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Design and Fabrication of Curb-Climbing Mechanism for a Wheelchair using 3D Printing Technology. Lye Siew San

Design and Fabrication of Curb-Climbing Mechanism for a Wheelchair using 3D Printing Technology by Lye Siew San Dissertation submitted in partial fulfilment of the requirements for the Bachelor of
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Design and Fabrication of Curb-Climbing Mechanism for a Wheelchair using 3D Printing Technology by Lye Siew San Dissertation submitted in partial fulfilment of the requirements for the Bachelor of Engineering (Hons) (Mechanical Engineering) JANUARY 2015 Universiti Teknologi PETRONAS Bandar Seri Iskandar, Perak Darul Ridzuan, Malaysia i CERTIFICATION OF APPROVAL Design and Fabrication of Curb-Climbing Mechanism for a Wheelchair using 3D Printing Technology by Lye Siew San A project dissertation submitted to the Mechanical Engineering Programme Universiti Teknologi PETRONAS in partial fulfilment of the requirement for the BACHELOR OF ENGINEERING (Hons) (MECHANICAL ENGINEERING) Approved by, DR KHURRAM ALTAF UNIVERSITI TEKNOLOGI PETRONAS BANDAR SERI ISKANDAR, PERAK January 2015 ii CERTIFICATION OF ORIGINALITY This is to certify that I am responsible for the work submitted in this project, that the original work is my own except as specified in the references and acknowledgements, and that the original work contained herein have not been undertaken or done by unspecified sources or persons. LYE SIEW SAN iii ABSTRACT The main problem that the wheelchair users faced is very limited movement where ordinary wheelchairs are unable to climb curb or stairs and this bring troubles to the users where they cannot use public transport or even go out from their houses. Various scopes and designs of different curb climbing wheelchairs were studied and reviewed based on the past researches and designs did by others. This project came out with a design of mechanism of wheelchair that can climb a curb manually. The rear wheels of the wheelchair were modified into bearing-like wheels together with curb climbing handles. CATIA software was used in this project for drafting and detailed 3D modeling. The function ability of the wheelchair mechanism prototype and proving of idea was tested by 3D printing rapid prototyping and the results shows that the idea was a success. iv ACKNOWLEDGEMENTS Thank you Universiti Teknologi Petronas for given chance for the author to have chance for doing the Final Year Project of design a curb-climbing mechanism of wheelchair using 3D printing technology that is available in Universiti Teknologi Petronas. Thank you for Petronas company for sponsor the author for the whole project for the materials and the fees of the course. Special appreciation is to be given to supervisor Dr Khurram Altaf for given very good supervisory job during the whole period of doing the project. Dr Khurram also gave a lot of encouragement and mentally support so that the author would not give up during facing the problems occurred during the project period. Besides, Dr Khurram also gave physically help where during the process of 3D printing and assembly of the mechanism. The author also would like to show appreciation to family members and friends that supported the author and gave mentally support throughout the project period. v Table of Contents CERTIFICATION OF APPROVAL...ii CERTIFICATION OF ORIGINALITY... iii ABSTRACT... iv ACKNOWLEDGEMENTS... v Table of Contents... vi List of Figures... ix List of Tables... xi CHAPTER 1 INTRODUCTION BACKGROUND PROBLEM STATEMENT OBJECTIVE SCOPE OF STUDY... 