Friction stir welding (FSW) is widely developed because of its advantages: clean welding technology. A robotic manipulator needs to be developed to improve the precision of FSW, especially for long welding. Hence, robust control is essential to be designed as part of the robot’s needs. In this study, a fuzzy PID was proposed to control the tip of the FSW tool to match the required welding trajectory. To demonstrate the controller performance of the fuzzy PID, comparisons with conventional PIDs were made in this study. Based on the comparison results, there is no overshoot on the fuzzy PID controller, but the rise time and the settling time are still far from conventional PID controllers.