COUPLED AND CONSTRAINED SYLVESTER EQUATIONS IN SYSTEM-DESIGN

Several design problems, including reduced observer and compensator de sign, output feedback, and finite transmission zero assignment, are ex amined using the vehicle of the coupled Sylvester equations. The coupl ing is generally provided through a third equation involving the solut ions of the two linear Sylvester equations, thus serving as a constrai nt on the allowed solutions. The Sylvester approach allows the unifica tion of algebraic and geometric approaches, and provides numerical des ign algorithms through the tool of the Hessenberg form.