Seri Rahayu Kamat

Development of a Decision Support System for Analysis and Solutions of Prolonged Standing in the Workplace

Background Prolonged standing has been hypothesized as a vital contributor to discomfort and muscle fatigue in the workplace. The objective of this study was to develop a decision support system that could provide systematic analysis and solutions to minimize the discomfort and muscle fatigue associated with prolonged standing. Methods The integration of object-oriented programming and a Model Oriented Simultaneous Engineering System were used to design the architecture of the decision support system. Results Validation of the decision support system was carried out in two manufacturing companies. The validation process showed that the decision support system produced reliable results. Conclusion The decision support system is a reliable advisory tool for providing analysis and solutions to problems related to the discomfort and muscle fatigue associated with prolonged standing. Further testing of the decision support system is suggested before it is used commercially.

Analysis of Muscle Activity using Surface Electromyography for Muscle Performance in Manual Lifting Task

In industries, manual lifting is commonly practiced even though mechanized material handling equipment are provided. Manual lifting is used to transport or move products and goods to a desired place.Improper lifting techniquescontribute to muscle fatigue and low back pain that can lead to work efficiency and low productivity.The objective of this study were to analyze muscle activity in the left and right Erector Spinae, and left and right Biceps Brachii of five female subjects while performing manual lifting taskwithdifferent load mass, lifting height and twist angle.The muscle activitywere measured and analyzed using surface electromyography (sEMG).This study found that the right Biceps Brachii, right and left Erector Spinae experienced fatigue while performingasymmetric lifting (twist angle = 90°) at lifting height of 75 cm and 140 cm with load mass of 5 kg and 10 kg. Meanwhile, the left Biceps Brachii experienced fatigue when the lifting task was set at lifting height of 75 cm, load mass of 5 kg and twist angle of 90°.The load mass and lifting height has a significant influence to Mean Power Frequency (MPF) for left Biceps Brachii, left and right Erector Spinae. This study concluded that reducing the load mass can increase the muscles performance which can extend the transition-to-fatigue stage in the left and right Biceps Brachii and Erector Spinae.

A Plug Assembly Line: An Assessment of Workstation Design and Working Posture

In most industry, assembly line job environments such as workstation design and working posture are factors contribute to workers’ performance. Workstation design such as: standing or sitting, the use of tools such as jig and the height of working table are influencing worker’s productivity. Meanwhile, working posture such as: position of body: arm and wrist, neck, trunk and leg determine comfortability and safe posture while working. These aspects also play a significant role in productivity.

Mismatch in Anthropometric Parameters of Malaysian Manufacturing Workers

The software Digital Enterprise Lean Manufacturing Interactive Application (DELMIA) is a virtual simulation software that was used in digital product manufacturing. In contrast with Computer Aided Three-dimensional Interactive Application (CATIA), DELMIA ergonomics feature is built with Human Task Simulation which can simulate the design workspace virtually. However, population available for the human manikin population are excluding Malaysian population. This study is aiming to investigate the gap and the error of anthropometry data in Malaysian manufacturing workers between the Japanese and American population in DELMIA V5R2016. A sample population of 241 people at manufacturing industries was taken in this study. The total number of anthropometric parameters used for experimentation are 100 parameters obtained from literature studies. The American and Japanese population are chosen to represent the Caucasian and Asian population for comparison of 15 randomly selected parameters of anthropometry. There are several mismatches found in the anthropometry parameter between the three comparisons of the population where the percentage of error and gap in between populations are more than 5%. In conclusion, this study recommended that future research increase the sample size of the anthropometry subjects for database comparison. For future research, it is recommended to use other methods available for measurement such as digital measurement for the anthropometry database to compare the accuracy with the traditional measuring method.

Mathematical Modelling of Biomechanics Factors for Push Activities in Manufacturing Industry

In manufacturing industries, many working tasks require their workers to perform the works in push-pull activities. The workers need to push or pull the tool or material handling in a long distance into a workplace and performing these activities continuously throughout the working hours, may lead to an early initiation of musculoskeletal disorders (MSDs) symptoms as workers developed muscle fatigue particularly concerning the hand muscles. Grip strength is the force applied by the hand to pull objects and is a part of hand strength. This paper is about the mathematical model of biomechanical factors that contributes to fatigue while worker involved on the push activities in manufacturing industry. The experimental was conducted by using Tekscan system to evaluate the muscle fatigue and hand grip pressure force while workers performing pushing excessive loads. The input parameters were time exposure, hand side and body mass index (BMI); while the output responses are muscle fatigue (voltage), hand grip pressure force (left hand), and hand grip pressure force (right hand). An important parameter that affects the output response is also identified. The finding result from mathematical model for both factors, show that the muscle fatigue was influenced by time exposure, hand side, BMI, and interaction between hand side and BMI; while hand grip pressure force was influenced by time exposure, hand side, BMI, interaction between time exposure and hand side, interaction between time exposure and BMI, and interaction between hand side and BMI.