2 CHAPTER 2 LITERATURE REVIEW SCOPE OF 3D PRINTING Applications of 3D Printing Materials Available for 3D Printing SCOPE OF WHEELCHAIR Types and Usage of Wheelchair Criteria of Wheelchair IDEA OF MECHANISM OF CURB-CLIMBING OR STAIRS- CLIMBING WHEELCHAIRS Leo, Alex and Gennaro s design (2011) Ekachai and Teerapol s design (2011) Murray and Takakazu s design (2003) Lin & Xi s design (2012) CHAPTER 3 METHODOLOGY METHODOLOGY vi 3.2 GANTT CHART & KEY MILESTONE CHAPTER 4 RESULTS AND DISCUSSION FIRST STAGE DESIGN Drawings of design using CATIA software Dimensions of design SECOND STAGE DESIGN Drawings of design using CATIA software Dimensions of design THIRD STAGE DESIGN Drawings of design using CATIA software Dimensions of design FIRST PROTOTYPE 3D PRINTING FOURTH STAGE DESIGN Drawings of design using CATIA software Dimensions of design SECOND PROTOTYPE 3D PRINTING FINALIZED DESIGN Assembly Drawing Rear Wheel Small Wheel Handle Frame Engineering Drawings of Each Components and Assembly FINALIZED 3D PRINTING AND ASSEMBLY STRESS ANALYSIS Deformation Analysis Von Mises Stress Analysis CHAPTER 5 CONCLUSION AND RECOMMENDATION REFERENCE APPENDICES APPENDIX A. Assembly Engineering Drawing APPENDIX B. Rear Wheel Assembly Engineering Drawing vii APPENDIX C. Outer Wheel Engineering Drawing APPENDIX D. Inner Wheel Engineering Drawing APPENDIX E. Ball Bearings Engineering Drawing APPENDIX F. Handle Engineering Drawing APPENDIX G. Small Wheel Engineering Drawing APPENDIX H. Frame Engineering Drawing viii List of Figures Figure 1: Components of Ordinary Wheelchair (Source: Armstrong, et al. (2008) Guidelines on the Provision of Manual Wheelchairs in Less Resourced Settings)... 7 Figure 2: Design of Curb Climbing Wheelchair of Leo, Alex and Gennaro (Source: Leo, Alex and Gennaro (2011) Curb Climbing Wheelchair)... 8 Figure 3: Ekachai and Teerapol s Wheelchair with Two 5-spoke Wheels and Slot Plates (Source: Ekachai and Teerapol (2011) A Prototype of a Stair-Climbing System for a Wheelchair)... 9 Figure 4: Slot Plate Function of Wheelchair (Source: Ekachai and Teerapol (2011) A Prototype of a Stair-Climbing System for a Wheelchair)... 9 Figure 5: Murray and Takakazu s High Step Stair-Climbing Mechanism in (a) Barrier-free Mode and in (b) Stair-climbing Mode (Source: Murray and Takakazu (2003) Modelling of a Stair-Climbing Wheelchair Mechanism with High Single-Step Capability) Figure 6: Murray and Takakazu s Stair Climb Operation when (a) Ascent and (b) Descent (Source: Murray and Takakazu (2003) Modelling of a Stair-Climbing Wheelchair Mechanism with High Single-Step Capability) Figure 7: Lin & Xi s Stairs-Climbing Wheelchair Design (2012) (Source: Lin and Xi (2012) An Optimization Design for the Stair-Climbing Wheelchair) Figure 8: Lin & Xi s Stairs-Climbing Wheelchair s Assembly Diagram and Exploded View (Source: Lin and Xi (2012) An Optimization Design for the Stair-Climbing Wheelchair) Figure 9: Processes of Research and Design for FYP I and FYP II Figure 10: Isometric Front View Figure 11: Isometric Back View Figure 12: Side View of Handle Figure 13: Front View of Handle Figure 14: Curb Dimension Figure 15: Isometric View Figure 16: Side View Figure 17: Small Wheel and Rear Wheel Dimensions Figure 18: Isometric View Figure 19: Outer Wheel Figure 20: Fixed Slider Figure 21: Handle Inner Lock Figure 22: Ball Bearing Location ix Figure 23: First Prototype Printing Figure 24: Inner View of Outer Wheel Figure 25: Modifications Needed Figure 26: Isometric View Figure 27: Side View Figure 28: Ball Bearings Figure 29: Side View of Inner Wheel Figure 30: Location of Ball Bearing Figure 31: Second Prototype Printing Figure 32: Outer Wheel with Figure 33: Rough Surface Printing Figure 34: Isometric View of Assembly Figure 35: Side View of Assembly Figure 36: Isometric View of Rear Wheel in Different View Condition Figure 37: Side View Figure 38: Isometric View Figure 39: Isometric View Figure 40: Isometric View Figure 41: Assembly of Curb Climbing Mechanism Figure 42: Properties of Aluminium Figure 43: Mesh Properties Figure 44: Frame Deformation Analysis Figure 45: Handle Deformation Analysis Figure 46: Small Wheel Figure 47: Von Mises Stress Analysis of Frame Figure 48: Von Mises Stress Analysis of Handle Figure 49: Von Mises Stress Analysis of Small Wheel x List of Tables Table 1: Types and Usage of Wheelchair (Source: Waugh (2013) Glossary of Wheelchair Terms and Definitions Version 1.0 and Weinberg & Mignolo (2012) 35 Wildly Wonderful Wheelchair Design Concepts)... 