A PRODUCT DESIGN METHODOLOGY IMPLEMENTING ERGONOMIC S ASPECTS IN MAN ARTEFACT ENVIRONMENT SYSTEMS

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1 Abstract Virtual Concept Workshop 2014 Innovation in product design and manufacture A PRODUCT DESIGN METHODOLOGY IMPLEMENTING ERGONOMIC S ASPECTS IN MAN ARTEFACT ENVIRONMENT SYSTEMS Johana Hoyos Ruiz, Jose Fernando Martínez, Gilberto Osorio, Ricardo Mejía (1) : Universidad EAFIT Medellin Colombia ext { jhoyosr2, jmartine, gosoriog, rmejiag }@eafit.edu.co Short Abstract: If an object, a system or an environment is destined to a human interaction, then the design must be based upon the physical and mental characteristic of that user. That s the reason why a methodology of design that gathers the Man Artefact Environment with physical and cognitive ergonomics has been developed; implementing a synergy structure of design methodologies and criteria centering the user as a prime element in every stage of product development; guarantying a major adaptation to the context, capacities and necessities of the person, in a way that improves the efficiency, safety and wellbeing of consumers. Key words: Man Artefact Environment system, Ergonomic, Human Factor, Product design methodology, Human centered design, User experience, Usability 1- Introduction In the book The design of everyday things [N2] the work of a product designer it is linked to the interaction that the user should have with the object; making sure that people want to know how things work, and beyond that, they want to know and learn how to operate them. There s already existing a great number of products for which appears that the human factor wasn t taken into account during the design process (Ergonomic design), stating that designers, quite often forget about the user or just do not consider him. In the Handbook of Usability Testing: How to Plan, Design, and Conduct Effective Tests [RJ1] Jeffrey Rubin talks about the infinity of current high tech products or everyday use products at sale that are very difficult to use, due in fact for many reasons, all of them including the lack of ergonomic in the designs. The author considers that during the development of the product, the approach it is the product itself, and not the person who is the final user; suggesting that the elements that should be considered are as follows: Human (User interaction), context (Environment in which the interaction would take place) and activity (Approach to the individual in terms of safety, economy and so on). There s also been pointed out the late reaction of designers against the evolution of technology and the users expectations. The study in the ergonomic factors of the products, seeks to create products and elements of everyday use, or specific to adapt at certain characteristics of a determinate user. The problem is that the developers of products or concepts link the user to the product, evading the necessity of including him in a physical and cognitive form within the environment and the process design in every stage of the development. 2- Literature review 2.1 Ergonomic aspects The fields of application in ergonomics have evolved through time, today there s an ergonomics destined to health [AF1], related to psychosocial and labor risk prevention, safety accidents and OSH management; involving judicial aspects of the ergonomic when analyzing the elements and criteria of disability, accident reconstruction, the professional diseases [B3] originated with ergonomic risk factors and injury casualty. In the case of industrial design [VM1], there s market and users research, were specifications applied to anthropometry and biomechanics are analyzed to develop a better connection of the product with the user needs [J1]. The philosophy of design that would optimize the efficiency and effectiveness in the use of products or systems on behave of the user it being called User centered design [M1], name that s being consider for many authors as a synonym of ergonomic or human factor. 2.2 User centered design The same [WW1] states that User centered design it is a new way of design team work and not just a set of individual techniques applied to the design. Authors like Dursteler (2000) [C1] [LS1] and Rubin (1994) [AMP1], propose three principles that present relevance in the implementation of a new work philosophy for the product design area; the first one is the approach towards users and the tasks that are going to be developed with the product, starting at the beginning of Paper Number -1- Copyright of Virtual Concept

