Control design of flexible systems and H-infinity loop-shaping method

The control design methodology for flexible systems is closely related with the specific flexible characteristics. From the control point of view, flexible systems can be divided into three categories, i.e. the driving-shaft system, the truss structure, and the panel-like structure such as solar panels of the satellite. The panel-like structure is a highly flexible structure exhibiting a sharp decline in the amplitude-frequency characteristics within the system bandwidth. The design difficulties can be treated effectively with the H-infinity loop shaping design. It is pointed out that the performance index of the H-infinity-norm in the H-infinity loop shaping design is not the performance index of the system in the general sense, and is just the stability margin of the closed-loop system. The design example also shows that the robustness of the design is not the robustness against the coprime factor perturbations. The robustness of the H-infinity loop shaping design has its own meanings and is different from the common conception.