High-Frequency-Gain Identification and Gain Tuning in Nonlinear Singularly Perturbed Control Systems

O.V. Bocharova and V.D. Yurkevich (Russia)


Nonlinear systems, adaptive control, singular perturbations


The paper treats a question of an adaptive controller de sign for nonlinear systems where discussed controller is an extension of the adaptive PI (PID) control scheme. The presented design methodology guarantees desired output transient performance indices by inducing of two time-scale motions in the closed-loop system where the controller dynamics is a singular perturbation with re spect to the system dynamics. Stability conditions im posed on the fast and slow modes and sufficiently large mode separation rate between fast and slow modes can ensure that the full-order closed-loop nonlinear system achieves the desired properties in such a way that the output transient performances are desired and insensi tive to external disturbances and plant’s parameter vari ations. The novelty in the paper is that Fourier filter is incorporated in the control system for purpose of a high-frequency-gain online identification and then, by an adaptive gain tuning of the controller, the two-time-scale structure in the closed-loop system trajectories and sta bility of fast-motion transients are maintained for a large range of plant’s parameter variations.

Important Links:

Go Back