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ERGONOMIC ASPECTS IN 
DESIGNING PEDAL CAR 
;j;l!!VF:!S:: V , iViC-.AVL.'WA. S3i iARSZSA 
O R A T U W A 
by 
M.S.M. Zuhair 
Supervised by 
Dr. M.A.R.V. Fernando 
This thesis was submitted to the Department of Mechanical Engineering of the 
University of Moratuwa in partial fulfilment of the requirements for the Degree of 
Master of Engineering in Manufacturing Systems Engineering 
Department of Mechanical Engineering 
University of Moratuwa 
Sri Lanka 
July- 2006 
U n i v e r s i t y o f M o r a t u w a 
87887 
8 7 8 8 7 
DECLARATION 
This Dissertation paper contains no material which has been accepted for the award of any 
other degree or diploma in any University or equivalent institution in Sri Lanka or abroad, 
and that to the best of my knowledge and belief, contains no material previously published 
or written by any other person, except where due reference is made in the text of this 
Dissertation. 
I carried out the work described in this Dissertation under the supervision of 
Dr.M.A.R.V. Fernanado. 
Signature Date : 18 m July, 2006 
Name of Student : M.S.M. Zuhair 
Registration No : 02/9641 
Signature Date 
Name of Supervisor : Dr. M.A.R.V. Fernanado 
ii 
Abstract 
Transportation has become one of the key issues currently we face in Sri Lanka. Situation 
has become more complex with soaring fuel price, further petroleum fuel powered 
vehicle causes enormous environmental problems particularly in urban areas. On the 
other hand being a poor nation, Automobile is a luxury for the average person. Therefore 
the use of Human Powered Vehicle (HPV) for day to day transportation becomes worth 
investigation and promotion. 
The simplest and oldest HPV, Pedal-cycle (Push bike) is being widely used both in 
village and urban areas for their day-to-day work especially for short distance traveling. 
However this has several drawbacks, some of which are (1).Rider is not protected from 
sun and rain. (2). encounters poor balancing while moving (3) Rider often ends up with 
severe injuries during an accidents. (4) Danger is more compared with other motor 
vehicles due to very high direct impact. (5). Bike is not being in fashion in Sri Lanka 
particularly among our younger generation. 
In countries like in Bangladesh "Rickshaw" is very popular in city areas for transporting 
goods and people particularly for short distances. A survey in Dhaka showed rickshaw 
takes the highest share, accounting for 35 percent. This is in spite that the design of these 
machines are with no regard to "Ergonomic" aspects. A proper Ergonomically designed 
human powered vehicle will be not only to work efficiently, but also to reduce the rider 
fatigue. Accordingly a novel HPV, a pedal car, was designed taking in to consideration 
ergonomic aspects and other features. One embodiment was fabricated, tested and 
exhibited attracting strong interest from public. This article deals with the development of 
Ergonomic aspects of the Pedal Car. 
iii 
Acknowledgments 
My most sincere gratitude is due to Dr. M.A.R.V. Fernando, senior lecture, Department 
of Mechanical Engineering, University of Moratuwa, for his mature guidance and 
concern without which this study would not have been possible. 
Particular thanks must go to Dr. G.K. Wathugala, senior lecture, Department of 
Mechanical Engineering, University of Moratuwa, for many valuable insights and 
continues guidance and support given during my academic period for this study. 
My gratitude also goes to Mr. A.Edirisingha and his team at Government Factory 
(Kolonnawa) and Mr. M.L.C.Y Molligoda for the support given to me as subordinate 
researchers. 
