Ergonomic Analysis Study and Its Use in Designing of Adjustable Bicycle Handlebars for Kids

Journal of Automation and Automobile Engineering e-ISSN: 2582-3159 Volume 4 Issue 3

Ergonomic Analysis Study and its Use in Designing of Adjustable Bicycle Handlebars for Kids

Prashant V Thorat*, Dr. D.S.More ME Student, Professor Department of Mechanical Engineering, Dr. D.Y. Patil School of Engineering, Charoli Budurk, Pune, Maharashtra, India Email: [email protected] DOI: http://doi.org/ 10.5281/zenodo.3580577

Abstract Bicycle riders’ position is mostly depends on the position of the handlebars, type of handlebars. If the handlebars are at optimum height , then bicycle rider will get more comfort while riding the bicycle whereas if bicycle handlebars are at lower position compared to saddle position, bicycle rider will get more stresses and pain in his upper body parts like hands, neck and mostly in back. For manage discomfort and fatigue, the cyclist may stop to rest or sit erect without holding onto the handlebars while still riding. By not holding the handlebars, the rider has little control over steering and no control over braking or changing gears. A solution is to adjust the handlebars from the lower to higher position and still allow access to the hand controls. This project objective is to design new parts and extension for the handlebar which can be used to adjust the height of the handlebars as per the anthropometric size of the rider. This project mostly targets the age group of 6 to 9 years as those are the age in which spinal cord system is in development stage and kids mostly start using bicycle. Retaining complete control of steering, braking, and changing gears. Pending positive results from structural testing, the expectation is that the availability of these handlebars will add to the enjoyment of cycling for a larger audience with diverse cycling needs.

Keywords: Comfort, FEA, Bicycle, Cycling.

INTRODUCTION range in price from a few hundred rupees The bicycle is a relatively new device as to several thousand rupees. For this reason, viewed over the history of humankind. The it is understandable that the causal user configuration of the modern bicycle is will limit the number of bicycles to a small credited to John Kemp Starley in 1885 number, such as one or two. Their choice with his introduction of the Rover Safety of style will likely depend on the type of (R. Penn, p. 25). It had a diamond shaped riding that they do most of the time. frame, both wheels were the same size, the rider’s center of gravity was in the middle Bicycle riding is a universal activity of the bicycle, and both feet could touch throughout the world. There are myriad the ground. reasons why the bicycle is so widely used, some of which are transportation, work, Since that time, the bicycle’s popularity exercise, recreation, and competitive has waxed and waned. Currently, the racing. Each of these areas has their bicycle is popular again for recreation, unique attributes, challenges, purposes, fitness, and basic transportation. Along functionality and enjoyment. The scope of with the upsurge of use is the variety of this paper will focus on one style of bicycles from which to choose. Bicycles bicycle and the challenge of rider comfort.

Journal of Automation and Automobile Engineering e-ISSN: 2582-3159 Volume 4 Issue 3

