DISCRETE-TIME ADAPTIVE CONTROL OF NONLINEAR BASE ISOLATED STRUCTURES

This paper deals with an active control system for base isolated structures. The isolator device has a hysteretic nonlinear behavior. An adaptive backstepping approach is used for the control design in order to handle the nonlinearity and the presence of uncertainties. The control is formulated in continuous time and further discretized into a discrete time control algorithm to go closer to a digital implementation. The paper shows that the implementation of this algorithm with a zero-order hold is able to keep uniformly all the signals of the closed loop within certain bounds and to give an upper bound of the asymptotic tracking error.