Robotic manipulators have been widely used in many arenas; when the robotic arm performs positioning, traditional controller (e.g., PID controller) has the problem of not being able to compensate the payload variations, i.e., when the end-effector of the robotic arm grasps different payload masses, as most applications require, the output of joint motion will vary, which decreases end-effector positioning accuracy of the robotic arm system. Based on the model reference control approach, the payload variation effect can be solved effectively and therefore, to further improve the robotic arm positioning accuracy performance.