$$\left\{ \begin{array}{lll}\dot{x}_{1} & = & x_{2}\\\dot{x}_{2} & = & \left(1-x_{1}^{2}\right)\cdot x_{2}-x_{1}+u\end{array}\right. $$
$u\in[-0.5,0.5]$
Search space: $[-6, 6]\times[-6,6]$