Design And Analysis On Mechanical Structure Of Climbing Robot Leg.

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UNIVERSITI TEKNIKAL MALAYSIA MELAKA

DESIGN AND ANALYSIS ON MECHANICAL

STRUCTURE OF CLIMBING ROBOT LEG

Thesis submitted in accordance with the partial requirements of the Universiti Teknikal Malaysia Melaka for the

Bachelor of Manufacturing Engineering (Robotic And Automation) with Honours

MUHAMMAD KHOIRUDIN BIN ZAKARIA

Faculty of Manufacturing Engineering MAY 2008

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UTeM Library (Pind.1/2007)

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

BORANG PENGESAHAN STATUS LAPORAN PSM

JUDUL:

DESIGN AND ANALYSIS ON MECHANICAL STRUCTURE OF CLIMBING ROBOT LEG

SESI PENGAJIAN:

Semest er 2 2007/ 2008

Saya Muhammad Khoirudin b. Zakaria mengaku membenarkan laporan PSM / t esis (Sarj ana/ Dokt or Falsaf ah) ini disimpan di Perpust akaan Universit i Teknikal Malaysia Melaka (UTeM) dengan syarat -syarat kegunaan sepert i berikut :

1. Laporan PSM / t esis adalah hak milik Universit i Teknikal Malaysia Melaka dan

penulis.

2. Perpust akaan Universit i Teknikal Malaysia Melaka dibenarkan membuat salinan

unt uk t uj uan pengaj ian sahaj a dengan izin penulis.

3. Perpust akaan dibenarkan membuat salinan laporan PSM / t esis ini sebagai bahan

pert ukaran ant ara inst it usi pengaj ian t inggi.

4. *Sila t andakan (√)

SULIT TERHAD

TIDAK TERHAD

(Mengandungi maklumat yang berdar j ah keselamat an at au kepent ingan Malaysia yang t ermakt ub di dalam AKTA RAHSIA RASMI 1972)

(Mengandungi maklumat TERHAD yang t elah dit ent ukan oleh organisasi/ badan di mana penyelidikan di j alankan)

(TANDATANGAN PENULIS) Alamat Tet ap:

LOT 1113, KG.BADANG, JALAN PANTAI CAHAYA BULAN,

15350 KOTA BHARU, KELANTAN DARUL NAIM

Tarikh: _______________________

(TANDATANGAN PENYELIA) Cop Rasmi:

Tarikh: _______________________

* Jika laporan PSM ini SULIT at au TERHAD, sila lampirkan surat daripada pihak organisasi berkenaan dengan menyat akan sekali sebab dan t empoh t esis ini perlu dikelaskan sebagai SULIT at au TERHAD.

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DECLARATION

I hereby, declare this thesis entitled “Design and Analysis on Mechanical Structure of Climbing Robot Leg” is the result of my own research

Except as cited in the references.

Signature :……….

Author’s Name : Muhammad Khoirudin B. Zakaria

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APPROVAL

This thesis submitted to the senate of UTeM and has been accepted as partial fulfillment of the requirements for the degree of Bachelor of Manufacturing Engineering

(Robotic And Automation) with Honours. The members of the supervisory committee are as follow:

……… Main Supervisor

( En. Khairol Anuar B. Rakiman ) Faculty of Manufacturing Engineering

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ABSTRAK

Projek ini menerangkan tentang rekabentuk dan analasis mengenai struktur mekanikal untuk robot memanjat. Di dalam projek ini terdapat banyak peringkat yang perlu ditiikberatkan dalam menghasilkan robot memanjat. Di dalam proses merekabentuk,“3D Solid work“ digunakan untuk melukis dan mencantum bahagian yang siap dilukis untuk menghasilkan robot memanjat. Untuk komponen utama robot ini,“ suction cup” digunakan sebagai kaki yang bertindak untuk melekat pada dinding. Daya yang diperlukan untuk robot memanjat melekat didinding juga dikira. Di samping itu juga pengiraan tentang tegasan bahan juga dianalisis. Ciri-ciri penentuan tahap untuk rekabentuk juga dibuat supaya bahan yang akan digunakan nanti mudah untuk didapati, kos yang murah dan sebagainya. Simulasi untuk robot memanjat juga di laksanakan di dalam perisian rekabentuk untuk mengenalpasti rekabentuk dan mengelak berlakunya gangguan antara ketidakbolehupayaan struktur robot dengan mekanismanya.

