Biomedical Engineering Reference
In-Depth Information
2.5
2.5
Sinusoid input
Triangular input
2.0
2.0
1.5
1.5
1.0
1.0
0.5
0.5
0.0
0.0
0
1
2
3
4
5
0
1
2
3
4
5
Time (sec)
Time (sec)
2.5
2.5
Sawtooth input
Square input
2.0
2.0
1.5
1.5
1.0
1.0
0.5
0.5
0.0
0.0
0
1
2
3
4
5
0
1
2
3
4
5
Time (sec)
Time (sec)
(V
input
= 1.2 V
rms,
ω
= 0.5 Hz, L = 1 in, W = 0.25 in, m
eff
= 0.2 g)
FIGURE 3.25
Force response characteristics of the IPMNC under different voltage wave forms.
of 2 min with proper electrodes. Figure 3.25 shows that the IPMNC artificial muscle
responds very closely to the input sinusoidal, triangular, and sawtooth waveforms
and that force responses are nearly equal in the traveling direction. However, in the
case of square wave input, a very short delay of force is observed. Although it could
be due to the capacitor charging process (Bar-Cohen, Leary et al., 1999; Kim and
Shahinpoor, 1999), it is our belief that the water leakage through the porous electrode
also contributes to such delayed responses (see fig. 3.24, bottom) (Moor, 1972).
3.3.5
E
LECTRODE
P
ARTICLE
C
ONTROL
Based upon our manufacturing experience, controlling the electrode consisting of
platinum particles (concentration and size distribution) within the polymer matrix
was also found to be a nontrivial issue that can directly affect the performance of
IPMNC. Here, we discuss the importance of
a repetitive platinum reduction process
the use of dispersing agents
base material stretching (i.e., uniaxial mechanical stretching)
