Stabilization of a Plastic-Deformed Structure by Air Jet Pulse

When a strong earthquake occurs, many buildings are destroyed. For the inhabitants of such buildings, having sufficient time to take refuge is critical. This study presents the basic concept of a control system for stabilizing a plastic-deformed building by jetting out compressed gas while the inhabitants escape. This system features easy installation. Constant pressure gas is employed, and is controlled to jet or to stop jetting. The plastic-deformed building is modeled as a two-link inverted pendulum, and the design of the stabilizing controller is based on the sliding mode control theory. The validity of the system is confirmed by numerical simulations and model experiments. The results indicate that (1) an unstable structure can be stabilized by air jet pulses, (2) a robust bang-bang type controller can be derived by designing the switching surface to have an equivalent control input equal to zero, and (3) chattering of the control input is suppressed by setting an insensitive zone.