Controller tuning via minimization of time weighted absolute error

The parameters of a fixed controller structure are tuned so that the output signal of an unknown system responds as quickly as possible to a set point change. The criterion that is minimized with respect to the controller parameters is a function of the absolute value of the output error, where zero weight is put on the transient part. Estimations of the gradient of the loss function are provided by the iterative feedback tuning method and these are used in a trust-region method in the minimization. A thorough discussion on how to choose the length of the zero time weight interval is given and the advantages of the proposed method are illustrated.