Robust stability of a continuous‐time self‐tuning controller

A continuous‐time self‐tuning controller, based on the well‐known discrete‐time generalized minimum‐variance self‐tuning controller, is introduced. Using input—output stability methods, frequency domain conditions are derived which ensure L∞ stability in the face of multiplicative process perturbations. The analysis is illustrated using an example of Rohrs et al.