Digital Human Modelling Tools Research Articles

ErgoReality: A Virtual Reality Simulations Software for Ergonomic Analysis of Workstation Design

Traditional tools for ergonomic assessments of workstation designs often involve ergonomists using Digital Human Modeling (DHM) software to simulate worker motions. However, these tools can be limited by posture prediction algorithms that fail to capture the full range and variability of human behavior. Virtual Reality (VR) offers an alternative by enabling workers to perform tasks within simulated workspaces, where their movements are captured using motion tracking systems. This approach generates kinematic data that can overcome the shortcomings of DHM tools, facilitating improved accuracy in the ergonomic evaluation of workstation design. Building multiple alternative virtual workstations is not only quicker but also more cost-effective than building physical prototypes. In this paper, we introduce a VR application, ErgoReality, and discuss its three main components: simulation development, data collection, and ergonomic analysis. We also explore further research areas to enhance the tool, address potential limitations, and propose strategies to mitigate these challenges.

SimMACT, a Software Demonstrator to Improve Maximum Actuation Joint Torques Simulation for Ergonomics Assessment.

The maximum actuation joint torques that operators can perform at the workplace are essential parameters for biomechanical risk assessment. However, workstation designers generally only have at their disposal the imprecise and sparse estimates of these quantities provided with digital manikin digital human model (DHM) software. For instance, such tools consider only static postures and ignore important specificities of the human musculoskeletal system such as interjoints couplings. To alleviate the weaknesses of existing approaches implemented in digital human modeling tools relying on torque databases, this paper describes a methodology based on a class of polytopes called zonotopes and musculoskeletal simulation to assess maximum actuation torques. It has two main advantages, the ability to estimate maximum joint torques for any posture and taking into account musculoskeletal specificities unlike existing digital human modeling tools. As a case study, it also compares simulated maximum actuation torques to those recorded during an experiment described in the literature, focusing on an isometric task of the upper limb. This simulation has led to similar or smaller errors than DHM software tools. Hence, this methodology may help in interpreting interjoint couplings, choosing appropriate mathematical models or design experimental protocols. It may also be implemented in DHM software to provide designers with more comprehensive and more reliable data.

Digital Human Modeling: A Review and Reappraisal of Origins, Present, and Expected Future Methods for Representing Humans Computationally

ABSTRACT The effective use of computational modeling and simulation tools early in the design process is arguably becoming a gold standard for modern product development. Compared to many mechanistic computational design approaches, modeling and simulating humans, due to their inherent complexities of physiological and cognitive attributes, provides one of the most challenging undertakings. With the rapidly expanding use of computer, sensor, and visualization technologies, digital human modeling (DHM) emerged as a computerized design support methodology that enables modeling and simulation of humans within a computer-aided design (CAD) or virtual environment (VE). Implementing DHM with physical or digital mockups brings the advantages of running various “what-if” design scenarios early in design; thus, enhancing concept generation efforts by filtering out infeasible ideas and exploring better design alternatives. A modern product development process with DHM can also help to reduce the overall cost and time required in the long run. Although several DHM software packages are available and many companies have been designing with DHM, the domain has not reached maturity in resolving theoretical research questions and fostering simulation-based ergonomics practice. Besides, the growing body of literature, software platforms, and technology integration makes it challenging for newcomers and specialists from disciplines other than human factors engineering (HFE) to recognize the power of DHM tools. This paper aims to provide a comprehensive review of the DHM domain and summarize the evolution, current status, and future trends of the DHM design support tools. We hope this review will provide a guideline for designers and serve as a roadmap for current and future researchers interested in DHM-related research to find out new venues and opportunities for further international collaborations.

Development and evaluation of an anthropometric module for digital human modelling systems

This paper presents the development of a software module and a graphical user interface which aims to support the definition of anthropometry of manikins in a digital human modelling (DHM) tool. The module is developed from user interviews and literature studies, as well as mathematical methods for anthropometric diversity consideration. The module has functionality to create both single manikins and manikin families, where it is possible to combine or analyse different population datasets simultaneously. The developed module and its interface have been evaluated via focus group interviews and usability tests by DHM tool users. Results from the studies show that the developed module and its interface has relevant functionality, fits well into industrial work processes, and is easy to use. The study also identifies possibilities to further increase usability.

Ergonomic risk assessment in DHM tools employing motion data - exposure calculation and comparison to epidemiological reference data

Digital human modelling (DHM) allows ergonomic risk assessment to be performed at early stages of design and development. Such assessment is typically based on observational methods, which do not take advantage of the potential of DHM tools to provide precise posture and motion data. This paper describes and illustrates an alternative assessment approach employing DHM tools, inspired by risk assessment based on direct measurements. A literature survey established a reference database of epidemiological associations between exposure and wrist-related disorders. This approach is illustrated by a DHM simulation of a car assembly task. Wrist posture and motion were simulated and compared to the database, predicting the prevalence of work-related musculoskeletal disorders on the basis of direct measurements.

