Improving digital human modelling for proactive ergonomics in design

This paper presents the need to improve existing digital human models (DHMs) so they are better able to serve as effective ergonomics analysis and design tools. Existing DHMs are meant to be used by a designer early in a product development process when attempting to improve the physical design of vehicle interiors and manufacturing workplaces. The emphasis in this paper is placed on developing future DHMs that include valid posture and motion prediction models for various populations. It is argued that existing posture and motion prediction models now used in DHMs must be changed to become based on real motion data to assure validity for complex dynamic task simulations. It is further speculated that if valid human posture and motion prediction models are developed and used, these can be combined with psychophysical and biomechanical models to provide a much greater understanding of dynamic human performance and population specific limitations and that these new DHM models will ultimately provide a powerful ergonomics design tool.     

Improving digital human modelling for proactive ergonomics in design

This paper presents the need to improve existing digital human models (DHMs) so they are better able to serve as effective ergonomics analysis and design tools. Existing DHMs are meant to be used by a designer early in a product development process when attempting to improve the physical design of vehicle interiors and manufacturing workplaces. The emphasis in this paper is placed on developing future DHMs that include valid posture and motion prediction models for various populations. It is argued that existing posture and motion prediction models now used in DHMs must be changed to become based on real motion data to assure validity for complex dynamic task simulations. It is further speculated that if valid human posture and motion prediction models are developed and used, these can be combined with psychophysical and biomechanical models to provide a much greater understanding of dynamic human performance and population specific limitations and that these new DHM models will ultimately provide a powerful ergonomics design tool.     

Development of a digital human model generation method for ergonomic design in virtual environment

A group of digital human models (DHMs) representing the target population under consideration is used to design products and workplaces in virtual environment. The present study proposes a two-step method which generates a group of DHMs in various sizes to properly accommodate the designated level of the human size variability of the target population. In the first step, a designated number of pairs of stature and weight within a specified accommodation range are generated from the bivariate normal distribution of stature and weight of the target population. In the second step, for each pair of stature and weight, the sizes of the DHM body segments are determined using hierarchical regression models and corresponding prediction distributions of individual values. The proposed generation method was applied to the 1988 US Army anthropometric survey data and then implemented to a web-based system for passenger car interior design. This web-based generation system is capable of generating a group of DHMs as nationality, gender, accommodation percentage, and the number of DHMs required is specified.

Relevance to industry

A digital human simulation system has been used as an effective tool for ergonomic design and evaluation of products and workplaces in virtual environment. The human model generation method proposed in the present study is of use to efficiently generate a group of human models representing the target population.     

人机设计中的虚拟人仿真技术研究

虚拟人是产品人机设计中的有效辅助手段,是计算机辅助人机设计的基础。本文分析了虚拟人研究现状,提出了基于H-anim标准的虚拟人仿真。根据H-anim定义的关节骨架模型,实现了人体的几何建模和关节动画仿真,利用STEP语言,在语义层次实现对虚拟人的交互控制。最后介绍了利用虚拟人的计算机辅助人机设计系统。     

Standardisation of digital human models

Digital human models (DHM) have evolved as useful tools for ergonomic workplace design and product development, and found in various industries and education. DHM systems which dominate the market were developed for specific purposes and differ significantly, which is not only reflected in non-compatible results of DHM simulations, but also provoking misunderstanding of how DHM simulations relate to real world problems. While DHM developers are restricted by uncertainty about the user need and lack of model data related standards, users are confined to one specific product and cannot exchange results, or upgrade to another DHM system, as their previous results would be rendered worthless. Furthermore, origin and validity of anthropometric and biomechanical data is not transparent to the user. The lack of standardisation in DHM systems has become a major roadblock in further system development, affecting all stakeholders in the DHM industry. Evidently, a framework for standardising digital human models is necessary to overcome current obstructions. Practitioner Summary: This short communication addresses a standardisation issue for digital human models, which has been addressed at the International Ergonomics Association Technical Committee for Human Simulation and Virtual Environments. It is the outcome of a workshop at the DHM 2011 symposium in Lyon, which concluded steps towards DHM standardisation that need to be taken.     

