385 Strojniki vestnik - Journal of Mechanical Engineering 54(2008)6, 385-397 Cognitive Product Development: A Method for Continuous Improvement of Products And Processes Strojniki vestnik - Journal of Mechanical Engineering 54(2008)6, 385-397 UDC 658.5 Cognitive Product Development: A Method for Continuous Improvement of Products And Processes Wim Gielingh Delft University of Technology, Faculty of Civil Engineering, The Netherlands In current engineering practice, designers usually start a new project with a blanc sheet of paper or an empty modeling space. As a single designer has not all knowledge about all aspects of the product, the design has to be verified by other experts. The design may have to be changed, is further detailed, again verified and approved, and so on, until it is ready. But only the final product, once it exists, will prove the correctness of the design. Given the complexity of modern industrial products, the intermediate verification and change processes require substantial time. This has a major negative impact on the development time and costs of the product. Cognitive Product Development, as proposed here, approaches design as a scientific learning process. It is based on a well known and successfully applied theory for Cognitive Psychology. In stead of relying solely on the experiences of a single individual, CPD makes the combined knowledge of multiple disciplines, acquired throughout the life of existing products, available through generic design objects. CPD thus approaches design as the configuration of existing and verified knowledge. It is expected that this accelerates the product development process and results in designs of higher quality and reliability without affecting the creative freedom of the designer. © 2008 Journal of Mechanical Engineering. All rights reserved. Keywords: product development, cognitive engineering, continuous improvement, parametric modelling Paper received: 28.2.2008 Paper accepted: 15.5.2008 *Corr. Author’s Address: Delft University of Technology, Faculty of Civil Engineering, Section of Building Processes, Stevinweg 1, 2628 CN Delft, The Netherlands, wgielingh@tiscali.nl 1 INTRODUCTION 1.1 The High Costs and Risks of Product Development The development of complex systems such as buildings, plants, infrastructures, off-shore structures and aircrafts, has a high risk of budget and time overruns. In the construction sector, for example, budget overruns between 10% and 30% happen frequently. But overruns of 80% or more are not exceptional [9]. Also the aerospace, automotive and railway industries are often plagued by serious budget and time overruns. These costs and risks make many enterprises reluctant with the introduction of new products or the investment in new projects. Although many different factors may contribute to these overruns, two factors appear to be essential for most cases: (1) problems caused by high complexity, and (2) the unpredictability of consequences of ‘new’ knowledge. The complexity of a system can be defined as the total number of interactions or interdependencies between components of a system [13]. Complexity depends on the number of components, but tends to grow more than proportional to this number. Also the number of interaction- or dependency-types may increase complexity. Examples of interaction types are mechanical interaction (such as mechanical fixation), electrical-, chemical-, and control interaction. If a system has n components and i interaction-types, it may have maximally i . n . (n- 1) interactions with other components. Complexity can thus be reduced by reducing the number of components or by reducing the number of interactions or dependencies. The latter can be accomplished by modularizing a design such that each module behaves as a ‘black box’ that has minimum interactions with its environment. On the other hand, the trend towards ‘mass- customization’, i.e. the offering of client specific solutions based on a generic design, increases product complexity because designers have to keep all variant-solutions and their consequences in mind.