Simultaneous Optimal Uncertainty Apportionment and Robust Design Optimization of Systems Governed by Ordinary Differential Equations

The inclusion of uncertainty in design is of paramount practical importance because all real-life systems are affected by it. Designs that ignore uncertainty often lead to poor robustness, suboptimal performance, and higher build costs. Treatment of small geometric uncertainty in the context of manufacturing tolerances is a well studied topic. Traditional sequential design methodologies have recently been replaced by concurrent optimal design methodologies where optimal system parameters are simultaneously determined along with optimally allocated tolerances; this allows to reduce manufacturing costs while increasing performance. However, the state of the art approaches remain limited in that they can only treat geometric related uncertainties restricted to be small in magnitude. This work proposes a novel framework to perform robust design optimization concurrently with optimal uncertainty apportionment for dynamical systems governed by ordinary differential equations. The proposed framework considerably expands the capabilities of contemporary methods by enabling the treatment of both geometric and non-geometric uncertainties in a unified manner. Additionally, uncertainties are allowed to be large in magnitude and the governing constitutive relations may be highly nonlinear. In the proposed framework, uncertainties are modeled using Generalized Polynomial Chaos and are solved quantitatively using a least-square collocation method. The computational efficiency of this approach allows statistical moments of the uncertain system to be explicitly included in the optimization-based design process. The framework formulates design problems as constrained multi-objective optimization problems, thus enabling the characterization of a Pareto optimal trade-off curve that is off-set from the traditional deterministic optimal trade-off curve. The Pareto off-set is shown to be a result of the additional statistical moment information formulated in the objective and constraint relations that account for the system uncertainties. Therefore, the Pareto trade-off curve from the new framework characterizes the entire family of systems within the probability space; consequently, designers are able to produce robust and optimally performing systems at an optimal manufacturing cost. A kinematic tolerance analysis case-study is presented first to illustrate how the proposed methodology can be applied to treat geometric tolerances. A nonlinear vehicle suspension design problem, subject to parametric uncertainty, illustrates the capability of the new framework to produce an optimal design at an optimal manufacturing cost, accounting for the entire family of systems within the associated probability space. This case-study highlights the general nature of the new framework which is capable of optimally allocating uncertainties of multiple types and with large magnitudes in a single calculation

A Model-based Approach for Designing Cyber-Physical Production Systems

The most recent development trend related to manufacturing is called "Industry 4.0". It proposes to transition from "blind" mechatronics systems to Cyber-Physical Production Systems (CPPSs). Such systems are capable of communicating with each other, acquiring and transmitting real-time production data. Their management and control require a structured software architecture, which is tipically referred to as the "Automation Pyramid". The design of both the software architecture and the components (i.e., the CPPSs) is a complex task, where the complexity is induced by the heterogeneity of the required functionalities. In such a context, the target of this thesis is to propose a model-based framework for the analysis and the design of production lines, compliant with the Industry 4.0 paradigm. In particular, this framework exploits the Systems Modeling Language (SysML) as a unified representation for the different viewpoints of a manufacturing system. At the components level, the structural and behavioral diagrams provided by SysML are used to produce a set of logical propositions about the system and components under design. Such an approach is specifically tailored towards constructing Assume-Guarantee contracts. By exploiting reactive synthesis techniques, contracts are used to prototype portions of components' behaviors and to verify whether implementations are consistent with the requirements. At the software level, the framework proposes a particular architecture based on the concept of "service". Such an architecture facilitates the reconfiguration of components and integrates an advanced scheduling technique, taking advantage of the production recipe SysML model. The proposed framework has been built coupled with the construction of the ICE Laboratory, a research facility consisting of a full-fledged production line. Such an approach has been adopted to construct models of the laboratory, to virtual prototype parts of the system and to manage the physical system through the proposed software architecture

An Integrating Framework for Mixed Systems

International audienceTechnological advances in hardware manufacturing led to an extended range of possibilities for designing physical-digital objects involved in a mixed system. Mixed systems can take various forms and include augmented reality, augmented virtuality, and tangible systems. In this very dynamic context, it is difficult to compare existing mixed systems and to systematically explore the design space. Addressing this design problem, this chapter presents a unified point of view on mixed systems by focusing on mixed objects involved in interaction, i.e. hybrid physical-digital objects straddling physical and digital worlds. Our integrating framework is made of two complementary facets of a mixed object: we define intrinsic characteristics of an object as well as extrinsic characteristics of an object by considering its role in the interaction. Such characteristics of an object are useful for comparing existing mixed systems at a fine-grain level. The taxonomic power of these characteristics is discussed in the context of existing mixed systems from the literature. Their generative power is illustrated by considering a system, Roam, which we designed and developed

