Stability of input amplitude constrained adaptive pole placement control systems

This paper presents stability analysis for discrete time pole placement control system with input saturation constraints. It is shown that the adaptive closed-loop system for a class of stable type-m plants is globally stable in the sense that all the signals in the loop remain bounded. It is also shown that certain degree of robustness with respect to modelling uncertainties and disturbances can be achieved for the adaptive control system by implementing a simple fixed dead zone in the parameter estimator. If the plant is free from modelling uncertainties and disturbances and the control input is not saturated for a finite period of time, then the closed-loop adaptive control system will asymptotically be characterized by the desired closed-loop poles within this time period.