Reliability And Validity Of Virtual Build Methodology For Ergonomics Analyses

This study was conducted to assess the validity and reliability of the Virtual Build methodology for ergonomics design and analysis. Thirty-six human subjects participated in this study and performed a set of six tasks. The tasks were performed twice in both real and virtual environment. The subject?s motion in performing tasks was analyzed by ergonomics assessments by using Virtual Build methodology. Criteria-related validity was evaluated by comparing the Virtual Build ergonomic assessment results with manual calculation. Test-retest reliability was evaluated by correlating ergonomics assessment results between two trials. The result shows that the Virtual Build methodology is reliable for ergonomic assessments. 48 out of 51 reliability index scores are higher than 0.8. The Virtual Build with virtual environment has lower over-time reliability performance than the real environment. The t-test shows that the Virtual Build is valid for 1991 NIOSH lifting equation assessment when using real environment. Some improvements in enhancing human perception need to be done to make Virtual Build valid when using virtual environment

Digital manufacturing in fiat group automobiles: virtual simulations for preliminary ergonomics optimization of workcells in the design phase of a new car model

New standards on work organization in the automotive industry, require a new concept of design methods: the human centred process. In Fiat Group Automobiles (FGA) the “Digital Manufacturing” (DM) project has started with the goal to create simulation tools and methods to improve the design of new cars’manufacturing processes giving a special attention to manual operations. The DM approach is based on a detailed “virtual plant” where virtual mannequins interact with digital models of car’s components, equipment, containers, etc. in order to simulate and improve working conditions with many benefits on ergonomics, safety, final product quality, work organization and general production costs. The key factor for this approach is that with DM methodologies, designers and engineers have, already in the design phase of a new car’s manufacturing process, a preliminary estimation of the numerical indices used in the plants to check if workcells are compliant to international standards and regional safety laws. In this way the most important ergonomic indices (like Niosh, Snook & Ciriello, EAWS, etc.) become a “design tool” that allow to change/improve project solutions (designing easy and comfortable work tasks, equipment, tools, etc.) and to distribute the work load in an optimal way between workers

Comparative ergonomic workflow and user experience analysis of MRI versus fluoroscopy-guided vascular interventions:an iliac angioplasty exemplar case study

Purpose A methodological framework is introduced to assess and compare a conventional fluoroscopy protocol for peripheral angioplasty with a new magnetic resonant imaging (MRI)-guided protocol. Different scenarios were considered during interventions on a perfused arterial phantom with regard to time-based and cognitive task analysis, user experience and ergonomics. Methods Three clinicians with different expertise performed a total of 43 simulated common iliac angioplasties (9 fluoroscopic, 34 MRI-guided) in two blocks of sessions. Six different configurations for MRI guidance were tested in the first block. Four of them were evaluated in the second block and compared to the fluoroscopy protocol. Relevant stages’ durations were collected, and interventions were audio-visually recorded from different perspectives. A cued retrospective protocol analysis (CRPA) was undertaken, including personal interviews. In addition, ergonomic constraints in the MRI suite were evaluated. Results Significant differences were found when comparing the performance between MRI configurations versus fluoroscopy. Two configurations [with times of 8.56 (0.64) and 9.48 (1.13) min] led to reduce procedure time for MRI guidance, comparable to fluoroscopy [8.49 (0.75) min]. The CRPA pointed out the main influential factors for clinical procedure performance. The ergonomic analysis quantified musculoskeletal risks for interventional radiologists when utilising MRI. Several alternatives were suggested to prevent potential low-back injuries. Conclusions This work presents a step towards the implementation of efficient operational protocols for MRI-guided procedures based on an integral and multidisciplinary framework, applicable to the assessment of current vascular protocols. The use of first-user perspective raises the possibility of establishing new forms of clinical training and education

Applications and benefits of digital human models to improve the design of workcells in car’s manufacturing plants according to international standards

During last years, the car’s manufacturing process has deeply changed because of several factors affected the automotive global scenario. As a consequence, design methodologies of the plant’s workcells have changed. In particular, ergonomics for manufacturing system has become a key factor to improve product’s quality, safety and work organization. In this paper, the authors show the approach used in Fiat Group Automobiles (FGA) based on simulation tools to analyse ergonomic aspects of work-cells already in design phase. Simulation tools allow a deep postural analysis that is one of the main criticism in the design phase. The principles of Digital Human Modeling have been used to develop an easy internal virtual manikin, the Human Model. The tool, based on ISO standards and on a worldwide anthropometric database, allows designers to simulate the most probable postures engaged by operator during work tasks as well as to validate improvements and corrective actions

Development, application, and reliability of methods for ergonomic workload assessments in production evaluation and workstation design

Ergonomics assessments of conditions for humans at workstations and in manufacturing processes are necessary to prevent work-related musculoskeletal disorders and enhance efficiency and quality. Many methods can be used for this from systematic observations to direct measurements and simulation. Investigations of the accuracy and reliability of many methods as well as comparisons between them have been performed, but there is still need for further work as well as development of new methods.The inter- and intra-rater reliability of the OCRA checklist was studied through eleven ergonomists’ risk-assessments of ten video-recorded work tasks on two occasions. The statistical analysis included several parameters of reliability of which Cohen\u27s linearly weighted kappa was the primary measure. The inter-rater agreement of the OCRA checklist was 39%, and the weighted kappa was 0.43; the intra-rater dittos were 45% and 0.52. This indicated that the OCRA checklist is a moderately reliable tool.A risk assessment approach for digital human modelling (DHM) was developed. The approach included a reference database of epidemiological relationships between directly measured exposure and related musculoskeletal disorders. For illustration, a case in manual assembly was simulated; exposures were calculated and compared to the reference data to indicate the risk of WMSDs. The application and detailed assessment would be helpful to prioritise among different design solutions.A 3D digital prototype laparoscopic robotic console was ergonomically evaluated using the DHM tool IMMA with 12 manikins representing anthropometries of the Swedish and US population. Work-ranges of the console and the manikins were calculated, compared and ergonomically assessed using the Swedish standards and a US checklist for computer work. The assessment criteria related to the adjustable ranges of the screen height, height of the armrest, adjustable range of the pedals were not fulfilled. The DHM tool IMMA provides the possibility for a pre-production assessment of static work tasks

