Trajectory Tracking Control Using Fractional-Order Terminal Sliding Mode Control With Sliding Perturbation Observer for a 7-DOF Robot Manipulator

A novel control scheme utilizing fractional-order terminal sliding mode control with sliding perturbation observer (FOTSMCSPO) is proposed herein. It was used to solve the trajectory tracking problem on a seven-degree-of-freedom robot manipulator. The fractional-order terminal sliding mode in FOTSMCSPO provides a finite convergence time for reaching the sliding surface. In this article, a sliding perturbation observer (SPO) is used to estimate the disturbance from the environment and modeling uncertainties. The new control scheme exhibits high precision, fast convergence, and robust performance against the lumped uncertainties. These advantages are ensured through the newly designed fractional-order terminal sliding surface and the SPO. The stability is analyzed based on the Lyapunov functions for general and fractional-order systems. An implementation on a real robot manipulator demonstrated the effects and performance of the new control method.