An optimal adaptive H-infinity tracking control design via wavelet network

In this paper,an optimal adaptive H-infinity tracking control design method via wavelet network for a class of uncertain nonlinear systems with external disturbances is proposed to achieve H-infinity tracking performance. First,an alternate tracking error and a performance index with respect to the tracking error and the control effort are introduced in order to obtain better performance,especially,in reducing the cost of the control effort in the case of small attenuation levels. Next,H-infinity tracking performance,which attenuates the influence of both wavelet network approximation error and external disturbances on the modified tracking error,is formulated. Our results indicate that a small attenuation level does not lead to a large control signal. The proposed method insures an optimal trade-off between the amplitude of control signals and the performance of tracking errors. An example is given to illustrate the design efficiency.