Decentralised adaptive control for large-scale non-linear systems with unknown high-frequency-gain signs

For the first time, a decentralised adaptive control scheme for large-scale non-linear systems is proposed, which does not require a priori knowledge of subsystems´ high-frequency-gain signs. In each local adaptive controller, a Nussbaum-type function is incorporated, and its argument is tuned online via an appropriately designed update law. The stability of the closed-loop system is analysed. It is shown that all signals in the closed-loop system are bounded, and that asymptotic regulation is achieved.