This article presents a method for estimating linear time-varying approximation of general class nonlinear (NLTV) systems. It starts from noisy measurements the response NLTV system to special periodic excitation signals. These are subject measurement noise, process and trend. The proposed is two-step procedure. First, disturbing noise variance quantified. Next, using this knowledge, dynamics e...

Abstract We extend Fring-Tenney approach of constructing invariants constant mass time-dependent system to the case a particle. From coupled set equations described in terms guiding parameter functions, we track down modified Ermakov-Pinney equation involving function. As concrete example focus on an exponential choice