Comparison of switching control algorithms effective in restricting the switching in theneighborhood of the origin

Abstract

The active interaction control (AIC) system consisting of a primary structure, an auxiliarystructure and an interaction element was proposed to protect the primary structure againstearthquakes and winds. The objective of the AIC system in reducing the responses of theprimary structure is fulfilled by activating or deactivating the switching between theengagement and the disengagement of the primary and auxiliary structures through theinteraction element. The status of the interaction element is controlled by switching controlalgorithms. The previously developed switching control algorithms require an excessiveamount of switching, which is inefficient. In this paper, the excessive amount of switching isrestricted by imposing an appropriately designed switching boundary region, whereswitching is prohibited, on pre-designed engagement–disengagement conditions. Twodifferent approaches are used in designing the newly proposed AID-off and AID-off2 algorithms.The AID-off2 algorithm is designed to affect deactivated switching regions explicitly, unlike the AID-offalgorithm, which follows the same procedure of designing the engagement–disengagementconditions of the previously developed algorithms, by using the current status of the AICsystem. Both algorithms are shown to be effective in reducing the amount ofswitching times triggered from the previously developed AID algorithm under anappropriately selected control sampling period for different earthquakes, but the AID-off2 algorithm outperforms the AID-off algorithm in reducing the number of switching times.