This work addresses the problem of controlling a rigid arm (one degree of freedom robot manipulator) directly driven by an induction motor. A Lyapunov-based adaptive nonlinear controller is designed. The developed controller compensates for parametric uncertainty associated with the resistance of the rotor windings and it is capable to track asymptotically a trajectory for an angular position keeping all the internal signals bounded and guarantees the asymptotical stability of the system. Simulations are presented to illustrate the performance of this controller.