Modified output error method with parameter mismatch compensation for improved performance model reference adaptive control

A method for model reference adaptive control (MRAC) with improved transient performance is introduced. It is shown that with this method the zero-state output error can be made arbitrarily small. For the linear system case, the value of the high frequency gain, k_p, of the plant does not have to be known a priori, i.e., some uncertainty on k_p is allowed. The structure of the proposed controller allows for existing convergence results such as exponential convergence of output and parameter errors in the presence of sufficiently rich reference inputs to remain valid. It is also shown that the proposed controller demonstrates improved robustness in the presence of bounded disturbances and/or modeled dynamics, as well as in the case in which adaptation is switched off