Control of Serial Link Manipulator Using a Fractional Order Controller

This paper proposes a fractional-order controller for serial link manipulator to track desired trajectories in the joint space. The proposed control strategy consists of two main parts. First, a PID fractionional controller is developed using five parameters. By adding the extra degrees of freedom, the fractional order controller can achieve better control performance than the conventional PID controller. In contrast of the first part of the proposed controller which depends on the error between the desired and real values, the second part depends on the robot dynamics. This proposed control law guarantees the global asymptotic stability of the tracking errors. This global stability is proved using Lyapunov theory. The control strategy is tested ona 2 DOF robot manipulator. Simulation results and the comparison with the computed torque approach show the effectiveness of the approach with good tracking performance.