Direct adaptive control with integral action for nonminimum phase systems

This note presents a direct adaptive control scheme for nonminimum phase systems where controller parameters are estimated from the recursive least-squares algorithm. Some additional auxiliary parameters are obtained from the proposed polynomial identity,, and a local convergence is guaranteed without any extra conditions. Integral action is incorporated into the adaptive controller to eliminate the steady-state error, and to satisfy a condition of the unique solution for the polynomial identity as well.