Riding a bicycle is a purely physical of creative minds adapting it for specific endeavour. As with most physical activity, purposes, there may already be a design the better a person’s physical condition the solution or product on the market that has better they can enjoy the activity. A person addressed the problem that this project is does not need to be in peak physical focused to solve, namely a system that condition to enjoy bike riding; however, allows the rider to change riding positions they may find that their endurance to go quickly in the field to relieve fatigue and distances without discomfort and fatigue riding discomfort. A literature review was will be limited. Pain is a major factor in a conducted to identify existing material on person’s ability to perform most the design of handlebars and their activities—cycling is no different. An elite relationship to bicycle ergonomics. The athlete’s muscles are toned to sustain them purpose for analyzing the literature was to for extended periods of time without identify the parameters used to evaluate measurable discomfort. But the weekend the recognized ergonomic standards of the or occasional rider’s muscles are limited in bicycle industry. The ergonomic the amount of stress that they can endure parameters were used as references for before there is noticeable discomfort. distance and angle deltas from standard handlebars for construction of the The hypothesis of this project is that prototype. bicycle handlebars that have the ability to let the rider change the angle of the torso Shih-Wen Hsiao et al. [1], ―Applying in relationship to the erectness of their riding-posture optimization on bicycle sitting position quickly in the field would frame design‖ (2015). reduce fatigue and add comfort to the riding experience. This project focuses This study proposed a method for three riding positions, classic, city, and measuring the comfortable postures of trekking. For purposes of this paper the bicycle riding and applied the results to trekking configuration is referred to as the bicycle frame design. This method could mountain position. be used to effectively measure the best frame size for riders of different height LITERATURE REVIEW ranges on different bicycle types. In the Literature reviews were conducted to process of conducting the experiment, the discover the fundamentals of bicycle best riding posture was defined in this ergonomics that provide comfort to the study as the most comfortable riding rider. The reviews not only identified the posture the testers found in terms of the generally accepted ergonomic parameters standard riding posture. According to the for comfort, but also the causes for verification after riding, the customized discomfort. Using data gathered from peer frame sizes and common frame sizes reviewed studies, the possibility of raised by this study all met the changing from an aggressive style of requirements from riders of all height handlebars to a more casual style seemed ranges. Based on the frame size data, it plausible. could be inferred that for people of different height ranges, the biggest The bicycle is a universal utility vehicle difference in ideal frame size was in the and has many uses as such commerce, distance from the saddle to the ground, the recreation, physical therapy, competitive second largest difference was in the sports, security patrols, and transportation. distance from the handlebar to the ground, Given the longevity that the bicycle has and the smallest difference was in the been interwoven in society and the number distance from the crank center to the

Journal of Automation and Automobile Engineering e-ISSN: 2582-3159 Volume 4 Issue 3 ground. Lastly, the experimental results fatigue in upper extremity and low back were further incorporated into the bicycle muscle groups, which could reflect in poor frame design, thus applying the concept of balancing of bicycle while manoeuvring ―fitting an object to the human body‖ to SP bicycle compared to RF and the SU bicycle design and development. The best bicycles. The results also suggest that the riding postures discussed in this study SU bicycle shows evidence of how well were explored via an established concept, the suspension prevents muscular fatigue thus limiting the study results within the and vibration-induced low-back pain. existing bicycle design patterns. These significant differences among the three bicycle designs have been However, centered on this study, a demonstrated by means of MVC test designer could venture outside the before and after cycling and real-time established bicycle designing concept and monitoring of muscle activity during on- produce a creative bicycle type with a road cycling. This study helps to satisfactory degree of riding comfort. understand the variation of muscle activity caused by the mechanical factors of V Balasubramanian et al. [2], ―Muscle bicycle design. These inferences could be Fatigue Based Evaluation of Bicycle considered for ergonomics design of Design‖ (2014). A study of bicycle design bicycle. concluded that riding comfort is related to the postures required for specific Neuss J [3], ―Bike Ergonomics for All configurations. Three bicycle designs were People‖ (2007). When the test subjects used in this study, the rigid frame, the assumed the more erect position of the suspension, and the sport. The handlebars rigid and suspension configurations, there for the sport design are lower than the was less fatigue and discomfort. An saddle. This gives the riders a lower analysis of the spine’s curvature with profile and less aerodynamic drag, relationship to bicycle handlebar however, there is greater downward forces configuration identified plausible causes on the back muscles, the neck, arms and for fatigue (Neuss, 2007). Three areas hands. were the focus of the study, the arms and shoulders, the back muscles, and the crank The findings of this study indicate that or pedal area (see Fig. 6). there is a substantially higher muscular

Figure 1: Three important areas to look at in bike ergonomic.