On motion planning for narrow-clearance assemblies using virtual manikins

Digital Human Modeling (DHM) is an important tool to improve assembly ergonomics and thereby also productivity and product quality. State-of-art DHM tools can simulate challenging assembly operations by solving inverse kinematic problems so that the positions/orientations of the hands/feet of a manikin match some manually-specified targets. However, it is still difficult and time-consuming for a simulation engineer to perform an assembly with narrow insertion clearances by manually setting hand targets. We present a novel and highly automated approach that explores the 4D space (position of a fingertip plus pronation/supination of the arm) around an initial path for a sphere.

Multi-directional one-handed strength assessments using AnyBody Modeling Systems

Digital human modeling tools support proactive ergonomics in optimizing work tasks and workplace layouts. Empirical-statistical model based tools are often used to estimate the force exertion capability of the operators. This work is intended to serve as an initial probing into the usability of a musculoskeletal model based software, AnyBody Modeling Systems (AMS), in evaluating the force exertion capability at different points in the workspace and for various exertion directions. As a first step, it focuses on the modeling approach and the accuracy of one-handed isometric strength estimates of AMS. An existing literature database was used to compare the predicted strength at 8 hand locations and in 26 exertion directions, while simulating the empirical postures. The results show a correlation coefficient of 0.7 between the simulated and the experimental strength. AMS emphasizes the biomechanical advantages in strength due to the alignment of force exertion direction with the shoulder. Additionally, some discrepancies have been identified and discussed.

Digital human modelling over four decades

This paper aims to provide a retrospective of the use of a digital human modelling tool (SAMMIE) that was perhaps the first usable tool and is still active today. Relationships between digital human modelling and inclusive design, engineering design and ergonomics practice are discussed using examples from design studies using SAMMIE and government-funded research. Important issues such as accuracy of representation and handling multivariate rather than univariate evaluations are discussed together with methods of use in terms of defining end product users and tasks. Consideration is given to the use of the digital human modelling approach by non-ergonomists particularly with respect to understanding of the impact of human variability, jurisdiction and communication issues.

Creating and shaping the DHM tool IMMA for ergonomic product and production design

The history, status and outlook of the research and development actions associated with the creation of the digital human modelling tool intelligently moving manikins (IMMA) are described. The underlying fundamental concepts are described and research and development results so far are illustrated or referred to. Two case studies illustrating use of IMMA on industry-based problems are described. The paper also covers reflections on conceptions for prospective DHM tool developments from a general perspective, relating to areas of ergonomics and design methodology, as well as describing some of the plans for further developments and applications of the IMMA tool. These may be of assistance when identifying challenges for future research and development of DHM tools that are used in product and production design processes in industry.

Accommodation Levels for Ellipsoid Versus Cuboid Defined Boundary Cases

The definition and use of boundary cases is a common approach when aiming to anthropometrically accommodate a desired percentage of the targeted population by a design. The cases are defined based on anthropometric data that represents the targeted population. Approaches that define cases based on the variation within just one body measurement are poor for most design problems in representing anthropometric diversity. Hence, the consideration of variation within several body measurements is preferred. However, an approach that is based on performing several separate studies of the variation within a number of measurements leads to undesired reduction of accommodation due to the lack of consideration of the effects of correlations between measurements. This paper compares theoretical accommodation levels when using an ellipsoid versus a cuboid based approach for defining boundary cases to represent anthropometric variation within three body measurements. The ellipsoid approach considers correlations between body measurements whereas the cuboid approach does not consider correlations between body measurements. The paper suggests the application of the ellipsoid method for defining boundary cases for better reaching desired accommodation levels in boundary case based design problems. These cases can be used to define computer manikins when using digital human modelling tools. The method is also applicable when wishing to select extreme but representative real people to be involved in physical fitting trials.

Implementation of Suitable Comfort Model for Posture and Motion Prediction in DHM Supported Vehicle Design

Driver-vehicle interaction analyses are done to ensure a successful vehicle design from an ergonomics perspective. Digital Human Modelling (DHM) tools are often used to support such verifications, particularly at early stages of the product development process. When verifying that a vehicle design accommodates the diversity of users and tasks, a DHM tool needs to be able to represent postures and motions that are likely under certain conditions. This functionality is essential so that the tool user will obtain objective and repeatable simulation results. The DHM tool IMMA (Intelligently Moving Manikins) predicts postures and motions by using computational methods. This offers the possibility to generate postures and motions that are unique for the present design conditions. IMMA was originally developed for simulating manual assembly work, whereas the work presented here is a step towards utilizing the IMMA tool for occupant packaging and related tasks. The objective is a tool for virtual verification of driver-vehicle interaction that supports and automates the simulation work to a high degree. The prediction functionality in IMMA is based on the use of optimization algorithms where one important component is the consideration of comfort level. This paper reports results from an basic investigation of driving postures and available comfort models suitable in a driving context, and shows initial results of seated posture and motion prediction functionality in the IMMA tool.

