Application of practical observer to semi-active suspensions

This paper presents the development of gain-scheduled observers for semi-ac tive suspensions. The states of the semi-active suspensions must be accurat ely obtained because the accuracy directly affects system performances such as ride comfort. Nonlinearity in the absorber of the semi-active suspensio ns is a difficult problem for estimating the accurate states using conventi onal linear observer theories. To solve this problem, we have designed a ne w gain-scheduled observer by introducing two improvements. The validity of this nonlinear observer was confirmed by simulations and experiments. The r esults indicate that the present observer can accurately estimate the suspe nsion stroke velocity using the vertical acceleration sensor on the sprung mass. [S0022-0434(00)02302-9].