This work has to do with the MIMO (Multiple Input Multiple Output) nonlinear tracking control of an articulated robot arm of 3DOF (3 Degrees of Freedom) employing backstepping, sliding mode, robust predictive, and FO PID (Fractional Order Proportional Integral Derivative) controllers. The controlled outputs (angular positions of the base, forearm, and arm of the robot) as well as the corresponding control forces (armature voltages applied to the DC servomotors) of the designed control systems are plotted for comparison purposes. Simulation studies demonstrate the all designed MIMO nonlinear control systems show good performance.