  In this work, we propose the design and analysis of a novel continuous robust
controller for a class of multi--input multi--output (MIMO) nonlinear uncertain
systems. The systems under consideration contains unstructured uncertainties in
their drift and input matrices. The proposed controller compensates the overall
system uncertainties and achieves asymptotic tracking where only the sign of
the leading minors of the input gain matrix is assumed to be known. A Lyapunov
based argument backed up with an integral inequality is applied to prove
stability of the proposed controller and asymptotic convergence of the error
signals. Simulation results are presented in order to illustrate the viability
of the proposed method.
