Eigenstructure assignment for time-varying linear systems

The problem of eigenstructure assignment via output feedback for time-varying linear systems is treated, and the sufficient and necessary condition and two simple effective algorithms are presented. Two forms of parametric representations of the set of closed loop eigenvector matrices and the set of feedback gains with respect to the closed loop eigenvalues and two groups of parameter vectors are established. Without any constraint to the closed loop poles, the obtained results have generalized many previous results even in the constant case, and have also overcome their defects.