It would be worthwhile and relevant to acknowledge the cooperation of the Assamese agricultural laborers who enabled the collection of anthropometric and biomechanical data and the field testing of pedal-operated paddy threshing machines. The design of agricultural implements and equipment for agricultural laborers in the northeastern region of India should not only be in accordance with the anthropometric and biomechanical characteristics of the potential users, but also be portable to ensure easy and comfortable transportation in different terrains.
CONTENTS
Introduction
- Northeast India – At a Glance
- NER – The Agricultural Perspectives
- Agricultural Mechanization Status in Northeast India
- Northeast Agriculture – Ergonomics Awareness Status
- Scope and Rationale behind Present Research
- Lacuna – Queries to be Resolved
- Objectives
- Hypothesis
- Framework of the Research
- Layout of the Thesis
Technical error of the measurement (TEM), relative technical error of the measurement (%TEM) and coefficient of reliability (R) were calculated. A systematic outcome assessment was conducted for design intervention of pedal-powered threshers.
Design, Development and Calibration of Isometric Vertical Leg Strength Measuring Device
- Introduction
- Background
- Requirement of Leg Strength Measurement Device
- Essential design principles
- Development of the device
- Conceptualization
- Creation of digital human models and rendering for range of adjustment Review of literatures revealed serious lack of normative database for Assamese
- Finite element analysis
- Product Development – Leg Strength Measuring Device
- Calibration of leg strength measuring device
Some of the competent thoughts for the proposed isometric vertical force measuring device are shown in Figure. Normally, the accuracy of the measuring device under test should be closest to the standard, i.e.
Development of Normative Anthropometric and Biomechanical Database for Assamese Farmers
Introduction
Anthropometric and biomechanical databases are a much-needed and valuable pursuit for designing user-friendly tools and equipment from an ergonomic point of view. It is widely recognized that the process of designing tools and equipment begins with a discussion of the end user's limitations and capabilities.
Ergonomics / Human Factors in Tools and Equipment Design
- Application of ergonomics in tools and equipment design
User-centered tools and equipment design are the need of the hour for Indian farmers, where consideration of ergonomic aspects, mainly anthropometric data and force variability database, is crucial (Patel et al., 2014). Several studies have shown that the design of agricultural implements and equipment is not consistent with user-specific anthropometric references (Dixit and Namgial, 2012;.
Pilot Studies
- Pilot study 1 – Anthropometric data measurement
- Objective
- Equipment
- Statistical analysis
- Results and Discussion .1 Subject characteristics
- Reliability analysis
Similarly, Agrawal et al., 2010 reported anthropometric data of farmers from Meghalaya and recommended a minimum grip diameter of 3.7 cm for men and 3.3 cm for farmers; handle height 89.5 cm for men and 85.7 cm for women and 95.6 cm and 101.2 cm for male and female workers respectively for the 5th and 95th percentile of body mass to maintain an elbow angle of 1000. From the above discussion it can be deduced , that there was reasonable similarity in the recommended values in some construction dimensions for male and female agricultural workers, such as gripper diameter values. However, some researchers have also reported differences in recommended design dimensions for other regions of India, such as Agrawal et al. 2011) who suggested some design recommendations based on case studies such as weed arm height in cm to ensure a comfortable hold for both men and women; handle diameter ranging from 3.2 - 4.0 cm for women and 3.6 - 4.2 cm for male workers; minimum handle length is 109mm for male and 96mm for female tools and strap length is 675mm for knapsack sprayer for agricultural workers from Madhya Pradesh.
A pilot study was conducted before the main study. The purpose of the pilot study was not only to establish the reliability and validity of anthropometric measurements, but also to establish a protocol for collecting anthropometric data from farmers in the field.
A Pilot Study 2 – Isometric Leg Strength Measurement
- Objective
- Equipment
- Experimental design
- Experimental procedure
- Results and Discussion
Participants were verbally encouraged during the experiment in order to inspire them to apply their maximum force. The maximum strength of the right and left legs for knee joint angles of 90°, 120° and 150° for males and females is tabulated as shown in Table 3.4. Repeated measures ANOVA for within-subject variance revealed significant differences in peak isometric force values across the knee joint angle (F P < 0.01) as shown in Table 3.5.
