Daniel D. Jensen

PRINCIPLES OF PRODUCT FLEXIBILITY

Contemporary products need to evolve to accommodate competitive market pressures, rapid technological change and transient and multi-dimensional customer requirements. Product flexibility is defined as the adaptability of a system in response to these factors. Currently, flexible products are realized with ad hoc methods that rely on the experience and intuition of the designer. In this work, a set of formal principles is presented for guiding the design of flexible products. These principles are derived from the results of an empirical study of the United States patent repository. As part of the study, patents are analyzed with a dissection tool, and representative principles are derived from the data. The utility of these principles is demonstrated via the design of a flexible fuel cell system. The effectiveness of these principles is validated using a Change Modes and Effects Analysis (CMEA) tool to compare the resulting fuel cell concept to a typical device of similar functionality.Copyright

Prototype Partitioning Based on Requirement Flexibility

Prototype partitioning is an often-overlooked step in the product development process that has great potential for improving project success. This paper discusses the importance of applying a systematic prototype partitioning strategy to a product development project. Quite often, prototypes are chosen based on historical reasons, with the premise that requirements are rigid and inflexible. Alternatively, a method is proposed here for prescribing a partitioning strategy that is tailored to the specific characteristics of a project and is based upon the three components of requirement flexibility: cost, schedule, and performance. By considering the realistic flexibility in these requirements, strategic prototyping decisions may be made to promote the success of a development project. Three product development applications illustrate the proposed method: the Black & Decker SnakeLight™, a senior-level design project at the United State Air Force Academy, and the product development of a new umbrella concept based on compliant components.© 2004 ASME

A Systematic Method for Design Prototyping

Scientific evaluation of prototyping practices is an emerging field in design research. Prototyping is critical to the success of product development efforts, and yet its implementation in practice is often guided by ad hoc experience. To address this need, we seek to advance the study and development of prototyping principles, techniques, and tools. A method to repeatedly enhance the outcome of prototyping efforts is reported in this paper. The research methodology to develop this method is as follows: (1) systematically identify practices that improve prototyping; (2) synthesize these practices to form a guiding method for designers; and (3) validate that the proposed method encourages best practices and improves performance. Prototyping practices are represented as six key heuristics to guide a designer in planning: how many iterations to pursue, how many unique design concepts to explore in parallel, as well as the use of scaled prototypes, isolated subsystem prototypes, relaxed requirements, and virtual prototypes. The method is correlated, through experimental investigation, with increased application of these best practices and improved design performance outcomes. These observations hold across various design problems studied. This method is novel in providing a systematic approach to prototyping.

GUIDELINES FOR PRODUCT EVOLUTION USING EFFORT FLOW ANALYSIS: RESULTS OF AN EMPIRICAL STUDY

The results of an empirical product study aimed at deducing product evolution design guidelines are presented. The derived design guidelines support a directed product evolution methodology known as effort flow analysis. Effort flow analysis provides a systematic framework for identifying component combination opportunities leading to either rigidbody or compliant mechanisms in the domain of mechanical effort transmissions. Design guidelines, effort flow analysis, and the empirical study are discussed. A classified list of the derived guidelines is presented along with analysis of a sample product group from the study.

The Way Makers Prototype: Principles of DIY Design

Recent research demonstrates the importance of prototyping to support early stage design efforts. There remains a substantial opportunity to provide tools that codify the leap between the logical objectives of the design effort, and an individual’s intuitive design and fabrication experience. This study investigates project articles on the open source, Do-It-Yourself (DIY) design repository, Instructables.com. The database contains guides for producing low cost functional prototypes. Many entries in the repository include documentation of the design process along with instructions for fabrication. Through a systematic research methodology, we extract five prototype design and fabrication principles from articles in the database. An online crowdsourced assessment enables inter-rater testing, with multiple parallel raters. This assessment validates presence of the principles in the database. A controlled study was conducted in which one of two groups was exposed to the principles. This study evaluates connectivity, successful adoption of the principles by participants in the experimental group, and resulting design performance effects. Two case studies of prototyping are also provided. Observations indicate that application of the principles positively impacts prototyping outcomes. A potential area for improvement is edge case evaluation, i.e. principles only found in a single extraordinary sample.Copyright

