Development and Evaluation of an Attachable Anti-Vibration Handle for Blueberry Hand Shaker

Development and Evaluation of an Attachable Anti-Vibration Handle for Blueberry Hand ShakerElectronic Theses and Dissertations Theses, Dissertations, and Major Papers
Summer 2021
Handle for Blueberry Hand Shaker Handle for Blueberry Hand Shaker
Jashwant Thota University of Windsor
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Recommended Citation Recommended Citation Thota, Jashwant, "Development and Evaluation of an Attachable Anti-Vibration Handle for Blueberry Hand Shaker" (2021). Electronic Theses and Dissertations. 8831. https://scholar.uwindsor.ca/etd/8831
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Shaker
By
through the Industrial Engineering Graduate Program
in Partial Fulfillment of the Requirements for
the Degree of Master of Applied Science
at the University of Windsor
Windsor, Ontario, Canada
Development and Evaluation of an Attachable Anti-Vibration Handle for Blueberry Hand
Shaker
By
______________________________________________
______________________________________________
iii
Declaration of Originality
I hereby certify that I am the sole author of this thesis and that no part of this thesis has
been published or submitted for publication.
I certify that, to the best of my knowledge, my thesis does not infringe upon anyone’s
copyright nor violate any proprietary rights and that any ideas, techniques, quotations, or any
other material from the work of the other included in my thesis, published or otherwise, are fully
acknowledged in accordance with the standard referencing practices. Furthermore, to the extent
that I have included copyrighted material that surpasses the bounds of fair dealing within the
meaning of the Canada Copyright Act, I certify that I have obtained a written permission from
the copyright owner(s) to include such material(s) in my thesis and have included copies of such
copyright clearances to my appendix.
I declare that this is a true copy of my thesis, including any final revisions, as approved
by my thesis committee and the Graduate Studies office, and that this thesis has not been
submitted for a higher degree to any other University or Institution.
iv
Abstract
Blueberry production has skyrocketed in the past two decades due to an exponential increase in
consumer demand around the world. The harvesting of fresh, high-quality blueberries requires
extensive care. Large-scale automatic harvesters damage the fruit and make it unsuitable for
storage and transportation, which requires more than two weeks to complete. Therefore, hand
harvesters are used, avoiding damage to the fruit, and increasing harvesting efficiency multifold
when compared with that of hand-picking. The downside of these hand harvesters is their high
Hand Arm Vibration (HAV), which is very dangerous for the worker and can cause hand-arm
vibration syndrome (HAVS). This syndrome affects osteoarticular, vascular, and neurological
systems of the upper limbs, generating motor control problems that make it difficult to maintain
control over the harvesting instrument after a certain period of time. The aim of this study is to
propose a spring-based attachable anti-vibration handle that can be attached to the vibrating
equipment (blueberry hand harvester). Four different parameters were measured on 15 participants
for the developed spring-based handles: hand arm vibration, wrist posture, muscle activity, and
subjective discomfort rating. One-way ANOVA and two-way repeated measures ANOVA
analyses were performed on the results obtained for these four parameters. Results have shown
that the use of a spring-based handles was superior in reducing the HAV by 61.1% and in
improving the wrist posture by 51.1% when compared with traditional hand shaker. Thus, I except
that this study will contribute to reduce the pain and work-related musculoskeletal disorder
(WMSD) risk factors associated with vibrations in the field of blueberry harvesting.
Keyword: Anti-vibration Handle, Hand Arm Vibration, Blueberry Hand Shaker
v
Acknowledgements
I wish to express my sincere gratitude and thanks to my supervisor, Dr. Eunsik Kim for providing
me the opportunity to work on such an interesting project. All his guidance, encouragement,
supervision, feedback, and support during all stages of this research made this project successful.
This project would not have been possible without his help and the valuable time that he has given
me amidst his busy schedules.
I would like to thank my thesis committee members Dr. M. Wang and Dr. N. Zamani for their
support and valuable advice which helped me to successfully complete my Thesis.
In addition, I would also like to thank the Department of Mechanical, Materials and Automotive
Engineering for Graduate Assistantship (GA) opportunity, Mitacs for the scholarship, Secretarial
services of Ms. Angela Haskell and all faculty and staff members of the Department of Mechanical,
Materials and Automotive Engineering and the Faculty of Graduate Studies for their help.
Finally, I would like to thank my parents, fiancée, brother, and other family members for their
love, patience, understanding and support throughout this research. You were always there for me
and I sincerely appreciate everything you all did for me.
