Indirect adaptive periodic control

A new indirect adaptive control method is presented. This method is based on a lifted representation of the plant which can be stabilized using a simple periodic control scheme. The controller parameter computation involves the inverse controllability/observability matrix. Potential singularities of this matrix are avoided by means of an appropriate estimate modification. This estimate transformation is linked to the covariance matrix properties and hence it preserves the convergence properties of the original estimates. This modification involves the singular value decomposition of the controllability/observability matrix estimate. As compared to previous studies in the subject the controller proposed here does not require the frequent introduction of periodic n-length sequences of zero inputs. Thus with the new controller the system is almost always operating in a closed loop, which should lead to better performance characteristics