一种基于国标人体测量学数据的虚拟人建模方法

针对目前利用国标人体测量学数据构建的虚拟人模型,只有单一的骨骼层或皮肤层,不便于同时对虚拟人进行实时运动控制和皮肤动态变形研究的问题,提出一种利用GB 10000-88的19个人体测量学特征数据、用3ds max构造出虚拟人的皮肤网格、层级建模方法构建出虚拟人的骨骼关节运动模型与四元数球面混合插值技术相结合的虚拟人建模方法。实验结果表明,该方法构建的虚拟人双层模型有利于对准确的国标人体测量学数据的虚拟人角色进行建模、皮肤逼真变形、实时运动仿真和人机工效学分析。     

Interior layout design of passenger vehicles with RAMSIS

The interior of passenger vehicles and the adapting of interior components to the human body are designed with historical guidelines, based on the experiences of the manufacturer. In contrast to this, the aim of the following study is to create a consistent and theoretically justified procedure to design the interior layout. Using the advantages of virtual design, this will be done with the software tool RAMSIS from scratch. First, four theoretical seating concepts are generated, each fixing one point of the human body (eye point, H‐point, hand point, or heel point) at fixed coordinates for all anthropometric types. Then, the most practical concept is applied together with the geometry of a given vehicle. To generate a realistic and ergonomic seating concept, studies are made concerning the posture of legs and feet in relation to the pedals of the vehicle. The result is a final seating concept with fields of adjustment for seat and steering wheel. © 2005 Wiley Periodicals, Inc. Hum Factors Man 15: 197–212, 2005.     

一种可编辑的三维人体蒙皮网格动画合成方法*

为了使虚拟人情感表达更加逼真,提出了一种可编辑的三维人体动画合成方法。首先建立了三维网格和人体骨架之间的蒙皮关系,构造了关节运动角度的参数模型;然后,对三维人体骨架进行操作,利用线性混合蒙皮算法,驱动虚拟人体的运动。在Visual C++平台上实现了在特定情感状态下的肢体动画,验证了该方法的有效性。     

Ergonomics risk assessment with digital human models in car assembly: Simulation versus real life

This study investigated how well ergonomics risk assessments on simulations with digital human models (DHM) match real‐life assessments obtained on a car assembly line. Two ergonomists evaluated 20 work tasks in real life and as a DHM simulation using a company‐specific version of the Automotive Assembly Worksheet (AAWS) for assessing static postures, action forces, manual material handling, and extra strains. Results demonstrate that DHM simulations provide good estimations of the workload in real‐life tasks. Additionally, significant correlations were found between AAWS risk assessments and subjectively perceived exertion measured on the Borg scale. Yet, there were also some significant differences in AAWS risk classification and AAWS total scores. DHM simulations appear helpful for reliably detecting static postures and extra strains, whereas action forces are harder to estimate than in real life. It is suggested that comprehensive methods such as AAWS should be incorporated in DHM software for enhancing efficiency and validity of digital ergonomics risk assessment. © 2010 Wiley Periodicals, Inc.     

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.     

Integrated Framework for Vehicle Interior Design Using Digital Human Model

Evaluating the human friendliness of vehicles is essential for designing new vehicles since large numbers of human-machine interactions occur frequently inside vehicles. In this research, we develop an integrated framework for vehicle interior design using a digital human model (DHM). In this framework, the knowledge-based parametric modelling function of vehicles is implemented using a commercial computer-aided design (CAD) system. The combination of the DHM and the CAD system enables designers into carry out ergonomic evaluations of various human-vehicle interactions and understand the effects of modifications of vehicle design parameters on occupants during designing. Further, the information on human-vehicle interaction obtained using this system can be transmitted to dedicated biomechanical analysis software. By analysing human motions inside vehicles using such software, we can obtain optimized interior design parameters.     

Two-dimensional manikins of children - models for design

The paper discusses anthropometric research for design for children and youth. Two-dimensional dimensional manikins are one of the forms of presenting anthropometric data. Manikins of children aged 1-6 are the object of the paper. The set consists of eight plexiglass models scaled 1:5. The models were prepared with regard to 5th and 95th percentile values and two views - i e, side view when the figure is in the sagittal plane, and top view when the figure is in the transverse plane. the models are used in design and ergonomics assessment of products including equipment and furnishings earmarked for children.     

