Model-reference impedance and admittance control of linear systems.

A variable structure model-reference adaptive control (VS-MRAC) of impedances and admittances (driving-point (DP) functions) is proposed. Only voltage and current measurements are required to implement the controllers. The inclusion of a prefilter in the reference model allows the synthesis of quite general DP functions, even with nonminimum phase zeros and unstable poles. It is shown that the stability of the closed-loop system depends only on the source DP function and the chosen reference model. The VS-MRAC guarantees global exponential stability properties, robustness to parameter uncertainties, disturbances, and unmodelled dynamics. Simulation results illustrate the performance and robustness of the VS-MRAC. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]