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ABSTRACT

This project presented the design and analysis the mechanical structure of climbing robot legs. There are many stages in design process to design this climbing robot. In this design, 3D Solid work used to draw a part and assembly the drawing. For the main part of the design, suction cup is used as a foot to attach against wall. The force that robot need to attach against wall is calculate. Besides that, the stress of material also is analyzed. The grading criteria for the design also will be done to make the material that used for design are available, low cost and so on. Simulation of the climbing robot on design software will be done in order to verify the design and to prevent the interference between the structures of the mechanism.

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DEDICATION

For my beloved family, friends, and lecturers in Universiti Teknikal Malaysia Melaka.

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ACKNOWLEDGEMENT

Alhamdulillah, I’m grateful that by the power of Allah, Most Gracious, Most Merciful and with much guidance also support my final year project is now completed. First of all,I would especially like to thank to my beloved family especially my parent , Mr Zakaria b. Mat yusof and Selamah Bt. Che Mat who recently was passed away for showing love, support and advice when in truly need.

I would like to express my greatest appreciations to my wise supervisor, Mr. Khairol Anuar b. Rakiman . This thesis would not have been possible without his guidance and resources, and I am grateful for the opportunity to learn so much from him. And equally essential was Mr Hasan B. Atan, who has volunteered countless hours and untold energies on my behalf. I would like to thank him for agreeing to help me in the simulation process in Solid Word drawing.

Finally, I also to present my gratefully acknowledge to anybody who helped directly or indirectly in this report for their contribution in guidance me finished this report completely.

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TABLE OF CONTENTS

1. INTRODUCTION

1.1. Problem Statements 1.2. Objectives 1.3. Scope 1 2 2 3

2. LITERATURE RIVIEWS

2.1 Introduction 2.2 Design Concept

2.2.1 The Hierarchical Design

2.1.2 3D Computer modeling 2.2 Properties of climbing robots 2.2.1 Robot Legs 2.2.2 Leg Design

2.2.3 Types Of Robot Leg 2.3 Friction Force

2.4 Sliding Frame 2.5 Wall climbing robots

2.5.1 Mobile climbing robots

2.5.2 Climbing robots on magnetic wheels 2.6 Climbing robot mechanism

2.6.1 Adhesion Mechanism 2.6.2 Dry Adhesion

2.6.3 Surface Changing Mobil Robot 2.7 Simplification of Robot-environment Modeling 2.8 Robot Kinematics

4 4 5 6 7 7 9 11 14 14 15 16 16 17 17 20 21 24 28

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3. METHODOLOGY

3.1 Introduction 3.2 Design Process 3.2.1 Function

3.2.2 Design requirement 3.2.3 Evaluation criteria 3.3 Flow Chart

3.3.1 Flow Chart Process 3.4 Project understanding

3.5 Planning of study

3.6 Design Analysis

3.7 Testing And Simulation

3.8 A Generic Development Process

30 30 30 31 31 32 33 34 34 35 36 37

4. LEG DESIGN: PRELIMINARY DESIGN

4.1 Planning

4.2 Concept Development 4.2.1 Design Concept 4.2.2 Grading Criteria

4.2.2.1 Direct Material cost 4.2.2.2 Market available 4.2.2.3 Standard part

4.2.2.4 Manufacturing view 4.2.2.5 Material

4.2.3 Concept in design (Generating Idea) 4.3 Conceptual Design

4.4 Detail design

4.4.1 Material Selection 4.4.1.1 Aluminum 4.4.1.2 DC Motor

38 39 42 42 42 42 43 43 43 43 47 50 50 50 51

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4.4.1.3 Screws 4.4.1.4 Bearing 4.4.1.5 Suction Cup

4.4.1.6 Acrylic. 4.4.2 Design with SolidWorks

4.4.3 Robot Weight estimation 4.5 Testing And Simulation

52 52 53 53 54 58 62

4. RESULTS AND DISCUSSION

5.1 Design

5.1.1 Full Assembly Design 5.2 Design Analysis

5.2.1 Analysis of robot kinematics and torque 5.2.2 Analysis of suction lifts force

5.2.3 Stress Analysis 5.3 Simulation 5.4 Discussion 64 64 66 66 68 71 77 83 5. CONCLUSION 6.1 Conclusion

6.2 Recommendation and Future Work

REFERENCES APPENDICES

84 85

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LIST OF FIGURES

Figure 2.1: Leg Configuration.

Figure 2.2: Roverwax Wheeled Robots. Figure 2.3 : Titan iv Legged Robots

Figure 2.4: hybrid biped leg wheeled robot. Figure 2.5: lynx motion tracked robot.

Figure 2.6 : Vacuum rotor package to generate aerodynamic attraction Figure 2.7: Exploded view of the vacuum chamber with flexible bristle skirt seal.

