Nonlinear Phenomena and Stability of Discretized Control Systems

This paper analyzes the nonlinear phenomena and stability of discrete-time and discrete-value (discretized/quantized) control systems in a frequency domain. By partitioning the discretized nonlinear characteristic into two sections and by defining a sectorial area over a specified threshold, the concept of the robust stability condition for nonlinear discrete-time systems, which was developed in the previous studies, is applied to the discretized nonlinear control system in question. As a result, the nonlinear phenomena of a discretized control system are clarified, and the robust stability of discretized nonlinear feedback systems is elucidated. Numerical examples are shown to verify the result