Biomedical Engineering Reference
In-Depth Information
First, a baseline test was performed for a sinusoidal waveform with sample 1.
The results showed that the IPMNC artificial muscle responds very closely to the
input sinusoidal waveform, meaning that force responses are nearly equal in the
traveling direction. Figure 3.50 shows a typical measured force response to an input
sinusoidal waveform of 2 V
rms
. It shows the results of the effective length for 10 and
20 mm. As expected, larger force was observed for the effective length of 10 mm.
Figures 3.51(a) and 3.51(b) summarize the test results that contain the measured
surface resistance of test samples 1, 2, and 3 and their maximum forces relative to
one produced by sample 1. Multiple measurements were performed and error bars
represent their corresponding standard deviations. As expected, overlayers of the
silver and copper significantly reduce the surface resistance of the IPMNC muscle.
It should be pointed out that the electrochemical deposition of silver (or copper)
is attractive; in fact, it can produce a thin homogenous metal phase on top of the
platinum particle surface electrode. This eliminates the problems associated with
large voltage drops away from the contact electrode. The bonding between the
platinum surface and silver (or copper) was favorable. However, the copper layer
eventually became bluish due to copper oxidation (as expected). A simple compar-
ison was made for actuation performance of samples 2 and 3 relative to sample 1.
Multiple measurements were performed.
In general, the IPMNC artificial muscle with silver (or copper) deposited shows
significantly improved actuation performance (roughly 10-20% more force relative
to one without silver or copper layers). For samples 2 and 3, it is interesting to note
that more active water movement was found relative to sample 1.
It is clear that the electromechanical dynamics associated with the IPMNC
artificial muscles are complex. However, our approach to alleviate the inherent
particle surface electrode resistance seems practical and effective. The fact that the
2.5
L
eff
= 10 mm
2.0
L
eff
= 20 mm
1.5
1.0
0.5
0.0
0
1
2
3
4
Ï„
(sec)
FIGURE 3.50
The IMPC artificial muscle response for sinusoidal wave input at 2 V
rms
. Tests
were performed in air and without preloading.
