A modified CGT method with the swap-term correction

Relaxation of the SPR-condition is developed for the command generator tracking (CGT) method for the input tracking of oscillatory waves given by the superposition of sinusoids. The CGT is modified in the form that it is free from the SPR-condition without making use of the plant augmentation, and simple in structure. A modified controller with the swap term correction is derived, which has faster speed of adaptation than a controller without the swap term correction. Simulations applied to an electrohydraulic servo with nonlinear valve and observation noise show the good tracking performance and the faster speed of adaptation.