Visualizing Relations Between Grammar Rules, Objectives, and Search Space Exploration in Grammar-Based Computational Design Synthesis1

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Corinna Königseder ◽  
Kristina Shea

Design grammars have been successfully applied in numerous engineering disciplines, e.g., in electrical engineering, architecture, and mechanical engineering. A successful application of design grammars in computational design synthesis (CDS) requires (a) meaningful representation of designs and the design task at hand, (b) careful formulation of grammar rules to synthesize new designs, (c) problem-specific design evaluation, and (d) selection of an appropriate algorithm to guide the synthesis process. Determining these different components of a CDS method requires not only a detailed understanding of each individual part but also of the interdependencies between them. In this paper, a new method is presented to support both CDS method development and application. The method analyzes the designs generated during the synthesis process and visualizes how the design space is explored with respect to design characteristics and objectives. The search algorithm as well as the grammar rules are analyzed with this approach. Two case studies, the synthesis of gearboxes and of bicycle frames, demonstrate how the method can be used to analyze the different components of CDS methods. The presented research can analyze the interplay between grammar rules and the search process during method development.

Author(s):  
Corinna Königseder ◽  
Kristina Shea

Design grammars have been successfully applied in numerous engineering disciplines, e.g. in electrical engineering, architecture and mechanical engineering. A successful application of design grammars in Computational Design Synthesis (CDS) requires a) a meaningful representation of designs and the design task at hand, b) a careful formulation of grammar rules to synthesize new designs, c) problem specific design evaluations, and d) the selection of an appropriate algorithm to guide the synthesis process. Managing these different aspects of CDS requires not only a detailed understanding of each individual part, but also of the interdependencies between them. In this paper, a new method is presented to analyze the exploration of design spaces in CDS. The method analyzes the designs generated during the synthesis process and visualizes how the design space is explored with respect to a) design characteristics, and b) objectives. The selected algorithm as well as the grammar rules can be analyzed with this approach to support the human designer in successfully understanding and applying a CDS method. The case study demonstrates how the method is used to analyze the synthesis of bicycle frames. Two algorithms are compared for this task. Results demonstrate how the method increases the understanding of the different components in CDS. The presented research can be useful for both novices to CDS to help them gain a deeper understanding of the interplay between grammar rules and guidance of the synthesis process, as well as for experts aiming to further improve their CDS application by improving parameter settings of their search algorithms, or by further refining their design grammar. Additionally, the presented method constitutes a novel approach to interactively visualize design space exploration considering not only designs objectives, but also the characteristics and interdependencies of different designs.


Author(s):  
ADITYA SOMAN ◽  
SWAPNIL PADHYE ◽  
MATTHEW I. CAMPBELL

The design of sheet metal components is perhaps one of the more challenging concurrent activities for design and manufacturing engineers. To aid this design process, a method is developed to encapsulate the constraints of sheet metal that make designing such components a tedious and iterative procedure. This project involves the implementation and testing of a geometric representation scheme for building feasible sheet metal components through the use of 17 grammar rules that capture manufacturing operations like cutting and bending. The implemented system has benefits both as a user interaction tool and as the basis for a computational design synthesis approach for designing sheet metal components. An example of a constructed sheet metal component is shown along with the method for invoking the sheet metal grammar to create this component.


2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Merel van Diepen ◽  
Kristina Shea

Soft locomotion robots are intrinsically compliant and have a large number of degrees of freedom. They lack rigid components that provide them with higher flexibility, and they have no joints that need protection from liquids or dirt. However, the hand-design of soft robots is often a lengthy trail-and-error process. This work presents the computational design of virtual, soft locomotion robots using an approach that integrates simulation feedback. The computational approach consists of three stages: (1) generation, (2) evaluation through simulation, and (3) optimization. Here, designs are generated using a spatial grammar to explicitly guide the type of solutions generated and exclude infeasible designs. The soft material simulation method developed and integrated is stable and sufficiently fast for use in a highly iterative simulated annealing search process. The resulting virtual designs exhibit a large variety of expected and unexpected gaits, thus demonstrating the method capabilities. Finally, the optimization results and the spatial grammar are analyzed to understand and map the challenges of the problem and the search space.


Author(s):  
Corinna Königseder ◽  
Kristina Shea

AbstractThe use of generative design grammars for computational design synthesis has been shown to be successful in many application areas. The development of advanced search and optimization strategies to guide the computational synthesis process is an active research area with great improvements in the last decades. The development of the grammar rules, however, often resembles an art rather than a science. Poor grammars drive the need for problem specific and sophisticated search and optimization algorithms that guide the synthesis process toward valid and optimized designs in a reasonable amount of time. Instead of tuning search algorithms for inferior grammars, this research focuses on designing better grammars to not unnecessarily burden the search process. It presents a grammar rule analysis method to provide a more systematic development process for grammar rules. The goal of the grammar rule analysis method is to improve the quality of the rules and in turn have a major impact on the quality of the designs generated. Four different grammars for automated gearbox synthesis are used as a case study to validate the developed method and show its potential.