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2.2 HAVS .................................................................................................................................... 9
Vascular disorders: ................................................................................................................ 10
Neurological disorders: .......................................................................................................... 11
Chapter 3 – Handle Design ........................................................................................................... 18
3.1 Spring selection ................................................................................................................... 18
3.3 Final prototypes of developed spring-based handles .......................................................... 20
Chapter 4 – Method ...................................................................................................................... 22
4.1 Study Design ....................................................................................................................... 22
4.4 Instrumentation and Data Acquisition................................................................................. 26
5.4 Wrist Posture ....................................................................................................................... 33
Chapter 6 - Discussion .................................................................................................................. 35
Chapter 7 – Conclusion ................................................................................................................. 39
Consent Forms and Background Information for Participants.................................................. 53
REB Approval ........................................................................................................................... 55
RSC Approval ........................................................................................................................... 56
HAV Data .................................................................................................................................. 57
EMG Data ................................................................................................................................. 58
Table 1: Comparison of three different blueberry harvesting methods .......................................... 2
Table 2: Demographics and personal characteristics of participants (n = 15) .............................. 24
Table 3: Results from a one-way ANOVA on the effect of different handle types based on HAV.
....................................................................................................................................................... 29
Table 4: Results from a one-way ANOVA on the effect of different type of handles based on
muscle activity .............................................................................................................................. 31
Table 5: Results from a one-way ANOVA on the effects of different handle types based on
subjective discomfort rating .......................................................................................................... 33
Table 6: Results from a one-way ANOVA on the effects of different type of handles based on wrist
posture ........................................................................................................................................... 34
Table 8: FDS muscle activity for all ten handles .......................................................................... 58
Table 9: FPL muscle activity for all ten handles .......................................................................... 59
Table 10: EDC muscle activity for all ten handles ....................................................................... 60
Table 11: ECRB muscle activity for all ten handles ..................................................................... 61
Table 12: Discomfort level in wrist for all ten handles ................................................................ 62
Table 13: Discomfort level in lower arm for all ten handles ........................................................ 63
Table 14: Discomfort level in upper arm for all ten handles ........................................................ 64
Table 15: Discomfort level in shoulder for all ten handles ........................................................... 65
Table 16: Discomfort level in low back for all ten handles .......................................................... 66
Table 17: Wrist posture in ulnar direction for all ten handles ...................................................... 67
Table 18: Wrist posture in extension direction for all ten handles ............................................... 68
ix
Figure 1: Increase in demand of blueberry ..................................................................................... 1
Figure 2: Involvement of three different regions of hand in HAV ................................................. 2
Figure 3: Semi-automatic blueberry hand shaker ........................................................................... 4
Figure 4: Anatomy of WMSD ........................................................................................................ 6
Figure 5: Prevalence of WMSD ...................................................................................................... 7
Figure 6: Frequency of WMSD reporting for different areas of body during farming................... 8
Figure 7:Vascular injury ............................................................................................................... 10
Figure 9: Impact on hands due to HAVS ...................................................................................... 11
Figure 10: Over-the-Row Automatic harvesting machine ............................................................ 14
Figure 11: Manual blueberry harvesting ....................................................................................... 15
Figure 12: Semi mechanical harvesting ........................................................................................ 16
Figure 13: Three different type of springs based on application of load ...................................... 18
Figure 14: Design of One, Two, and Three spring handles .......................................................... 20
Figure 15: Nine developed spring-based handle designs .............................................................. 21
Figure 16: Svantek SV103 device................................................................................................. 22
Figure 18: Borg CR10 Scale ......................................................................................................... 23
Figure 19: Electro goniometer ...................................................................................................... 23
Figure 20: Equipment attached on participant .............................................................................. 25
Figure 21: Evaluation of hand shaker using 10 different handles ................................................ 26
Figure 22: Means and standard deviations of HAV by using nine developed handles ................ 30
Figure 23: Means and standard deviations of EDC muscle activity among the nine developed
handles .......................................................................................................................................... 32
Figure 24: Dominant hand is close to the shaking head of the traditional hand shaker ............... 37
x
EDC Extensor Digitorum Communis
ELV Exposure Limit Value
MVC Maximum Voluntary Contraction
WMSD Work-related Musculoskeletal Disorder
1.1 Background
The demand of blueberries has been rapidly increasing over the past few years, as shown in Figure
1. Blueberry production and demand have grown increasingly due to the fruits link with health
benefits. In both developing and developed countries, blueberry harvesting is done using a variety
of methods. These include manual harvesting, semi-mechanical, and automatic harvesting. In
previous years, blueberry harvesting was done manually and it used to take a lot of time to pluck
them, but the demand at that time was low compared to the present. Intensive labor is required in
manual harvesting of blueberries as it involves constant use of hand and arm movement (Benos et
al., 2020). Because of these reasons, we cannot use hand harvesting in the present world as it would
not meet the requirement.
