Abstract—The kinematics of manipulators is a central problem in the automatic control of robot manipulators. Theoretical background for the analysis of the 5 Dof Lynx-6 educational Robot Arm kinematics is presented in this paper. The kinematics problem is defined as the transformation from the Cartesian space to the joint space and vice versa. The Denavit-Harbenterg (D-H) model of representation is used to model robot links and joints in this study. Both forward and inverse kinematics solutions for this educational manipulator are presented, An effective method is suggested to decrease multiple solutions in inverse kinematics. A visual software package, named MSG, is also developed for testing Motional Characteristics of the Lynx-6 Robot arm. The kinematics solutions of the software package were found to be identical with the robot arm’s physical motional behaviors. Keywords—Lynx 6, robot arm, forward kinematics, inverse kinematics, software, DH parameters, 5 DOF ,SSC-32 , simulator. I. INTRODUCTION HE transformation between the joint space and the Cartesian space of the robot is very important. Robots are operated with their servo motors in the joint space, whereas tasks are defined and objects are manipulated in the Cartesian space [1]. The kinematics solution of any robot manipulator consists of two sub problems forward and inverse kinematics. Forward kinematics will determine where the robot’s manipulator hand will be if all joints are known whereas inverse kinematics will calculate what each joint variable must be if the desired position and orientation of end-effector is determined Hence Forward kinematics is defined as transformation from joint space to cartesian space whereas Inverse kinematics is defined as transformation from cartesian space to joint space. In this study, the standard Denavit-Harbenterg [2] approach has been used for modeling the Lynx-6 Robot Arm seen in Fig. 1. Many industrial robot arms are built with simple geometries such as intersecting or parallel joint axes to simplify the associated kinematics computations [3]. But their costs are high for students and research workers. Lynx-6 is a good alternative for such robot manipulators, because it’s inexpensive, flexible and similar to industrial robot arms. There is a large amount of literature which discusses the kinematics analysis of industrial robots [4]. Majority of them shy away from discussing the low cost educational robot arms. So in this paper mathematical model and kinematical analysis of the Lynx-6 educational robot arm is studied. A Manuscript received August 28, 2007. Authors are from the Computer Engineering Department of Ankara University, Ankara, Turkey (e-mails: bkoyuncu@ankara.edu.tr, mguzel@eng.ankara.edu.tr). Fig. 1 Lynx 6 Robotic arm visual software program was also developed to show the robot arm motion with respect to its mathematical analysis. II. DESCRIPTION Lynx 6 robot arm has 5 directions of motion (DOF) plus a grip movement (5+1). It is also similar to human arm from the number of joints point of view. These joints provide shoulder rotation, shoulder back and forth motion, elbow motion, wrist up and down motion, wrist rotation and gripper motion. A graphical view of all the joints was displayed in Fig. 2. Fig. 2 Modeling of Lynx-6 Robotic Arm Lynx-6 has five rotational joints and a moving grip. Joint 1 represents the Base and its axis of motion is z 0 . This joint provides a rotational θ 1 angular motion around z 0 axis in x 0 y 0 plane. Joint 2 is identified as the shoulder and its axis is perpendicular to Joint 1 axis. It provides an angular motion θ 2 in x 1 y 1 plane. z axes of Joint 3 (Elbow) and Joint 4 (Wrist) are parallel to Joint 1 z axis, They provide θ 3 and θ 4 angular motions in x 2 y 2 and x 3 y 3 planes respectively. Joint 5 is identified as the grip. Its z 4 axis is vertical to z 3 axis and it provides θ 5 angular motion in x 4 y 4 plane. Lynx-6 Robot Arm rotational joints and the grip are controlled by dedicated servo motors. These motors are connected to a serial servo controller card (SSC32) to control the Lynx-6 from a computer through the serial port, Fig. 3. A sequence of 3 consecutive unsigned bytes is sent to serial servo controller from the computer. These are the default sync byte, the joint servo identifier byte and the Software Development for the Kinematic Analysis of a Lynx 6 Robot Arm Baki Koyuncu, and Mehmet Güzel T World Academy of Science, Engineering and Technology International Journal of Computer and Information Engineering Vol:1, No:6, 2007 1575 International Scholarly and Scientific Research & Innovation 1(6) 2007 ISNI:0000000091950263 Open Science Index, Computer and Information Engineering Vol:1, No:6, 2007 publications.waset.org/10518/pdf