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DESIGN AND FABRICATION OF HUAUNOID ROBOT HAND
David Tiong Wei Jye
Ti
211 1594 2008
Bachelor of Engineering with Honours
(Mechanical and Manufacturing Engineering)
2008
Pusat Khidmat Maktumat Akademik UNTVERSTTT MALAYSIA SARAWA. K
DESIGN AND FABRICATION OF HUMANOID ROBOT HAND
DAVID TIONG WEI JYE
This project is submitted in partial fulfilment of
the requirements for the degree for Bachelor of Engineering with Honours (Mechanical Engineering and Manufacturing System)
Faculty of Engineering
UNIVERSITI MALAYSIA SARAWAK
2007 / 2008
i
UNIVERSITI MALAYSIA SARAWAK
BORANG PENGESAHAN STATUS TESTS
Judul: DESIGN AND FABRICATION OF HUMANOID ROBOT HAND
SESI PENGAJIAN: 2007/2008
Saya DAVID TIONG WEI JYE
(HURUF BESAR)
mengaku membenarkan tesis * ini disimpan di Pusat Khidmat Maklumat Akademik, Universiti Malaysia Sarawak dengan syarat-syarat kegunaan seperti berikut:
1. Tesis adalah hakmilik Universiti Malaysia Sarawak.
2. Pusat Khidmat Maklumat Akademik, Universiti Malaysia Sarawak dibenarkan membuat salinan untuk tujuan pengajian sahaja.
3. Membuat pendigitan untuk membangunkan Pangkalan Data Kandungan Tempatan.
4. Pusat Khidmat Maklumat Akademik, Universiti Malaysia Sarawak dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi.
5. ** Sila tandakan ( %I ) di kotak yang berkenaan F7SULIT
(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972).
TERHAD (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/
badan di mana penyelidikan dijalankan).
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Tarikh:
CATATAN
TIDAK TER-HAD
(TANDATA GAN PENULIS)
Alamat tetap:
. 96000, SIBU
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(TANDATA
Disahkan oleh
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NO. 8, LANE 4, LUCKY RD. EN. SHAHROL BIN MOHAMADDAN
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**
Nama Penyelia
Tarikh: 21 IN / 3006
Tesis dimaksudkan sebagai tesis bagi ljazah Doktor Falsafah, Sarjana dan Sarjana Muda.
Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai
SULIT dan TERHAD.
ii
Approval Page
The project report attached here to, entitled "Design and Fabrication of Humanoid Robot Hand" prepared and submitted by DAVID TIONG WEI JYE in partial fulfilment of the requirement for Bachelor of Engineering with Honours in Mechanical Engineering and Manufacturing System is hereby read and approved by:
b/p
Mr. SHAHROL BIN MOHAMADDAN, Supervisor
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Date
APRIL 2008
111
Dedication
This study is principally dedicated to Faculty of Engineering UNIMAS for better improvement in Design and Robotics Research.
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ACKNOWLEDGEMENT
First of all, my deepest gratitude goes to my Supervisor, En. Shahrol Bin Mohamaddan; for being patience on me and guides me all the way along to accomplish this project. Without his supports and helps, I believed that this project would not be completed satisfactory.
Other than that, my gratitude goes to our Faculty of Engineering; UNIMAS for being kindly support us in this project. Thus, studies in Humanoid Robot Hands or End Effectors will improve robotics researches of University Malaysia of Sarawak (UNIMAS). Besides, we are not trying to design a conceptual idea but to make those ideas become applicable into real lives. With the efforts of this project, hopefully it can give some contributions to our lovely university (UNIMAS) so that we are able to compete with other universities in some Robot Competitions and showing them that
... "UNIMAS BOLEH".
Lastly, my thanks go to my Robocon Teammate, U. M. Koo Yoon Yin and Mr.
Chow Kar Kean for conducting me a lot in Circuit Board Design and also providing lots of precious knowledge in 8051-Based Programming.
