The Technology of Language and How Advances Will Affect Mechanical Design

The Importance of Language To Mechanical Design Increasingly, an information-centric view of the design process is being offered as the key to improvements in mechanical engineering. In such views, the focus on the importance, requirements, and problems of language is clear.

The Roles of Features and Abstraction in Mechanical Design

This paper describes the roles of features and abstraction mechanisms in the mechanical design process, mechanical designs, and product models of mechanical designs. It also describes the relationship between functions and features in mechanical design. It is our experience that many research efforts exist in the areas of design and product modeling and, further, that these efforts must be cataloged and compared. To this end, this paper culminates with the presentation of a multi-dimensional abstraction space which provides a unique framework for (a) comparing mechanical engineering design research efforts, (b) relating conceptual objects used in the life cycle of mechanical products, and (c) defining a product modeling space.

Conflict Resolution in Concurrent Engineering Processes

Naive interpretations of concurrent engineering may expect extreme parallelization of tasks and simultaneous accommodation of multiple perspectives. In fact, from our efforts at modeling tasks in a MEMS (Micro-Electro-Mechanical Systems) pressure sensor design project, it appears that data dependencies due to the structure of tasks and the product itself result in scenarios of decision and action that must be carefully coordinated. This paper refines a previously described information model for defining evolving contexts of product model aspects and team member perspectives, with software agents acting on behalf of team members to execute tasks. The pressure sensor design project is analyzed in the framework of the information model. A scenario of decision and action for design of the pressure sensor is modeled as a design process plan. Conflict on a shared parameter occurs as a consequence of introducing some parallelism between the capacitance and deflection agents in the process. We present a technique for negotiating such conflicts by definition and propagation of utility functions on decision parameters and axiomatic negotiation.

An Improved Shape Annealing Method for Truss Topology Generation

A method for the design of truss structures which encourages lateral exploration, pushes away from violated spaces, models design intentions, and produces solutions with a wide variety of characteristics is introduced. An improved shape annealing algorithm for truss topology generation and optimization, based on the techniques of shape grammars and simulated annealing, implements the method. The algorithm features a shape grammar to model design intentions, an ability to incorporate geometric constraints to avoid obstacles, and a shape optimization method using only simulated annealing with more consistent convergence characteristics; no traditional gradient-based techniques are employed. The improved algorithm is illustrated on various structural examples generating a variety of solutions based on a simple grammar.

A Study of the Information Handling Behavior of Designers During Conceptual Design

The research reported in this paper examines the design process from an informational perspective. The study is based on the premise that there is a need to understand and formalize the information generating, accessing and analyzing behavior of designers in order to build tools and methods which can be smoothly integrated with their technical and social work environment. Results from an experimental study, conducted using the verbal protocol method, are discussed. A measure for the amount of information designers handle has been explored. A framework for analyzing the information handling behavior of designers is also presented.

A Generic Mechanism Model for Computer-Aided Conceptual Design of Machines

This paper presents an application data model for the representation of conceptual structures of mechanisms. The main features in building this model are (1) to use semantic database modelling approaches and (2) to have a generic model. The model has been used in developing a software environment system for integrated design and manufacturing of mechanisms. Both conceptual design and implementation issues concerning this model are discussed. The system intelligence can be increased via a proper application data model. In particular, the concepts handling raw data and handling different views from the same object are clarified. The necessity and the technique to support them are discussed both in a general sense and in our mechanism data model.

Robust Product Design Using Manufacturing Adjustments

Tuning variables represent factory floor manufacturing adjustments commonly used to correct variational noise errors in a product. Some examples are voltage supply adjustments, adjustable links and screws, or shims. This paper presents methods to determine the increased performance and robustness when using different possible manufacturing adjustments. All possible potential tuning adjustments that exist in a design are identified. Given this, the tuning variable model can be used to calculate the reduced product variation when using any of the potential tuning adjustments, including none at all. This process can be used to help select which product variables should be adjusted, based on the increased robustness to noise and the increased difficulty in manufacture. Doing so allows for more robust product performance at reduced manufacturing expense, by allowing the potential adjustment on many different possible variables. This is better than always adjusting the source of the manufacturing errors, which can be expensive.

Creating an Advanced Collaborative Open Resource Network

Carnegie Mellon, in collaboration with several other universities and companies, is beginning to develop ACORN, an Advanced Collaborative Open Resource Network. ACORN will provide the infrastructure to create an electronic community which will be able to design and sell engineered products in competitive markets as well as conduct research and development by collaborating through a network. Creating such a community is a task of national proportions and cannot be accomplished by our group alone since the target community encompasses the entire country. We have an unprecedented opportunity to create and experiment with an electronic community which can serve as the model for a larger national community. In this paper, we outline the architecture for an information infrastructure to create and sustain such a community. This paper is not a standard research paper; it is being published to invite the members of the community to participate in the evolution of the ideas expressed here and to encourage the shared development of the infrastructure necessary to create this network.

Analyzing Inter and Intra Group Information Exchanges in Conceptual Collaborative Design

This paper reports preliminary results from a technique used to study inter and intra group information exchanges which occur in the conceptual stages of collaborative group design. In the early stages of conceptual design, there is little information to guide the designers and they find themselves groping to find pertinent information which may help them. In collaborative group design the members are able to pool in both their knowledge as well as knowlwdge from other groups. Currently there are no techniques, which exist, to help track this group information exchange. In this paper, we use the sense-making theory to guide us in assessing the information needs of the designers engaged in group collaborative design. In this study, the sense-making theory is described and adapted for applications in the engineering design domain. The analysis technique is a two step process. First the records are transcribed and labeled and then interpreted. The technique allows one to obtain a chronological map of the information seeking, helps obtained, and the decisions made. Results from the first design session show that during the early phases of group design, the most needs arose in establishing the knowledge base and in identifying the design process. There was a strong need for inter and intra group information exchange.

Abstractions, Design Views and Focusing

Abstractions serve to reduce the complexity of the design process by providing a simple yet still useful representation of the design. Abstractions change one or all of the focus, resolution and accuracy of the design representation. Focusing abstractions direct the designer’s attention to fundamental relationships amongst design variables and requirements. The process of forming focusing abstractions incorporates the design relations and variables that are of concern to the designer, while mitigating the complexity of the resulting design view for the designer. The complexity is minimized by reducing the number of variables and relations considered simultaneously. This is done in a manner which allows the designer to determine the need for further refinements in configuration, to make parametric decisions, and to identify critical design relationships. The appropriate use of focusing abstractions can improve both the design process and the final design. Several basic approaches to creating focusing abstractions are described and one method, based upon Gröbner Bases, is developed in detail. This method is appropriate for a design object representation consisting of parametric constraints represented as sets of polynomial equations. This approach is demonstrated within the context of a sample electro-mechanical design problem, a cordless screwdriver.