Combination of decentralized sliding mode control and online wavelet analysis for control of equipment with isolation system

Abstract

Critical equipment and machinery, especially the one in the technology facilities, hospitals, data centers, etc., are vulnerable to strong earthquakes, and most importantly, the failure of the critical equipment will result in countless economic loss, directly and indirectly. For decades, passive control devices in the form of isolation systems between the equipment and its supporting structure have been acknowledged as an effective measure to promote the earthquake resistibility on the basis of theoretical and experimental results. Alternative to passive isolation systems, researchers found that adding a semiactive device to the isolation system can increase damping and lessen the isolator displacement. In order to mitigate the acceleration of equipment, various control algorithms have been developed to reduce the response produced by the internal forces. However, little attention has been given to the balance between the response of equipment and the structural response. In this study, an innovative control algorithm is developed based on decentralized control architecture and wavelet analysis, and this control algorithm is proposed for semiactive isolation systems to protect acceleration-sensitive equipment against strong earthquakes. Subsequently, a full-scale specimen is constructed; moreover, a curved surface slider (CSS) system with a magneto-rheological (MR) damper are placed between the equipment and the floor to suppress the vibration. The experiment is conducted with a feedback control system to validate the performance and efficiency of proposed control algorithm. In the last place, the discussion and some conclusion are also drawn in this paper.