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This work is concerned with the contouring control problem of robotic manipulators using the method of equivalent errors. The method was previously proposed for multi-axis motion systems with emphasis on the machine tools applications. It is shown in this paper that the method of equivalent errors is equally applicable to the robot manipulators. For robotic systems, a desired path is usually described in terms of the position of the end-effector (task space), but the system dynamics are described in generalized coordinates (joint space). The proposed method utilizes the forward kinematics to transform the desired path in the task space into that in the joint space. As such, the equivalent errors can be easily defined. A two-link robot manipulator contouring a circular path has been numerically studied. It is found that the contouring errors are virtually zero (order of fento meter), verifying the effectiveness of the method.