An eigenstructure assignment technique for vibration suppression and a
ctive vibration isolation for mechanical systems is presented. The tec
hnique assigns a nominal eigenstructure to an existing system, and the
n adjusts the eigenstructure to minimize the mean square vibration of
the system. The technique can be used to design a static output feedba
ck controller for an actively controlled structure or to optimize the
eigenstructure of an analytic model for purposes of design or simulati
on. The technique is restricted to smaller order models due to computa
tional requirements. Analytical examples are presented in which the vi
bration suppression technique is used to minimize the vibration of an
actively controlled building due to an earthquake excitation, and to i
solate an electronics box from base vibration.