Youbai Xie

Technical note: A knowledge-based framework for creative conceptual design of multi-disciplinary systems

Designers often have difficulty in fulfilling creative conceptual designs of multi-disciplinary systems due to the lack of sufficient multi-disciplinary knowledge. Therefore, this paper proposes a knowledge-based framework for the creative conceptual design of multi-disciplinary systems through reusing and synthesizing known principle solutions in various disciplines together. It comprises a formal constraints-based approach for representing the desired functions, a domain-independent approach for modeling functional knowledge of known principle solutions, and a heterogeneous-object-state-search-based approach for synthesizing known principle solutions together for achieving the desired functions. A design case illustrates that the proposed framework can successfully achieve creative conceptual design of multi-disciplinary systems. A prototype system, called the Intelligent Creative Conceptual Design Platform, is implemented based on this framework.

Partial retrieval of CAD models based on local surface region decomposition

Most existing methods for 3D model retrieval focus on the global shape description and matching. However, partial shape description and retrieval may be used more frequently in the fields of product design and manufacture. In order to resolve the problem that the retrieval efficiency for complex model descriptors is low, a CAD model retrieval method based on local surface region decomposition is presented in this paper. First, according to the salient geometric features of the mechanical part, the surface boundary of a solid model is divided into local convex, concave and planar regions. Then, we give a kind of region codes that describe the surface regions and their links in the CAD model. Finally, the model retrievals are realized based on the similarity measurement between two models region codes. Experimental results have shown that this approach is able to support partial retrieval of CAD models.

Technical note: A part affordance-based approach for capturing detailed design knowledge

Design knowledge reuse is widely accepted as an effective strategy for designers to develop robust artifacts with less time and lower cost. However, there has been very little research on how to help designers capture detailed design knowledge for reuse. As a result, most detailed design knowledge still has to remain in designers memories as tacit knowledge, which can easily get lost due to oblivion or the mobility of designers. Therefore, this paper attempts to develop a part affordance-based approach for externalizing and capturing detailed design knowledge for effective reuse. It first introduces a part model for representing the detailed design-related information. Based on the relational theory for design, the concept, part affordance, is then employed to help designers externalize and capture various lifecycle factors that are implicit in a detailed design. Based on the affordance constraint axiom, a systematic approach is then proposed for deriving tacit design knowledge from captured part affordances through the analysis of extreme working situations. The proposed approach has been implemented as the Design Knowledge-Capturing System (DKCS). A fixture design case has been employed to illustrate the proposed approach.

Knowledge flow in engineering design: An ontological framework

Engineering design is a structured and systematic process of finding solutions to meet certain requirements. Research in this field has focused heavily on developing more effective and efficient product realization process models. Today’s engineering design has become a knowledge intensive and collaborative process, requiring multidisciplinary design knowledge. Therefore, the modeling of knowledge flow plays a key role in determining a successful design alternative, which provides valuable insights into design problems for designers. This article proposes an ontological framework, purpose-function-working space-structure-behavior (PFWSB) for knowledge representation and knowledge flow based design process modeling. An illustrative case is also presented to demonstrate how to use the proposed framework to represent engineering design knowledge and describe the knowledge flow between decision makers during a design process. The results show that this framework can help designers capture the flow of knowledge in engineering design process more effectively.

Toward a scientific ontology based concept of function

Abstract Function is an ambiguous concept, whereas having explicit and precise concepts is critical for building a systematic science of engineering design. Based on Bunges scientific ontology, this paper is devoted to developing an explicit and precise concept of function for design science. First, we attempt to clarify the concept of behavior, which is closely related to function and is also shown as an ambiguous concept in engineering. Second, the concept of action is imported from scientific ontology into design science. Third, a scientific ontology based concept of function is proposed, together with an ontology-based functional taxonomy. A case of a function definition of a civil aircraft type demonstrates that the proposed concept of function is more explicit and precise than previous ones, and it can lead to better functional design results.

