A Project Report on “Design, Fabrication and Control of an Articulated Robotic Arm” Submitted In partial fulfillment of the requirements of degree of Bachelor of Technology- Mechanical Engineering By Sahil R. Makwana BTM862 Divya H. Shah BTM868 Kahaan P. Shah BTM 869 Under the guidance of Dr. Rajesh Buktar Department of Mechanical Engineering (SESSION: 2014-2015) Bharatiya Vidya Bhavan’s Sardar Patel College of Engineering (An Autonomous Institute affiliated to University of Mumbai) Munshi Nagar, Andheri (West), Mumbai-400058. i CERTIFICATE This is to certify that this project report entitled ‘DESIGN, FABRICATION AND CONTROL OF AN ARTICULATED ROBOTIC ARM’ is the bona-fide work of MR. SAHIL MAKWANA, MR. DIVYA SHAH and MR. KAHAAN SHAH, the students of BACHELOR OF TECHNOLOGY- MECHANICAL ENGINEERING, BATCH OF 2015 at SARDAR PATEL COLLEGE OF ENGINEERING, who carried out the project work under my supervision and have completed it to my satisfaction. Dr. Rajesh Buktar Dr. P. H. Sawant Project Guide Principal HOD- Mechanical, S.P.C.E. S.P.C.E. ii CERTIFICATE This is to certify that this project report entitled ‘DESIGN, FABRICATION AND CONTROL OF AN ARTICULATED ROBOTIC ARM’ submitted by MR. SAHIL MAKWANA, MR. DIVYA SHAH and MR. KAHAAN SHAH, is found to be satisfactory and approved for the degree of BACHELOR OF TECHNOLOGY- MECHANICAL ENGINEERING. Dr. Rajesh Buktar Dr. Santosh Rane Prof. Sachin Vankar Project Guide Examiner Examiner HOD- Mechanical Associate Professor Assistant Professor iii DECLARATION OF THE STUDENT I declare that this written submission represents my ideas in my own words and where others' ideas or words have been included, I have adequately cited and referenced the original sources. I also declare that I have adhered to all principles of academic honesty and integrity and have not misrepresented or fabricated or falsified any idea / data / fact / source in my submission. I understand that any violation of the above will be cause for disciplinary action by the Institute and can also evoke penal action from the sources which have thus not been properly cited or from whom proper permission has not been taken when needed. Sahil Makwana Divya Shah Kahaan Shah Seat No.: BTM 862 Seat No.: BTM 868 Seat No.: BTM 869 Date: May 12, 2015. Date: May 12, 2015. Date: May 12, 2015. iv ACKNOWLEDGEMENT The success and final outcome of this project would not have been possible without the able guidance and help from many people and we are extremely fortunate to have got this throughout the completion of the project work. We hereby take this opportunity to thank and show our gratitude towards everyone who supported us. We thank our professor, project guide and the Head of Department- Mechanical Engineering, Dr. Rajesh Buktar for guiding us throughout the way and for advising us on various aspects of our project. We thank him for offering much- appreciated and sought-after advice and suggesting thought-provoking ideas throughout the semester. We are indebted to our guide for offering us the freedom to explore and work on challenging aspects of the project. His constant support and guidance has helped us complete our project successfully. We also thank him for supporting us by providing great learning oriented infrastructure coupled with laboratory equipment and plethora of varied literature of scholarly levels incorporated in the Institute’s library which made our search and quest for research materials a lot easier. We would also like to express our sincere thanks to all our professors, colleagues and friends from different fields whose periodic inputs, informal discussions and varied perspectives have given us a better understanding of our progress. v ABSTRACT The report documents the conceptualization, design, fabrication and control of a six degree of freedom articulated robotic arm by means of design and analysis followed by manufacturing specific to a particular work envelope and payload. The motivation for this project is creating a generalized robotic arm for educational purposes at the Institute which will contribute to acquiring a deeper understanding of theories of robotic arms and at the same time enable research in various applications of robotic manipulators. The designs implemented through CATIA v5 computer software followed by payload calculations and analysis for materials and stresses have been presented as a part of this project. Manufacturing was implemented by importing designs via the drawing exchange format onto laser-cutting machines. Programming was implemented through Arduino MEGA microcontroller using C++ language. The final prototype will