Industrial practitioner's perception on the application of exoskeleton system in automotive assembly industries: A Malaysian case study

The automotive industry is a key manufacturing industry for the Malaysian economy, where manual jobs and task are still common. Hence, Work-related Musculoskeletal Disorders (WMSD) is a common type of injury among workers. Exoskeleton system has gained global traction as a possible solution to reduce the risk of MSD among workers. Nonetheless, the application of exoskeleton in the automotive industry in Malaysia remains unknown. As such, this study attempts to provide insight into the industry's perception on the potential of exoskeleton application within the context of Malaysian automotive assembly sector. Therefore, a total of 52 management level respondents from various manufacturers participated in this study. It is found that, although the technology seems to be relatively new and disruptive, the respondents have a positive perception towards it with an acceptance rate of 86.5%. Cost of implementation exoskeleton technologies seems to be primary concern from the respondents, other concern such as maintenance cost and ease of application into existing application is also highlighted.

Design and Characterization of a Low-Cost and Efficient Torsional Spring for ES-RSEA

The design of torsional springs for series elastic actuators (SEAs) is challenging, especially when balancing good stiffness characteristics and efficient torque robustness. This study focuses on the design of a lightweight, low-cost, and compact torsional spring for use in the energy storage-rotary series elastic actuator (ES-RSEA) of a lumbar support exoskeleton. The exoskeleton is used as an assistive device to prevent lower back injuries. The torsion spring was designed following design for manufacturability (DFM) principles, focusing on minimal space and weight. The design process involved determining the potential topology and optimizing the selected topology parameters through the finite element method (FEM) to reduce equivalent stress. The prototype was made using a waterjet cutting process with a low-cost material (AISI-4140-alloy) and tested using a custom-made test rig. The results showed that the torsion spring had a linear torque-displacement relationship with 99% linearity, and the deviation between FEM simulation and experimental measurements was less than 2%. The torsion spring has a maximum torque capacity of 45.7 Nm and a 440 Nm/rad stiffness. The proposed torsion spring is a promising option for lumbar support exoskeletons and similar applications requiring low stiffness, low weight-to-torque ratio, and cost-effectiveness.

QFD-Based Research on Sustainable User Experience Optimization Design of Smart Home Products for the Elderly: A Case Study of Smart Refrigerators

In the current situation of global aging, the current market shortage of age-appropriate smart home products and the recent epidemic have led to greater isolation of the elderly, seriously affecting their physical and mental health. In order to optimize the sustainable user experience of the elderly when using smart home products, this paper proposes a research method based on Quality Function Deployment (QFD) for the optimal design of user experience of smart home products for the elderly, taking the design of age-appropriate home smart refrigerators as an example. Firstly, based on the results of market research and user interviews, the requirements of smart refrigerators for the elderly are screened and integrated, and the Kano model is used to prioritize these needs, resulting in the identification of important features needed in smart refrigerators for the elderly. Secondly, based on QFD, user requirements are transformed into design requirements, and a quality house model is established to ascertain the degree of importance of each design requirement through user ratings so as to obtain the key requirements as the theoretical basis for the solution design. Finally, optional solutions are generated for concept evaluation based on PUGH concept selection, comparing the advantages and disadvantages of the solutions and recombining them into an evaluation to determine the best solution. The quantitative evaluation of the four solutions reveals that Solution A has the highest score of 117.358, followed by Solution D with 113.259, Solution B with 96.415, and Solution C with 85.511, which is the lowest. The scoring allows the best design solution to be selected and applied to product development. The results show that the introduction of the Kano model and PUGH concept selection into QFD can be effectively used as a research method for optimizing the user experience of smart refrigerators for the elderly, and a corresponding design strategy for sustainable user experience optimization is proposed. The method and strategy provide guidance for the innovative design of new smart home products.

