NONLINEAR MODAL CONTROL METHOD

This work extends previous work on nonlinear normal modes to include t he case of forced response. This allows the nonlinear normal mode meth od to be applied to the feedback control problem providing a new metho d of controlling nonlinear multiple-degree-of-freedom systems. The pro posed method uses a transformation proposed earlier for homogeneous sy stems written in state-space form. The coordinate transformation for t he forcing vector is defined here in state space and related to the ph ysical coordinate system. The result is a pseudomodal decoupling trans formation of a nonlinear inhomogeneous system. Although interesting in its own statement, this transformation also provides a nonlinear moda l control scheme. This result is applied to a known coupled two degree of-freedom oscillator with a cubic stiffness term. The results illust rate the design of a nonlinear modal control law.