Frequency domain performance analysis of marginally stable LTI systems with saturation

In this paper we discuss the frequency domain performance analysis of a marginally stable linear timeinvariant (LTI) system with saturation in the feedback loop. We present two methods, both based on the notion of convergent systems, that allow to evaluate the performance of this type of systems in the frequency domain. The first method uses simulation to evaluate performance, the second method is based on describing functions. For both methods we find sufficient conditions under which a frequency domain analysis can be performed. Both methods are practically validated on an electromechanical setup and a simulation model of this setup.