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Novel Robustness Measures for Engineering Design Optimisation

Authors: P. Fleck (FhOÖ-HEAL), M. Kommenda (FhOÖ-HEAL), T. Prante (VRES), M. Affenzeller (FhOÖ-HEAL)

Abstract: This paper presents novel robustness measures to analyse and compare the robustness of solutions for constrained optimisation problems in the eld of engineering design optimisation. First, we de ne uncertainty in production processes and present a method to quantify uncertainty. Based on the variations of a solution that are introduced by uncertainty, we want to assess the robustness of those solutions towards those variations. We show how a solution's quality and feasibility (with regards to constraint violation) change with increasing uncertainty and discuss how those changes determine the robustness of that solution. Furthermore, we present a method of aggregating that information into a single, real-valued robustness measure. This novel robustness measure can be used to select solutions that have a high robustness along with a high quality. To test the presented measures extensively, we apply them to various solutions for benchmark
problems from published literature in the eld of engineering design optimisation.

Keywords: engineering design optimisation, uncertainty, robustness, optimisation, benchmark, constrained optimisation, multi-objective

Conference / Journal: International Journal of Simulation and Process Modelling

March 2018

Task categorisation for identification of design automation opportunities

Authors: E. Rigger (VRES), T. Stankovic (ETH-EDAC), K. Shea (ETH-EDAC)

Abstract: Engineering design automation has been an active field of research and application for more than five decades. Despite a multitude of available methods stemming from research fields such as Knowledge-Based Engineering (KBE) and Computational Design Synthesis (CDS) the application context in industry is mostly limited to routine tasks. Here we propose a means to foster the transition of academic methods to industrial practice through a comprehensible and comprehensive design automation task categorisation that allows practitioners to grasp the opportunities state-of-the-art design automation offers. The categorisation is based on a critical investigation of 77 papers stemming from KBE and CDS, respectively, and is detailed with respect to knowledge needed for complete formalisation of a task, i.e. inputs, outputs and goals, as well as available automation methods. A thorough discussion indicates the context of the work with current design practice and provides a consolidation of the research fields KBE and CDS including the derivation of technological requirements for design automation task definition by practitioners. Thus, this paper contributes not only by consolidating two research fields but also by presenting technological requirements for further streamlining the process of realising design automation applications in industry.

Keywords: Design automation; Knowledge-Based Engineering; Computational Design Synthesis; Task Categorization; Task Definition

Conference / Journal: Journal of Engineering Design

January 2018

Multi-Objective Optimal Design of Obstacle-Avoiding Two-Dimensional Steiner Trees with Application to Ascent Assembly Engineering

Authors: A-C. Zavoianu (JKU-Linz), S. Saminger-Platz (JKU-Linz), D. Entner (VRES), T. Prante (VRES), M. Hellwig (FhV-PPE), M. Schwarz (LWN), K. Finck (LWN)

Abstract: We present an effective optimization strategy that is capable of discovering high-quality cost-optimal solution for 2D path network layouts that, among other applications, can serve as templates for complete ascent assembly structures. The main innovative aspect of our approach is that our aim is not restricted to simply synthesizing optimal assembly designs with regard to a given goal, but we also strive to discover the best trade-offs between geometric and domain-dependent optimal designs. As such, the proposed approach is centered on a variably constrained multi-objective formulation of the optimal design task and on an efficient coevolutionary solver. The results we obtained on both artificial problems and realistic design scenarios based on an industrial test case empirically support the value of our contribution to the field of design automation.

Keywords: Manufacturing , Design , Design automation , Optimization , Tradeoffs

Conference / Journal: ASME Journal of Mechanical Design

December 2017

State-of-the-Art Overview on 3D Model Representations and Transformations in the Context of Computer-Aided Design

Authors: C. Schinko (FhA-VC), A. Riffnaller-Schiefer (TU-Graz), U. Krispel (TU-Graz), E. Eggeling (FhA-VC); T. Ullrich (FhA-VC)

Abstract: Within a virtual world, either in virtual reality or in a simulation environment, the digital counterparts of real objects are described by mathematical and computational models. Depending on the purpose, the field of application, and the used toolchain a wide variety of model representations is established. As a consequence, conversion methods and transformation algorithms are becoming increasingly important. This article gives a state of the art overview on model representations and on the most important transformation techniques.