2 the process, gathering structured, systematic and objective data. The second one is the use of prototypes or tests for the empirical measurement from the beginning of the design, and the third principle is design in an interactive and cyclical repetitive way, parameters modification and tests of usage of the product from the beginning, making cycles until the outcome it is completely satisfactory. [NS1] Jean-Claude Sagot, makes an analysis of the contribution that ergonomic has within the process of design of new products, refereeing to a methodology [SG1] of product development as a cooperative and retroactive process. 2.3 Design tools Some universities have created methodologies to engage more actively in ergonomic issues in the design stages, but are not explicitly developed, so do not optimize the product development process. In reference to human factors, the Institute of Biomechanics of Valencia University in Spain [LP1], establishes in the design education methodology, that the design processes of any system or product must be primarily identified to correct the incompatibilities existing between the user and the rest of the components, considering aspects like the system objective, that is to say, the activities that the user must do and the physical, sensorial and mental demands associated with it; the environment of the use of the system or product such us environmental conditions, and social or organizational scopes, among others. [S1] The U.P.B University in Colombia, (Universidad Pontificia Bolivariana), presented a methodological proposal to ergonomics learning from the relation with the design, seeking to answer human needs, optimizing the contexts in which it is developed, projected and applied to the disciplines that back up ergonomic. [RG1] Another methodology of design mentioned in some of the stages of ergonomic is The key for design [PC1] which is organized in stages or work phases that seek some specific objectives, and that gather all the life cycle of the product. 3- Proposal methodology Authors like Rothwell (1994) propose different generations for the set of tools grouped in a sequential form within the design process, using a logical-rational paradigm for the solution of problems quoted by Roozenburg (1995). The evolution of the models presents two premises, the first one bases upon the product life cycle [R1] and the second one in the functions by a company department (Marketing, design, and/or production) [RS1]; even though Eekels (2000) starts from an operational design in the hand of actions and specific activities in each stage of the design process. Each human activity requires a set of activity patrons in order to achieve an objective, through human capabilities (Physical and cognitive) and the means available (Objects and special conditions) Garcia (2002). For the development of a design methodology and participative ergonomics, some stages of the design and development of conventional products proposed by specific authors were correlated, as well as tools or methods of integration, making a methodology an explicit and adaptable process in cases of design and redesign. Was proposed in a matrix structure in which there is a logic in the phases of the process NPD (New Product Development) in an transversal way on the X axis considering every stage as an iterative and circular element, and the components of the system of the technique (Man- Product-Environment) manifesting in a deliberated way on the Y axis; using a determinate number of tools in each axis according to the predominant component among the design accordingly to the stage and the designer objective. Figure 1: Matrix structure (own development) The methodology of design mentioned allows to incorporate in the different stages of design, considerations of the relation Man Artefact Environment system using criteria implemented in the physical and cognitive ergonomic, seeking to guarantying a major adaptability with the technic products in the contexts in which they are used, as well as the capabilities and needs of people that interact with them, in a way in which efficiency, safety, and wellbeing of the users is improved. Currently product and/or services designers implement different steps to develop an innovative concept or redesign and improve the functioning and the formal quality of a product. Some methods focus their analysis on the evolution of the product itself from the sketch of an idea, through production and acceptance of it in a real market. Generally design processes like the ones of Demirbilek & Demirkan (2004) have limited progress with regard to human factors accordingly to Cañas and Waerns (2001), because they are designs based on the system, identifying human characteristics (capabilities and limitations) to generate design principles, which are evaluated at the end, but the changes are applied to future designs [B1]. Authors like [E1] propose a method in which before the final design, the concept is redefined and tested, without specifying an interaction with the user or the context. Within the method of user centered design [N1] ergonomics is incorporated to the psychological cognitive conceptualization of the user, anticipating his interaction with the product; tests and evaluations are conducted throughout the design process. The resource proposed in this article, is a systemic observation methodology, employed as a scoring guide that takes into consideration variables related to the use of the product and the human factors, generating a collaborative design, and integrating the user directly with a perspective from the physical ergonomics (Anthropometry and biomechanics) and cognitive (sociocultural and emotional). Paper Number -2- Copyright Virtual Concept

3 Figure 2: Proposal methodology (Own development) The methodology engage design methods at different stages, adding aspects related to ergonomics and participative design, because users are the ones who know better their dynamics and problems associated with the use or creation of a product. Although this is used for prevention and improvement proposals, to break into a synergy of feedback between planning processes, user analysis, identification of design criteria based on human factors, concept development, evaluation, systematic design, final design and production, the interaction between Man- Product- Environment is balanced with the adaptation of needs, considering aspects related to motivation, effectiveness and efficiency when using the product, differentiating it for it is functional, formal and emotional, connection with the user. (Figure 2) 4- Case Study The design of a body protective system for the manipulation of posts or poles in a mountainous terrain, is a high engineering development, due to the fact that it involves exigent conditions of performance, such us up and down climbs, user requirement with specific anthropomorphic characteristics, body positioning of controlling loads, and musculoskeletal injuries in the short and long run that decrease the safety and the conditions for the activity. Initially was designed a type A vest (Figure 3a.) following some of the conventional design stages in the process and product development, taking into account the user at the stage of tests in the system, in the perception of usage and in the understanding of the user manual. In this case the method of design applied was the one proposed by Gerhard Pahl and Wolfgang Beitz, as guidance and not as a rule to follow, due to the fact that it has a lack in a development stage of functional models, prototypes and additional documentation required in the project. The final result was a design barely adapted to the user requirements, a product with expensive components that did not fulfill their function the design inhabits the user when generating manipulation movements- decreasing the performance in the process and did not absorb nor distributed adequately the loads. To validate the design methodology and participative ergonomic proposed in this article, the type A vest was redesigned, redefining the design criteria in terms of biomechanical and ergonomic, analyzing variables such as mass, center of gravity location; which can vary every time the operators change their position in the irregularity of the mountainous terrain; and the increase of the contact area of the load, to distribute pressure and generate greater comfort. Figure 3: a) Type A vest b) Type B vest Paper Number -3- Copyright Virtual Concept