5 Table 2: Timeline for FYP I Table 3: Timeline for FYP II xi CHAPTER 1 INTRODUCTION 1.1 BACKGROUND 3D printing technology is now an arising potential technology which uses the method of additive manufacturing in doing models, prototypes and real functional things. 3D Printing Industry (2014) mentioned that additive manufacturing is quite different from the ordinary existing manufacturing technologies which it builds up the parts layers by layers additively at a very small increasing scale. 3D printing was invented since 1984 by Charles Hull and continues to be research by people until present and these researches and design process will be continue on in the future (T. Rowe Price Connections, 2011). This is due to 3D printing technology brings a lot of advantages. 3D printing is capable to do many complex designs where it is very difficult or impossible to do with the ordinary traditional manufacturing techniques such as casting (Tyagi, 2012). In this case, 3D printing save a lot of time, money, materials, manufacturing processes and manpower in the design, testing and manufacturing and assemble process of a new product. The reasons that 3D printing technique is chosen for this project is that it is expected to see increase of build rates by each 3D printer in the future where labor costs can be reduced (Roland Berger Strategy Consultants GmbH, 2013). On the other hand, Roland Berger Strategy Consultants GmbH also mentioned that it is also expected that the manufacturing material powder prices to be going down in the future where this actually can reduce the costs of the products being produced. So, 3D printing enable people to think of more creative and innovative ideas and they are all possible to be achieve by 3D printing technology (Srinivasan and Bassan, 2012). 1 1.2 PROBLEM STATEMENT There are some surveys and researches done on the wheelchair users regarding the problems usually faced by them. The results showed that users on wheelchairs feel very limited movement which is only can move in same floor and it is very hard for the usage of public transport or even just go out from their house. An issue being raised up here about whether wheelchairs can climb curb. So this project is going to resolve the problems for the main problems usually faced by wheelchair users which the mechanism can be done by using 3D printing prototyping. To solve the problems that users face every day, curb climbing mechanism can be one of the solutions (Leo & Gennaro, 2011). The curb climbing mechanism should be can climb can also descend a curb safely and smoothly (Leo & Gennaro, 2011). 1.3 OBJECTIVE To design and fabricate a concept model of manually curb climbing mechanism of wheelchair via functional prototype by 3D printing technology. 1.4 SCOPE OF STUDY To study about the scope of curb climbing wheelchair and the function ability of the new design curb climbing mechanism of wheelchair. 2 CHAPTER 2 LITERATURE REVIEW 2.1 SCOPE OF 3D PRINTING According to McMath (2006) Fabricating components for research and development work presents a special problem. In general, the quantities required are very small, making the delays associated with traditional manufacturing processes unacceptable. Rapid prototyping has evolved specifically to address this challenge. Based on a variety of additive processes, rapid prototyping can produce components in days, or sometimes hours, rather than weeks, and without extensive labour costs. Rapid prototyping has become suitable for the one-off production of complex fully-functional models, and can even be used to manufacture components in reasonably-sized production volumes. (p ) Applications of 3D Printing 3D printing technology can be applied in many different sectors in industries. In medical and dental sector, people use 3D printing technology to produce medical devices such as hearing aids, orthotic insoles for shoes especially for people who met accidents and sick of diabetes (3D Printing Industry, 2014). 