Design And Development Of Pneumatic Gripper For Comau Robot.

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UNIVERSITI TEKNIKAL MALAYSIA MELAKA

DESIGN AND DEVELOPMENT OF PNEUMATIC GRIPPER

FOR COMAU ROBOT

This report submitted in accordance with the requirements of the Universiti Teknikal Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering

(Robotic and Automation) with Honours.

MOHD NAZILI BIN YAACOB

FACULTY OF MANUFACTURING ENGINEERING 2009

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Alamat Tetap: Kampung Telosan 16800 Pasir Puteh Kelantan Darul Naim

Tarikh: _________________________

** Jika Laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh laporan PSM ini perlu dikelaskan sebagai SULIT atau TERHAD.

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA

TAJUK: Design and Development of Pneumatic Gripper for COMAU Robot

SESI PENGAJIAN: 2008/09 Semester 2

Saya MOHD NAZILI BIN YAACOB

mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut: 1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan

untuk tujuan pengajian sahaja dengan izin penulis.

3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan pertukaran antara institusi pengajian tinggi.

4. **Sila tandakan (√)

SULIT

TERHAD

TIDAK TERHAD

(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia yang termaktub di dalam AKTA RAHSIA RASMI 1972)

(Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)

Disahkan oleh:

Cop Rasmi:

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DECLARATION

I, hereby, declared this report entitled “Design and Development of Pneumatic Gripper for COMAU Robot” is the result of my own research except as cited

references.

Signature : ………..

Author’s Name : MOHD NAZILI BIN YAACOB

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APPROVAL

This report is submitted to the Faculty of Manufacturing Engineering of UTeM as partial fulfillments for the degree of Bachelor of Manufacturing Engineering (Robotic and Automation) with Honours. The member of supervisory committee is as follow:

……….. (Pn. Syamimi binti Shamsuddin)

Main Supervisor

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ABSTRACT

Gripper is an important component for an industrial robot because the application of the robot is verified according to the type of gripper utilized as its end effector. The aim of the project is to design and develop a new and improved pneumatic gripper for pick and place applications to be integrated with the COMAU robot available in the Robotics Laboratory at Faculty of Manufacturing Engineering (FKP). This project is focused in producing a pneumatic gripper that can grasp object of various sizes and shapes effectively. Knowledge in computer aided design (CAD) and fluid power are vital in order to complete this project. In this project, 4 types of gripper design were suggested and the best design was selected to be fabricated. Solidworks 2005 software had been used for detail design and documentation of the gripper. The new improved gripper is parallel type which utilizes a double acting cylinder as a driver for the jaw movement only has one movable jaw. The other jaw is fixed and acts as a supporter for the object to be gripped. To analyze its functionality and effective, the gripper had been tested to grasp several shapes of object such as spherical shape, block shape, and cylindrical shape. Results confirmed that the improved gripper is able to grasp bigger object with various shapes compare to the current gripper available with COMAU robot.

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ABSTRAK

Pencengkam merupakan komponen penting dalam sesebuah robot industri. Tujuan utama projek ini adalah untuk mencipta dan membangunkan satu pencengkam pneumatik baru yang telah dibaikpulih untuk aplikasi angkat dan letak bagi diintegrasikan dengan robot COMAU yang terdapat di makmal robotik, fakulti kejuruteraan pembuatan (FKP). Projek ini difokuskan kepada penghasilan pencengkam pneumatik yang boleh memegang pelbagai saiz dan bentuk objek secara cekap. Pengetahuan di dalam pereka berbantu komputer (CAD) dan kuasa bendalir amat penting dalam melaksanakan projek ini. Dalam membangunkan pencengkam yang baru, empat rekaan pencengkam telah dicadangkan dan rekaan yang terbaik dipilih untuk di bina. Perisian SolidWorks 2005 digunakan untuk proses memperincikan rekaan dan dokumentasi. Pencengkam yang baru ini merupakan pencengkam jenis selari yang menggunakan silinder pneumatik dua arah sebagai penggiat kepada pergerakan rahang pencengkam. Pencengkam ini hanya mempunyai satu rahang yang bergerak and satu lagi rahang merupakan rahang tetap yang bertindak sebagai penyokong untuk objek. Untuk menganalisis fungsi dan keberkesanan pencengkam ini, beberapa ujian telah dijalankan dengan menggunakan beberapa jenis objek yang berlainan bentuk. Daripada keputusan yang diperolehi menunjukkan pencengkam baru yang telah dibaikpulih ini dapat memegang objek yang lebih besar dan berbagai bentuk berbanding dengan pencengkam yang sedia ada.