Three‐dimensional analysis of a driver‐passenger vehicle interface

This article presents a method of analyzing how drivers' anthropometric data are best accommodated by a specific driver‐vehicle interface. Three‐dimensional (3‐D) manikins with 18 links were developed using anthropometric data for the U.S. 95th percentile male and 5th percentile female. In addition, an adjustable seating buck was constructed to control 7 package variables. After the manikins were positioned in each driving environment, 3‐D Cartesian coordinates for the manikins' articulations were determined using a coordinate measuring machine. The data were then converted into joint angles to suggest suitable driving environments that consider appropriate driving postures. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 269–284, 2004.     

一种具有逼真效果的虚拟人动画生成方法

针对传统的虚拟人动画逼真度低、动画生成复杂、且动画存在飘移现象的问题,提出了一种基于视频关键帧获取运动数据的虚拟人动画生成方法。首先利用线性混合蒙皮算法建立了新的人体几何模型;其次利用正向运动学方法驱动虚拟人的骨骼模型,并利用平移补偿原则消除虚拟人运动中的飘移现象;最终实现了基于双目正交视觉获取关节运动参数的虚拟人动画。实验结果表明,新方法能逼真地模拟真实人体动作,且方法易于实现、实用性强。     

Calculation and visualization of the dynamic ability of the human body

There is a great demand for data on the mobility and strength capability of the human body in many areas, such as ergonomics, medical engineering, biomechanical engineering, computer graphics (CG) and virtual reality (VR). This paper proposes a new method that enables the calculation of the maximal force exertable and acceleration performable by a human body during arbitrary motion. A musculoskeletal model of the legs is used for the calculation. Using our algorithm, it is possible to evaluate whether a given posture or motion is a feasible one. A tool to visualize the calculated maximal feasibility of each posture is developed. The obtained results can be used as criteria of manipulability or strength capability of the human body, important in ergonomics and human animation. Since our model is muscle‐based, it is possible to simulate and visualize biomechanical effects such as fatigue and muscle training. The solution is based on linear programming and the results can be obtained in real time. Copyright © 1999 John Wiley & Sons, Ltd.     

Mismatch between classroom furniture and anthropometric measures of university students

The appropriate design of tools, equipment and accessories for human body sizes, while meeting the social, cultural, economic and psychological needs of people, provides maximum benefit. This is crucial for students who spend most of their time using school furniture. The aim of the study is to investigate the mismatch between school furniture dimensions and students’ anthropometric measures. Nine anthropometric measures were taken of 225 students (68 female and 157 male) from nine departments of an engineering faculty using a specially designed measurement tool. The mismatch percentages between the existing classroom furniture dimensions and the anthropometric measures were determined using some well-known criterion equations. The results indicated a considerable mismatch: 44.45% for seat height, 100% for seat depth, and 21.28% for desk height. Two types of proposed classroom furniture achieved much higher percentage matches. The match percentages were above 70% for four dimensions for type A and above 95%, except for seat height and width of backrest, for all of the dimensions for both types.Relevance to industryThis study helps in establishing and motivating necessary further studies in classroom ergonomics in university settings.     

Ted Megaw: an appreciation

Driver workspace design and evaluation is, in part, based on assumed driving postures of users and determines several ergonomic aspects of a vehicle, such as reach, visibility and postural comfort. Accurately predicting and specifying standard driving postures, hence, are necessary to improve the ergonomic quality of the driver workspace. In this study, a statistical clustering approach was employed to reduce driving posture simulation/prediction errors, assuming that drivers use several distinct postural strategies when interacting with automobiles. 2-D driving postures, described by 16 joint angles, were obtained from 38 participants with diverse demographics (age, gender) and anthropometrics (stature, body mass) and in two vehicle classes (sedans and SUVs). Based on the proximity of joint angle sets, cluster analysis yielded three predominant postural strategies in each vehicle class (i.e. ‘lower limb flexed’, ‘upper limb flexed’ and ‘extended’). Mean angular differences between clusters ranged from 3.8 to 52.4° for the majority of joints, supporting the practical relevance of the distinct clusters. The existence of such postural strategies should be considered when utilising digital human models (DHMs) to enhance and evaluate driver workspace design ergonomically and proactively.

Statement of Relevance: This study identified drivers' distinct postural strategies, based on actual drivers' behaviours. Such strategies can facilitate accurate positioning of DHMs and hence help design ergonomic driver workspaces.