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ABSTRACT
The "Design and Fabrication of Humanoid Robot Hand" project introduces a multi-fingered robotic hand so called URH-1 (UNIMAS Robot Hand 1) which is a fresh idea that comes to University Malaysia of Sarawak as a first step to do a prototype of designed robot hand through self-fabrication. The URH-l consists of four fingers (Ideal Finger, Middle Finger, Ring Finger, and Thumb) with each fingers have three joints (except finger thumb) which are Metacarpophalangeal (MCP) joint, Proximal Inter-Phalangeal (PIP) joint, and Distal interphalangeal (DIP) joint. The thumb has only two joints which are Metacarpophalangeal (MCP) joint and Distal interphalangeal (DIP) joint. Limit Switch is used as sensors for the force control feedback in grasping. Furthermore, the concept of this design is using the Purely Gears System for fingers deflection between each other. This project only consists of four Servo Motors. The Servo Motors will generate the rotational motion to the Double-Layer Spur Gear and then to the Fixed Face Gears and Free Rotate-Able Face Gear at Proximal Phalange (PP) Part. However, energy that generated to the Middle Phalange (MP) is supported by coupling gears which is linked to the Free Rotate-Able Face Gear. Moreover, Distal Phalange (DP) is connected to the Middle Phalange with a fixed angle. Therefore, URH-l will have the basic human hand grasping ability that depends on the programming command setting. Finally, springs are used to pull the fingers back to its original position and also function as damping purpose that will increase the longevity life of the robot hand.
V1
ABSTRAK
Projek "Design and Fabrication of Humanoid Robot Hand" memperkenalkan tangan robot URH-1 (UNIMAS Robot Hand 1) yang merupakan suatu idea baru di Universiti Malaysia Sarawak, yang telah mangambil langkah inisiatif untuk menghasilkan prototaip tangan robot yang direka melalui Self-Fabrication. URH-1 mempunyai empat jari, iaitu Jari Telunjuk, Jari Tengah, Jan Manis, dan Ibu Jari.
Setiap jari dilengkapi dengan tiga sendi (kecuali ibu jan yang hanya terdapat dua sendi), iaitu Metacarpophalangeal (MCP), Proximal Inter-Phalangeal (PIP), dan Distal interphalangeal (DIP). Dua sendi yang terdapat pada ibu jari pula ialah Metacarpophalangeal (MCP) dan Distal Interphalangeal (DIP). Untuk mengawal tekanan yang terhasil semasa proses genggaman, Limit Switch telah digunakan.
Selain itu, konsep rekaan ini telah menggunakan Sistem Gear secara kesuluruhan untuk tujuan pergerakan jari. Projek ini hanya menggunakan empat Motor Servo.
Motor Servo ini akan menghasilkan gerakan putaran ke atas Double-Layer Spur Gear yang kemudiannya mengerakkan Fixed Face Gears dan Free Rotate-Able Face Gear pada bahagian Proximal Phalange (PP). Tenaga yang dihasilkan ke atas Middle Phalange (MP) pula akan disokong oleh Coupling Gears yang dihubungkan kepada Free Rotate Able Face Gear. Selain itu, Distal Phalange (DP) akan dihubungkan dengan Middle Phalange (MP) pada satu sudut darjah yang tetap. Oleh yang demikian, URH-1 mempunyai asas genggaman menghampiri tangan manusia yang bergantung kepada tetapan programming. Bagi mengembalikan jari ke posisi asalnya selepas genggaman, spring akan digunakan. Selain itu, spring ini juga berfungsi sebagai damping yang akan meningkatkan hayat tangan robot ini.