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DEDICATION

For my parents, Yaacob bin Che Noh and Halimah binti Daud, for all my siblings and friends, and for my beloved supervisor.

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ACKNOWLEDGEMENT

I would like to give my gratitude toward Allah S.W.T because of His merciful and graceful, I manage to finish up my project entitle Design and Development of Pneumatic Gripper for COMAU Robot. I would like to thanks my beloved supervisor, Pn. Syamimi binti Shamsuddin for all her guidance and advices along the development of this project until finish. Without her guidance and advice, I would have been lost. Not forgotten my co-supervisor, En. Arfauz bin A. Rahman, thanks for supporting me while my real supervisor was not around. I truly appreciate his effort in ensure I’m not stray from the objective of my project. I also would like to thanks all the technicians that involve during the development of this project in helping and give good advices on the usage of the laboratory equipment. Their guidance is important for me in achieving my goals. To all my beloved friends and family, thanks for supporting and helping me when I’m in need. Thank you so much.

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TABLE OF CONTENT

Abstract i

Abstak ii

Dedication iii Acknowledgement iv Table of Content v

List of Tables ix

List of Figures x

1. INTRODUCTION 1

1.1 Background 1

1.2 Problem Statement 2

1.3 Project Aim and Objective 2

1.4 Project Scope 3 1.5 Benefit of Project 3

1.6 Project Planning 4 2. LITERATURE REVIEW 6

2.1 Definition of Robot 6

2.2 Industrial Robot 7

2.2.1 Industrial Robot Anatomy 8

2.2.2 Types of Industrial Robot 10

2.2.2.1 Cartesian Robot 10

2.2.2.2 Cylindrical Robot 11

2.2.2.3 Spherical Robot 11

2.2.2.4 Articulated Robot 12

2.2.3 Robot Kinematics 12

2.2.4 Robot Programming 14

2.2.4.1 Robot Programming Method 15

2.2.4.2 Robot Programming Languages 18

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2.3 End Effector 21

2.4 Tools 23

2.4.1 Definition of Tools 23

2.4.2 Types of Tools 23

2.5 Grippers 28

2.5.1 Definition and Conceptual Basics 29

2.5.2 Gripper Flexibility 32

2.5.3 Gripper Classification. 33

2.5.4 Gripper Selection 35

2.5.5 Gripper Types 41

2.5.5.1 Impactive Gripper 41

2.5.5.2 Ingressive Gripper 44

2.5.5.3 Astrictive Prehension 45

2.5.5.4 Contigutive Prehension. 46

2.5.6 Gripper Mechanism 47

2.5.6.1 Linkages Actuation 47

2.5.6.2 Rack-pinion Actuation 47

2.5.6.3 Cam Actuation 48

2.5.6.4 Screw actuation 48

2.6 Design Tools / Software 49

2.6.1 AutoCAD 50

2.6.2 CATIA 50

2.6.3 SolidWorks 50

2.7 Pneumatic Gripper in FKP’s Robotic Laboratory 52

2.7.1 Gripper Characteristics 53

2.7.2 Gripper Mechanism 54

2.8 Previous Studies on Gripper Design for Industrial Robot 54

2.9 Summary 56

3. METHODOLOGY 57

3.1 Project Understanding and Planning 57

3.2 Research and Literature 59

3.2.1 Internet 59

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3.3 Study the Current Gripper 59