Opportunities for meeting sustainability objectives

It is inevitable that theory and good practice in Human Factors/Ergonomics (HF/E) should comprise engineering for sustainability to safeguard ecology and maintaining the quality of life. There are immediate and longer-term opportunities for HF/E community to be a key contributor in solving sustainability issues. However, sustainability research in HF/E domain has only been partially explored. A further theoretical and practical contribution is needed. Digital Human Modeling (DHM) is a potential method to integrate human element into sustainability research. However, current DHM tools are limited in resolving these issues until sustainability objectives are explicitly considered. There are DHM tools available to evaluate human performance. However typically do not consider sustainability aspects of the work environment. This study introduces two conceptual digital ergonomics toolkits, Air Quality Index Assessment and Metabolic Energy Expenditure, to demonstrate the potential use of DHM in evaluating the health risks and worker's performance in work design. Incorporating human element into sustainability through DHM (digital ergonomics toolkits) reduces the need for in-situ human data collection and physical prototyping for work environments that are subject to poor air quality, toxic exposure and handling of hazardous materials. The DHM toolkits proposed in this study can bring attention towards building multidisciplinary collaboration that can enhance HF/E outreach goals in sustainability-related engineering design. Relevance to IndustryDHM can help industry to minimize the need of in-situ human data collection, reduce the need of physical prototyping, and optimize overall system performance for where subjects are exposed to poor air quality, toxic exposure, and handling of hazardous materials.

A cost-benefit ergonomics methodology applied to service industry with digital human modelling

Diverse authors have shown the influence and importance that ergonomics has on the optimisation and improvement of processes quality and management, and in company business strategies. This paper intends to show the advantages that can arise by joining an ergonomic project methodology with a continuous improvement procedure unified with a cost-benefit analysis with the help of digital human modelling (DHM) tools in any service industry. The aim of this study particularises this continuous improvement methodology in an industrial laundry workplace, identifying and analysing the work related musculoskeletal disorders with risk assessment methods together with 3D CAD design and DHM. It also performs a cost-benefit analysis as a systematic process, in order to continuously improve ergonomic design of existence or future workplaces. The implementation offered good results, obtaining safer and more efficient workplaces and therefore it can be assured that it can be extrapolated to different work scenarios.

From virtual reality to web-based multimedia maintenance manuals

This paper focuses on a structured methodology that uses virtual reality (VR) and digital human modeling (DHM) to study maintenance procedures of industrial products. VR technologies help to highlight the most critical aspects of maintenance operations, while DHM tools allow detailing working sequences. Data coming from these analyses are then used to draw up a multimedia maintenance manual based on digital video animations, audio comments, explanatory images and written recommendations. Information is available to maintenance personnel directly on the working site through portable electronic devices. Further, web-based multimedia manuals can be updated on-line and help to shorten learning time and maintenance downtimes.

Designing and Ergonomic Evaluation of a Shoe-Rack in CAD Environment

Most of the shoe racks available in market are required to be in tune with ergonomic criteria to enhance their usability. Keeping this fact in mind, an attempt was initiated to design an ergonomic multi-purpose shoe rack for a small family with 5-6 members of varying age group starting from kids to grandparents to suit present day apartment model residential dwellings. Following a small user survey and brain storming, it was decided that the intended design should be usable for all family members and all shoes in each rack to be visible for someone standing in front, easy to move, simplicity in use (taking shoes/socks, put on shoes, tying lace etc.), compact and aesthetically appealing. Protection from dust, availability of proper clearance dimensions and inclusion of safety aspects were also considered as added features. Following development of 3D-CAD model of desired shoe rack from concept sketching, various human factor aspects were evaluated in DELMIA software with digital manikins representing Indian anthropometric data to justify the design for Indian users. Present paper demonstrates virtual ergonomic evaluation process to confirm whether design of shoe rack would really be acceptable to targeted users and satisfy their need in real scenario. Readers are expected to visualize the simplicity of using digital human modeling tools for virtual ergonomic evaluations and thus advocate its use as and when required for diverse applications.

