Servo self-tuners
Peter E. Wellstead, P. Zanker · International Journal of Control · 1979
The problem of adding reference inputs to self-tuning systems is considered using the classical device of set-point feedforward. The resulting configuration requires more effort during self-tuning but can converge to the desired servo/regulator feedback system. As a bonus enough additional information is generated to formulate a novel approximate maximum likelihood estimator for use with self-tuned systems.