$$\left\{ \begin{array}{lll}\dot{x}_{1} & = & x_{2}\\\dot{x}_{2} & = & -9.81\cdot\sin(\frac{1.1\cdot\sin(1.2\cdot x_{1})-1.2\cdot\sin(1.1\cdot x_{1})}{2})-0.7\cdot x_{2}+2+u\end{array}\right.$$
$u\in[-3,3]$
Search space: $[-1, 13]\times[-6,6]$