  This paper introduces a multiple-input discrete Urysohn operator for
modelling non-linear control systems and a technique of its identification by
processing the observed input and output signals. It is shown that, due to the
nature of the discrete Urysohn operator, the identification problem always has
an infinity of solutions, which exactly convert the inputs to the output. The
suggested iterative identification procedure, however, leads to a unique
solution with the minimum norm, requires only few arithmetic operations with
the parameter values and is applicable to a real-time identification, running
concurrently with the data reading. The efficiency of the proposed modelling
and identification approaches is demonstrated using an example of a non-linear
mechanical system, which is represented by a differential equation, and an
example of a complex real-world dynamic object.