3D Printing Industry mentioned that medical implants also being carried out where the supports, bones and even organs are being 3D printed to assist in this area and it does help on a lot of people who sick of fracture of bones and etc. 3D Printing Industry also mentioned that 3D printing technology is used in aerospace industry for product development and prototyping for some of the parts of the aircraft. There is a first 3D printed robotic aircraft created on 2011 where it save a lot of money and 3D printing technology allows the wings of the airplane to be built in elliptical shape which can 3 improve the efficiency besides reduce costs and time of manufacturing (T. Rowe Price Connections, 2011). 3D printing also being used in automotive area for prototyping and developing improve materials of automotive parts while on the other hand 3D printing technology actually helps out in jewellery, fashion, art, design, sculpture, and architecture sector in reducing the steps of fabrication and maximize the creativity (3D Printing Industry, 2014). 3D Printing Industry also mentioned that 3D printing is also looking forward to be a process of food production in the future Materials Available for 3D Printing ZPrinter 450 is the 3D printer that will be used in this project. The types of materials that are suitable for this 3D printer to print are zp130 which is known as the High Performance Composite powder, zp131 which is also known as the Premium Performance powder, zp140 which is also known as High Performance Plus powder (Z Corporation, 2007) and zp150 which can produce stronger parts with nice color which also consists of incredible whiteness and water cure finishing option (Z Corporation, 2010). The zp130 has high feature definition, vibrant colors, good dimensional accuracy and high strength with infiltration while the zp131 can print very tough objects, has extreme accuracy with nice colors (Z Corporation, 2007). The zp140 has water cure post-processing option available, lower costs and has the brightest white color among all the materials (Z Corporation, 2007). This project used material zp150 for the printing of the mechanism for prototype because of the availability of this material in Universiti Teknologi PETRONAS and to produce strong parts for testing purpose. 4 2.2 SCOPE OF WHEELCHAIR Cross (2012), Waugh (2013) and Armstrong, Borg, Krizack, Lindsley, Mine, Pearlman and etc. (2008) defined wheelchair as a manually or electric powered mobile wheeled device and seating support system which it can consist of three or more wheels which usually provide seating position for the usage of people with mobility impairments Types and Usage of Wheelchair There are varieties of wheelchairs in the market nowadays. TABLE 1 below shows the several types of wheelchairs and usage of each type of wheelchair. Table 1: Types and Usage of Wheelchair (Source: Waugh (2013) Glossary of Wheelchair Terms and Definitions Version 1.0 and Weinberg & Mignolo (2012) 35 Wildly Wonderful Wheelchair Design Concepts) No. Types Usage 1 Manual wheelchair Ordinary wheelchair which need the users or an assistant to move the wheelchair. 2 Sport wheelchair Specifically designed for sports such as racing, dancing and basketball. 3 Variable positioning wheelchair Available to provide alternative positions other than sitting position, such as standing, tilt, recline, laying down and other positions. 4 Aisle wheelchair Used in narrow aisles such as on aircrafts. 5 Activities of Daily Living (ADL) Used for daily living activities functions such as for shower, bath and toilet. wheelchair 6 Specialty power wheelchair Designed for specific functions such as stairs climbing and balancing purpose. 