A Review on Ergonomics Factors Determining Working in Harmony with Exoskeletons

@#Exoskeletons are wearable devices that can enhance human strength and are used in various fields, such as healthcare and the manufacturing industry. However, poorly designed exoskeletons can strain the muscles and cause injuries to users. The objectives of this review paper are to review the ergonomics factors that contribute to a harmonious user-exoskeleton interaction and to explore the current trends, challenges, and future directions for developing ergonomically designed exoskeletons. In this review, 102 relevant papers published from 2015 to 2023 were retrieved from Web of Science, Scopus, and Google Scholar. These papers were considered in the analysis for gathering relevant information on the topic. The authors identified six ergonomics factors, namely kinematic compatibility, contact pressure, postural control, metabolic cost, cognitive workload, as well as task demands and workplace conditions, that can influence the interaction between users and exoskeletons. By understanding and addressing these ergonomics factors during the design and development process, exoskeleton designers can enhance the user experience and adoption of the devices in daily living activities and industrial applications.

Elbow-Height Handle and Staggered Stance Exhibited Greatest Force in Pushing and Pulling: A Study among Malaysian Adults

@#Introduction: Pushing and pulling activities are common in daily life and industrial workplaces. These activities are potentially contributing to muscle fatigue in the back and shoulder if not managed ergonomically. Therefore, this study aimed to quantify the maximum strength of Malaysian adults in horizontal symmetrical two-handed pushing and pulling with different handle heights and stances. Methods: Forty-seven participants of 24 males and 23 females were recruited in pushing and pulling experiments. The participants were assistant engineers and postgraduate students of a technical university. The dependent variable was the magnitude of push/ pull force. The independent variables consisted of action, handle height and stances. The experimental design was set for 2 actions, 3 handle heights and 2 stances, yielding 12 variables combinations. Results: Key findings of this study revealed that combination of pull action, handle height at elbow level and staggered stance exhibited greatest force. On the contrary, combination of push action, handle height at knuckle level and parallel stance resulted in lowest force. In pushing test, both male and female participants obtained greatest force of 233.3 N and 121.7 N, respectively, when the handle height was at elbow level and staggered stance. Similarly, in pulling test, males and females obtained highest force of 242.9 N and 152.4 N, respectively. Conclusion: This study concluded that handle height at elbow level and staggered stance exhibited greatest force in pushing and pulling activities. This study provides information to individuals who involved in pushing and pulling tasks with least force exertion to minimize muscle fatigue in the back and shoulder. Future studies should consider the following recommendations: 1) Participants of study should involve manufacturing industry workers. 2) To study the effect of pushing and pulling tasks on muscle activity.

Design and Development of an Ergonomic Trolley-Lifter for Sheet Metal Handling Task: A Preliminary Study

BACKGROUND: There have been some concerns related to manual handling of large items in industry. Manual handling operations of large sheet metal may expose workers to risks related to efficiency as well as occupational safety and health. Large sheet metals are difficult to move and burdensome to lift/transfer, and handling the sharp sheet edges may result in contact stress and/or cut injuries on the workers. METHODS: Through observation, interview, and immersive simulation activities, a few problems related to current handling of sheet metals were identified. A sheet metal trolley-lifter was then designed and fabricated to address these issues. A pilot study on the use of the developed trolley-lifter for handling sheet metals was conducted to compare between the new and traditional handling methods. RESULTS: The pilot study of the trolley-lifter showed promising results in terms of improving the cycle time, manpower utilization, and working postures compared with the traditional handling method. CONCLUSION: The trolley-lifter offers an alternative solution to automation and a mechanized assistive device by providing a simple mechanism to assist the handling of sheet metals effectively and safely.

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.

Assessment of Muscle Fatigue Associated with Prolonged Standing in the Workplace

OBJECTIVES: The objectives of this study were to determine the psychological fatigue and analyze muscle activity of production workers who are performing processes jobs while standing for prolonged time periods. METHODS: The psychological fatigue experienced by the workers was obtained through questionnaire surveys. Meanwhile, muscle activity has been analyzed using surface electromyography (sEMG) measurement. Lower extremities muscles include: erector spinae, tibialis anterior, and gastrocnemius were concurrently measured for more than five hours of standing. Twenty male production workers in a metal stamping company participated as subjects in this study. The subjects were required to undergo questionnaire surveys and sEMG measurement. RESULTS: Results of the questionnaire surveys found that all subjects experienced psychological fatigue due to prolonged standing jobs. Similarly, muscle fatigue has been identified through sEMG measurement. Based on the non-parametric statistical test using the Spearman's rank order correlation, the left erector spinae obtained a moderate positive correlation and statistically significant (rs = 0.552, p < 0.05) between the results of questionnaire surveys and sEMG measurement. CONCLUSION: Based on this study, the authors concluded that prolonged standing was contributed to psychological fatigue and to muscle fatigue among the production workers.