In control systems, we use transfer functions a lot. One way to define transfer function is merely to use tf(). For example, we could define such transfer function as
But what I would like to do is to define G as G(s) without explicitly defining the underlying transfer function and treat it as transfer function so that I can use Control Toolbox (i.e. feedback(), series(), parallel(),...,etc) to carry out some manipulations. How one can achieve this ?