A possible revival of population-representing digital human manikins in static work situations - exemplified through an evaluation of a prototype console for robotic surgery

BACKGROUND: In the 90s, digital human manikins (DHMs) were introduced in planning ofworkstations, by static or semi-static simulations. Modern DHMs can simulate dynamic work and offer a rapid way for a virtual pre-production ergonomic evaluation. Work-related musculoskeletal disorders may affect surgical performance and patient safety. A prototype of an open console, which is contrary to the conventional closed consoles and may be seen as a representative for a new generation, has been designed to reduce workload for robotic surgery surgeons. OBJECTIVE: The aim of this project was to test a new DHM tool with improved usability to evaluate the ergonomics of a console of a robotic surgical system in a pre-production stage. METHODS: The DHM tool IMMA was used together with a 3D model of the prototype console. Twelve manikins who represented females and males from two national populations were introduced. Manikin-console distances, after console adjustments per manikin, were compared with a US checklist and Swedish standard for VDU work. RESULTS: The DHM tool was useful for this case, but the distances of the checklist and the standard were needed to be obtained "manually". The automatic functions of the DHM worked smoothly but were not optimized for VDU work. The prototype fulfilled most, but not all, of the ergonomic criteria of the checklist and the standard. CONCLUSIONS: There is room for improvements of the adjustable ranges of the console prototype. DHMs may facilitate rapid pre-production evaluation of workstations for static work; if ergonomic assessment models for VDU work are built-in, there may be a revival of DHMs in static work situations

Ergonomic Risk Assessment of Maintenance Workers in Educational Institute

Risks associated with ergonomics are pervasive groups that have crept into people\u27s daily lives. Ergonomic risks have been linked to long-term health effects like musculoskeletal disorders, cumulative trauma disorders, and lower back pain. Due to the limitations of their jobs, workers are most impacted by these repetitive, continuous labor activities. The main objective of this project is to provide a solution to the ergonomic problems that construction workers in the educational maintenance industry encounter. Based on the conditions, only a few jobs were identified, and samples were obtained by watching and asking people about their jobs. For tasks like plantation, rebar bending, material transportation, etc., the RULA and REBA method is used in this project. This study aims to investigate the ergonomic hazards experienced by educational maintenance construction workers

A more realistic digital human modelling (DHM) approach to manufacturing industry

Today’s globally competitive and challenging market place places demands on workers to perform at their best. Workers may have to struggle and maximize their efforts to meet the demands of modern manufacturing systems. Often, excessive workloads due to high production targets cause serious problems for the workers in the form of pain, injuries, fatigue, slips and falls. All these problems result in job dissatisfaction and the organization suffers from a loss in productivity and quality. In this globalized word, the diversity of organizations’ workforces is increasing with every passing year. In this context, it is challenging to propose suitable design solutions that can accommodate the maximum percentage of workers. Previously, Digital Human Modeling (DHM) tools have been successfully used for the assessment of design suitability at an earlier design phase. Now, there is a need to use these tools to identify mismatches between job demands and an individual’s capabilities for a more diversified workforce. This is especially so, as manufacturing assembly activities become very important as these still require a significant physical involvement of workers. A more realistic ‘design for all’ approach based on the actual working capabilities of individuals is considered helpful, so that better, safer and healthier workplaces for all workers might be assured. This can possibly lead to safer and more productive working environments where organizations gain benefits in terms of workforce satisfaction, improvement in productivity and quality of products

Can virtual reality predict body part discomfort and performance of people in realistic world for assembling tasks?

This paper presents our work on relationship of evaluation results between virtual environment (VE) and realistic environment (RE) for assembling tasks. Evaluation results consist of subjective results (BPD and RPE) and objective results (posture and physical performance). Same tasks were performed with same experimental configurations and evaluation results were measured in RE and VE respectively. Then these evaluation results were compared. Slight difference of posture between VE and RE was found but not great difference of effect on people according to conventional ergonomics posture assessment method. Correlation of BPD and performance results between VE and RE are found by linear regression method. Moreover, results of BPD, physical performance, and RPE in VE are higher than that in RE with significant difference. Furthermore, these results indicates that subjects feel more discomfort and fatigue in VE than RE because of additional effort required in VE

Anthropometric rigging for variable manikin appearance

DHM (Digital Human Modeling) tools have increasingly become a contributor to human factors engi-neering and user-centered design. Sources report however that little attention has been paid to the appear-ance of DHM virtual human models, i.e. manikins. Aspects of visual appearance have considerable im-pact on conveying beliefs and attitudes, something often used in industrial design to motivate solutions. This work aims to synthesis the need of correct anthropometric representation in DHM with the artistic freedom available in visual art industries and address the need of more humanlike appearances of manikins