Further, one-way ANOVA was also performed for the between-subjects effects of knee joint angle, feet and gender variations, as shown in Table 3.6.
Experimental Development of Normative Database for Assamese Male and Female Agricultural Workers
- Selection of sample size
- Selection of participants
- Procedures for anthropometric data measurement
- Results and Discussion
- Anthropometric data of male agricultural workers
- Anthropometric variations among male agricultural workers in India
- PCFA and regression analysis
- Female anthropometric data
- Comparison of anthropometric database between male and female Assamese agricultural workers
Descriptive statistics of the 27 dimensions measured for the agricultural worker database are summarized in Table 3.8. Continuing with RSH, it could be seen from Table 3.11 that Assamese people had a RSH of 0.52. Based on the eigenvalues more than ≥1, six factors were considered, which explained 71.21% of the variations in original quantitative characteristics as shown in Table 3.12.
Body anthropometric dimensions measured during the study and some important derived parameters such as RSH, BSA and BMI were analyzed for mean, standard deviation, minimum, maximum, median, coefficient of variation, percentage range for female agricultural workers (Table 3.15 ).
Experimental Procedures for Handgrip Measurement
- Results and Discussion .1 Hand grip strength
- Effect of hand grip strength for male and female among different age groups Handgrip strength depends upon various factors such as gender, age, physical fitness,
- Comparison of grip strength with other regions / zones of India
- Cumulative percentage distribution of handgrip force
The coefficients of variation for grip strengths for dominant and opposite hands were found to be higher for female participants compared to male participants. Handgrip strength was found to decrease with age for dominant and opposite hands in both men and women. The cumulative percentage distribution of hand grip strength for male and female dominant and opposite hands, respectively, was shown in Fig.
2014) also compared sixteen strength parameters including grip strength of dominant and opposite hands from the pooled Indian database with regional databases from different states, namely Gujarat, Jammu and Kashmir, Madhya Pradesh, Maharashtra, Orissa, Tamil Nadu, Meghalaya and Arunachal Pradesh.
Experimental Procedures for Leg Strength Measurement
- Isometric leg strength
- Leg strength of male and female among different age groups
- Distribution pattern of leg strength
- Cumulative percentage distribution of leg strength
Leg strength isometric database for three age groups for male and female agricultural workers is shown in the figure. In addition, a combined database of male and female farmers' leg strength across all age groups showed that the right leg performance was significantly higher (p<0.05) than the left. Therefore, the recommended value for leg strength for male and female agricultural workers in Assam should be the 5th percentile of female data, which were 11.47 kg for the right leg and 8.34 kg for the left.
Cumulative percentage distribution of isometric leg strength for men's and women's right and left legs, respectively, is shown in fig.
Ergonomic Design Modification, Testing and Evaluation of Pedal Operated Paddy Thresher
Introduction
In developed countries, however, the harvesting and threshing of rice is almost entirely mechanized, which has resulted in an extraordinary reserve of time and labor. In terms of mechanization, NER is still in the early stages of development. Several motorized or electric rice threshers have been designed and developed in the past, but they have not been successful in hilly areas due to cost, weight, and power problems.
Although many designs are popular in different parts of the country, the suitable design for NER is yet to be established.
Paddy Threshing ‒ Post-Harvest Processing Means
Manually operated machines such as wheel hoes, multi-purpose weeders, seed drills and pedal threshers have a better range in hilly areas. Farmers in northern states such as Punjab, Haryana and Uttar Pradesh have largely adopted the paddy thresher, while the traditional rice-growing areas of eastern and southern India are still dominated by manual pedal threshers. Mohammed Fazlul Haque of Assam invented a paddy thresher machine (Figure 4.2) where the entire stalk of paddy rice can be obtained instead of cut pieces, thus retaining the nutritional value in the whole stalk and is fed to cattle or sold.
In some parts of Assam, Meghalaya and Arunachal Pradesh, pedal driven pad thresher is used, supplied by neighboring states viz.
