hello
your "feedforward" approach is basically a prefilter in series with your plant. Eeven though the plant may not be strictly invertible , you can do some pole - zero compensation between your filter and the plant. Add some aditionnal high frequency poles , as many as needed to make the filter realisable and stable : the nb of poles of the filter must be equal or greater than its number of zeroes (that are the poles of the plant);