Figure 1: Increase in demand of blueberry (Image source: dyson.cornell.edu)
Most of the large farms use fully automatic over-the-row (OTR) machines to harvest the
blueberries (DeVetter et al., 2019). OTR harvesting eliminates repetitive hand motions and
transfers all the work to simple lifting (Kim et al., 2018). However, the fruit harvested from these
machines for fresh market with good shelf life has been a challenge due to plant architecture,
excessive ground loss, and rapid fruit softening incurred from mechanical impact damage (Takeda
et al., 2013). Although OTR harvesters can significantly cut harvest labor, they cost more than
$200,000 per unit making them unaffordable for small and medium size blueberry farms (Takeda
et al., 2017). A semi-mechanical harvester could be an option for the small and medium size farms
(Sargent et al., 2020). Comparison of various parameters on the three type of blueberry harvesting
methods are shown in Table 1 (Takeda et al., 2017).
Table 1: Comparison of three different blueberry harvesting methods (source: mdpi agronomy)
Parameters Hand Harvesting Semi-automatic
Cost of harvest per Kg $2.80 $0.69 $0.26
% of fruit damaged 0% Upto 8% Upto 25%
Time to harvest/hectare 600 hr 45 hr 24 hr
However, operators of hand-held power tools, widely used in various industrial sectors, are known
to transmit substantial vibrations to the operator’s hand and arm (Sargent et al., 2020). Figure 2
shows the involvement of three different muscles in HAV (Raman and Mahadevan, 1996).
Figure 2: Involvement of three different regions of hand in HAV (Image source: sheilds.org)
Due to constant movement and induced vibration, workers working in blueberry harvesting are
exposed to hand arm vibrations (HAV), which are translated to hand arm vibration syndrome
(HAVS) if continued for a longer time (Sargent et al., 2020). HAVS is a disease that involves
circulatory disorders (e.g., vibration white finger), sensory and motor disorders, and
musculoskeletal disorders, which may occur in workers who use vibrating handheld tools, like
pneumatic drills, grinders, electric drills and saws, and jackhammers (Weir & Lander, 2005). Early
symptoms of HAVS are numbness in hands, finger discoloration, weakness in muscles, limited
motion of hands and loss of dexterity (Kim et al., 2019). HAVS contributes in reducing 45% of
manhours in agricultural sector (Kifle, 1972). Even though HAVS is an independent disease,
people exposed to HAVS have higher chances of acquiring other similar disease like Carpal
Tunnel Syndrome (CTS) and Raynaud’s syndrome (Barregard et al., 2003).
HAVS is a part of Work-related musculoskeletal disorders (WMSD), and these WMSD are
composed of more than 32% of days-away-from-work cases in all types of industries (Kim et al.,
2018). WMSD are a group of painful disorders of muscles, tendons, and nerves (Elashmawy,
2019). WMSD are usually occurred when the minimum physical requirements of the work exceed
the ability of workers working on site. The risk factors of WMSD include repetitive motion,
excessive force, vibrations, awkward and/or sustained postures, many of which are needed in
farming work labor (Fujiwara et al., 2017).
Several studies were conducted to reduce the risk factors related to awkward postures, excessive
force, and repetitive motions to prevent the WMSD in agriculture (Bhattacharyya & Chakrabarti,
2012; Kotowski et al., 2009). However, there are limited previous studies conducted to reduce
and/or control the vibrations in agriculture. Therefore, this study focusses to reduce the disorders
associated with these hand transmitted vibrations by developing an attachable spring-based handle.
1.2 Problem Statement
Agricultural workers whose work is dependent on power tools are exposed to a great extent of
vibrations. This could have a negative effect on the health of workers and could damage their
muscles, circulation and sensory nerves which may also lead to considerable pain or even disability
(Bovenzi, 1998; Weir & Lander, 2005). Figure 3 shows the semi automatic hand shaker used for
blueberry harvesting whose configuration (low mass, long pole) and high stick velocity produces
high vibrations. The vibrations produced from the blueberry hand shaker is more than 10 m/s2,
which is far greater than the safety limits of exposure action value (EAV) = 2.5 m/s2 and exposure
limit value (ELV) = 5 m/s2. These limits are stated by European Directive 2002/44/EC for A(8)
(average of 8 hours) (Hand-arm vibration, 2019).
4
Figure 3: Semi-automatic blueberry hand shaker
There are very few ergonomic studies to tackle the WMSD problems faced by agriculture workers
in blueberry harvesting (Kim et al., 2018). However, to the best of my knowledge there is no
previous study conducted to reduce the vibrations received by farmer using the semi-automatic
hand shaker under the ELV. In response to this problem, the study attempts to reduce the vibrations
produced from semi automatic hand shaker experienced by blueberry farm workers to a safer level.
