“…To determine the adaptation laws for parameters of matrices M, D, C and vector b, the function f is to be presented in the form of the regression model, after which the standard backstepping procedure can be applied. This approach is labour-intensive, requires huge computational effort, and leads to an excessively large number of estimated parameters, as stated in [23]. Instead, the components of the function f = [f 1 , f 2 , f 3 ] T can be approximated using three artificial RBF type neural networks NN i with the number of neurons l > 1.…”