An Integrating Framework for Mixed Systems

International audienceTechnological advances in hardware manufacturing led to an extended range of possibilities for designing physical-digital objects involved in a mixed system. Mixed systems can take various forms and include augmented reality, augmented virtuality, and tangible systems. In this very dynamic context, it is difficult to compare existing mixed systems and to systematically explore the design space. Addressing this design problem, this chapter presents a unified point of view on mixed systems by focusing on mixed objects involved in interaction, i.e. hybrid physical-digital objects straddling physical and digital worlds. Our integrating framework is made of two complementary facets of a mixed object: we define intrinsic characteristics of an object as well as extrinsic characteristics of an object by considering its role in the interaction. Such characteristics of an object are useful for comparing existing mixed systems at a fine-grain level. The taxonomic power of these characteristics is discussed in the context of existing mixed systems from the literature. Their generative power is illustrated by considering a system, Roam, which we designed and developed

An intelligent design retrieval system for module-based products

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file viewed on (June 30, 2006)Includes bibliographical references.Vita.Thesis (Ph. D.) University of Missouri-Columbia 2004.Dissertations, Academic -- University of Missouri--Columbia -- Industrial engineering.The manufacturing industry has shifted its approach from traditional manufacturing to agile manufacturing. The production of customized products will increase in response to the individual demands of customers. In exploring various industry trends, researchers have developed different approaches to designing structural products. The most popular and most commonly used approach in contending with structural products is the modularity approach. Moreover, there are several studies that address modularity with respect to structural representations. Even so, there is not yet a unified method for supporting product structure development and for integrating information. Another aspect that current research has not yet adequately addressed is product information retrieval. Those studies that did contend with product information retrieval, addressed one-level retrieval models, while ignoring structural products. Thus, limitations persist in current intelligent retrieval systems. To answer the aforementioned difficulty, a unified indexing scheme is introduced. In this study, the information can be put into numerical form as the proposed unified indexing scheme, which is represented by a component and structure matrix. The component and structure matrix is the way to achieve an application of modular design retrieval because (1) it is a unique presentation of a structural product and provides a uniform representation; and (2) it lists all modules, as well as all components, in one representation. As a result of the proposed method, an intelligent retrieval system will give an enterprise the ability to communicate with its partners efficiently. Therefore, the aim of this research is to develop a system that will enable more efficient and more effective product-design retrieval systems for structural products, and to demonstrate this framework through a Web-based application using Web technology. To obtain reference designs after utilizing the unified indexing scheme, a Fuzzy-ART neural network is implemented in order to handle retrieval tasks

CAGD based 3-D visual recognition

Journal ArticleA coherent automated manufacturing system needs to include CAD/CAM, computer vision, and object manipulation. Currently, most systems which support CAD/CAM do not provide for vision or manipulation and similarly, vision and manipulation systems incorporate no explicit relation to CAD/CAM models. CAD/CAM systems have emerged which allow the designer to conceive and model an object and automatically manufacture the object to the prescribed specifications. If recognition or manipulation is to be performed, existing vision systems rely on models generated in an ad hoc manner for the vision or recognition process. Although both Vision and CAD/CAM systems rely on models of the objects involved, different modeling schemes are used in each case. A more unified system will allow vision models to be generated from the CAD database. We are implementing a framework in which objects are designed using an existing CAGD system and recognition strategies based on these design models are used for visual recognition and manipulation. An example of its application is given

Special Session on Industry 4.0

No abstract available

CAGD based 3-D visual recognition

Journal ArticleA coherent automated manufacturing system needs to include CAD/CAM, computer vision, and object manipulation. Currently, most systems which support CAD/CAM do not provide for vision or manipulation and similarly, vision and manipulation systems incorporate no explicit relation to CAD/CAM models. CAD/CAM systems have emerged which allow the designer to conceive and model an object and automatically manufacture the object to the prescribed specifications. !f recognition or manipulation is to be performed, existing vision systems rely on models generated in an ad hoc manner for the vision or recognition process. Although both Vision and CAD/CAM systems rely on models of the objects involved, different modeling schemes are used in each case. A more unified system will allow vision models to be generated from the CAD database. We are implementing a framework in which objects are designed using an existing CAGD system and recognition strategies based on these design models are used for visual recognition and manipulation. An example of its application is given