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TABLES OF CONTENT
TITLE
CERTIFICATION FORM OF THESIS STATUS APPROVAL PAGE
DEDICATION
ACKNOWLEGEMENTS ABSTRACT
LIST OF FIGURES LIST OF TABLES
CHAPTER 1: INTRODUCTION
1.1 Overview of Industrial Robot End Effectors
1.2 Problems Approached in Humanoid Robot Hands 1.4 Aims and Objectives
CHAPTER 2: LITERATURE REVIEW
2.1 Existing Concept of Robotic Hands
Page
1
ii
111
iv
V
V1
X11
xvi
1 4 5
6 2.1.1 Compliant and Force Sensing (CFS) Hand 7 2.1.2 Nara Institute Science and Technologies (NAIST) Hand 9 2.1.3 Shape Depositional Manufacturing (SDM) Robotic Hand 14 2.2 Processors
2.3 Sensors
18 18
Vlll
2.4 Actuators
2.4.1 Servo Motor 2.5 Power Transmission 2.6 Types of Gears
2.6.1 Spur Gear
2.6.2 Rack and Pinion Gear 2.6.3 Internal Ring Gear
2.6.4 Helical Gear 2.6.5 Helical Rack
2.6.6 Double Helical Gear 2.6.7 Face Gear
2.6.8 Bevel Gear 2.6.9 Miter Gear
2.6.10 Worms and Worm Gears 2.6.11 Hypoid Gear
CHAPTER 3: METHODLOGY
3.1 Functional Requirements 3.2 Design Parameters
3.3 Base-Frame Design of Robot Hand
3.4 Sources for Robot Parts and Materials Selection 3.5 Mechanical Design via CAD
3.6 Simulation for Designed Mechanism 3.7 Electronic Selection
19 19 22 23 23 24 24 25 26
26
27 27 28 28 29
30 31 31 32
33 34
35 36
ix
3.8 Fabrication Processes 36
3.9 Programming
3.10 Experimental Testing
3.11 Expected Problems during the Process
38 38 39
CHAPTER 4: RESULTS AND DISCUSSION 40
4.1 Introduction
4.2 Designed Concept of Humanoid Robot Hand 4.3 Conceptual Design and Fabric-Able Design 4.4 Dimension of Fabric-Able Design
4.5 Designed Mechanism 4.6 Gears Specifications
4.7 Servo Motors Specifications
4.8 Computational Simulation Testing 4.8.1 Collision Detection
40 42 44 45 46
49
51 52 52
4.8.2 Fingers Angle Limitation 53
4.8.3 Expand Limitation of Designed Robot Hand 54
4.8.4 Grasp Limitation 55
4.8.5 Grasping Abilities 56
4.9 Pressure / Force Limit 59
4.10 Electronic Circuit Design 60
4.11 Programming 62
X
CHAPTER 5: CONCLUSION AND RECOMMENDATION 5.1 Conclusion
5.2 Recommendation
APPENDICES
APPENDIX A APPENDIX B APPENDIX C APPENDIX D APPENDIX E
REFERENCES
65 66
68 78 82 85 120
125
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List of Figures
Page
Figure 1.1: End Effectors used for Bags Picker 1
Figure 1.2: An example of Humanoid Robot Hand
Figure 1.3: Robot Hand with the Array of Tactile Sensors
Figure 1.4: WABOT-2
2
3
3
Figure 2.1: The design for the force sensing and compliant hand 6
Figure 2.2: Force diagram for the actuator force sensor. A force 8 perturbation dF causes deflection du of moment arm M.
Figure 2.3: NAIST Hand: 4 Finger Dexterous Hand
Figure 2.4: Finger Module (Without Fingertip)
Figure 2.5: 3-Axes Driving Mechanism: MP (Adduction/abduction), MP (flexion/extension), and PIP (flexion/extension)
Figure 2.6: 3-Axes Driving Mechanism in Detail
Figure 2.7: Coupling Link Mechanism
Figure 2.8: Prototype Fingertip Sensor
9
10
11
12
12
13
xii
Figure 2.9: Stable Grasp with Vision-based Tactile Sensation
Figure 2.10: SDM hand
Figure 2.11: Details of finger parts and placement of components
Figure 2.12: Actuation Schematic of SDM Hand
Figure 2.13: The grasper is mounted on an actuated linear slider
Figure 2.14: Servo Motor
Figure 2.15: Internal Parts of Servo Motor
Figure 2.16: Pulse Coded Modulation
Figure 2.17: Spur Gears
Figure 2.18: Rack and Pinion Gear
Figure 2.19: Internal Ring Gear
Figure 2.20: Helical Gear
Figure 2.21: Helical Rack Gear
Figure 2.22: Double Helical Gear
Figure 2.23: Face Gear
Figure 2.24: Bevel Gears
13
14
15
16
17
19
20
21
23
24
24
25
26
26
27
27
xiii
Figure 2.25: Miter Gears
Figure 2.26: Worms and Worm Gears
