Page 257 - Flexible Robotics in Medicine

246 Chapter 10

mechanisms such as a lever configuration to increase the deflection of the tentacle structure.
However, such a configuration would cause the force initially applied to decrease further,
hence trying more softer materials than silicone elastomer would be a suitable option for
such configurations. A more advanced design of balance could be tested to compromise
between the potential applied force and contraction stroke of the wire.
The input power is adjusted during actuation to achieve the desired bending of the specific
length of the SMA wire. With a variable resistor, it would be possible to adjust the actual length
of the wire according to the power output available. The setback is that, currently, there is no
variable resistor with the lower limit starting from 0.5 Ω in the market. A current divider, or a
voltage divider, could be a solution to attain more flexibility regarding this issue.

The time taken for actuation cycles could be reduced by having an additional pneumatic
channel for cooling down the SMA at a faster rate than its natural time. This is the most
preferred method for this application since the air channels do not consume more space and
do not add weight to the current prototype. Moreover, in the earlier part of this chapter, it
was mentioned that the idea of using pneumatic actuation with SMA was considered.

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