Computer-Aided Design and Digital Human Modeling
- DHM in product design and development
- Applications of computer-aided design in agricultural engineering
- Applications of digital human modeling in agricultural sector
With advanced technology, a greater number of features are being included for analysis and simulation in engineered designs (Antonucci et al., 2013). For incorporating ergonomic principles into product/process and workplace design, the role of DHM software appears to be inevitable (Patel et al., 2013). Most of the available literature reported DHM applications only on off-road vehicles, especially for the tractor cab.
This can be illustrated with the example of the ergonomic evaluation of the structure and function of a 3D tractor cabin model (Fig. 4.7).
Pilot Study – Pedal Operated Paddy Thresher
- Results and Discussion
- Availability of pedal operated paddy thresher
Twenty-nine manufacturers willingly responded and provided detailed technical figures related to the design and construction of the pedal thresher. Surprisingly, most of the Assamese farmers had not even seen any pedal thresher before this survey. A total of 46 participants answered questions related to musculoskeletal problems when operating a pedal thresher.
The lower leg condition was apparently predominant (95.65%) among the farmers using pedal operated paddy threshing machine.
Virtual Product Development
- Digital prototype of pedal thresher
- Finite element analysis
- Creation of digital human models and rendering of comfort posture
- Interfacing digital human models with the virtual paddy thresher
- Working posture assessment and biomechanical analysis
Mechanical design feature of DELMIA (V5R19) digital human modeling software was used to generate CAD model of the existing and proposed threshers. Based on the findings of the result, it was assumed that the design dimensions are within safe range. Anthropometric data of Assamese population was compiled and referred for ergonomic design and subsequent evaluation of CAD model of the conceptualized pad thresher.
The existing pedal thresher model was found to be anthropometrically compatible only for the 5th percentile, 50th percentile female, and 5th percentile male mannequins (Fig. 4.17).
Physical Fabrication of Thresher
Therefore, 60 cpm was chosen and provided the necessary chain mechanism to maintain 300 rpm threshing cylinder speed. In this study threshing cylinder length was determined using anthropometric database of Assamese population. Assuming that the clearance on each side is 5 cm, the width of the threshing cylinder was calculated to be 56 cm.
The optimum height of the threshing cylinder was therefore on average 94 cm, which provides usability for both male and female farmers.
Laboratory Testing ‒ Surface Electromyography
- EMG system specifications
- Electrod placement on the skin
- Participants
- Data collection procedure
- Data analysis
- Results and Discussion
- Raw EMG Data of Selected Muscles
- EMG (%MVC) for selected muscles
- MCV (Newton, N) for Selected Muscles
The placement of electrodes in the appropriate place, i.e. parallel to the muscle fibers, is one of the most important factors for optimal signal acquisition. The arrow of the electrode placed in the middle of the muscle belly (away from tendons at the edge of the muscle) should be parallel to the muscle fibers under the sensor. In this experiment, EMG was obtained from the four selected muscles during the maximal voluntary contractions.
Each participant repeated the entire experiment in three trials at 3 min intervals, and for each of the selected muscles the best reading was considered for record and analysis.
Laboratory Testing ‒ Measurement of Actuating and Working Forces
- Meteorological station
- Monitoring of heart rate
- Subjective ratings
- NASA task load index
- Energy expenditure rate
- Oxygen consumption rate
- Work rest schedule
- Results and Discussion .1 Subject characteristics
- Heart rate measurement
- Physiological cost of work
- Muscular fatigue
- NASA task load index
- Body part discomfort
- Work-rest scheduling
- Threshing capacity
Resting and working heart rates were averaged to obtain the average heart rate value for the workers. The work pulse value was calculated by subtracting the average heart rate during work from the average heart rate during rest. Ratings were obtained using a modified version of the Bishop-Corlett body map (Corlett and Bishop, 1976) and the Borg CR 10 scale (Borg, 1990). Participants rated discomfort for their whole body and each of 25 local body parts (Fig. 4.36). Oxygen consumption rate (the amount of oxygen consumed by the whole body per unit time) was calculated from the operator's heart rate values and is given by the following equation (Singh et al., 2008).