1.3 Purpose
The purpose of this study is to develop a spring-based attachable anti-vibration handle to reduce
the vibrations produced from the traditional hand shaker. More specifically, this study is to develop
an attachable handle with the help of spring that can (1) reduce the vibrations transferred from the
semi-mechanical hand shaker to the human hand, (2) reduce the muscle activity, (3) reduce the
level of discomfort to operate the hand shaker, and (4) to improve the wrist posture. The spring-
based handle is validated statistically with the traditional hand shaker by computing the one-way
ANOVA and two-way repeated measures ANOVA. In addition, I developed nine spring-based
handle prototypes with the different combination of type of springs and number of springs in order
to figure out which combination is the best to reduce the risk factors of HAVS.
1.4 Hypothesis
1. The proposed spring-based handles should reduce the HAV produced from the semi-
automatic blueberry hand shaker under the ELV limit.
5
Spring is a flexible element which is used to exert a force or a torque and, at the same time
to store the energy (Gaikwad & Kachare, 2013). So, it was assumed that using spring-based
handles over the traditional hand shaker will decrease the HAV, as spring restricts and
isolates most of the vibrations (Aoki et al., 2016).
2. The operation of a semi-automatic blueberry hand shaker using the developed spring-based
handles should reduce the muscle activity.
Considering the previous paper (Widia, 2011), more vibrations lead to more muscle
activity. Since the spring-based handles will reduce the vibration, I made the assumption
that the muscle activity will also be reduced compared with the traditional hand shaker.
3. Discomfort level should be reduced by attaching the developed spring-based handles to
operate the semi-automatic blueberry hand shaker.
When the negative influence of the vibrations is decreased, thereby reducing the transfer
of vibrations to the body parts, comfort level is improved (Zimprich et al., 2020). So, it
was presumed that discomfort level while using the spring-based handles would be
minimal when compared to the traditional hand shaker.
4. Wrist posture should also be improved by using the developed spring-based handles.
From the previous study conducted by Yu et al. (2016), shiftable handle will achieve more
comfort and neutral body postures. As, the holding angle for traditional hand shaker is
fixed, it was assumed that using spring-based handles would improve the wrist posture
over the traditional hand shaker based on the developed design which will allow shifting
the handle, leading to optimum task performance and usability.
6
Chapter 2 – Literature Review
2.1 WMSD in Agriculture
WMSD is a condition in which the work environment and performance of work are made worse
due to longer work conditions (Bernard & Putz, 1997). Figure 4 shows the anatomy of WMSD
involves tendons, ligaments, joints, wrist, or spinal discs that support limbs, neck, and back
(Kearney et al., 2016).
Figure 4: Anatomy of WMSD (Image source: nps.edu)
WMSD are not a result of a distinctive, singular event, but are cumulative-type injuries that
develop gradually by exerting excessive physical effort over time (Kearney et al., 2016). If they
are untreated, WMSD can cause to permanent pain and disability in the workers (Kim, 2016). The
International Labor Organization (ILO) has stated that almost 160 million workers in agricultural
sector are prone to WMSD and agriculture is regarded as one of the most unsafe working
environments related to occupational health and safety (Naeini et al., 2014). A study conducted by
Kumaraveloo and Lunner (2018) stated that the most common risk factors associated with WMSD
among agricultural workers were physical factors, followed by individual and psychosocial risk
factors in low to middle-income countries. In a study conducted by McMillan et al. (2015), on
adults in Saskatchewan farms reported 85.4% WMSD and 27.9% reported pain in at least one
anatomical site that was interruptive or interfered with their ability to participate in regular
activities. The US Department of labor Statistics reported it accounted for 31% of all workers off
sick from non-fatal occupational injuries and illnesses. Figure 5 shows the prevalence of WMSD,
percentage of different body part injuries, and the risk of agriculture jobs compared with other
fields leading to WMSD.
Figure 5: Prevalence of WMSD (Image source: ergo-health.co.uk)
Examples of work conditions that lead to WMSD in agriculture include daily exposure to whole
body vibration, routine overhead work, routine lifting of heavy objects, digging and shoveling,
hand transmitted vibrations and performing repetitive forceful tasks (Walker & Palmer, 2002).
WMSD have significant impact not only on agricultural workers, but also on healthcare system
and their employers (Bevan, 2015). Both the employer and healthcare system are impacted due to
the loss of productivity due to poor work performance or absenteeism, healthcare expenditure, and
workers compensation for disability (Kumaraveloo, 2018).
The study conducted by Henry et al. (2015) on palm plantation workers showed that the most
prevalent musculoskeletal disorder was in low back, followed by upper extermities and lower
extermities which can be seen in the Figure 6.
Figure 6: Frequency of WMSD reporting for different areas of body during farming (Henry et
al., 2015)
Kang et al. (2016) found that the risk factors of WMSD increased significantly with agriculture
type, ergonomic factors, and number of years of farming. Another study was carried out on
agricultural workers of Southeast Spain, the results showed that the most frequent WMSD
symptoms were related to neck, upper back, shoulders, lower back,…