Figure 2.8: The pressure force isolation rim is made of re-foam. Figure 2.9: Left: Robtank immersed in a water tank while inspecting the tank floor;Right: Robot climbing on a glass wall after transition from floor to wall.

Figure 2.10 Left: Solid drawing of RobTankRight: Vehicle climbing on curved wall (3 metre Diameter)

Figure 2.11: Transit gait of robot from ground to wall. Figure 2.12: World coordinate system

Figure 2.13: Foot tip trajectories

Figure 2.14: Rotation method of two virtual and limitation. Figure 2.15: Set of serial links connected by joints.

Figure 3.1: Flow Chart. Figure 4.1: Sketch robot 1. Figure 4.2: Sketch robot 2 Figure 4.3: Sketch robot 3.

Figure 4.4: This figure show the step by step in the design concept Where from a cube, it will transform to become object.

10 11 12 12 13 15 18 21 19 23 23 28 25 27 27 28 32 39 39 40 44

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Figure 3.6: This figure show from step by step how the object Designed are transform and become a climbing robot. Figure 4.6: This figure show the finish of climbing robot sketching. Figure 4.7: Sketch for climbing robot design.

Figure 4.8: Sketch of view climbing robot design.

Figure 4.9: Sequence movement of climbing robot in side view A. Figure 4.10: Aluminum.

Figure 4.11: DC motor Figure 4.12: Screws Figure 4.13: Bearing. Figure 4.14: Suction Cup Figure 4.15: Acrylic

Figure 4.16: One of the parts of components is draw in parts file. Figure 4.17: Parts was mate in assembly files.

Figure 4.18 : The climbing robot assembly Figure 4.19: Robot leg parts

Figure 4.20: Suction cup assembly as foot Figure 4.21: Body parts.

Figure 4.22 : Bracket Figure 4.23: Dc Motor. Figure 4.24: Body joint. Figure 4.25: Robot shaft.

Figure 4.26: Body joint for suction cup.

Figure 5.1: The Overview design of climbing robot. Figure 5.2: The orthographic view of climbing robot. Figure 5.3: The climbing robot attaches the wall. Figure 5.4: Suction cups used for lift a flat sheet Figure 5.5: Load Location for shaft

Figure 5.6: Stress for shaft

Figure 5.7: Stress result table for shaft

45 46 47 48 49 50 51 52 52 53 53 55 56 57 58 58 59 59 60 60 61 61 64 65 66 69 72 73 73

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Figure 5.8: Displacement for shaft

Figure 5.9: Displacement result table for shaft Figure 5.10: Design Check for FOS

Figure 5.11: Start simulation with choose the mechanism. Figure 5.12: Direction chooses with suitable parts. Figure 5.13: Simulation in calculate.

Figure 5.14: Simulation start to run. Figure 5.15: Simulation in progress.

Figure 5.16: Simulation still in progress and waiting to finish

74 75 76 77 78 79 80 81 82

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LIST OF ABBREVIATIONS

DC PSM

- -

Direct current

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CHAPTER 1 INTRODUCTION

Robotic systems are invariably formed of multiple bodies that interact with each other and with the environment in a variety of modes. Design and analysis of such systems are challenging for number reasons; these include the complexities of deriving models of motion resulting from the applied actuation, composing controllers to achieve the desired motions and forces, and, choosing the correct design parameters. Deriving motion models is especially difficult if effects of system dynamics are considered. The derivation of forces resulting from the body accelerations is complex, especially, when multiple bodies and multiple environmental contacts are involved. For these reasons dynamics is often ignored and quasi-static motions are implemented in robots.

However, there are situations when dynamics is critical for performance and ought to be included in the system models. We are developing a method to model the kinematics as well as the dynamics of complex robotic systems with the focus on deriving models from the engineering design perspective. The common approach is to derive models to plan motions under kinematics and force constraints. We present a complementary approach that can predict how the design choices affect the constraints. Not only do we need to know what motions are possible under given constraints but we also want know

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what design choices critically affect the constraints and also what design changes are advantageous. In the design and analysis of climbing robot, there is a need for better understanding of the relation between the design choices and critical constraints. For example there is no unified approach for determining under what environmental conditions (eg. ground friction) a robot will walk reliably and what design choices can be made to improve the performance. Study of robot dynamics has been identified to be important and open problem.