Facilitating Design-by-Analogy: Development of a Complete Functional Vocabulary and Functional Vector Approach to Analogical Search

Design-by-analogy is an effective approach to innovative concept generation, but can be elusive at times due to the fact that few methods and tools exist to assist designers in systematically seeking and identifying analogies from general data sources, databases, or repositories, such as patent databases. A new method for extracting analogies from data sources has been developed to provide this capability. Building on past research, we utilize a functional vector space model to quantify analogous similarity between a design problem and the data source of potential analogies. We quantitatively evaluate the functional similarity between represented design problems and, in this case, patent descriptions of products. We develop a complete functional vocabulary to map the patent database to applicable functionally critical terms, using document parsing algorithms to reduce text descriptions of the data sources down to the key functions, and applying Zipf’s law on word count order reduction to reduce the words within the documents. The reduction of a document (in this case a patent) into functional analogous words enables the matching to novel ideas that are functionally similar, which can be customized in various ways. This approach thereby provides relevant sources of design-by-analogy inspiration. Although our implementation of the technique focuses on functional descriptions of patents and the mapping of these functions to those of the design problem, resulting in a set of analogies, we believe that this technique is applicable to other analogy data sources as well. As a verification of the approach, an original design problem for an automated window washer illustrates the distance range of analogical solutions that can be extracted, extending from very near-field, literal solutions to far-field cross-domain analogies. Finally, a comparison with a current patent search tool is performed to draw a contrast to the status quo and evaluate the effectiveness of this work.Copyright

Virtual or Physical Prototypes Development and Testing of a Prototyping Planning Tool

A new prototyping planning tool guides designers in choosing between virtual vs. physical prototyping strategies based on answers to Likert-scale questions. We developed this tool to augment prior work in design methods seeking to facilitate prototyping strategy development. This new tool was tested with a pilot experiment in which engineering students were tasked with optimizing the design of a four-bar linkage to be used to draw a specific shape. The students were then instructed to use the new prototyping planning tool to decide whether to create a virtual or physical prototype of a four-bar linkage, with the goal of maximizing the performance metric detailed in the design problem statement. This paper describes the new prototype strategy planning tool, the pilot experiment, and results and conclusions. The very encouraging pilot results provide a template and strong motivation for conducting a larger scale experiment for generic prototyping applications.

Analogy Seeded Mind Maps: Testing of a New Design-by-Analogy Tool

Recent research has investigated methods based on design-by-analogy meant to enhance concept generation. This paper presents Analogy Seeded Mind-Maps, a new method to prompt generation of analogous solution principles drawn from multiple analogical domains.The method was evaluated in two separate design studies using senior engineering students. The method begins with identifying a primary functional design requirement such as “eject part.” We used this functional requirement “seed” to generate a WordTree of grammatically analogical words for each design team. We randomly selected a set of words from each WordTree list with varying lexical “distances” from the seed word, and used them to populate the first-level nodes of a mind-map, with the functional requirement seed as the central hub. Design team members first used the word list to individually generate solutions and then performed team concept generation using the analogically seeded mind-map. Quantity and uniqueness of the resulting verbal solution principles were evaluated. The solution principles were further analyzed to determine if the lexical “distance” from the seed word had an effect on the evaluated design metrics. The results of this study show Analogy Seeded Mind-Maps to be useful tool in generating analogous solutions for engineering design problems.Copyright

A FUNCTION-BASED STRATEGY FOR ANALYSIS OF ENERGY SYSTEMS IN TRANSPORTATION VEHICLES

Six functions are identified as the most critical (“core” functions) to transportation vehicle energy systems. These selections are validated through analysis of 25 function structures as well as observations of a number of existing energy systems. Identifying which of the core functions and which of the energy types are involved in a given energy system is the Core-Function Modeling strategy (CFM strategy). These functions and energy types (the framework of CFM) are used to categorize approximately fifty processes and devices. This list is the Energy Morph Matrix (EMM). An experiment is performed that demonstrates how the EMM can be used as an aid to the concept generation process. The EMM also adapts well to a more automated approach for designing energy systems when used in combination with a search algorithm to identify chains of energy components. By incorporating a metric such as system efficiency or energy density into the search and computing this metric for each chain of energy components, these chains can be ranked and leading candidates can be highlighted for further analysis.