A novel semi-heuristic planning approach for automated conceptual design synthesis

Automated conceptual design often shows significant promise for generating conceptual solutions automatically through searching and synthesizing known principle solutions for a desired function. However, existing automated conceptual design systems lack an efficient heuristic search strategy and a knowledge-based planning mechanism, which lead to less chance of finding promising principle solutions within a limited time. This article proposes a novel semi-heuristic planning approach for automated conceptual design which comprises two successive steps, i.e. DESIGN PLAN and DESIGN COMBINATION. During the stage of DESIGN PLAN, the planning-graph technique is employed to extract a design plan from a planning graph, which is composed of various principle solution clusters. Under the guidance of the design plan, in the second stage, DESIGN COMBINATION combines compatible principle solutions from the principle solution clusters in the design plan until finding promising conceptual solutions. A prototype system and design case illustrate that the proposed semi-heuristic planning approach can successfully achieve an automated conceptual design synthesis.

A multi-agent-based approach for conceptual design synthesis of multi-disciplinary systems

It is encouraged that designers should explore in wide multi-disciplinary solution spaces for finding novel and promising principle solutions to desired functions during conceptual design. However, due to lack of sufficient multi-disciplinary knowledge, it is often difficult for human designers to explore in wide multi-disciplinary solution spaces. Therefore, this paper proposes a multi-agent-based approach for assisting designers in achieving multi-disciplinary conceptual design synthesis. The roles of different kinds of designing agents are identified, and the collaborative mechanisms among these agents are also elaborated. The conceptual design test case of a solar toy demonstrates that the proposed multi-agent-based design synthesis approach, compared with our previous approach, can achieve higher efficiency and better robustness through collaborative conceptual design synthesis.

A knowledge-based system for multi-disciplinary conceptual design synthesis

Exploring wide multi-disciplinary solution spaces to create conceptual design solutions is a difficult task for human designers due to lack of sufficient multi-disciplinary knowledge. A viable approach would be to develop a computer-aided system to synthesize the wide variety of knowledge for a given design task. However, the existing design synthesis systems are mainly domain-specific, focusing on conceptual design synthesis in a single or few limited disciplines. Therefore, this article introduces the development of a knowledge-based system for multi-disciplinary conceptual design synthesis, including the establishment of a knowledge base for organizing multi-disciplinary principle solutions and a design synthesis algorithm. The implementation of a prototype software is also reported, with the conceptual design of a solar fountain as a demonstrative case. The results of the case study show that the system can automatically and conveniently generate multi-disciplinary conceptual solutions.

A General Knowledge-Based Framework for Conceptual Design of Multi-disciplinary Systems

Designers are encouraged to explore in wide multi-disciplinary solution spaces for finding novel and optimal principle solutions during conceptual design. However, as cultivated in limited disciplines, they often don’t have sufficient multi-disciplinary knowledge for fulfilling such tasks. A viable solution to this issue is to develop an automated conceptual design system so that knowledge from various disciplines can be automatically synthesized together. Since conceptual design is often achieved through reusing and synthesizing known principle solutions, this paper proposes a knowledge-based framework for achieving automated conceptual design of multi-disciplinary systems, which comprises three primary parts, i.e. a flexible constraint-based approach for representing desired functions, a situation-free approach for modeling functional knowledge of known principle solutions, and an agent-based approach for synthesizing known principle solutions for desired functions. A design case demonstrates that the proposed framework can effectively achieve automated conceptual design of multi-disciplinary systems. Therefore, designers can then be automatically guided to explore in multi-disciplinary solution spaces during conceptual design.

A formal functional representation methodology for conceptual design of material-flow processing devices

Abstract Although there has been considerable computer-aided conceptual design research, most of the proposed approaches are domain specific and can merely achieve conceptual design of energy flows-processing systems. Therefore, this research is devoted to the development of a general (i.e., domain-independent) and knowledge-based methodology that can search in a wide multidisciplinary solution space for suitable solution principles for desired material-flow processing functions without designers biases toward familiar solution principles. It first proposes an ontology-based approach for representing desired material-flow processing functions in a formal and unambiguous manner. Then a rule-based approach is proposed to represent the functional knowledge of a known solution principle in a general and flexible manner. Thereafter, a simulation-based retrieval approach is developed, which can search for suitable solution principles for desired material-flow processing functions. The proposed approaches have been implemented as a computer-aided conceptual design system for test. The conceptual design of a coin-sorting device demonstrates that our functional representation methodology can make the proposed computer-aided conceptual design system to effectively and precisely retrieve suitable solution principles for a desired material-flow processing function.