystick can be translated accurately to forceps distal end Yes
Forceps should be rigid and stable to remove the sample Yes
Forceps jaw is able to cut through the tissue cleanly to provide ease of removal Yes
The material selected is to be resistant to tension such that it will not break when it is being Yes
withdrawn from within the lumen of the endoscope