Analysis and Design of Limited Bandwidth Active Hydropneumatic Vehicle Suspension Systems

This paper describes the analysis and design of a hydropneumatic limited bandwidth active suspension system. The design is based on hydropneumatic suspension components taken from an existing European saloon.

Mathematical modeling based on the well-known quarter car model is used to compare the performance of the proposed suspension with both the baseline passive system and an idealised fully active system. Practical features, such as actuator time delays and self-levelling controllers, are included in the model of fully active suspension system, and of the limited bandwidth suspension respectively. The controller design for the proposed suspension is based on limited state feedback, and the Nelder-Mead simplex algorithm was used to calculate the gains to optimise the performance index.

Overall, the performance of the proposed system appears to be nearly as good as that of the idealised fully active system. Further experimental work is now planned in order to verify the results and to investigate the influence of time delays on the practical performance of the controlled suspension.