Environmental Engineering Reference
In-Depth Information
35
35
30
30
25
25
20
20
15
15
10
10
5
5
0
0
0.0
1.0
2.0
3.0
4.0
0.0
1.0
2.0
3.0
4.0
i
[A]
i
[A]
Fig. 13.11
Bingham model parameters for the prototype MR dampers
Fig. 13.12 Qualitative
trends in current and voltage
for two alternative
approaches to control MR
dampers (t* is the instant of
command)
voltage spike
Current-driven
scheme
desired level
of voltage
initial level
of voltage
Voltage-driven
scheme
time
Current-driven
scheme
desired level
of current
initial level
of current
Voltage-driven
scheme
time
t
*
period a voltage spike and then sets the voltage to the reference value, whereas if
the current must be decreased, a negative spike of voltage is issued.
Figure
13.12
qualitatively shows what happens to voltage and current into an
MR damper when the two approaches are adopted, showing the delay with which
the current (and the corresponding magnetic field) reaches the desired value when
a voltage-based approach is adopted.
It is experimentally demonstrated that using current-based strategy for control
and an appropriate and suitably tuned electric hardware, the response time of the
above-mentioned prototype SA MR dampers can be comfortably bounded to
8-10 ms.