3.4 Define Problems and Suggest Improvement 60

3.5 Conceptual Design of a New Gripper 60

3.5.1 Procedures to used Solidwork 2005 for 3D Modeling 63

3.6 Process Planning and Tools Selection 65

3.7 Material Selection 65

3.8 Fabrication and Assembly 65

3.9 Testing and Analysis 66

3.10 Result and Troubleshooting 66

4. DESIGN AND DEVELOPMENT 67

4.1 Design Stage 67

4.1.1 First Design 68

4.1.2 Second Design 69

4.1.3 Third Design 70

4.1.4 Forth Design 71

4.1.5 Choosing the Best Design 72

4.1.6 Detail Design and Documentation 72

4.2 Development Stage 74

4.2.1 Device Selection 75

4.2.2 Material Selection for Mechanical Parts 76

4.2.3 Cutting Material into Desired Parts 76

4.2.4 Dimension Marking 78

4.2.5 Produce Shaft (Turning Process) 79

4.2.6 Milling Process 80

4.2.7 Drilling and Tapping Process 82

4.2.8 Gripper Assembly 84

4.2.9 Cost Breakdown of the Improved Gripper 87

4.2.10 Integration of the New Gripper with COMAU Robot 88

4.2.10.1 Procedure on Programming Using Teach Pendant 90

4.2.10.2 New Gripper Operation 93

5. TESTING, RESULT AND DISCUSSION 95

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5.1.1 Result and Observation 95

5.2 Gripping Test 97

5.2.1 Block Shape Test 97

5.2.2 Cylindrical Shape Test 98

5.2.3 Spherical Shape Test 99

5.2.4 Result and Observation 100

5.3 Discussion 104

6. CONCLUSION AND SUGGESTIONS FOR FUTURE WORKS 107

REFERENCES 109

APPENDICES

A. Detail Drawing and Documentation B. Programming

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LIST OF TABLES

1.1 Gantt chart for PSM 1 4

1.2 Gantt chart for PSM 2 4

1.3 Detail plan for fabrication works and report writing in PSM 2 5

2.1 Classification of gripper comprising 4 gripper categories 34

2.2 Selection consideration of gripper 36

2.3 The specification of the current pneumatic gripper 52

4.1 Pugh method for choosing the best design. 72

4.2 Description of gripper parts 74

4.4 Information of the pneumatic cylinder 75

4.3 List of materials 76

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LIST OF FIGURES

2.1 The base, arm, wrist, and end-effector forming the

mechanical structure of a manipulator 9

2.2 Cartesian robot 11

2.3 Cylindrical robot 11

2.4 Spherical robot 12

2.5 Articulated robot 12

2.6 General kinematic configuration of a robot system 14

2.7 Process of on-line programming 15

2.8 Lead-through programming process 16

2.9 Walk-through programming method 16

2.10 Of-line programming method 17

2.11 Classification of programming methods for industrial robot 18

2.12 Typical examples of end effector 23

2.13a Spot welders 25

2.13b Arc welder 25

2.14a Grinder 26

2.14b Deburrer 26

2.15 Spray gun 27

2.16 Drill as end effector 28

2.17 Possibilities for prehension of a spherical object 30

2.18 Subsystem of a mechanical gripper 31

2.19 Functional model of a gripper 32

2.20 Technical solution on achieving gripper flexibility 33

2.21 Gripper Classification 35

2.22 Consideration parameters 37

2.23 Flowchart guide to aid gripper selection 39

2.24a Pneumatic cylinder 42

2.24b Membrane drive 42

2.24c Electromechanical drive with a rotating screw nut and guiding (skew preventing) rod 42

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2.24d Electromagnetic drive, opened by spring force 42

