Defining Requirements in Prototyping: The Holistic Prototype and Process Development
DS 91: Proceedings of NordDesign 2018, Linköping, Sweden, 14th - 17th August 2018
Year: 2018
Editor: Ekströmer, Philip; Schütte, Simon and Ölvander, Johan
Author: Schork, Stefan; Kirchner, Eckhard
Series: NordDESIGN
Institution: Technische Universität Darmstadt
ISBN: 978-91-7685-185-2
Abstract
Designers and developers use prototypes in the product development process to gather information about the final product and its behavior as early as possible as well as to lower the risk of developing failing products. Literature describes prototyping as needed in general, but does not offer methodical approaches to the development of those prototypes themselves with the aim of gaining a maximum of knowledge. Prototyping is therefore primarily intuitive and iterative which often leads to an inefficient process. In most cases, no particular requirements to the prototype other than the requirements for the final product are specified. This paper therefore discusses the differences in requirements for different types of prototypes (e.g. functional, design and packaging) in different stages of the product and process development chain. The first part consists of the differentiation of types of prototypes, their relation to different stages of the product development process and accompanying requirements. Those types come in different forms and manifestations, for example virtual or real and focused or comprehensive. For each form and manifestation of the prototype, the developer has to specify different requirements. Those requirements depend mostly on the functions and phenomena the developer aims to investigate and the stage of the product development process. Nevertheless, the developer has to take into account that the manufacturing process of the prototype may differ from the process of the final product, which also leads to different requirements for the prototype. Another major difference between the final product and the prototype is the group of users or testers respectively. Depending on the group of testers, ranging from the developer himself over the management to the customer or even the end user, the developer has to anticipate the behavior of those testers and has to consider that behavior when specifying requirements. For example, a colleague, who also works on the product, may interact with the prototype in a different way than a randomized tester, who never saw the product before. Each prototype and subsequently each prototype testing phase then creates new information for the developer who is then able to transform the received information into new requirements for the next iteration of a prototype or the final product. Following these first results regarding requirements for prototypes, the paper discusses a holistic approach to the prototype and process development. The model is based on the holistic product and process development and visualizes the different influences and connections between the prototype development process and the prototype life cycle. The postulated model adapts the existing model and defines the prototype as a product itself, which then takes the place of the product in the product lifecycle chain. In addition, the prototype testing phase replaces the product use phase. This new model also includes the gained information from earlier versions of the prototype that the developer may respect in further iterations. The goal of this visualization is to provide an overview over the holistic prototyping process and the different requirements the developer has to take into account
Keywords: Requirements engineering, prototyping, mechatronic machine elements, design methodology