Catálogo de publicaciones - libros

Iteration is an inherent component of any design process. It is a very important characteristic since it influences product development cost and time. In this paper, an experiment is used to make observations about iterations in a geographically distributed design process. Our objective is to understand how and why iterations occur in the design process. This investigation will help us in the classification of iterations in order to distinguish useful iterations from negative ones. The results of such work could be used to improve assumptions adopted to develop engineering design models, which is very helpful in design planning. We provide a brief review of some design models integrating the iterative aspects of engineering design. After describing the experiment environment, the research method is presented, and observations are then analyzed.

In this paper, we propose an analysis approach for the collaborative design process. That is centered on the messages generated by the actors. It is structured with two levels: the first level concerns the analysis of interactions between actors inside each discussion, whereas the second level concerns the analysis of relationships between different discussions. The analysis distinguishes between three concepts: the formation of micro-groups; the articulation of design process around one or several key actors; and the types of interactions. The application of the proposed approach in collaborative design experience allowed the identification of three properties of this process: the auto-organization, the dynamics and the auto-similarity.

Understand the way the actors organize their activities is needed for better managing the resources used in distance collaborative design. We introduce here the notion of design workspaces and distinguish them according to the number of actors (individual versus collective) and the type of activity (communication versus cooperation, related to the presence or absence of Intermediary Objects - IO - on these spaces). A method for analysing a design meeting in order to delimit and then qualify design phases is presented. A specific device was used to delimit the different workspaces. Audio and video records allow for a precise observation of glances, gestures, and exchanged words. From these observations, we coded: actions on the IO (we distinguish draw, point, annotate, and handle), attentions from the glances (to another actor, or to an IO, noting its workspace), and design acts which are requests and propositions of information, solution, criteria definition and evaluation. Several graphs representing the different data versus time are proposed and used for identifying and qualifying phases. Analyzing a short (1 hour) experiment with 4 designers gave two main results. First, a significant modification of the designers’ attention is revealed to be a good indicator for phase shift detection, especially when an IO appears in the collective space thus six phases were identified. Second, the type of actions and design acts used for each phase show important differences between the three main phases that were analyzed. These results are promising and show relevant indicators for segmenting, and qualifying design phases. Repeating such analyses should lead to activity models onto which new design tools could be proposed.

The majority of design projects involve adapting a known solution to meet new requirements. Therefore, understanding the issue of engineering change is of vital importance if companies are to deliver product development projects on time and to budget. When a change is made to part of a product, the change is likely to propagate to affect other components or systems. This paper examines the engineering change process within a UK engineering firm and focuses on the issue of change propagation. The findings are compared with an earlier study in the aerospace industry. Four reasons why propagation occurs are proposed and discussed.

Gaining momentum in several fields of study is the recognition of the need for a viewpoint that includes the human element as an integral part of the modern production system beyond traditional ergonomics. The “intellectual capital” is as much of a resource as money, materials, software and hardware. A model that considers the human players in tandem with the physical elements is needed to provide insights into the sensitivities of the manufacturing system. Using Systems Analysis and Design methods, a framework has been developed, which is valid for different perspectives and environments, to assess the elements of manufacturing complexity. The manufacturing complexity index allows people with diverse backgrounds to rapidly evaluate alternatives and risks with respect to the product, process or operation tasks. In this paper, the technique for evaluating the process complexity metric is presented. An analysis is performed comparing the relative process complexity for a power steering pump bracket that is manufactured in a CNC machining cell and a dedicated line. The areas of complexity are clearly evident. This provides insight for risk assessment as this systematic approach can be used to “mathematically” show tradeoffs for each important criterion during the design stages.

The great importance of human aspects in industrial environments have changed the viewpoints of designers and developed Human-Centered design approaches. One of the fundamentals of this approach is to consider human factors at all stages of the design process. The integration of human factors in the design process phases requires effective use of the appropriate human models. This paper presents definitions of human models and their classification in industrial applications with emphasis on industrial design processes. We also focus on the application of the human models in a human-centered industrial system approach. Specifically, we discuss future approaches relevant to the use of human models in the virtual environment.

Recently, efforts have been made to define the role of “context” in the Product Realization Process. This paper treats only a small slice of this problem and applies the notion of context to the automatic merging of geometric models created with the computer graphics language OpenGL. Context can be thought of as a set of properties or environmental variables of some entity that constrains or governs the behavior of that entity. The entity in this case is a three-dimensional geometric model and its context is the set of properties for viewing that model: lighting, viewing parameters, material reflective properties, colour. Now suppose a geometric model is made up of a collection of sub-models, each within its own context. If each context is associated with an integer, then the contexts can be ordered hierarchically. Thus the topmost context in the hierarchy becomes the global context for all the sub-models in the collection. Stated in another way, once a contextual hierarchy is defined, then the structure for combining these sub-models is established independently of when and in what individual contexts the sub-models are created. Consequently, context allows a concurrent generation of models within a formalized structure that automatically deals with conflict resolution — albeit in a limited way in this work. This paper describes a compiler in XML that will merge the OpenGL files automatically.

Traditionally, a designer forms the link between the customer and the final product by interpreting customer demands and desires and translating them into geometry. By combining 3D CAD systems and software tools for analysis, a designer is able to examine whether the created geometry complies with these customer demands and desires. However, in the process of translation and examination, a measure of subjectivity is added to the design. A virtual prototyping environment (VPE) can be created by utilizing Virtual Reality technology, in which the customer is able to specify the Product’s behavior in a direct way, without designer interference. In this way, not only is the design process is made more objective, but also significant amounts of time and money are saved since less physical prototypes are required. This paper describes the design and evaluation of a VPE for manually operated gearboxes in passenger cars. Based on measurements taken of the gearlever on a test vehicle, an application is designed that simulates its gearshift feel. This application incorporates a commercially available haptic device. In order to determine whether the virtual gearshift feel conforms with the real gearshift feel, a usability test is performed. The test group considered the feel of the simulated “virtual” gearshift to be quite similar to the “real” gearshift feel of a test vehicle. By further developing this VPE, it should become possible to define gearshift feel by customer assessment through haptic simulation, after which the physical gearbox is designed in such a way that it matches the preferred shifting behavior.

This paper presents a modeling approach that can be used as an engineering design tool to predict the effects of various design choices on product quality. The mathematical model provides a rigorous functional relationship between dependent and independent variables. The dependent variables quantify product quality in the physical domain in terms of design functional requirements the product must possess. The independent variables quantify the design choices in terms of nominal dimensions, degrees of freedom and tolerances. An example application is presented to illustrate how product quality can be achieved by appropriately tuning the design parameters in a constrained design context.

The world of the designer is three dimensional, and the language of tolerancing is a set of ISO specifications. We have built a methodology in order to compute geometric specifications on parts and clearances in joints through a mathematical model based on the small displacement torsors. A tolerancing object becomes a 6D object thanks to the developed solver. One objective is to represent 6D polytopes in the 3D world of the designer in order to inform him of the results for his tolerancing choices: assemblability performance, best and worst precision zones, and functional requirements. Therefore, it is necessary to indicate, the results to the designer graphically. This representation will be done in a CAD application by means of zones (3D volumes), which will be associated with functional features of the mechanism. An assembly example is presented to illustrate this method.