2.25 Basic design strategies for electric motors driven grippers 43

2.26 Concept of electromagnetic drive gripper 44

2.27 CluPicker mechanism gripper 45

2.28 Possibilities for vacuum production 46

2.29 Adhesive tape gripper 46

2.30 Linkages actuation 47

2.31 Rack-pinion actuation 48

2.32 Cam actuation 48

2.33 Screw actuation 49

2.34 Current pneumatic gripper attached to COMAU robot 52

2.35 Cross sectional diagram of the gripper with dimensions 53

2.36 Two three-axis gripper with force sensors 55

2.37 Reconfigurable robotic gripper 56

3.1 Project’s Flow Chart 58

3.2 Design stage 61

3.3 Solidworks 2005 software 62

3.4 Solidwork 2005 main window 63

3.5 New Solidwork document window 63

3.6 Main window for start sketching 64

3.7 Sketch and 3D features 64

4.1 Isometric view of the first design 68

4.2 Isometric view of the second design 69

4.3 Isometric view of the third design 70

4.4 Isometric view of the forth design 71

4.5 Exploded view of the new gripper design 73

4.6 Main process under fabrication 74

4.7 Laser cutting machine 77

4.8 Parts undergoes laser cutting process 77

4.9 Cutting aluminum block using band saw 78

4.10 Marking process 78

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4.12 Turning process 80

4.13 Vertical milling machine 80

4.14 End milling process 81

4.15 Setting the work piece to be perpendicular with cutting tool 81

4.16 The final outcomes of milling process 82

4.17 Center Drill 82

4.18 Drilling process 83

4.19 Tapping process 83

4.20 Gripper assembly 84

4.21 Holes on the side of gripper’s movable jaw 85

4.22 Assembly of pneumatic cylinder with gripper’s body 85

4.23 Alignment of the guided shaft 86

4.24 Fix jaw assembly 86

4.25 New gripper mounted on the wrist end of the COMAU robot 88

4.26 COMAU robot teach pendant features 89

4.27 DOUT command to control the gripper 89

4.28 5/2 ways directional control valve 90

4.29 Create new program 91

4.30 Enter program name 91

4.31 Insert empty line for new command 91

4.32 Insert command 92

4.33 Press START to execute command 92

4.34 Program for testing the functionality of the new gripper 93

4.35 Pneumatic system 93

4.36 Operation flow 94

5.1 Function test. 96

5.2 Gripper’s jaw stuck with guided shaft. 96

5.3 Dimension of aluminum block. 97

5.4 Designed layout for pick and place operation (for the first shape). 98

5.5 Dimension of the mildsteel pipe 98

5.6 Designed layout for pick and place operation (for the 2nd shape). 99

5.7 Dimension of the golf ball. 99

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5.9 Gripping the block shape object 100

5.10 Gripping the cylindrical shape object. 101

5.11 New gripper’s jaw design. 102

5.12 Gripper’s jaw design without V-shape grove. 102

5.13 Gripping the spherical shape object 103

5.14 Comparison between gripping a golf ball and tennis ball 104

5.15 The fitting of the pneumatic cylinder 104

5.16 The movable jaw slant while gripping the ball. 105

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CHAPTER 1 INTRODUCTION

1.1 Background

Pneumatic system is commonly used in industries such as in the robotic arm application without having to worry about polluting the environment because the systems only use air. It can be said that the pneumatic system is environmental friendly. A pneumatic gripper is a specific type of pneumatic actuator that typically involves either parallel or angular motion of surfaces that will grip an object and is commonly used as part of a "pick and place" system that will allow a component to be picked up and placed somewhere else as part of a manufacturing system.

Some grippers act directly on the object they are gripping based on the force of the air pressure supplied to the gripper, while others will use a mechanism such as sensors to control the amount of force applied to the object being gripped. Grippers can also varied in terms of the opening size, the amount of force that can be applied, and the shape of the gripping surfaces frequently called "Jaws". They can be used to pick up everything from very small items to very large items. Grippers are frequently added to industrial robots as end effectors in order to allow the robot to interact with other objects.

This project is aimed to design and develops a working pneumatic gripper to be integrated with the COMAU robot in Robotics Laboratory at Faculty of Manufacturing Engineering (FKP) at Universiti Teknikal Malaysia Melaka (UTeM). The design shall incorporate proper valves and cylinder system for pick and place application for the robot. In order to achieve the goal of the project, CAD design and pneumatic circuitry knowledge is crucial. Other knowledge that is required in

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finishing this project includes machine design, applied mechanic, programming, fabricating and material selection.

1.2 Problem Statement

The current pneumatic gripper for COMAU in FKP’s robotic laboratory is small in size and can only grip small and light weight material. The base of the gripper attached with the end of the robot arm is only about 55 mm x 55 mm in dimension. The dimension of the gripper body is 50 mm x 42 mm and the thickness is 27 mm. The jaw of the gripper it self is small. The thickness is only 1/3 from the thickness of the body. The jaws can open maximum 10 mm both side and only can grip up to 30 mm of the material. It is also not suitable for gripping a heavy cylindrical object because the probability the object will slip is high. The hard surface of the jaw can easily damage the soft material surface and edge (the gripper did not construct with build in force sensor to begin with) when grasping the material. Because the size is small, the jaws cannot strongly hold a heavier object and probably will slip while running the pick and place process. The external gripping force per finger effective value is 42 N and the internal gripping force per finger effective value is 66 N.

