Integrated Actuator–Sensor Placement and Hybrid Controller Design of Flexible Structures Under Worst Case Spatiotemporal Disturbance Variations

The aim of this study is to propose a methodology for placing actuating devices in flexible structures that, in addition to possible modal controllability and enhanced performance, may also address spatiotemporal effects of disturbances. The resulting actuator locations enhance the controllability properties of selected modes, improve the performance of the closed-loop system by integrating the controller design and actuator location, and finally address the spatial variability of disturbances by minimizing the location-parameterized norm of an associated transfer function. When the spatial distribution of disturbances is known a priori, it should be utilized in the placement criteria, and if it is unknown, then a “worst” such distribution may be assumed and subsequently used for actuator placement in order to attain spatial robustness. To further address possible “moving” disturbances, where the spatial distribution of disturbances is changing with time and space, a supervisory scheme is proposed where both an actuator and its associated controller are chosen to be activated (switched in) from a set of candidate actuators that are optimally mounted on the flexible structure. Extensive simulation studies demonstrating the effects of spatial distributions of disturbances on the actuator locations, along with a switching actuator–controller scheme to better address the effects of spatiotemporally varying disturbances, are included.