4 The form of type B vest (Figure 2b) is based upon the characteristics of the human body, specifically in the upper body, generating a soft backing and other rigid backing to protect the parts involved in the manipulation of heavy loads. To determine the required dimensions and distances of the structure and the protective vest, was necessary to identify the anthropometric dimensions, through a bibliographic search and a qualitative search aimed at a specific sample. For the type B vest were added analysis and synthesis stages of problems before the development of the concept, incorporating the human factors in every stages of the design; evaluating the tools and activities from the components of the system Man- Product-Environment (Figure 4), finding an appropriate equilibrium in the final results of it and a major adaptability in form, use and experience. The important is to analyze and retort the concept, debugging accordingly to the approach it has with the user and the context, before passing to the final and definitive stage of design, manufacture and production. midline of the body, since deviation from that position creates an imbalance of forces generating a torque (roll when walking) - Body subconscious attempt to reduce the imbalance of forces. When a person is standing, transmits the load from the head to the lower limbs, the trunk and upper limbs or any other charges. The lumbar vertebrae, which are located in the lower part of the column, support the total load. This should lead from the front and the closest to the body as possible, symmetrically spreading the weight between the two arms. After applying the design and participative ergonomics methodology, the time of development was reduced by 33.33%, which shows an increase in process efficiency. However this may vary accordingly to the learning curve of the project, compiled from design type A vest. This is why it is essential to reassess the methodology in a controlled group with similar conditions, decreasing the mobilizing factors and quantify indicators of usability and effectiveness of the product using a conventional methodology versus the one presented in this paper. 6- Conclusion The considerations of ergonomics can contribute to the solution of many problems related to health, safety, comfort and efficiency. If products are developed taking into account ergonomic criteria within a given environment, it could prove to be a successful topic in the social, human and economic perspective, improving the user experience and performance and adaptability against the target user. Figure 4: Human factor inputs and outputs 5- Analysis of results Authors like Rothwell It were decided to redesign the type A vest, because some of the anthropometric dimensions of the operators are not established under common percentiles of the Colombian population. The jacket wasn t able to limit the movement of the operator, while performing their work in the process of scoot poles, as it can damage their health by handling loads improperly and jeopardize the health of other workers. As the vest is an industrial product it should not be bulky or contain parts that may damage or lose easily. If the jacket is too big and bulky, there s the risk that the operators will not use it while handling loads, preventing the commercialization of the product. The final design solution (type B vest) allows distributing the loads on the shoulders and/or the trapezius to the lumbar vertebral column and to the hips and waist, improving the strength and resistance of the operator when handling heavy loads. By placing the column in a proper position, the inclination and twist of the column is prevented during transportation. It is possible to walk aligning movement on the There s currently a wide variety of methodologies, tools and design methods for product development [B2] [E1], some of them incorporate in the analysis phases or activities of user verification ergonomic criteria that do not go beyond a literature search for guidelines and a qualitative analysis of the target user. Often designers models are not the same as the user models (mental models, use models, allusion models), for it is said that the designer does not take into account the human activity model (operation of the product) during the projection of his design, thus minimizing the satisfaction and quality of work. It is fundamental to define a methodology or an explicit tool in the systematical processes of design that allows gathering the considerations and functional aspects, biomechanics, anthropometrics and cognitive elements, among others, diminishing the iteration cycles and optimizing the relation between user and product. This could increase the safety and efficiency of the task being done by the user, by being subject to an environment that limits the use experience of a product. 7- References [AF1] Apud, E. a. F. M. (2003). "La importancia de la Ergonomía para los profesionales de la salud." Ciencia y enfermería Paper Number -4- Copyright Virtual Concept

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