1.1 PROBLEM STATEMENTS

The climbing robot is being design and analysis to ease the climbing process without use human to climb too high and difficult surface of wall. Usually climbing process for do the work like cleaning, painting and repairing is being carried out with human power and if the worker is being doing the same action in the high place, it can be danger for them. By using this particular robot, the worker will no longer have to do the dangerous action and it also can increase the efficiency of work. Climbing robots perform tasks that are too difficult or too dangerous for the human worker. These tasks govern construction or reconstruction work as well as inspection work in hazardous environments, i.e. in nuclear power plants. Cleaning or painting of engineering surfaces is also part of their field of application. Although the technology for climbing on engineering surfaces has almost been exhaustively investigated climbing robots still haven’t been able to penetrate the service market. This is due to two different reasons. First, most of today’s commercially available climbing robots have an insufficient payload-to weight ratio. Second, all of the most recent developments have been engineered for one very specific task. However customer needs demand a new approach: A climbing robot that is competitive with other solutions should not only be able to perform the task but to perform the task economically. Moreover the climbing robot should also be able to perform a variety of tasks so that the return of investment for the

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customer is improved. Therefore a customer driven solution should be lightweight and modular.

1.2 OBJECTIVE / OUTCOME

The objectives of this project are the following:

a) To create and design a climbing robot leg.

b) To analysis the joint and link of climbing robot leg. c) To analyses mechanical designs of leg climbing robot.

1.3 SCOPE

The scopes of this study are:

a) To design a leg climbing robot.

b) To simulate the movement of climbing robot. c) To analyst material selection for leg robot part. d) To produce design model of robot leg.

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CHAPTER 2 LITERATURE REVIEWS.

2.1 Introduction

A Literature review is a body of text that aims to review the critical points of current knowledge on a particular topic. Most often associated with science-oriented literature, such as a thesis, the literature review usually precedes a research proposal, methodology and results section. For this Thesis, the step how the climbing robot leg design and analyze is explained.

2.2 Design Concept

Product Design can be defined as the idea generation, concept development, testing and manufacturing or implementation of a physical object or service. It covers more than the discipline name - Industrial Design. Product Designers conceptualize and evaluate ideas, making them tangible through products in a more systematic approach. The role of a product designer encompasses many characteristics of the marketing manager, Product management, industrial designer and design engineer. The title name of Industrial designer has in many cases fallen into the category of an art. The role of

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product designer combines art, science and commerce for tangible non-perishable items. This evolving role has been facilitated by digital tools that allow designers to communicate, visualize and analyze ideas in a way that would have taken greater manpower in the past. . As with most of the design fields the idea for the design of a product arises from a need and has a use. It follows certain method and can sometimes be attributed to more complex factors such as association and Telesis.

Aesthetics is considered important in Product Design but designers also deal with important aspects including technology, ergonomics, usability, human factors and material technology. The values and its accompanying aspects which product design is based on vary, both between different schools of thought and among practicing designers. [ Holm, Ivar.(2006)]

Product designers are equipped with the skills needed to bring products from conception to market. . They should also have the ability to manage design projects, and subcontract areas to other sectors of the design industry. Also used to describe a technically competent product designer or industrial designer is the term Industrial Design Engineer.

2.2.1 The Hierarchical Design

A Hierarchical Selection process is proposed to search for the best assembly and solution in the modular design workspace. Methodology is the key to propose and the best way to analyze and design by finding the method how to design the robot through the researcher by researching journal, articles, magazine and other source that has been done before. By this way, the identification , improvement or other initiative can be make to produces the perfect robot and increasing their performance beside to decreasing the producing cost. Methodology is useful to apply physically based rules to reduce the search space to a computationally feasible size. Then a genetic algorithm is applied to perform the final search in a greatly reduced search space. This process is

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based on the observation that simple physically based rules can eliminate large sections of the design space to greatly simplify the search. The process consists of tests and filters various levels. The tests and filters exploit the physical nature of the system and the task.

At the first level, individual modules are considered. If a module can be removed early in the design process, it will eliminate a vast number of sub-assemblies and an even larger number of assemblies. Hence, filters at the early stages are very effective in reducing the size of the design space later in the process. At a second level a group of modules, or sub-assembly, can be considered. [Farritor, S.On. (2000)]

2.1.2 3D Computer modeling

In the past decade, the dominant mode of representing design has shifted dramatically from drawing, often created using a computer to 3D computer Models. These model represent designs as collection of 3D entities, each usually constructed from geometric primitives, such as cylinder blocks and holes. The advantages of 3D computer include:

a) The ability to easily visualize the three dimensional form of the design.

b) The ability to automatically compute physical properties such as mass and volume.

c) Efficiency arising from of one creation of one and only one canonical description of the design.

