TRANSFORMATION OF NONLINEAR-SYSTEMS IN OBSERVER CANONICAL FORM WITH REDUCED DEPENDENCY ON DERIVATIVES OF THE INPUT

The transformation of nonlinear multi-input-multi-output systems x = f(x, u), y = h(x, u) into an observer canonical form with reduced dependency on derivatives of the input is studied. Necessary and sufficient conditions for its existence and a straightforward algorithm for obtaining the canonical model are derived. The proposed method involves the solution of a nonlinear algebraic equation system and systems of first order linear partial differential equations. The nonlinear canonical form obtained permits global observer error linearization and it is a stage in the design of nonlinear observers. The method is illustrated by an example.