The overall percentage difference in workload was 20.73 and Student's t-test for the paired sample showed a significant difference in workload (t p<0.001). The greater demand for effort to operate the existing threshing machine could be due to ignorance of.
Summary and Conclusion
Summary
For the design and manufacture of the said instrument, the following criteria were considered − (1) versatility, (2) safety, (3) convenience, (4) use-reuse flexibility, (5) system calibration, (6) accuracy and (7) ) ) cost. Comparisons of handgrip strength between Assamese farmers and the other regions of India showed that the database of Assamese population differed significantly (p<0.05) in most of the cases. After the virtual ergonomic evaluation of the thresher model with subsequent modification of the design, the physical prototype was turned over.
Some important design features of the newly developed paddy thresher considering the prerequisite of hilly/plain agriculture were as follows.
Conclusion
Key Contributions of Present Thesis towards Agricultural Research
By the next decade, it can be expected to serve as a key tool for engineering design and ergonomic analysis. Newly designed pedal driven pad threshers were found to be superior compared to the existing one. The ergonomically designed pedal operated pad thresher which is an outcome of current research carries important design features keeping in mind the prerequisites of agriculture of NER.
These features are (a) a grain shield to reduce the spread of dust/flakes and thus respiratory protection; (b) a 'chain gear' mechanism instead of a 'four-way link' mechanism to simplify the power transmission system;.
Limitations of the Study and Future Research Directions
Proceedings of the National Workshop on Agricultural Machinery Design Methodology, Central Institute of Agricultural Engineering, Bhopal, India, 192 ‒ 198. Anthropometry of male agricultural workers of north-east India and its use in the design of agricultural implements and equipment. All India Coordinated Research Project on Human Engineering and Safety in Agriculture, Central Institute of Agricultural Engineering, Bhopal, India.
Proceedings of the XXXVII Annual Convention of the Indian Society of Agricultural Engineers, Maharana Pratap University of Agriculture Technology, Udaipur, India.
Proforma for Anthropometric Survey
- Weight: Body weight as measured on a calibrated weighing scale. The subject stands erect and look straight forward
- Stature: The vertical distance from the standing surface to the top of the head
- Acromial (shoulder) height: The vertical distance from the standing surface to the most lateral point of the acromial process of the scapula. The subject stands erect
- Bideltoid (shoulder) breadth: The horizontal distance across the body at the level of the deltoid landmarks. The subject stands erect with his arms hanging naturally
- Shoulder grip length: The horizontal distance from a pointer held in the subjects’
- Arm reach from wall: The distance from the wall to the tip of the middle finger measured with the subject's shoulders against the wall, the hand and arm
- Olecranon height: The vertical distance from the standing surface to the height of the under surface of the elbow, measured with the arm flexed 90 degree and the
- Elbow height: The vertical distance from the standing surface to the depression at the elbow between the humerus and the radius. The subject stands erect with his
- Trochanteric height: The vertical distance from the standing surface to the most superior point of the greater trochanter of the femur. The subject stands erect
- Instep length: The distance from the plane of the heel to the point of maximum medial protuberance of the foot
- Hand breadth across thumb: The breadth of the hand as measured at the level of distal end of the 1 st metacarpal of the thumb
- Palm length: The distance from the base of the hand to the furrow where the middle finger folds upon the palm
- Grip diameter (inside): Subject holds a cone around the largest circumference that can be grasped with the thumb and middle finger just touching. Record the
- Grip strength: The grip strength of the hand measured with handgrip dynamometer when the subject stands erect with his arms hanging downwards
- Maximum grip length: The maximum length between the tip of the index finger and the tip of the thumb while the palm, thumb and fingers are in grip position
Trochanteric height: The vertical distance from the surface of the foot to the most superior point of the greater trochanter of the femur. Sitting Height: The vertical distance from the sitting surface to the top of the head. The distance from the heel of the foot to the front foot with the knee straight.
The subject stands with the weight of the heel to the tip of the most prominent toe.
Specification Trigno ™ Wireless EMG Systems
Specification of Polar heart rate monitor
Specification of Novatech load cell
Battery 2 off AAA alkaline, included, user replaceable Temperature (1 sec response)
