Response time effect of magnetorheological dampers in a semi-active vehicle suspension system: performance assessment with quantitative feedback theory

초록

This paper presents vibration control performances of a semi-active full-car suspension system with very-fast response magneto-rheological (MR) dampers. In this study, MR damper dynamics is captured by the first order model which is realistic, efficient and simple form. As a first step, the response time of the proposed MR damper and one of commercial MR dampers is experimentally identified as around 7 ms and 26 ms, respectively. The control strategies to access ride comfort and road holding of the full-car suspension system are adopted as the passive, the sky-hook control and the quantitative feedback theory (QFT). Especially, the solid design of the QFT is undertaken in frequency domain. The suspension performance of the different controllers with two different MR dampers are evaluated and compared at random road excitation. It is shown that the peak value of the vertical acceleration of the suspension with the fast response MR damper is remarkably reduced compared with the slow response MR damper under the QFT control realization. It is also shown that between the skyhook and the QFT controller with the fast response MR damper, the acceleration power spectral density is reduced by 30% via the QFT controller.

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