More focused description such as cross sectional views, can be created. 3D computer model also can be used to detect geometric interference among part and the underlying representation for more focus analyses for example kinematics or stress. These 3D computer designs have begun to serve as prototype. In some setting the use of the 3D computer modeling has eliminated one or more physical prototypes. A 3D computer

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model of an entire product is known, depending of the industry setting, as a “digital mock up”, ”digital prototype” or “virtual prototype”. [Karl T. Ulrich. (2003)]

2.2 Properties of climbing robots

Climbing robots represent a specific kind of walking robots, which are useful while operating in environments unfriendly or harmful for a human. Moreover, climbing robots are specially designed for moving on sloping or vertical surfaces, as Well as on horizontal ones( e.g. ceilings). In such situations, the influences of gravitational forces become very important - the design of the legs should assure reliable fastening to the working surface. There are generally two ways so fastening the climbing robot to the surface:

a) Durable mechanical connection between the robot’s grippers (legs) and the environment, using pliers-like grippers; this is typical for robots climbing on constructions made of metal profiles (pipes, T-profiles, etc.)

b) making use of adhesive forces between the gripper’s surface and the working surface; the tightening force is produced by under pressure or — for robots climbing on surfaces made of ferromagnetic materials—electromagnetic grippers. [ P. Dutkiewicz, K. Kozłowski and W. Wroblewski ( 2004)]

2.2.1 Robot Legs

Legs are a viable choice for general robot locomotion because they offer agility and speed. Wheels may be faster on level ground, and wings or rotors offer the third dimension, but legs have demonstrated an agility moving about the surface of the earth unsurpassed by any other form of locomotion. Wheels is not suitable for the wall climbing robot, this is because the force applied on wheels is not enough to stabilized the robot movement so the suitable way to make the stability of climbing robot is using

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adhesive foot for the robot like suction cup or other type of adhesive. [Garth Zeglin. (2002)]

Dynamical stability can be defined that the system which allows something in the system to be stable like in the big place, to support the centre of mass of body to stabile without collapse. With this dynamic stability, dynamic gaits can stay in case stable to back up something burden with identify the steps to make sure his stability.

In general, in many design process those aspects should be taken into consideration, among its consideration as the loss stability, stability over end and attraction land to work face locomotion on uneven terrain. However, a designer can control the number of DOF that are retained and eliminated. There are three step to control DOF by changing types of articulation, joint and links likes introducing rigid connection, retaining one DOF by introducing a single lower-pair joint and retaining the full two DOF by introducing at least two lower-joint pairs. The increasing of DOF which consist chain must be control either activelyby actuation, semi activelyusing springs and dampers or passively by adding some form of structural equilibration using hardware constraints.[Wallace,D (1994)]

In designing process, the number of possible assemblies that can be created using a given inventory can be computed with a set of robot assembly rules. Firstly, the robots that want to assemblies must contain a power or control module. This power is used for the movement of the robot or to control the robot movement. Without this power, robot can’t move or not function because the power is important to control it. All modules are assembled in a serial chain called limbs. This chain used for joint to connect part with another part. All limbs are attached to ports on the power or control module. The power drive the limb for movement and also for another part that connected. All limbs must terminate in a module classified as end effectors. All modules in the inventory do not need to be used in producing a design. [ Farritor, S.On (2000)]

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2.2.2 Leg Design

In the designing process, the leg of a walking and wall-climbing robot must be designed to have the following capabilities:

a) Supporting the robot on ground.

b) Gripping the walls and ceilings not allowing the robot to fall down especial during climbing motion.

c) Performing maneuverability left or right.

d) Changing the posture of the robot while on transition movement.

Leg design especially for climbing robot can be built with different numbers of legs. If the designs contain more number of leg, that mean the robot produce is more stability to stand up and for movement, but it also means more weight and more power consumption. Normally for the robot static and dynamic stability, the robot must have at least four number of legs. Robot with more DOFs means that the movement and orientation of the robot can move better than normal because can move or do the task given wetter in difficult angle. Robot with more DOFs is maneuverability, but it also means more actuators, additional mechanisms, and more control requirements, which means heavier weight, more complicated structure, and more power consumption. For this reason, the least efficient number of DOFs for wall climbing robot is the best option. In our wall climbing robot, thee electrical actuators are used to achieve three DOFs, which is the least required number of DOFs. For the power transmitting system, the three electrical motors are mounted on the first link, which swings on the trunk of the body. The hip horizontal and vertical joints are actuated from the motors directly, through spur gear systems. While the knee joint is actuated through a timing belt, which connects a timing pulley fixed to the joint with another pulley rotates freely with a spur gear moved by another gear fixed to the motor. This system reduces the weight of the knee and hence the inertia of the leg and the torque applied on the hip joints. [Agus Priyono, Rosbi Mamat (2000)]

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CHAPTER 2

LITERATURE REVIEWS.