Implementation of hybrid structural control using fuzzy logic

The use of a controller based on fuzzy set theory, to control a hybrid isolated structure is considered in this work. The objective of the hybrid system is to obtain an ideal sliding system with 'complete' base isolation for structures subjected to earthquakes. As the hybrid system approaches a state of 'complete' isolation, the effects of imperfections, measurement noise, model limitations, and compensation errors start to play a dominant role in the system performance. Fuzzy logic provides a simple framework to capture the effects of nonlinearities and uncertainties in a real problem, without an explicit model of the plant or controller. The applicability of this approach is investigated on a benchmark experimental model consisting of a 1:4 scale sliding base isolated system complemented at its base by a servo controlled actuator, with a digital computer to provide real-time control. The results of this experimental and analytical study show the feasibility of the implementation of fuzzy logic based control to highly nonlinear civil engineering structures.