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

Abstract

The active interaction control (AIC) system consisting of a primary structure, an auxiliary structure and an interaction element was proposed to protect the primary structure against earthquakes and winds. The objective of the AIC system in reducing the responses of the primary structure is fulfilled by activating or deactivating the switching between the engagement and the disengagement of the primary and auxiliary structures through the interaction element. The status of the interaction element is controlled by switching control algorithms. The previously developed switching control algorithms require an excessive amount of switching, which is inefficient. In this paper, the excessive amount of switching is restricted by imposing an appropriately designed switching boundary region, where switching is prohibited, on pre-designed engagement-disengagement conditions. Two different approaches are used in designing the newly proposed AID-off and AID-off 2 algorithms. The AID-off 2 algorithm is designed to affect deactivated switching regions explicitly, unlike the AID-off algorithm, which follows the same procedure of designing the engagement-disengagement conditions of the previously developed algorithms, by using the current status of the AIC system. Both algorithms are shown to be effective in reducing the amount of switching times triggered from the previously developed AID algorithm under an appropriately selected control sampling period for different earthquakes, but the AID-off 2 algorithm outperforms the AID-off algorithm in reducing the number of switching times.

Vibration isolation systems, considered as systems with single degree of freedom

“…These systems work by changing the structural stiffness thereby altering the natural period of the structure and thus escaping resonance. The changing of the structural stiffness is done by switching devices which are controlled by control laws [10][11][12]. Some of these devices incorporate dampers such that there is either stiffness or damping added to the structure, depending on the feedback response [11,13].…”

“…The changing of the structural stiffness is done by switching devices which are controlled by control laws [10][11][12]. Some of these devices incorporate dampers such that there is either stiffness or damping added to the structure, depending on the feedback response [11,13]. In [5] smart rubber material with capability of changing its stiffness was studied to be used in variable stiffness base isolation system.…”