Application of real structured singular values to flight control law validation

Flight control law validation issues raised at NASA Dryden Flight Research Center are described, and these problems are recast into the real mu analysis framework, To solve these problems, a recently developed algorithm for computing real mu is extended to include repeated real perturbations. Worst-case direction information also is provided; such information is useful in applications that require proper weighting of the perturbation block structure. An iterative weighting procedure is described that indicates the relative importance of the real uncertainties being analyzed. Other developments motivated by flight-test issues also are described: block structures for analyzing phase margin and transport delay, robustly guaranteed gain and phase margins, and implementation on simulated flight data. These tools and techniques are demonstrated on X-31 flight control laws.