Ergonomics Study of Working Postures in Manual Hand Layup Process

In composite manufacturing, hand layup is of the fabrication methods that is widely used. Composite is the basic material used in the manufacturing of products such as shipbuilding and the process requires manual handling. Currently, there is a significant number of absenteeism that due to low back pain, indicating that workers in manual composite manufacturing have problems related to musculoskeletal disorder (MSD). The objective of this paper is to study the working posture and discomforts experienced by workers in layup process station. A preliminary survey is conducted on 45 workers to obtain their experience of discomforts while working. Survey results show that 83.33% of the workers experience discomforts on the lower back of the body. When rating their level of pain on the lower back on a scale from 1 (lowest) to 5 (highest), 41% of them rated 4 on the level pain. Pain and discomforts lead to lower productivity of workers. Consequently, this can jeopardise the quality of the products. At the layup station, this problem arises due to the design of current workspace and the posture of workers when executing the job tasks. Rapid Upper Limb Analysis in CATIA V5R20 software was used to calculate the RULA scores. All postures had scored more than 6 that need further investigation and immediate change. Ergonomically designed layup workstations and good education on proper working posture will be able to improve the workers’ health conditions on the future.

Development of Ergonomic Vehicle Model and Decision Support System for Driving Fatigue

Driving fatigue has been recognized as one of the significant contributory factors to the road accidents and fatalities in Malaysia. The aim of this study was to develop an ergonomic vehicle model (EVM) and decision support system (DSSfDF) model for improving the driving fatigue problem among the road users. The ergonomic vehicle model uses to capture the user information data and acts as the database storage to store all the input data and information. While the decision support system provides a systematic analysis and solution to minimize the risk and the number of accidents associated with driving fatigue. There are 6 main components as the pillars for the development of EVM and DSSfDF model; ergonomics evaluation tools, graphical user interface (GUI), ergonomics database, working memory, inference engine, and knowledge base. Both models are essential system and reliable advisory tool for providing analysis on risk factors that contribute significantly to driving fatigue and providing solutions and recommendation to the problem related to driving fatigue. Further analysis and validation are required in future to get the reliable system before being commercialized.

Redesign Materials Handling System by Using Ergonomic Approaches to Reduce Back Pain Risk

This paper is about the redesign material handling device through the study of psychological and biomechanical factors that related the activities push and pull trolley. The project has been conducted in the automotive industry. Data about the problems encountered through a questionnaire among 14 workers Sat Receiving Area, since it has the highest number of ergonomic risk factors. The result shows the main problem is the existing trolley design seems not suitable and giving musculoskeletal disorder (MSD) of the workers especially back pain. Therefore, the aim of this paper is to redesign the materials handling system by using ergonomic approaches to reduce back pain. The Tekscan software will be used for evaluating hand pressure distribution force on the existing and alternatives trolley. Results obtained will be used as a benchmark for the concept of trolley to be redesigned. The Rapid Upper Limb Assessment (RULA) was applied to analyze the posture of workers on the existing and alternative trolley and redesign trolley to be proposed by ABC Company. Based on the RULA analysis, the redesigned trolley has improved the posture of the workers. Hence, this study concludes that considering ergonomic features for the redesigned trolley contributed to safe body posture.

A Preliminary Study of Body Discomforts of Hand Lay-up Process Workers in Composite Manufacturing

Low Back Pain (LBP) is one of the chronic diseases that have been correlated with musculoskeletal disorder or occupational disease when the process of manufacturing involves manual processes. Composite manufacturing especially requires skilled workers that can complete manual task primarily hand lay-up process in conjunction with composite fabrication methods. Lay-up process is one of the methods in fabricating composite. Mostly, parts of products using composite are enormous; such aircraft body, pools and ship body. This study aims to segregate potential respondents for ergonomics experimental specifically focusing on hand lay-up workers in a composite manufacturing facility. The study uses survey for 28 participants to identify the workers experience on the body discomfort while doing lay-up process activity. Out of sixteen activities in the lay-up process, results show that nine activities are suitable for postural analysis. However, for the preliminary study, only three selected postures which are the most frequent are analyzed. Rapid Upper Limb Analysis (RULA) in Computer-Aided Three-Dimensional Interactive Application (CATIA) V521 software shows RULA score that is above than 5. Hence, the study recommended that the experimentation stage will cover on body parts in upper and lower back of workers. Thus, the respondents for the next step of the research is determined based on their (Body Mass Index) BMI and experience on body discomforts that were obtained from the surveys.

Digraph Representations of Machine Vision Workspace for Monitoring Worker’s Behavior

If motions are repeated normally for every few seconds, and for prolonged periods about an 8-h shift, fatigue and muscle strain may occur. Suppose that we have a worker who is operating a machine. We need to monitor the worker’s behavior through real-time video streaming. Our challenge is to approximate the locations to place the tripods. We propose workspace geometry and workspace configuration so that, there is a proper methodology for designating the operator’s initial position, the machine position as the origin of the workspace. We deduce that, for a typical local manufacturing setting, there is a generalized workspace configuration usable for a wide-ranging machine operators’ height measurement. Implementing the proposed procedures, the camera placement is therefore defined by digraphs.