At last, to countless other people who have been generous with their time, support, and 
encouragement please know I am great full to you all. 
iv 
Table of Contents 
Page No 
£ Title i 
Abstract iii 
Acknowledgments iv 
List of contents v 
List of illustration viii 
List of Table ix 
Chapter 1 - Introduction 1 
^? 1.1 Over view 1 -3 
V 1.2 Background of the Problem 3-4 
Chapter 2 - Literature Review 5 
2.1 Ergonomic Aspects 6-7 
2.1.1 Energy requirement for pedaling. 7-9 
# 2.1.2 Effect of Equipment & Inertial weight on Pedaling 9-10 
2.1.3 Effect of Air Drag, Wind and Drafting on the Rider 11-13 
2.1.4 Speed, Acceleration & Power requirement at various Speed 13-15 
2.1.5 Evaluating Energy requirements of the Rider for Pedaling 15-19 
2.1.6 Important Factors to be considered Seat designing. 20-21 
* 
2.1.7 Anthropometrics for Seat Design 21 -26 
2.1.8 Pedaling at "Recumbent position" 26-31 
2.1.9 Effect of crank arm -length on Pedaling duration in Recumbent position 
32-37 
2.2 Automotive Vehicle Propulsion 37 
2.2.1 Resistance to Forward Motion 37-39 
2.2.2 Gradient Resistance in moving non flat roads 40 
2.2.3 Air Resistance 40 
2.2.4 Traction Resistance (Axle) 41 
2.2.5 Demand Power 41-42 
2.3 Chassis & Body construction 42 
2.3.1 Main frame construction 42-45 
C h a p t e r 3 - G o v e r n i n g Pr inc ip les of cons truc t ing pedal car 4 6 
3.1 Evaluating the Energy requirement for pedaling 46-48 
3.2 Appropriate crank arm length for recumbent position 48-49 
3.3 Total forces on the rider 49-50 
3.4 Engineering principles of vehicle propulsion. 51-53 
vi 
Chapter 4- Embodiment of the First Prototype 54 
4.1 Selection of chassis frame 54-55 
4.2 Application of Recumbent position for maximum power usage. 
55-56 
4.3 Determining optimum seat angel & seating posture 57-59 
4.4 Determining optimum crank angle 59-62 
4.5 Seat Pan contour, cushioning & Suspension 62-63 
4.6 Matching Anthropometric data in frame construction 63-64 
4.7 Fabrication of the Prototype 65-67 
Chapter 5 - Test Performance of the First Prototype 68 
# 5.1 Testing the Model for Rigidity using COSMOS Analysis 68-72 
Chapter 6 - Conclusion 73 
6.1 Related issues in constructing the model and subsequent testing 73 
6.2 Further improvements to be done in future embodiments 74-82 
BIBLIOGRAPHY 
* 
APPENDIX I - Bill of Materials for construction of Pedal car Al 
APPENDIX II - Drawings of the model B1-B2 
APPENDIX III - Photograph of the peddle car in construction stages. C1-C4 
vii 
* 
List of Illustrations 
Figure Page No. 
2.1.4.1 Rider Distance VS Time 13 
2.1.4.2 Rider speed VS Time 14 
2.1.4.3 Rider Acceleration VS Time 15 
2.1.4.4 Rider Power VS Speed 16 
2.1.5.2 Energy consumptions Vs Velocity 17 
2.1.5.3 "AnyBody" Model muscle recruitments 19 
2.1.6.1 Pressure on the Spine at seating posture 20 
2.1.7.1 Anthropometric Data for seat designing 21 
2.1.8.1 Recumbent positions 28 
2.1.9.1 Optimum crank arm length 34 
2.3.1.1 Frame types "Delta" Vs "Tad Pole" 42 
4.1.2 Initial Model 52 
4.5.1 Front & Rear suspension 56 
5.1.1 Defection on frame at various loading vales 64 
6.2.2 Hand Power Assisted Mechanism 69 
6.2.5 Energy Storing Device 71 
6.2.7 Aerodynamics Body Shapes 72 
viii 
t 
List of Tables 
Table Pafie No. 
2.1.7.1 Anttiropometric Data for seat design 22 
g 2.1.9.1 Cycling duration and joint angles 33 
2.2.1.1 Rolling Resistance 37 
4.2.1 Percentile values of stature of Male (Sri Lankan) 53 
4.3.1 Anthropometric Data Seat dimensions 54 
4.6.1 Percentile values of weight of Male & Female (Sri Lankan) 58 
5.1.1 COSMOS Analysis results (for load testing frame) 63 
ix