Analysis of Response of Second-Order Sliding Mode Control Systems to Exteral Inputs

Response of systems with the second-order sliding mode (SOSM) control algorithms to an external harmonic excitation is analyzed in the frequency domain. The analysis is done via application of the concept of the equivalent gain of a nonlinear function. The equivalent gain is used as a model of propagation of averaged values of signals through nonlinear elements of the system. Two SOSM algorithms: twisting and super-twisting are analyzed. The results are presented in the format of the conventional amplitude and phase frequency response