Sano A., Terasawa T.

This paper is concerned with a new fully adaptive control scheme for vibration isolation of structure using a semi-active MR damper. To cope with model uncertainties in both MR damper and structure, the proposed control scheme is composed of two adaptive controllers. One is an adaptive inverse controller which compensates for nonlinearity of MR damper and gives necessary input voltage to the MR damper so that its actual damper force coincides with a desired damper force. The input voltage is decided using a nonlinear adaptive observer with identified model parameters of the MR damper which expresses hysteresis behavior of nonlinear dynamic friction mechanism of the MR fluid. A role of the adaptive inverse controller followed by the MR damper is to construct its inverse model to linearize from the desired damper force to the actual damper force even in the presence of uncertainty in MR damper model. The other is an adaptive reference controller which generates a desired damping force such that the controlled structure dynamics may coincide with a desired reference dynamics even when the structure model involves uncertain parameters. Hence the proposed fully adaptive algorithm can deal with the uncertainty in the MR damper model as well as the uncertainty of the structure. Stability conditions of the total control system are analyzed on some feasible assumptions, since the overall algorithm and system configuration is rather complicated. In experimental study, the proposed algorithm is applied to vibration isolation of 4-story structure installed with MR damper, and the results validate its effectiveness comparing with previous methods.