Page 351 - Mechatronics for Safety, Security and Dependability in a New Era

Ch68-I044963.fm Page 335 Tuesday, August 1, 2006 8:30 PM
Tuesday, August
8:30 PM
1, 2006
Page 335
Ch68-I044963.fm
335
335
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= lOMPa p s =10MPa
p s
/ % = 50Hz f c = 50Hz
-50 -
-100 0 +100 -100 0 + 100
O//
ut ;
(a) Without compensation ® } r °l (b) With compensation Duty I
Figure 4: The Duty-velocity characteristics of an ON/OFF valve
Next, Figure 4 shows the valve characteristics between suspension cylinder speed and duty when the
valves are driven by the duty signal. It is seen in Figure 4(a) that a dead zone exists in the vicinity of
the origin because of the delay time of the valve. This kind of nonlinear characteristic, however, can
easily be compensated into a linear one by adopting an appropriate compensation method. That is, in
order to cancel the influence of the dead zone, we can impose a wider pulse width than the estimated
Duty by the amount of the delay time. The results of compensation are shown in Figure 4 (b).
CONSTRUCTION OF THE BENCH SYSTEM

The dynamic performance of the proposed system was investigated experimentally using a quarter-car
test bench system as shown in Figure 5.

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Figure 5: Quarter-car test bench system
Tn the bench system, the hydraulic actuator (5) supports the 200 kg mass (1) which corresponds to a
quarter of a car's body mass. The eccentric disk (7), which is a physical model of the displacement