Two possible layouts of a slow-active suspension model are analysed. Optimal control laws for different actuator bandwidths and various amounts of road preview are generated, and estimates of power consumption are made. Higher bandwidth systems (10 Hz) require less preview to obtain a given level of performance than those with a lower bandwidth (3 Hz) but use more energy in doing so. Similar performance is available from the two systems considered, although the second uses considerably less energy to obtain that performance. Higher bandwidth systems require less preview to achieve their maximum potential than lower bandwidth ones, a 10 Hz system typically requiring around 0.15 s of preview to obtain its minimum cost function value, compared to a corresponding 3 Hz system requirement of 0.25 s - 0.3 s. In reality, the availability of only short preview times is likely to be a limiting factor in the design of these types of system. Considering a potentially realisable preview distance of 1 m ahead of the front wheels of a vehicle, it would seem that there is little to be gained for a system with a bandwidth of 3 Hz or 6 Hz. At 10 m/s a preview distance of 1 m corresponds to a preview time of 0.1 s and at 30 m/s to 0.033 s. For 3 Hz and 6 Hz systems these preview times have little effect on the performance compared to the zero preview case. Even for a 10 Hz bandwidth system, 0.033 s of preview is of little use, although 0.1 s is very useful. The benefits of presently realistic amounts of preview with the systems studied here appear to be limited. However, it may be more useful in improving control of the rear of the vehicle, where the effective preview time is equal to the preview time ahead of the front wheels plus the wheelbase travel time. The performance of any of these systems is tied in very closely with the amount of power it consumes. Any significant improvement in performance due to the use of preview or higher bandwidth actuators comes with a corresponding increase in power consumption which is largely independent of the type of road input.
Performance potential and power consumption of slow-active suspension systems with preview
Leistungspotential und Energieverbrauch eines schwach aktiven Federungssystems mit Vorausschau
Vehicle System Dynamics ; 25 , 3 ; 169-183
1996
15 Seiten, 14 Bilder, 9 Quellen
Article (Journal)
English
Performance potential and power consumption of slow-active suspension systems with preview
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