28
28
Figure 2.27: Hypoid Gear 29
Figure 3.1: SolidWorks 2007 CAD Software 33
Figure 3.2: Example of Gear Driven System 34
Figure 3.3: Solid Works 2007 Animator Feature 35
Figure 3.4: Flow of Fabrication Process 37
Figure 4.1: The Drawing of Conceptual Robot Hand Design in 3D View 40
Figure 4.2: The Drawing of Conceptual Robot Hand Design in 2D View 41
Figure 4.3: Degree of Freedom of MCP Joint at Pitch axis 43
Figure 4.4: Coupling Motion between PIP and MCP 43
Figure 4.5: Fabric-Able Design of Robot Hand 44
Figure 4.6: Dimension of Fabric-Able URH-1 45
Figure 4.7: Double-Layer Spur Gear and Face Gears Connection 46
Figure 4.8: Designed Mechanism of Metacarpal Phalangeal (MCP) Joint 47
Figure 4.9: Broken-Out Section View of Coupling Mechanism 48
xiv
Figure 4.10: Gears Interlink Mechanical Motion 48
Figure 4.11: Dimension of Double-Layer Spur Gear 49
Figure 4.12: Dimension of Spur Gear 49
Figure 4.13: Dimension of Face Gear 50
Figure 4.14: Image of Cytron-36S Servo Motor and Dimension Drawing 51
Figure 4.15: Collision Detection Testing at PIP and MCP Joints 52
Figure 4.16: Angle Limitation of the Fingers 53
Figure 4.17: Expand Limitation of the Designed Robot Hand 54
Figure 4.18: Grasp Limitation of the Designed Robot Hand 55
Figure 4.19: Three Points Touching Formation of Small Spherical Object Grasp 56
Figure 4.20: Four Points Touching Formation of Bigger Spherical Object Grasp 57
Figure 4.21: Grasping Ability on Smaller Cylindrical Rod 58
Figure 4.22: Grasping Ability on Bigger Cylindrical Rod 58
Figure 4.23: Electronic Component Switch 59
Figure 4.24: Designed 89C51 Microcontroller Based System Circuit 60
xv
List of Tables
Page
Table 4.1: Gears Specification 50
Table 4.2: C36S Servo Motor Specification [20] 51
xvi
Design and Fabrication of Humanoid Robot Hand Introduction
CHAPTER 1
INTRODUCTION
1.1 OVERVIEW OF INDUSTRIAL ROBOT END EFFECTORS
In robotics research, Robot End Effectors can be defined as the hand or gripper portion of the robot which attaches the end of the arm or manipulator and performs the operations of the robot [1]. These robot end effectors are considered as a most important part that ought to be required in every robot. Especially in industrial robots, end effectors are unquestionably needed for gripper as shown in Figure 1.1, welding, assembling, parts loading, spray gun painting, vacuum cup, materials handling, and also other manufacturing processes. Other than that, surgery robots end effectors can be also a scalpel or other tools which used in surgery operations.
Figure 1.1: End Effectors used for Bags Picker 171
1 University Malaysia of Sarawak
Design and Fabrication of Humanoid Robot Hand Introduction
Since 1980s, a robotics research is getting more concerned on multi-fingered robot hands (end effectors) and it is still actively studied till now [2]. These robot hands almost have the same degree of freedom (D. O. F) and also have the same size with human hands [3]. Therefore, it is also called as Humanoid Robot Hands. Normally, these robots consist of sensors, actuators, analyzers, drives, and also other electronic for achieving human-like dexterity. In 1997, German Aerospace Research Center (DLR) had developed one of the first Humanoid Robot Hands with completely integrated actuators and electronic [4]. But recently, there is even much more humanoid robot hands had being developed such as UTAH/MIT Hand (Figure 1.2), NAIST Hand, GIFU Hand, and etc. These Humanoid Robot Hands will eventually supplant human labor in the execution of intricate and dangerous tasks in areas such as manufacturing, space, the seabed and etc [5].