Journal of Automation and Automobile Engineering e-ISSN: 2582-3159 Volume 4 Issue 3

PROBLEM DEFINITION AND handlebars meet the safety thresholds, OBJECTIVE surveys that focus on the rider’s comfort Problem Statement and demand for this adjustable feature It is not uncommon to encounter several should be administered if the product is to different types of terrain on a riding outing be marketed. such as off road, rugged hills, well-worn trails, or pavement. There are bicycles Objectives built to accommodate all these types of The objective is to find a solution for terrains, however, it is not practical to fatigue and discomfort caused from riding carry several bicycles to change out for a bicycle too long with the handlebars in different surfaces. the same position.

Using a style of bicycle that is not made The scope of this project is to design for a certain terrain can lead to unpleasant adjustable handlebars and produce a and possible unsafe riding. For example, a prototype that will enable the rider to have high handlebar configuration may be the ability to change the height of the perfect for city surfaces and riding through handlebars in the field. urban parks but if the rider comes across an area that is of rugged terrain and The handlebars will allow the rider to have decides to take it on, the high center of optimum control for a mountain bike gravity may cause the rider to fall or ride posture while the alternate configuration slowly enough not to fall but by doing so, will allow the rider to change positions to the thrill of off road riding is diminished. a posture for comfort and still retain the same total control. The project is to stay A solution to not having the correct within the budget. bicycle for a specific surface is to have the ability to change the rider’s centre of THEORETICAL ANALYSIS gravity and thereby reducing discomfort Comfort Angle Analysis with extended and relieving fatigue. It is proposed that a handle bar for different positions: change in the height of the handlebars will Comfort angle analysis is done for accomplish this. different positions of extended handle bar with the help of standard Creo Manikin to The purpose of this project was to design a determine the best positions to decide prototype for handlebars that adjust from a locking hole positions of handle bar. low mountain bike position to that of a city or classic upright positions. The operation Also using this data, the FEA analysis is of the hand controls for applying the done to determine the stability of the brakes and changing gears were to remain design. in the three positions, low, medium, and high. The transformation had to have the Comfort Angle Analysis ability to be done quickly in the field with Comfort Angle analysis is done for the no additional tools. original position of the handlebar and with the extended position of the handlebar. A prototype will be designed and professionally fabricated that had a delta For the both positions the comfort score of six inches from the lower position to the for the shoulder joint and the elbow joint higher position. The ability to operate the for both hands is calculated and compared. hand controls remained intact. The next Comfort angle analysis is done for three phase is to stress test the prototype for different positions of the extended handle compliance to the safety standards for the bar with changed Manikin postures as handlebar stem strength. Once the below:

Journal of Automation and Automobile Engineering e-ISSN: 2582-3159 Volume 4 Issue 3

Figure 2: Pie charts representation of comfort angle analysis of manikin in creo –manikin software without extended handle bar position.

Figure 3: Pie charts representation of comfort angle analysis of manikin in creo – manikin software with extended handle bar position.

FINITE ELEMENT ANALYSIS design factors could contribute to the The concept of having the option to raise device’s failure during operation. The next or lower the handlebars is a simple one at phase is to stress test for compliance to the first glance. However, a deep dive into safety standards as set for the handlebar what is required for reliable and safe stem strength. functionality identified numerous areas To know the deformation and stress and topics to consider. For example, the because of extended handle bar FEA structural integrity of the material and the analysis of the CAD model is performed.

Journal of Automation and Automobile Engineering e-ISSN: 2582-3159 Volume 4 Issue 3

Figure 4: Weight distribution at the points of contact between men and engine.

CAD model finite element analysis is done  Defining the loads on the surfaces of in Creo simulate software. the stem component, Steps used for finite element analysis are:  Constraining the model at the base to  Opened CAD model in Creo Simulate. determine the deformation and stress  Assigning the material – Steel Alloy. when the stem is at its higher extended  Creating the P-type meshing to position. perform simulation on the model.

Analysis Result of Baseline Model

Figure 5: Loads and constraints for the FEA analysis when the handlebar is extended with 150 mm length.

Journal of Automation and Automobile Engineering e-ISSN: 2582-3159 Volume 4 Issue 3

Figure 6: Resulting forces at the handle bar, calculated from the possible misuse situations.

