Sliding Mode Control for Nonlinear and Hysteretic Structures

Control methods based on the theory of variable structure system or sliding mode control are presented for applications to seismically excited nonlinear and hysteretic civil engineering structures. These control methods are robust with respect to parametric uncertainties of the structure. The controllers have no adverse effect should the actuator be saturated due to unexpected extreme earthquakes. Emphasis is placed on continuous sliding mode control methods that do not have possible chattering effects. Static output feedback controllers using only the measured information from a limited number of sensors installed at strategic locations are also presented. When a controller is installed in each story unit of a building, a complete compensation of the structural response can be achieved and the response state vector can be reduced to zero. Among the contributions of this paper are the establishment of saturated controllers and controllers for static output feedback. The robustness of the control methods, the applications of the static output controllers, and the control effectiveness in case of actuator saturation are all demonstrated by numerical simulation results. Simulation results indicate that the performance of the sliding mode control methods is remarkable.