A computational framework for requirements-driven automated design synthesis

Computer-Aided Design (CAD) software is used pervasively in product development to speed up the creation, analysis and realization of products. However, state-of-the-art CAD software does little more than accept the input of designs that have already been conceived by a designer; They do not provide any help in actually conceiving designs. This limitation is inherently due to the mathematical framework on which they are implemented.; This research investigates a next-generation requirements-driven CAD framework with new declarative-variational mathematical underpinnings. It allows design changes to be accepted seamlessly from multiple stakeholders and the computer software itself. In this framework, the input design requirements entered by the user and through engineering knowledge are both applied as requirements on the design. The requirements can be posed in terms of dynamically applied algebraic, geometric, physical, and semantic relationships, including requirements on attribute values and the existence of the design objects and relationships. This is made possible by using an existing data structure called design exemplar and a new automated synthesis algorithm developed in this research. The framework allows designs to be under-constrained to allow for tweaking of the design and allows designs to be over-constrained allowing for detection of incompatible requirements. Once the requirements are specified, solutions are synthesized by the system using the available engineering knowledge and help from human designers who can work on the design directly. Promising solutions are then explored in detail by refining the requirements, modifying them and repeating this overall process recursively.; This research investigates in detail the process of requirements driven design synthesis. It implements a representation of design requirements using the design exemplar data structure and applies design requirements simultaneously while detecting incompatibilities in the requirements using a new generic high-level algorithm. The new algorithm records a set of proposed changes, compares them, and then applies them, effectively executing the exemplar algorithm simultaneously for many different requirements. We describe the computational framework for this system through the running example of the conceptual design of a delivery truck.; The current state of the system is also discussed as are the current challenges and future work. As a result of this research the activities of synthesis, evaluation, and selection in the systematic design process will be supported in a common framework. The paradigm of requirements driven computations is expected to be a vital part of next-generation CAD systems. Besides promoting innovative designs, the use of knowledge-bases will promote safer, less costly products with fewer design errors. The use of requirements as a basis for collaboration will also reduce instances in which design modifications detrimentally influence the intent of earlier design decisions.