Adaptive pole placement control subject to input amplitude constraints

The authors present a stability analysis for discrete-time pole placement control systems 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 a certain degree of robustness with respect to modeling 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 modeling 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. Several simulation examples for discrete time plants are presented.