Eigenstructure assignment by PD state feedback in linear systems

The limits in altering the eigenstructure of linear descriptor systems by proportional-and-derivative (PD) state feedback are studied. Necessary and sufficient conditions are established for a set of invariant polynomials and positive integers to represent the finite and infinite eigenstructure of a system obtainable from the given descriptor system by PD state feedback. The result implies a constructive procedure to calculate the actual feedback gains.<<ETX>>