*(English)*Zbl 1038.34041

The problem of chaos control is considered for the modified Chua circuit

Conditions are given for the asymptotic stabilization of a fixed-point in the presence of the feedback control term $-k(x-\overline{x})$, which is introduced in the equation for the $x$ variable. $\overline{x}$ is the $x$-component of the fixed-point under consideration. This point is shown to be unstable in the absence of a controller. Then, the author derives conditions for the stabilization of the fixed-point in the presence of adaptive controller $-g(x-\overline{x})$, where $g$ is updated according to the following algorithm ${g}^{\text{'}}=\gamma {(x-\overline{x})}^{2}$. Finally, adaptive synchronization of two unidirectionally coupled identical Chua systems is considered.