Sliding Mode Control Compared to PID Control Applied for a 4 Cables Parallel Robot

Abstract

This paper present a study the performance of sliding mode controller (SM) against PID controller, this last SM control algorithm is based to provide the stability of the endeffecter and a PIDC is classical proportional integrated derivative controller. The aim contribution of this work is in the firstly IntroductionIn recent years, robots have made tremendous inroads into industries for manufacturing and assembly. However, for long reach robotics such as inspection and repair in shipyards and airplane hangars, application of robotics is still in its infancy. Conventional robots with serial or parallel structures are impractical for these applications since the workspace requirements are higher than what the conventional robots can provide. For these reasons, cables-driven robots have received attention and have been recently studied [1]. The cable parallel robot are a special class of parallel mechanisms, whose trusts consist of cables whose lengths are adjustable to control the end-effector's position and orientation [2], this last is a fully parallel mechanism in closed chains with n degrees of freedom for the end effector; this last is connected to fixed platform by m cables; and each cable connects an output point attached to the fixed based of the robot to the mobile platform.These robots have few moving parts, with reduced mass, and are most suitable for tasks required high performance such as speed and accuracy and provide a large workspace [3]. By moving the cables connections points, it also has a work space much more grace to rolling cables, which allow the effector to be very far from its base, and reduce the distance near zero with very high acceleration, and the main advantage of the cable are; a larger workspace for the same overall dimension of the robot; light weight cables resulting in very safe an transportable system [4]. The best-known is control of cameras in stadiums (Skycam), this application is moved a fixed camera on a moving platform, another field of interest in biomedical application is the monitoring of the movement. An example may be mentioned CaTraSys (Cassino Tracking System) was used for identifying kinematic parameters and the mobility of man. Also, rehabilitation applications transport [5], the main disadvantages of parallel manipulators lie in the nature Vol. 11, No. 1 (2018) 2 Copyright © 2018 SERSC Australia of the cables suffer from unidirectional constraints that can only be pulled and not pushed. In this variant of robots, the cables must be with the tension in the whole workspace [6]. This paper is organized as follow: the structure of the our parallel robot with 4 cables. Next, we present the demonstration of geometric and dynamic models and we present a graphical user interface for the point to point command, finally, presents the controls modeling and some simulation results for different tests. Structure of 4 Cables Parallel RobotIn Figures 1 shows the general structure of our robot which consist mainly of a fixed base, a moving platform that holds the ...