Design of Adaptive-Robust Finite-Time Nonlinear Control Inputs for Uncertain Robot Manipulators

Abstract

In this paper, an adaptive-robust finite-time trajectory tracking objective is studied for a wide group of n – degrees of freedom (n-DOF) robot manipulators subjected to parametric and modeling uncertainties and dead-zone input nonlinearities. By developing the nonsingular terminal sliding mode control (NTSMC) method, nonlinear input torques are designed. These suggested control inputs possess three major interconnected parts including innovative nonlinear sliding manifolds, reaching control laws, and finite-time nonlinear adaptation laws. It is mathematically proven the designed control inputs are able to ensure the global finite-time stability for the robot manipulator while its dynamic matrices are unknown and dead-zone nonlinearities exist in its joints. By exploiting the proposed input torques, all configuration variables of the robot precisely converge to the desired trajectories within an adjustable convergence finite time. Moreover, all estimations for unknown dynamical parameters exactly converge to constant values within the mentioned finite time. Finally, to illustrate the effectiveness of the designed control inputs, a numerical simulation is provided for a 2-DOF robot manipulator.