Digital test assembly of truck parts with the IMMA-tool - an illustrative case

Several digital human modelling (DHM) tools have been developed for simulation and visualisation of human postures and motions. In 2010 the DHM tool IMMA (Intelligently Moving Manikins) was introduced as a DHM tool that uses advanced path planning techniques to generate collision free and biomechanically acceptable motions for digital human models (as well as parts) in complex assembly situations. The aim of the paper is to illustrate how the IPS/IMMA tool is used at Scania CV AB in a digital test assembly process, and to compare the tool with other DHM tools on the market. The illustrated case of using the IMMA tool, here combined with the path planner tool IPS, indicates that the tool is promising. The major strengths of the tool are its user friendly interface, the motion generation algorithms, the batch simulation of manikins and the ergonomics assessment methods that consider time.

Description of boundary case methodology for anthropometric diversity consideration

This paper describes and evaluates the boundary case methodology for the simultaneous consideration of variance for a number of selected anthropometric variables. The methodology includes the calculation of key dimension values for extreme but likely anthropometric measurement combinations. This data can be applied when utilising digital human modelling (DHM) tools for proactive design work and entered as input data when representative manikins are defined. The mathematical procedure is clearly described and exemplified to demonstrate how to use the methodology in design work. The outcome of the method is illustrated and compared using several different cases where the number of measurements is varied and where principal component analysis (PCA) is used to reduce the number of dimensions in one case. The paper demonstrates that the proposed boundary case method is advantageous compared to approaches based on the use of univariate percentile data in design.

Digital Human Modeling Simulation Results and Their Outcomes in Reality: A Comparative Study within Manual Assembly of Automobiles

The objective of this study was to examine to what extent ergonomics simulations of manual assembly asks correctly predict the real outcomes in the plants and if recommended measures originating from ergonomics simulations are taken into consideration. 155 ergonomics simulation cases were used in the study and all cases were performed by nine simulation engineers at Volvo Car Corporation in Gothenburg. The evaluations of the ergonomics conditions of the simulated tasks were done by six professional ergonomists working at Volvo Car Corporation in Gothenburg. The results show that digital human modelling tools (DHM-tools) are useful for the purpose of providing designs for standing and unconstrained working postures. Furthermore, the design of various auxiliary devices and their needed space for movements is a prevalent use of DHM-tools. However, the study also identifies areas that require additional development in order to further improve the digital human modelling tools’ possibility to correctly predict a work task’s real outcome, i.e. hand access, push pressure and pull forces, leaning and balance behaviour and field of vision. Moreover, a better feedback of product and process changes and a more careful order description of simulation cases to the simulation engineers would lead to improved simulation results in current and future projects.

Digital human modelling for user-centred vehicle design and anthropometric analysis

Digital human modelling (DHM) is discussed as a design tool in the context of user-centred design, with a focus on DHM usage for anthropometric analysis in occupant packaging tasks in the vehicle interior design process. References are made to concepts of inclusive design, user-centred design, design cognition and design methodology. Examples are presented to illustrate how DHM can be of great use to the vehicle designer, but also to show some of the difficulties involved. This includes the complexity in considering anthropometric variation of the targeted product users in multivariate design problems, such as the design of vehicle interiors and suggestions on how to deal with this difficulty in an industrial design setting. Overall, the paper takes a designer's view of DHM tools and illustrates how the tools can be of value in the design process, but also considers what implications this has on the functionality and usability of the tools.

A comparative study of digital human modelling simulation results and their outcomes in reality: A case study within manual assembly of automobiles

The objective of this study was to examine to what extent ergonomics simulations of manual assembly tasks correctly predict the real outcomes in the plants and if recommended measures originating from ergonomics simulations are taken into consideration. 155 ergonomics simulation cases were used in the study and all cases were performed by nine simulation engineers at Volvo Car Corporation in Gothenburg. The evaluations of the ergonomics conditions of the simulated tasks were done by six professional ergonomists working at Volvo Car Corporation in Gothenburg. The results show that digital human modelling tools (DHM-tools) are useful for the purpose of providing designs for standing and unconstrained working postures. Furthermore, the design of various auxiliary devices and their needed space for movements is a prevalent use of DHM-tools. However, the study also identifies areas that require additional development in order to further improve the digital human modelling tools' possibility to correctly predict a work task's real outcome, i.e. hand access, push pressure and pull forces, leaning and balance behaviour and field of vision. Moreover, a better feedback of product and process changes and a more careful order description of simulation cases to the simulation engineers would lead to improved simulation results in current and future projects. Relevance to industry DHM-tools are increasingly the major means used to perform ergonomics analyses of manual assembly tasks in the automotive industry, but there is still a need for improvements of the tools. It is of great importance to disseminate end users' experiences of the use of different DHM-tools so these can be developed and applied in a more efficient way.