RESNA 28th Annual Conference - Atlanta, Georgia
Gavin R. Jenkins, MA, ATP, OTR
Despite recent changes in legislation, poorly designed environments and products continue to proliferate and exclude the needs of disabled and elderly people. Designers need to have an in-depth knowledge of human functioning if they are to create and sustain environments and products that allow disabled and elderly people to lead full and productive lives. Anthropometry has traditionally been seen as the means by which this information can be made available, although its ability to accurately characterise human function is limited. This work aims to develop characterisations of people with impaired function using human motion analysis for the development of Digital Human Models for use by designers and clinicians.
This paper reports on an innovative method, which involves the integration of Digital Human Models with 3D visualisations of products and living spaces, allowing real-time simulation and interaction; testing a product or environment’s performance prior to construction and therefore avoiding the need for expensive ‘mock ups’.
human motion, digital human models, disability, elderly, environment, design
The social model of disability has undoubtedly been the dominant paradigm in researching and understanding disability in recent years. Since being conceived and refined in the 1980s it has become increasingly influential as an alternative to the traditional model of disability as a personal medical tragedy.(1) The social model of disability is based on the principle that disability is a denial of civil rights caused by the exclusion of disabled people in all facets of society – redefining disability in terms of a disabling environment, repositioning disabled people as citizens with rights and reconfiguring the responsibilities for creating, sustaining and overcoming disablism. This paradigm demedicalises disability and presents it as a social issue about universal rights.
Pivotal to this is the extent to which the environment oppresses people by neglecting their needs. During the past few decades accessibility has become a major issue because of the political influence of growing numbers of elderly people and more positive attitudes to disability in general.(2) Demographic information indicates that the population of developed countries is aging and Gant draws attention to the increasing prevalence of disability associated with an ageing population.(3) Discounting social responsibility, in purely commercial terms it is crucial that those involved in forming and shaping our environments and products ensure that they are suitable for older and disabled users.(4)
There is an urgent need to incorporate all end-users in the design process to ensure that environments and products are designed in such a way that they are easy, convenient and safe to use. If designers could create products and environments that are within the functional abilities of the elderly and disabled people then they could use them easily, effectively and more safely. Moreover if such products are usable by disabled people then they would also meet the requirements of non-disabled people.
Despite some developments and exceptions, inadequately or poorly designed environments and products continue to impose barriers to disabled and elderly people. In order to create and sustain environments and products that are inclusive for all, designers need to understand human functioning in the performance of tasks. They require an understanding and useful characterisation of the functionality of disabled people so that these parameters can be incorporated into a modern design process.
Anthropometry data sets are one way of bringing the physical dimensions of users into the design process. However there are limitations that data presented in this way has for designers, for example the mode of presentation, primarily as tables and lists, which require reading and interpretation and the lack of holistic information, such as task specific behaviours and environmental factors.(5) In addition, data handbooks, such as Architects Data,(6) provide design guidelines based on anthropometric data which, often, neglects the specific characteristics and needs of disabled people.
A further limitation of anthropometry data is that the information sources are often fragmented, making it difficult for the user to locate and compile relevant data.(7) The most comprehensive anthropometric studies are focussed on non-disabled adults, with much of the data originating from military personnel. Studies that include children, elderly people and disabled people are scarce and generally involve much smaller sample populations with fewer measurements, despite the fact that the physical characteristics of these groups are very different.(8)
Steinfield states that anthropometry leaves some significant gaps in our knowledge about how disabled people interact with the environment and products. While anthropometric research focuses on measuring body dimensions (structural measurements) and general human performance abilities (functional measurements), this data cannot always be applied directly to design problems. Structural measurements are not sufficient to understand how a body moves in space and functional measurements, like reach envelope data, do not provide information about the adaptations that people make when interacting with a tangible product or space.(9)
The last few years have seen a dramatic increase in the capabilities of Digital Human Modelling. Parameterised computer simulations have been developed that allow testing of the anthropometric fit of a design in virtual space using digital manikins. While such manikins for able bodied people have been available for some time, Steinfield states that accurate and reliable manikins of disabled people are still not widely available.(10)
This paper reports on an effort to target the lack of ergonomically correct products and environments, which are useful to disabled and elderly people, by creating accurate visualisations of human motion in the form of manikins, that can interact with virtual spaces and objects, providing designers with a unique insight into the needs of these people.
The project is using motion capture technology to create Digital Human Models of disabled people, that accurately characterise the nuances of functional abilities, to ultimately instruct and inform the design process. The proposed activities will lead to improvements in the design and usability of environments and products used by elderly and disabled people.
In general terms the project involves the capture of human movement using an optical measurement hardware and Track Manager system© available from Qualysis. This system uses a 360º array of Motion Capture Unit digital cameras, which emit infrared light. This is reflected off low mass, retro-reflective targets, positioned on the person to capture the position of the targets with high spatial resolution.
Visual feedback is captured by connecting a video camera to the system, presenting a synchronised video image along with the acquired data. These two forms of data, motion capture and video can be contrasted and compared to validate the accuracy of the motion capture in representing the functionality of the sample population. Using Visual3D, a software package for rigorous and accurate analysis of 3D motion and the managing and reporting optical 3-D data, the visualisation of the motion data is being presented as mannequins. Visual3Ds’ modelling technique also allows for the analysis of mechanical movement, which allows the inclusion of assistive technologies.
Preliminary work with the system is creating comparative three-dimensional visualisations that represent the functionality of persons with varying degrees of impairment. These models can be used to illustrate the variability of human movement and accurately illustrate the subtleties of human function. They can also be used to illustrate such factors as the area that a person can reach for an object to be accessible to them or a space within which a person can interact. They can be used to illustrate the comparative space requirements of various users of mobility systems.
The primary goal of the work reported in this paper is to demonstrate an approach to the design of products and living spaces that are inclusive of the needs of disabled people, the elderly and others, embracing the ethos of universal design. Current design practice is constrained by a lack of accurate anthropometric data that represents the functionality of people, whose abilities are not necessarily captured by the 5 th to 95 th percentile of human function. This information needs to be presented in a way that can be effectively incorporated into the modern design process; in a manner that does not burden current practice. This is especially so where the obligation of total inclusion is still in its infancy or non-existent in terms of product design.
Development of the work will seek to integrate Digital Human Models with 3D visualisations of products and living spaces, allowing real-time simulation and interaction; testing a product or an environment’s performance prior to construction and therefore avoiding the need for expensive ‘mock ups’. The project is investigating the effectiveness of computer based systems in assisting designers to interpret the needs and requirements of disabled people and the elderly. Digital Human Models have the potential to enable designers to approach their designs from the viewpoint of a disabled person, or an elderly person. This could provide a powerful tool in helping designers to make informed decisions about important design issues in relation to disabled and elderly people.
Gavin R. Jenkins, MA, ATP, OTR
Senior Lecturer (HSC) PhD Research Student (FBE)
University of the West of England
Bristol, Glenside Campus
Bristol, BS16 1DD, UK.
Office Phone: +44 (0) 117 32 88454
Fax: +44 (0) 117 32 88404
Email: Gavin.Jenkins@uwe.ac.uk