2005 ◽  
Vol 5 (3) ◽  
pp. 171-181 ◽  
Author(s):  
Jonathan Cagan ◽  
Matthew I. Campbell ◽  
Susan Finger ◽  
Tetsuo Tomiyama

The field of computational design synthesis has been an active area of research for almost half a century. Research advances in this field have increased the sophistication and complexity of the designs that can be synthesized, and advances in the speed and power of computers have increased the efficiency with which those designs can be generated. Some of the results of this research have begun to be used in industrial practice, yet many open issues and research challenges remain. This paper provides a model of the automated synthesis process as a context to discuss research in the area. The varied works of the authors are discussed as representative of the breadth of methods and results that exist under the field of computational design synthesis. Furthermore, some guidelines are presented to help researchers and designers find approaches to solving their particular design problems using computational design synthesis.


2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Corinna Königseder ◽  
Kristina Shea

Graph grammars are used for computational design synthesis (CDS) in which engineering knowledge is formalized using graphs to represent designs and rules that describe their transformation. Most engineering tasks require both topologic and parametric rules to generate designs. The research presented in this paper compares different strategies for rule application to combine topologic and parametric rules during automated design synthesis driven by a search process. The presented strategies are compared considering quantity and quality of the generated designs. The effect of the strategies, the selected search algorithm, and the initial design, from which the synthesis is started, are analyzed for two case studies: gearbox synthesis and bicycle frame synthesis. Results show that the effect of the strategy is dependent on the design task. Recommendations are given on which strategies to use for which design task.


Author(s):  
Shraddha Sangelkar ◽  
Daniel A. McAdams

Graph grammars, a technique for formulating new graphs based on a set of rules, is a very powerful tool for computational design synthesis. It is particularly suitable for discrete categorical data where principal component analysis is generally not applicable. Furthermore, this technique utilizes three different programs in conjunction with a design repository, which is opposed to traditional methods that require experts to empirically derive graph grammars. This technique can be separated into three steps. These steps are the creation of the input, graph data mining, and interpretation of the output with the intention of these steps being to automate or assist an expert with the process of extracting engineering graph grammars. Graph grammars that can then serve as guidelines during concept generation. The results of this paper show that this technique is very applicable to computational design synthesis by testing only a small number of products and still producing tangible results that coincide with empirically derived graphs. Fifty electromechanical products from the design repository are used in this study. When comparing, the machine generated grammar rules with expert derived grammar rules, it can be seen that only 14% cannot be developed, 58% cannot be mined with the current setup and 28% were mined with the current set up. However, it is important to keep in mind a few considerations. Specifically, the technique does not replace the expert. Instead, the technique acts as more of an aid than a replacement. Also, while this technique has great potential in regards to computational design synthesis, it is limited to the products in the design repository and the current implementation of the aforementioned programs. Despite these minor considerations, this work proposes application of graph data mining to derive engineering grammars.


Author(s):  
Aditya Soman ◽  
Matthew Campbell

This paper involves the development, implementation and testing of a geometric representation scheme for building feasible sheet metal components. The approach taken here is based on prior shape grammar methods for engineering design. A series of seventeen grammar rules have been developed to represent a variety of cutting and bending operations that can be applied to sheet metal to construct feasible shapes. The implemented system has benefits as both a user interaction tool or as the basis for a computational design synthesis approach for designing sheet metal components. An example of a real component is shown as well as the method for invoking the sheet metal grammar to create this component.


Author(s):  
Merel van Diepen ◽  
Kristina Shea

Soft robots are intrinsically compliant, which makes them suitable for interaction with delicate objects and living beings. The vast design space and the complex dynamic behavior of the elastic body of the robots make designing them by hand challenging, often requiring a large number of iterations. It is thus advantageous to design soft robots using a computational design approach that integrates simulation feedback. Since locomotion is an essential component in many robotic tasks, this paper presents the computational design synthesis of soft, virtual, locomotion robots. Methods used in previous work give little insight into and control over the computational design synthesis process. The generated solutions are also highly irregular and very different to hand-designed solutions. Also, the problem requirements are solely modeled in the objective function. Here, designs are generated using a spatial grammar with a rule set that is deduced from known locomotion principles. Spatial grammars make it possible to define the type of morphologies that are generated. The aim is to generate gaits based on different locomotion principles, e.g. walking, hopping and crawling. By combining a spatial grammar with simulated annealing, the solution space is searched for locomotive designs. The designs are simulated using a mass-spring model with stable self-collision so that all generated designs can be evaluated. The resulting virtual designs exhibit a large variety of expected and unexpected gaits. The grammar is analyzed to understand the generation process and assess the performance. The main contribution of this research is modeling of some of the results in the spatial grammar rather than the objective function. Thus, the process is guided towards a class of designs with extremities for locomotion, without having to define the class explicitly. Further, the simulation approach is new and results in a stable method that accounts for self-collision.


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