Handling state variable constraints and actuator saturation in structural control strategies

Structural control is a very promising technique for the seismic protection of strategic structures and infrastructures against severe earthquakes. However, the conditions for making structural control a key point of modern seismic engineering are still far from being satisfied. In past years, the demand for a continuous power supply limited the number of active control applications in the field of civil engineering. Today, having overcome this drawback by introducing the concept of semi-active control, engineers involved in this field are increasingly called to satisfy reliability and robustness requirements. In light of these needs, the inherent limits of classic control devices, such as actuator saturations and stroke stops, cannot be neglected, especially when dealing with strong seismic demands. On this respect, the paper discusses some control strategies that allow to handle a variety of constraints directly in the control law. Applications to a case study are also presented via numeric simulations.