Robust Adaptive Control for Systems with Unknown Time Delay

Usualy a adaptive controler most in use is based on a lower-order model, due to the simpleness of model the unmodeled part of the true system often makes the control be not robust. This paper considers a robust class of models that G(s)=Ke-τs/(s-s1) … (s-sn), where τ, is time delay. For this class of model the unmodeled part of the system can be converted into a part of unknown time delay. Thus, the sampled system of G(s) has a fractional time delay ρ, 0≤ρ<1. Basing on combination of estimating the fractional time delay ρ and constructing a self-tuning controler, a robust adaptive control scheme is given in the paper. The simulations show that this adaptive control algorithm has indeed robustness