An output feedback tracking control based on neural sliding mode and high order sliding mode observer

In this paper, a novel output feedback tracking control scheme based on neural sliding mode without joint velocity measurement and the high order sliding mode observer for the uncertainty of robot manipulators are presented. Two second-order sliding mode observers are designed to estimate joint velocities and dynamic uncertainties of the robot manipulator, respectively. The first-second order sliding mode observer is used to estimate the state vector in a finite time without filtration. To estimate the uncertainties without filtration, the second second-order sliding mode nonlinear observer is designed. By integrating two observers, the resulting observer can theoretically obtain exact estimations of both joint velocities and dynamic uncertainties. They are used to design an output feedback tracking control scheme based on neural sliding mode controller. This proposed control scheme can reduce chattering and improves tracking performances. Finally, the simulation for a 2-DOF robot manipulator is given to show the effectiveness of this control strategy.