5 2.2.2 Criteria of Wheelchair A wheelchair is consider suitable and appropriate generally based on a few conditions such as when the wheelchair can achieve the needs of users and surrounding conditions, can provide a proper fit and suitable support, is tested safe and have a long-lasting life which does not spoil easily, design is safe where will not cause injuries to the users or assistants, available in the market of the country and the price is affordable by the user (Armstrong, Borg, Krizack, Lindsley, Mines, Pearlman, et al., 2008). Armstrong and etc. (2008) also mentioned that it is very important that a wheelchair actually allows mobility disable people so that they can work or study and participate in normal daily works and life. Thus, a wheelchair must fit the users well and provide a good postural support to the users so that can reduce the pressure and increase comfort of the users as they spend most of the time on the wheelchair their second legs (Armstrong, et al., 2008). In designing the wheelchairs, the strength of the materials must be taking into account to avoid failure or spoil of the wheelchair during function time (Armstrong, et al., 2008 and Brubaker, 1989). Brubaker (1989) stated that there are still a lot of areas to be improved in wheelchairs. According to Brubaker (1989) 1) Frames can have higher strength to lower weight ratio 2) Reduce the steps for manufacturing processes 3) Tires and wheels need to be improve in wear-resistance without affecting the ride of wheelchair users so that the tires and more durable and long-lasting 4) The seating materials need to increase the comfort, durability and ease of cleaning functions Figure 1 shows the components of an ordinary wheelchair. 6 Figure 1: Components of Ordinary Wheelchair (Source: Armstrong, et al. (2008) Guidelines on the Provision of Manual Wheelchairs in Less Resourced Settings) 7 2.3 IDEA OF MECHANISM OF CURB-CLIMBING OR STAIRS- CLIMBING WHEELCHAIRS As to be discussed in the section below are the designs of other researchers of curbclimbing or stairs-climbing wheelchair. These designs considerations and results are being considered and be reference when making the design for curb-climbing mechanism of this project Leo, Alex and Gennaro s design (2011) Leo, Alex and Gennaro (2011) design the wheelchair to run with DC battery and linear actuator. Their mechanism of climbing is combination using linkages, chains, sprockets and gears to lift up and to descend the wheelchair. Their total wheelchair lifting and descend process is about fourteen seconds and it is tested safe and make sure the wheelchair user is remain horizontal and stable in position. Leo, Alex and Gennaro (2011) also mentioned that in normal condition which is without climbing or descending a curb, the wheelchair is still able to move using the big wheels and the small wheels. The design is as shown in Figure 2. Figure 2: Design of Curb Climbing Wheelchair of Leo, Alex and Gennaro (Source: Leo, Alex and Gennaro (2011) Curb Climbing Wheelchair) 8 2.3.2 Ekachai and Teerapol s design (2011) Ekachai and Teerapol (2011) design their wheelchair as a stair climbing wheelchair which attached of two five-spoke wheels and slot plates on the wheelchair. The fivespoke wheels usage is to climb the stairs while the function of slot plates is slide the rear big wheels of wheelchair (Ekachai & Teerapol, 2011). Their wheelchair is powered by an electric motor. During process of climb stairs, the rear big wheels of wheelchair will slide to the front part of the wheelchair and go back to original position when it is moving on the floor (Ekachai & Teerapol, 2011). Ekachai and Teerapol s wheelchair can go up and come down the stairs with 200mm maximum riser height and 80kg maximum payload. The design of Ekachai and Teerapol is as shown in Figure 3 and Figure 4. Figure 3: Ekachai and Teerapol s Wheelchair with Two 5-spoke Wheels and Slot Plates (Source: Ekachai and Teerapol (2011) A Prototype of a Stair-Climbing System for a Wheelchair) Slot plate Wheel slide Lifted wheel Figure 4: Slot Plate Function of Wheelchair (Source: Ekachai and Teerapol (2011) A Prototype of a Stair-Climbing System for a Wheelchair) 9 2.3.3 Murray and Takakazu s design (2003) Murray and Takakazu had come out with a design of wheelchair mechanism with high single-step capability on The mechanism is based on front and rear wheel clusters connected to the base (chair) via powered linkages so as to permit both autonomous stair ascent and des
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