Habib Ahmadi - Assistant professor, Faculty of Mechanical and Mechatronics Engineering, Shahrood University of technology
Aisan Yahid - M.Sc. student, Faculty of Mechanical and Mechatronics Engineering, Shahrood University of technology

In this paper, the second-order sliding mode controller is designed to control the 4 degrees of freedom (DOF) SCARA robot. This robot has three revolute joints and one prismatic joint. This controller can track the path and perform the control goal in presence of the uncertainties and disturbance in the system. The purpose of robot control in this article is tracking the desired path by theend effector of the robot and consequently, it causes to the zero tracking error. For this purpose, the initial slip surface is first defined, and then by obtaining a secondary slip surface and a derivative of them, the control signal derivative is derived. By integrating it andapplying the controller to the dynamics of the system, the path tracking problem is taken. In addition, Lyapunov s theory is used to prove the overall stability of the system. Finally, numerical simulation is performed and the results show that the control goal hasbeen achieved.

SCARA robot, high order sliding mode control (SMC), tracking desire path