The authors regret the inclusion of an error in the above article. On page 2, Table 1 contains a mistake in the ZMP equations.
The correct version of the ZMP equation in Table 1 is provided below.
\begin{equation*} x_{ZMP}= \sum_{i=1}^{n} \!\left[\dfrac{{-I_{i}{\dot{{\unicode[Times]{x03C9}}}_{i}}+m_{i}x_{i}\!\left(\ddot{z}_{i}-\mathrm{g}\right)+m_{i}{\ddot{x}}_{i}\mathrm{z}_{i}}}{m_{i}\!\left(\ddot{z}_{i}-\mathrm{g}\right)}\right] \end{equation*}
\begin{equation*} y_{ZMP}= \sum_{i=1}^{n} \!\left[\dfrac{{-I_{i}{\dot{{\unicode[Times]{x03C9}}}_{i}}+m_{i}y_{i}\!\left(\ddot{z}_{i}-\mathrm{g}\right)+m_{i}{\ddot{y}}_{i}\mathrm{z}_{i}}}{m_{i}\!\left(\ddot{z}_{i}-\mathrm{g}\right)}\right] \end{equation*}
