Page 193 - Flexible Robotics in Medicine

180 Chapter 7

Figure 7.8
Mechanism of operation and actual working of the forceps.

hole of 0.3 mm was available for the forceps actuation system as the guides and tendons
occupied the other remaining inner space of the individual channels, Bowden cables were
attached to the forceps actuation mechanism and were routed through the 0.3 mm space
inside the channel. Exerting a push and pull force on the Bowden cable caused the forceps
to open and close. Furthermore, as the channel length increased, the Bowden cables that
were routed through the channels tend to bend within the channel when force was exerted.
Thus to ensure that the Bowden cable exerted only linear forces on the forceps actuation
mechanism, the Bowden cables were surrounded by flexible hollow sheets that restricted
the Bowden cables from bending within the channels

7.4.2 Electrocautery

Once a tumor has been identified and isolated, it must be resected by either cutting it,
cauterizing it, or using other methods such as burring or using liquid nitrogen. The process of
cutting tumors or cryosurgery requires sophisticated force application methods and bulky setup.
Hence, we decided to adopt electrocautery to cauterize the tumors. As the dimensions of the
electrocautery could not meet the requirement of the design constraints (diameter of 3 mm
and below, and control actuation mechanism with its diameter of 0.3 mm and below),
modifications were made. Two types of electrocautery were explored and modified to fit our
device: monopole and dipole electrocautery.