Trajectory Tracking Control of Delta-Robot Using 3rd Order Sliding Mode Control

No Thumbnail Available

Date

2016-04

Journal Title

Journal ISSN

Volume Title

Publisher

Addis Ababa University

Abstract

Robots are multi-input multi-output (MIMO) nonlinear systems with uncertainties and high coupling effects ; this makes the control of Robot more difficult and needs a robust control system. This thesis describes, the concept of higher order sliding mode control as applied to trajectory tracking of a 3-DOF Delta Robot using tracking error as the sliding surface. Third order sliding mode control technique is specifically applied for this purpose. With the Robot's complicated electromechanical parts, mutual interactions of Robot mechanics and drives, building the nonlinear dynamic model of the Robot using 3D-CAD (like SolidWorks) program was the best solution to model the Robot. Real parameters were introduced via 3DCAD Modeling. The SimMechanics link utility bridges the gap between geometric modeling and block diagram modeling and simulation. Dynamical model with all the kinematic constraints for a Robot will simply be found by exporting a 3D-CAD model of the Robot to SimMechanics. In this thesis a 3-DOF Delta Robot is designed in SolidWorks, the kinematic and dynamic models of the Robot have been developed, a 3-SMC sliding mode controller is designed and a circular trajectory tracking is achieved, with X & Z axis rms error of 3mm. The simulation result shows that the steady state tracking is reached before 3 seconds. Finite time convergence of sliding function and its first and second derivatives is also achieved. the plant has been subjected to the effects of joint internal mechanics, mass uncertainty and external disturbances of torques. The designed third order sliding mode control have fond to be smooth, model independent, robust and is insensitive to applied model parameter variations, external & internal effects beside eliminating the chattering effect of the standard SMC..

Description

Keywords

Control Engineering

Citation