Figure 1.2: An example of Humanoid Robot Hand (UTAH/MIT Hand) 181
2 University Malaysia of Sarawak
Design and Fabrication of Humanoid Robot Hand Introduction
Figure 1.3: Robot Hand with the Array of Tactile Sensors 161
In Japan, an inventor played a duet with his robotic creation, Wabot-2 (as shown in Figure 1.4), at the Tokyo Exposition. Building this kind of robot is a challenging task because the dexterity of the human hand is possibly the most difficult function to reconstruct mechanically. Although Wabot-2's performance did not be emotional, the technical accuracy will still be extremely high with an electronic scanning eye and also some quality components [6].
Figure 1.4: WABOT-2 16)
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Design and Fabrication of Humanoid Robot Hand Introduction 1.2 APPROACHED PROBLEMS IN HUMANOID ROBOT HANDS DESIGN
Recently, grasping and manipulating objects in unstructured environments has become one of the innermost challenges of robotics, where object properties are not known and sensing is prone to error. This results the object and the gripper contained some uncertainties and make it difficult to control the contact forces and establish a successful grasp.
Other than that, humanoid robots always impose to limitation on the size, weight, and packaging of the hand while demanding sufficient dexterity, strength, and speed.
Consequently, the ability of these hands to sense the force that applied by actuators did not met the satisfactory level. These matters tend to be short of mechanical robustness which is necessary used in unstructured and unknown environments where impacts and collisions are commonly happened. Once these features were included, the complexity, weight, size, and the cost of the hand will also be increased. Therefore, humanoid robot hands are notoriously difficult to design.
4 University Malaysia ofSarawak
Pusat Khidmat Maklumat A. kademik UNR'ERSITI MALAYSIA SARAWAK
Design and Fabrication of Humanoid Robot Hand Introduction 1.3 AIMS AND OBJECTIVES OF THE PROJECT
Objectives of this final year project are:
i. To study the existing Humanoid/Dexterous Robot's Hands and End Effectors.
ii. To design a basic Robot's Hand or End Effectors that based on some existing or non-existed concepts.
iii. To fabricate a prototype for the designed Robot's Hands or End Effectors.
S University Malaysia of Sarawak
Design and Fabrication of Humanoid Robot Hand Literature Review
CHAPTER 2
LITERATURE REVIEW
2.1 EXISTING CONCEPTS OF ROBOTIC HANDS
2.1.1 Compliant and Force Sensing (CFS) Hand
Figure 2.1: The design for the force sensing and compliant hand 191
A. Basic Concept of Compliant Force Sensing Robot Hand
The concept of this robot hand is using four modular Force Sensing Compliant (FSC) actuators on three fingers. First actuator will control the spread between the finger and the other three actuators will control the top knuckle of each finger independently. The top knuckle will be passively coupled by lower knuckle. In between the motor housing and hand chassis, there is a pair of torsion spring placed that will provide the compliance in fingers and also protect the motor gearbox from high impact shocks (refer to Appendix Al) [10].
6 University Malaysia of Sarawak
Design and Fabrication of Humanoid Robot Hand Literature Review B. Overview of Mechanism in CFS Robot Hand
There are three fingers which are mechanically identical in this robot hand. However, the two fingers of the lower part can rotate about an axis that perpendicular to the palm. These axes of rotation are mechanically couples though spur gears which can constrain a symmetrically spread in between the two fingers (refer to Appendix A2) [10].
CFS hand is employing a Cable-Drive Tendon System which can improve in mechanism design complexity. Therefore, this system is mostly applied to the links of the fingers which are passively coupled. Other than that, the three actuated knuckle are driven by cables as well.
A pair of torsion springs placed in between the motor housing and the hand chassis (refer to Appendix A3) which can help to determine the acting forces to actuators for providing the compliances to the fingers. Besides, due to the low mechanical impedance created by the springs, impact shocks to fingers are damped and protect the motor gear box from damage which will help to prolong the longevity of robot hand [9].
C. Sensors used in CFS Robot Hand 191
In CFS robot hands, Force Sensing Compliant Actuators are used other than some common tactile sensors that are used on every joint and finger. This actuator force sensor provides a very compact method of sensing the force that applied by the motor to a load, or conversely, an externally applied force at the finger. This sensor is mechanically simple and consequently inexpensive to manufacture, simple to assemble, and robust to component failure.
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