PID control for nonlinear discretized systems

This paper describes the robust stability and PID control for discrete-time and discrete-value (discretized/quantized) systems. Although all control systems are currently realized by discretized signal, the analysis and design of that type of control systems has not been elucidated. In this paper, the robust stability of discrete-time and discrete-value control systems that accompany discretizing units on the input and output sides of a nonlinear element are examined, and a designing (stabilizing) method of PID control for nonlinear discretized systems is proposed based on the modified Nichols diagram. Numerical examples are shown using two types of PID control scheme.