A variable fractional-order sliding mode controller for uncertain vibration building structures

Vibrations often affect real-world mechanical systems and engineering structures. Therefore, effective control methods for vibration suppression are crucial to guaranty systems’ stability and proper operation. This paper proposes a novel variable fractional-order (FO) sliding mode control to suppress vibrations on structures in the presence of uncertainties and disturbances. A novel variable fractional sliding mode surface is designed, and a hyperbolic tangent function is introduced in the control law. The control scheme ensures global stability of the system, finite time and fast convergence, and reduced chattering phenomena during the control process. Experiments, comparing the proposed control strategy with some alternatives, specifically the switching variable FO sliding mode controller (SVOSMC) and constant FO global sliding mode controller (COSMC), when controlling seismic induced vibrations of a building structure, demonstrate the superiority and effectiveness of the novel method.