validate and establish the capability of the robotic arm. It will serve as a research platform for extended functionality by adding and improving existing software environments and hardware devices. vi TABLE OF CONTENTS Acknowledgement v Abstract vi Table of Contents vii List of Figures ix List of Tables x 1. Introduction 1 1.1. Robotic Manipulator 2 1.2. Current Robotics Research 3 1.3. Purpose & Application 6 1.4. Approach 7 2. Literature Survey 9 2.1. Technical Terms 10 2.2. Robot Anatomy 11 2.3. Arm Configuration 16 3. Design 23 3.1. Overview 24 3.2. Torque Calculations 26 3.3. Components 28 4. Analysis 31 4.1. Direct Kinematics 33 5. Fabrication 38 5.1. Materials 39 5.2. Manufacturing- Laser Cutting 42 6. Control 50 6.1. Actuators 51 6.2. Microcontroller 53 6.3. Programming 57 7. Applications & Conclusion 62 7.1. Applications 63 7.2. Conclusion 66 7.3. The Future Scope 66 References 67 Annexure A- CAD Draft Files 68 Annexure B- Circuit Diagram 69 Annexure C- Arduino Program 70 Annexure D- Team Details 74 vii LIST OF FIGURES SR NO. FIGURE NO. TITLE PAGE NO. 1 Fig.2.1 The base, arm, wrist, and end effector 11 forming the mechanical structure of a manipulator 2 Fig.2.2 Two rigid binary links in free space 12 3 Fig.2.3 An open kinematic chain formed by joining 12 two links 4 Fig.2.4 Joint types and their symbols 13 5 Fig.2.5 Representation of six degrees of freedom with 14 respect to a coordinate frame 6 Fig.2.6 A two DOF planar manipulator-two links, 14 two joints 7 Fig.2.7 A 3 DOF Cartesian arm configuration and its 17 workspace 8 Fig.2.8 Gantry or box configuration Cartesian 17 manipulator 9 Fig.2.9 A 3-DOF cylindrical arm configuration and 18 its workspace 10 Fig.2.10 A 3 DOF polar arm configuration and its 19 workspace 11 Fig.2.11 A 3 DOF articulated configuration and its 20 workspace 12 Fig.2.12 The SCARA configuration and its workspace 21 13 Fig.2.13 A DOF RPY wrist with three revolute joints 21 14 Fig.2.14 Some fingered grippers for holding different 22 types of jobs 15 Fig. 3.1 An articulated Robotic Arm 25 16 Fig. 3.2 Link Diagram 26 17 Fig. 3.3 Picture of Assembly 1 28 18 Fig. 3.4 Picture of Assembly 2 28 19 Fig. 3.5 Links & Base Plate 29 20 Fig. 3.6 Universal Bracket 30 21 Fig. 3.7 C- Bracket 30 viii 22 Fig. 3.8 Circular Horn 30 23 Fig. 3.9 Servo Motor 30 24 Fig. 3.10 Micro Servo Motor 30 25 Fig.4. 1 D-H parameters 34 26 Fig.4. 2 3 DOF manipulator 35 27 Fig 4. 3 Link 36 28 Fig.5. 1 Laser cutting 42 29 Fig.5. 2 Laser cutting 43 30 Fig.5. 3 CO2 Laser Machine 44 31 Fig.5. 4 Neodymium (Nd) Laser Machine 45 32 Fig.5. 5 Process of Laser cutting 46 33 Fig.5. 6 Machine configuration 48 34 Fig 6. 1 Arduino mega 53 35 Fig 6. 2 50%, 75%, and 25% Duty Cycle Examples 61 36 Fig 7. 1 Stud welding 64 37 Fig 7. 2 Palletizing 65 38 Fig 7. 3 Medical application 65 ix LIST OF TABLES SR. NO. TABLE NO. TITLE PAGE NO. 1 Table 3. 1 Joint and functions 25 2 Table 3. 2 Servo motor dimension 30 3 Table 4. 1 Joint link parameter table 37 4 Table 5. 1 Physical properties of acrylic 39-40 5 Table 6. 1 Pin description of IC 7806 53 6 Table 6. 2 Arduino summary 54 7 Table A Team members 74 x Chapter 1 Introduction 1 1.1 ROBOTIC MANIPULATORS A robotic arm is a type of mechanical arm, usually programmable, with similar functions to a human arm; the arm may be the sum total of the mechanism or may be part of a more complex robot. The links of such a manipulator are connected by joints allowing either rotational motion (such as in an articulated robot) or translational (linear) displacement. The links of the manipulator can be considered to form a kinematic chain. The terminus of the kinematic chain of the manipulator is called the end effector and it is analogous to the human hand. The end effector, or robotic hand, can be designed to perform any desired task such as welding, gripping, spinning etc., depending on the application. For example robot arms in automotive assembly lines perform a variety of tasks such as welding and parts rotation and placement during assembly. In some circumstances, close emulation of the human hand is desired, as in robots designed to conduct bomb disarmament and disposal. The first robotic arm was developed in the 1950s by a scientist named George Devol, Jr., before which robotics were largely the products of science fiction and the imagination. The development of robotics was slow for a while, with many of the most useful applications being involved with space exploration. The use of robots to aid in industrialization weren‘t fully realized until the 1980s, when robotic arms began to be integrated in automobile and other manufacturing assembly lines.