Fractional order active disturbance rejection control for trajectory tracking for 4-DOF serial link manipulator

This paper presents fractional order active disturbance rejection control (FOADRC) for a 4-DOF serial link manipulator to track the desired path and to ensure the stability of the tracking error. The active disturbance rejection control (ADRC) is known as a good technique to estimate the total disturbances and compensate them through suitable feedback control. This work takes advantage of the ADRC and the fractional-order controller to control the robot manipulator. The proposed control strategy has three main phases. First, converting the cartesian space trajectory to joint space. Second, the FOARDC is developed to ensure good tracking in the joint space. The FOADRC uses the extended state observer (ESO) to estimate the disturbances and the fractional-order PD as a feedback controller. Finally, the forward kinematic is used to convert the real joint space trajectory to cartesian space coordination. Experimental results show that the FOADRC has better performance than the traditional ADRC.