6.2. H-INFINITY CONTROL METHOD 73
Without Control
Traditional PID Control
Optimized H∞ Control
1
0.5
0
-0.5
-1
-1.5
0 2 4 6 8 10
Time (s)
Rollover Index
Figure 6.9: Rollover indices of the vehicle under the Fishhook case.
the vehicle with the optimized H-infinity control method is lower and varies more smoothly
than that with the traditional PID control method.
Figure 6.10 show the results when the vehicle moves under the double-lane change ma-
neuver. e similar conclusions can be drawn as under the Fishhook case. So, this rollover avoid-
ance control system has a good robustness for different untripped driving situations.
To demonstrate the performance of the rollover avoidance control system when vehicle
runs on a road with bumps, two rollover cases are selected, as follows.
Case I
In a tripped rollover situation, the vehicle rollover happens due to external road input, such as
an unpredictable road bump under the right wheel when vehicle moves on a straight lane. e
maximum height of the road bump is 0.15 m, and the vehicle speed is 100 km/h.
Case II
In this case a combined untripped and tripped rollover due to an unpredictable road bump under
the right wheel while driving in a step steering is studied. e final value of the steering angle
of the front wheel is ı D 2
ı
, the maximum height of the road bump is 0.15 m.