On the use of modal sensitivity measures in flight control applications

One of the primary objectives of feadback control is to ensure that system response remain well behaved even under parameter uncertainty. Depending on the mathematical formulation of the problem and/or the synthesis approach employed, various measures can be postulated to ascertain system sensitivity properties. If role(eigenvalue) assignment criterion forms the basis of controller design the associated problem is clearly that of eigenvalue/eigenvector perturbation. Since system response is fully characterized by its eigenvalues and eignvectors their sensitivities form a national basis to analyse trajectory sensitivities of dynamic system in the present paper a set of modal sensitivity measures are derived using classical linear perturbation theory of the eigenvalue problem. Their utility is illustrated by designing minimum sensitivity controllers for an aircraft