International Journal of Robotics and Automation (IJRA) Vol. 5, No. 1, March 2016, pp. 61~66 ISSN: 2089-4856  61 Journal homepage: http://iaesjournal.com/online/index.php/IJRA Nonlinear Dynamic Modeling and Optimal Motion Analysis of Two-Link Manipulators M. Talezadeh*, M. Ghazal*, M. Taheri*, M. Nazemi-Zade* * Department of Mechanics, Damavand Branch, Islamic Azad University, Damavand, Iran Article Info ABSTRACT Article history: Received Nov 9, 2015 Revised Jan 26, 2016 Accepted Feb 13, 2016 Manipulators are used in various industrial applications to perform variant operations such as conveying payloads. Regarding to their applications, dynamic modeling and motion analysis of manipulators are known as important and appealing tasks. In this work, nonlinear dynamics and optimal motion analysis of two-link manipulators are investigated. To dynamic modeling of the system, the Lagrange principle is employed and nonlinear dynamic equations of the manipulator are presented in state-space form. Then, optimal motion analysis of the nonlinear system is developed based on optimal control theory. By means of optimal control theory, indirect solution of problem results in a two-point boundary value problem which can be solved numerically. Finally, in order to demonstrate the power and efficiency of method, a number of simulations are performed for a two-link manipulator which show applicability of proposed method. Keyword: Dynamic Manipulator Motion Optimal Two-link Copyright © 2016 Institute of Advanced Engineering and Science. All rights reserved. Corresponding Author: M. Taheri, Department of Mechanics, Damavand Branch, Islamic Azad University, Damavand, Iran. Email: mo.tahery93@gmail.com 1. INTRODUCTION Fixed and mobile Manipulators are used in many applications and perform several tasks such as conveying payloads, rehabilitation tasks and etc [1-6]. In fact, due to their advantage of high speed, accuracy and repeatability, robot manipulators have become major component of industrial applications and even now a days they become part of routine life. Regarding to their vast applications, dynamic modeling and motion analysis of such systems have attracted a great deal of interests by many robotic researchers. It is well known that robot manipulators are highly nonlinear, dynamically coupled and time-varying systems and their dynamic analysis is a complex and challenging issue. Luh [7] studied industrial manipulators and developed some conventional method to control dynamic motion of the manipulators. Song et al. [8] investigated dynamic motion of robotic manipulators and proposed a computed torque controller to handle requirement of precise dynamical models of robotic manipulators. Piltan et al. [9] presented dynamic motion of robotic manipulators and developed a nonlinear control strategy to motion control of highly nonlinear dynamic robot manipulator in presence of uncertainties. Rahimi et al. [10] studied dynamic analysis of elastic manipulators. They investigated trajectory optimization of such robot using optimal control theory. Moreover, they [11] proposed finite element method to model dynamics of elastic manipulators. In this work, nonlinear dynamics and optimal motion planning of two-link manipulators are investigated. To dynamic modeling of the system, the Lagrange principle is employed and nonlinear dynamic equations of the manipulator are presented in state-space form. Then, optimal motion analysis of the nonlinear system is developed based on optimal control theory. By means of optimal control theory, indirect solution of results in a two-point boundary value problem which can be solved numerically. Finally, in order to demonstrate the power and efficiency of method, a number of simulations are performed for a two-link manipulator which show applicability of proposed method.