ADAPTIVE SLIDING MODE CONTROL ALGORITHM FOR A MICROGRAVITY ISOLATION SYSTEM

An adaptive sliding mode control algorithm has been developed to achie ve the desired transmissibility Function for a microgravity isolation system with uncertainties in parameters such as umbilical stiffnesses. The theory has been presented for the design of an adaptive controlle r in the context of a single-degree-of-freedom system. The reference m odel corresponds to the desired transmissibility. A sliding line with the boundary layer is chosen in the state space consisting of error be tween the output of the actual system and the reference model and its derivative. The adaptation mechanism is based on the sliding mode cont rol theory. The results from numerical simulations are presented. It h as been found that the resulting transmissibility can be quite close t o the desired function by properly selecting the system bandwidth and the boundary layer thickness. (C) 1998 Elsevier Science Ltd. All right s reserved.