Design and Shape Optimization of Strain Gauge Load Cell for Axial Force Measurement for Test Benches

The load cell is an indispensable component of many engineering machinery and industrial automation for measuring and sensing force and torque. This paper describes the design and analysis of the strain gauge load cell, from the conceptional design stage to shape optimization (based on the finite element method (FEM) technique) and calibration, providing ample load capacity with low-cost material (aluminum 6061) and highly accurate force measurement. The amplifier circuit of the half Wheatstone bridge configuration with two strain gauges was implemented experimentally with an actual load cell prototype. The calibration test was conducted to evaluate the load cell characteristics and derive the governing equation for sensing the unknown load depending on the measured output voltage. The measured sensitivity of the load cell is approximately 15 mV/N and 446.8 µV/V at a maximum applied load of 30 kg. The findings are supported by FEM results and experiments with an acceptable percentage of errors, which revealed an overall error of 6% in the worst situation. Therefore, the proposed load cell meets the design considerations for axial force measurement for the laboratory test bench, which has a light weight of 20 g and a maximum axial force capacity of 300 N with good sensor characteristics.

Physical ergonomics awareness in an offshore processing platform among Malaysian oil and gas workers

Introduction. The reliability of offshore oil and gas (O&G) facilities depends on the operation and maintenance activities, where human physical intervention is involved. Workers are often exposed to ergonomics hazards due to inefficient workplace design. Ergonomics awareness among workers is a crucial factor in mitigating such hazards. Objectives. This study intends to evaluate the state of physical ergonomics awareness among Malaysian O&G workers and to assess their perception toward the criticality of physical ergonomics issues within an offshore processing facility. Methods. Data were collected through online questionnaire distribution. The respondents were required to evaluate three sections of the questionnaire to reflect their state of physical ergonomics awareness: design criteria in an offshore workplace that are related to physical ergonomics; effects of physical ergonomics implementation in design; criticality of physical ergonomics issues. Results. The results showed a good level of physical ergonomics awareness among respondents without them being influenced by dissimilar experiences (engineering design and operation/maintenance) and the range of experience in an offshore workplace. Conclusion. This study provides an overview of Malaysian O&G workers' outlook toward the physical ergonomics issues in an offshore workplace. These data could be further analyzed in future as relevant aspects of designing an offshore facility.

Exoskeleton robot control for synchronous walking assistance in repetitive manual handling works based on dual unscented Kalman filter

Prolong walking is a notable risk factor for work-related lower-limb disorders (WRLLD) in industries such as agriculture, construction, service profession, healthcare and retail works. It is one of the common causes of lower limb fatigue or muscular exhaustion leading to poor balance and fall. Exoskeleton technology is seen as a modern strategy to assist worker’s in these professions to minimize or eliminate the risk of WRLLDs. Exoskeleton has potentials to benefit workers in prolong walking (amongst others) by augmenting their strength, increasing their endurance, and minimizing high muscular activation, resulting in overall work efficiency and productivity. Controlling exoskeleton to achieve this purpose for able-bodied personnel without impeding their natural movement is, however, challenging. In this study, we propose a control strategy that integrates a Dual Unscented Kalman Filter (DUKF) for trajectory generation/prediction of the spatio-temporal features of human walking (i.e. joint position, and velocity, and acceleration) and an impedance cum supervisory controller to enable the exoskeleton to follow this trajectory to synchronize with the human walking. Experiment is conducted with four subjects carrying a load and walking at their normal speed- a typical scenario in industries. EMG signals taken at two muscles: Right Vastus Intermedius (on the thigh) and Right Gastrocnemius (on the calf) indicated reduction in muscular activation during the experiment. The results also show the ability of the control system to predict spatio-temporal features of the pilots’ walking and to enable the exoskeleton to move in concert with the pilot.

The impact of sustainable manufacturing practices on sustainability performance

Purpose

Sustainable manufacturing practices are one of the significant environmental initiatives taken by manufacturing industries to preserve the environment and improve the quality of human life while performing manufacturing activities. The emergence of the value creation concept, economic value no longer counts as a single factor for measuring manufacturing performance. Within the sustainability context, the impact of manufacturing activities on the environmental and social aspects should be taken into account as the basis for assessing manufacturing performance, which is called sustainability performance. The purpose of this paper is to examine the relationship of sustainable manufacturing practices with sustainability performance, which considers the environmental, economic and social aspects.

Design/methodology/approach

A questionnaire survey is carried out among 443 ISO 14001 certified manufacturing companies in Malaysia. Structural equation modelling is used to evaluate the relationship of sustainable manufacturing practices with sustainability performance.

