Sliding mode tracking control of a 2DOFSFL robot using nonlinear disturbance observer

In this article, a sliding mode control strategy is developed for the position tracking of a two-degree-of-freedom serial flexible link (2DOFSFL) robot. Considering that the 2DOFSFL robot usually suffers disturbances from internal friction produced by direct current motors and unknown external environment, a nonlinear disturbance observer (NDO) is introduced to improve the accuracy and robustness of the position tracking controller to complete practical missions. The unknown disturbances are estimated efficiently by using developed nonlinear disturbance observer. The simulation results are given to demonstrate the effectiveness of the proposed control strategy for the position tracking of the 2DSFL robot.