The identification of nonlinear systems using C_(t) - K _(t) plane coordinates

In order to instantaneously distinguish the C t (coefficient of viscous damping) and K t (coefficient of stiffness), which are both functions of time in an M.C.K. nonlinear system, a new identification method is proposed in this paper. The graphs of the C t - K t are analyzed and the dynamic behavior of M.C.K. systems in a C t - K t coordinate plane is discussed. This method calculates two adjacent sampling data, the displacement, velocity, and acceleration (which are obtained from the responses of a pulse response experiment) and then distinguishes C t and K t of an instantaneous system. Finally, this method is used to identify the aerostatic bearing dynamic parameters, C and K.