Findings

The findings of this study indicate that manufacturing process is the manufacturing stage that gives the most impact on the improvement of sustainability performance. Hence, it is concluded that manufacturing companies in Malaysia are highly focussed on the production bound when implementing sustainable manufacturing practices.

Research limitations/implications

Although this study indicates a good estimation of the proposed model, additional variables might be added to improve the prediction strength of the proposed model such as considering type of industries, economic scale or ownership. Adding the comparison of sustainable manufacturing practices between different countries also a valuable research to investigated.

Practical implications

The framework proposed here can also assist manufacturing industries to conduct sustainability assessments by providing elements of sustainability performance and can serve as a guideline to select appropriate sustainable manufacturing practices and to what level the practices need to be improved to leverage companies’ sustainability performance.

Originality/value

The framework proposed here can also assist manufacturing industries to conduct sustainability assessments by providing elements of sustainability performance and can serve as a guideline to select appropriate sustainable manufacturing practices and to what level the practices need to be improved to leverage companies’ sustainability performance.

Investigation of the head impact power of a Sepak Takraw ball on Sepak Takraw Players

<p><em>Sepak takraw</em> is a traditional sport in Asia in which the players use various parts of their bodies to hit the ball, with the exception of their hands. Unlike other sports such as soccer, boxing, and rugby, it is observed that none of the studies in the literature have examined the injuries resulting from the impact of the <em>sepak takraw</em> ball on the players’ heads during a game. This study was initiated following the incidents of the 24^th SEA Games in Korat, Thailand, in year 2007, whereby a number of players from the Malaysian Sepak Takraw Association (PSM) had to withdraw themselves from the championship. These players suffered from headaches which were believed to be caused by the impact of the <em>sepak takraw</em> ball, considering the fact that heading is one of the basic movements used to hit the ball. Moreover, it is expected that the <em>sepak takraw</em> ball travels at high velocities during the game. Hence, the objective of this study is to investigate the impact of the <em>sepak takraw</em> ball and its corresponding level of head injury among <em>sepak takraw</em> players in Malaysia by means of numerical simulations and experiments. In order to achieve this objective, a model of the scalp, skull, cerebrospinal fluid and brain is first developed and simulations are then carried out using finite element analysis (FEA) software. The results show that the maximum speed of the <em>sepak takraw</em> ball before heading is 13.581 m/s while the maximum impact force on the head obtained from the simulations is 688.11 N. The maximum displacement and maximum linear acceleration of the brain’s centre of gravity is found to be 0.0080 m and 1674.5 m/s², respectively, while the head impact power (HIP) is determined to be 11.366 kW. According to Newman et al. (2000), the probability of concussion is 39% and based on the results obtained in this study, it can be concluded that the players may suffer from mild traumatic brain injuries (MTBI) due to the high impact of the <em>sepak takraw</em> ball during heading. Hence, it is recommended that the players wear protective headbands to reduce the impact during heading and prevent the occurrence of MTBI in the long term.</p>

A fuzzy controller for lower limb exoskeletons during sit-to-stand and stand-to-sit movement using wearable sensors

Human motion is a daily and rhythmic activity. The exoskeleton concept is a very positive scientific approach for human rehabilitation in case of lower limb impairment. Although the exoskeleton shows potential, it is not yet applied extensively in clinical rehabilitation. In this research, a fuzzy based control algorithm is proposed for lower limb exoskeletons during sit-to-stand and stand-to-sit movements. Surface electromyograms (EMGs) are acquired from the vastus lateralis muscle using a wearable EMG sensor. The resultant acceleration angle along the z-axis is determined from a kinematics sensor. Twenty volunteers were chosen to perform the experiments. The whole experiment was accomplished in two phases. In the first phase, acceleration angles and EMG data were acquired from the volunteers during both sit-to-stand and stand-to-sit motions. During sit-to-stand movements, the average acceleration angle at activation was 11°-48° and the EMG varied from -0.19 mV to +0.19 mV. On the other hand, during stand-to-sit movements, the average acceleration angle was found to be 57.5°-108° at the activation point and the EMG varied from -0.32 mV to +0.32 mV. In the second phase, a fuzzy controller was designed from the experimental data. The controller was tested and validated with both offline and real time data using LabVIEW.