Adaptive Control Of Non-minimum Phase Systems Research Articles

Adaptive control of nonminimum-phase systems using shifted Laurent series

ABSTRACTWe present a direct discrete-time output-feedback adaptive control algorithm for single-input, single-output systems that are possibly unstable and nonminimum phase. The plant modeling information is given by impulse response components, and the plant is modelled within the algorithm by a truncated shifted Laurent series. A shifted Laurent series is a Laurent series at a point different from the origin in the complex plane and about infinity. The shifted Laurent series is analysed, including its convergence and its relationship to other Laurent series. In particular, we provide a technique for constructing a truncated shifted Laurent series using impulse response components. Numerical examples show that retrospective cost adaptive control can achieve asymptotic command following for a class of exponentially unstable, nonminimum-phase systems.

Modified approach to state-space self-tuning control with pole assignment

The paper presents a modified approach to state-space self-tuning pole-assignment control. The recursive prediction error method is used for joint state and parameter estimation in the controllable canonical form. This simplifies the state feedback law by eliminating the online computation of transformation matrices. The resulting algorithm is thus a feasible solution to the adaptive control of nonminimum-phase systems.

Suboptimal Strategies for the Control of a Stochastic System with Constant but Unknown Parameters

Computationally feasible suboptimal strategies for adaptive control of a multivariable discrete-time stochastic system are described. These strategies are based on the Bayesian approach to the system identification and on approximation of the dynamic programming procedure. Resulting algorithms - with computational simplicity which is comparable with one-step ahead strategy - can be used also for adaptive control of nonminimumphase systems.