Trajectory Control of Manipulator Robots With Uncertainties: A Saturated Continuous Integral Sliding Mode Approach

Abstract

This study addresses the trajectory tracking control for manipulator robots with uncertainties. The main objective is to ensure that the robot follows a desired trajectory despite the presence of uncertainties/disturbances and considering control input constraints. The approach is developed in the framework of continuous integral sliding modes. A saturated continuous integral sliding mode controller is used to achieve asymptotic tracking while sustaining input constraints. By suitably designing the sliding variable, the saturated continuous integral sliding mode controller can be expressed in a decoupled input-by-input form. As a result, asymptotic trajectory tracking is ensured, and compensation for uncertainties/disturbances within finite time. Additionally, simulations were carried out for nominal controllers under ideal conditions and in the presence of uncertainties/disturbances. The proposed saturated continuous integral sliding mode approach is compared against other continuous sliding mode control schemes, and their performance is compared using the root-mean-square value. Finally, experimental tests on a 2-DOF manipulator validate the applicability of the proposal.