ADAPTATION OF THE CONCEPT OF MODAL ANALYSIS TO TIMEVARYING STRUCTURES

The elegance and global character of modal analysis make it very attractive for adaptation to time-varying systems. Most of the concepts of modal analysis are well established in literature and widely understood for linear time-invariant systems. This paper discusses an adaptation of modal analysis concepts to time-varying systems. A typical contemporary example of a time-varying system is a flexible space manipulator or a reconfiguring space structure. An approximation of a time-varying transfer function is introduced by making assumptions about its variability. This approximate transfer function is referred to as a pseudo-transfer function. The modal parameters associated with the pseudo-transfer function are referred to as the pseudo-modal parameters. This paper discusses the validity and the extent of applicability of pseudo-modal parameters.