1.3 Project Aim and Objective

The aim of this project is to design and develop a new pneumatic gripper for COMAU. The aim is achieved through these objectives:

(a) To design and develop a new and improved pneumatic based robot gripper for the COMAU robot in FKP’s Robotic Laboratory.

(b) To integrate the gripper with the COMAU robot available in Robotic laboratory.

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1.4 Project Scope

This project is focused in designing and developing a new pneumatic based gripper that can grasp a bigger size object with efficient grip and can reduce impact to the object. The gripper will be designed using Solidwork software, the 3D software that can design, simulate, and analyze the material properties use in producing the gripper before being fabricate. This gripper will than be integrated with COMAU robot in robotic laboratory for pick and place of two or more shapes of object. In order to design and develop the gripper, a further study on the current gripper available in robotic laboratory on how it mechanism and characteristics should be conducted. At the end of the development process, testing will be carrying out to analyze whether the gripper can work properly or not.

1.5 Benefit of project

By the end of this project, hopefully the following benefits can be achieved:

(a) Improving the grasping mechanism of the current gripper to be more efficient and safe.

(b) Can grip various type of material shapes compare to the current robot gripper in FKP’s robotic laboratory.

(c) The continuous research and sharing information from this project can give an idea to develop various gripper types for more complex and flexible application.

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1.6 Project Planning

Table 1.1 shows the Gantt chart for activities in PSM 1 and Table 1.2 shows the Gantt chart for activities in PSM 2. Table 1.3 shows the detail plan (weekly target) for fabrication works (including testing and analysis) and report writing in PSM 2.

Table 1.1: Gantt chart for PSM 1

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Table 1.3: Detail Plan for fabrication works and report writing in PSM 2

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CHAPTER 2 LITERATURE REVIEW

This chapter discusses about information related to this project in order to give well understanding and good review about things that are crucially needed. This chapter also includes the study on the existing robot gripper available with the COMAU robot in FKP’s robotic laboratory. Beside that, the previous research from other people that related with this project also stated.

2.1 Definition of Robot

Robot is a computer-controlled machine that can be programmed to accomplish different task autonomously (Manseur, 2006). Different researchers divide the robot into different categories. International Federation of Robotic, et al. (2005) divided robot into two types which is service robot and industrial robot. According to their definition, service robot_{is a robot which operated semi or autonomously to perform} services useful to the well-being of humans and equipment, excluding manufacturing operation and industrial robot is an automatically controlled, reprogrammable, multipurpose manipulator programmable in three or more axes, which may be either fixed in place or mobile for use in industrial automation applications.

Manseur (2006) grouped the robot into several types which is robot arm, mobile robot, small-scale robot, nano-robot, parallel robot manipulator, special environment robot, and anthropomorphic robot.

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This research will go into detail concerning industrial robot because this project is base on industrial robot. The next sub topic will explain in detail about the industrial robot and its application in industries.

2.2 Industrial Robot

Groover (2008) define industrial robot as a general purpose, programmable machine possessing certain anthropomorphic characteristic like human. Its can also be define as a re-programmable multifunctional manipulator design to move material, parts, tools, or specialized devices through variable programmed motions for performance of a variety of task (McDonald, 1989 cited in Man Zhihong, 2004, p.1).

The most common anthropomorphic characteristic of industrial robot is mechanical arm or commonly called robot manipulator, which is use to performed various industrial tasks. Industrial robots are classified base on several characteristic. According to Richard and Andrew (1994), the most common general characteristic that is take consideration in classify an industrial robots are; arm configuration, number of axes (degree of freedom), load-carrying capability, work envelope, control system, power source, speed of movement, repeatability, accuracy, and reliability.

Industrial robots also refer to the automatic articulated programmable transfer and handling machine (Colestock, 2005). An industrial robot system not only includes industrial robots but also any devices and/or sensors required for the robot to perform its tasks as well as sequencing or monitoring communication interfaces (Man Zhihong, 2004).

By the research from reading books and articles, the advantages of using industrial robot in manufacturing industries can be stated as follow:

- accurate and consistent part loading - a reduction in part defect

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