Loading and Boundary Conditions condition. The load of 30 kg is applied on the top Also it is observed that maximum surface of the structure for having a deformation when the stem is at its compressive force on the structure and the extreme position is 2.132 mm with that of bottom surface is going to be fixed. 1.132 mm when the stem is extended by 50 mm. Post-Processing Stress and deformation calculation of Also the stress fringe pattern is compared Handle bar with and without extended for different extended stem positions and it position is done to compare the results. is observed that the stresses induced due to extended position are close to the values From the obtained results it is validated when handlebar is without extended that design will not fail in normal working position.

Figure 7: Maximum deformation of the original handlebar.

Journal of Automation and Automobile Engineering e-ISSN: 2582-3159 Volume 4 Issue 3

Figure 8: Maximum deformation of the modified handlebar.

Figure 9: Von mises stress and deformation for original handlebar.

CONCLUSION Alternatives to solving the problem of The driver for this project was initiated by sitting erect and losing control of the one of the immediate stakeholders bicycle were filtered down to two, experiencing discomfort and fatigue of the changing the actual configuration of the arms and neck after a brief bicycle outing. handlebars or retaining the configuration An erect sitting position brought relief but but adjusting the length of the handlebars’ created a hazard by riding without holding stem. Altering the stem length was the onto the handlebars. The surface terrain choice made due to simplicity. Altering the and the rider’s ability contributed to the length of the stem mainly focused on the assessment that riding without holding areas of elevation and stability. Whereas, onto the handlebars is a hazard. changing the configuration of the

Journal of Automation and Automobile Engineering e-ISSN: 2582-3159 Volume 4 Issue 3 handlebars involved modelling for Ergonomics, Volume 46, pp. 124−136. elevation, multiple segments, multiple 6. Defraeye T, Blocken B, Koninckx E, joints, and countering the effects of riding Hespel P, Carmeliet J (2010), forces. ―Aerodynamic study of different cyclist positions: CFD analysis and ACKNOWLEDGMENT full-scale wind-tunnel tests‖, Journal I take this opportunity to thanks Dr. D.S. of Biomechanics, Volume 43, Issue 7, More and Prof. A. N. Patil for valuable pp. 1262−1268. guidance and for providing all the 7. McKenna SP, Hill MR, Hull ML necessary facilities, which were (2002), ―A single loading direction for indispensable in completion of this work. fatigue life prediction and testing of handlebars for off-road bicycles‖, REFERENCES International Journal of Fatigue, 1. Hsiao, S. W., Chen, R. Q., & Leng, W. Volume 24, Issue 11, pp. 1149−1157. L. (2015). Applying riding-posture 8. Lépine J, Champoux Y, Drouet J optimization on bicycle frame design. (2014), ―Road bike comfort: on the Applied ergonomics, 51, 69-79. measurement of vibrations induced to 2. Balasubramanian V, Jagannath M, cyclist‖, Sports Engineering, Volume Adalarasu K (2014), ―Muscle Fatigue 17, Issue 2, pp. 113−122. Based Evaluation of Bicycle Design‖, 9. The Guide to Cycling Ergonomics – applied ergonomics, 45(2), 339-345. Tips on improving your Bike 3. Neuss J (2007), ―Bike Ergonomics for setuphttps://www.principlefourosteopa All People‖, Retrieved February, 14, thy.com/a-guide-to-cycling- 2010. ergonomics-tips-on-improving-your- 4. Lambros Laios et al. (2010), bike-set-up/. ―Ergonomic evaluation and redesign of 10. McKenna SP, Hill, M. R., Hull, M. L. children bicycles based on ―A single loading direction for fatigue anthropometric data‖, Applied life prediction and testing of ergonomics, 41(3), 428-435. handlebars for off-road bicycles. 5. Ayachi FS, Dorey J, Guastavino C International Journal of Fatigue, (2015), ―Identifying factors of bicycle 24(11), 1149-1157‖ (2002). comfort: An online survey with enthusiast cyclists‖, Applied