  In this paper, we consider the use of black-box Gaussian process (GP) models
for trajectory tracking control based on feedback linearization, in the context
of mechanical systems. We considered two strategies. The first computes the
control input directly by using the GP model, whereas the second computes the
input after estimating the individual components of the dynamics. We tested the
two strategies on a simulated manipulator with seven degrees of freedom, also
varying the GP kernel choice. Results show that the second implementation is
more robust w.r.t. the kernel choice and model inaccuracies. Moreover, as
regards the choice of kernel, the obtained performance shows that the use of a
structured kernel, such as a polynomial kernel, is advantageous, because of its
effectiveness with both strategies.