Keywords: 3D Model Representations; 3D Transformations; Computer-Aided Design

Journal: International Journal on Advances in Software, vol 10 no 3 & 4


September 2017

Interactive Optimization of a Path Planning Algorithm by Virtual Commissioning of the Robot

Authors: R. Fleisch (VRES), D. Entner (VRES), T. Prante (VRES), R. Pfefferkorn (Schelling)

Abstract: Optimized path planning contributes to reducing the non-productive time of material handling in fully automated manufacturing. This paper presents a case study from the machine-tool industry sector about optimization of a path planning algorithm with the goal to minimize the time a material handling gantry robot requires to follow a feedback path, i.e. feeding a just cut part again to the saw which had just cut it, in order to realize more and more complex cutting patterns. Particularities of the case study configuration led to the application of an interactive optimization approach based on the definition and manipulation of rules for smoothing of initially planned paths and the exploration of the impacts of the rules on the time the material handling robot requires for traversing these paths by means of visual examination as well as by virtual commissioning. The achieved results were deployed in plants for cutting wooden or metal panels.

Keywords: Robot Path Planning, Control System, Optimisation, Virtual Commissioning.

Conference / Journal: 12th International Conferences on evolutionary  and deterministic methods for design optimization and control with application to industrial and societal problems - EUROGEN 2017

September 2017

A Box-Type Boom Optimization Use Case with Surrogate Modeling towards an Experimental Environment for Algorithm Comparison

Authors: P. Fleck (FhOÖ-HEAL), D. Entner (VRES), C. Münzer (ETH-EDAC), M. Kommenda (FhOÖ-HEAL), T. Prante (VRES), M. Affenzeller (FhOÖ-HEAL), M. Schwarz (LWN), M. Hächl (LWN)

Abstract: Simulation-based optimization problems are often an inherent part in engineering design tasks. This paper introduces one such use case, the design of a box-type boom of a crane, which requires a time consuming structural analysis for validation. To overcome high runtimes for optimization approaches with numerous calls to the structural analysis tool, we here present several ways of approximating the structural analysis results using surrogate models. Results show a strong correlation between certain statics input and output parameters, and that various surrogate modeling approaches yield similar results in terms of accuracy and impact of the predictors on the output. The box-type boom use case together with the surrogate models shall serve as an industrial optimization benchmark for comparing various algorithms on this simulation-based optimization problem.

Keywords: Design Optimisation, Surrogate Modelling, Algortihm Benchmark.

Conference / Journal: 12th International Conferences on evolutionary  and deterministic methods for design optimization and control with application to industrial and societal problems - EUROGEN 2017

September 2017

On the Optimization of 2D Path Network Layouts in Engineering Designs via Evolutionary Computation Techniques

Authors: A-C. Zavoianu (JKU-Linz), S. Saminger-Platz (JKU-Linz), M. Hellwig (FhV-PPE), D. Entner (VRES), T. Prante (VRES)

Abstract: We describe an effective optimization strategy that is capable of discovering innovative cost-optimal designs of complete ascent assembly structures. Our approach relies on a continuous 2D model abstraction, an application-inspired multiobjective formulation of the optimal design task and an efficient coevolutionary solver. Results on both artificial problems and an industrial test case empirically support the value of our contribution to the field of design automation.

Keywords: Multi-Objective Optimisation, Design Automation, Ascent Assembly Design

Conference / Journal: 12th International Conferences on evolutionary  and deterministic methods for design optimization and control with application to industrial and societal problems - EUROGEN 2017

September 2017

Optimization of Ascent Assembly Design based on a Combinatorial Problem Representation

Authors: M. Hellwig (FhV-PPE), D. Entner /VRES), T. Prante (VRES), A-C. Zavoianu (JKU-Linz), M. Schwarz (LWN), K. Fink (LWN)

Abstract: The paper addresses the integration of optimization in the automated design process of ascent assemblies. The goal is to automatically search for an optimal path connecting user defined inspection points while avoiding obstacles. As a first step towards full automation of the ascent assembly design, a discrete 2D model abstraction is considered. This establishes a combinatorial optimization problem, which is tackled by the use of two distinct strategies: a greedy heuristic and a genetic algorithm variant. Considering multiple test cases, partly artificial and partly based on a manufactured crane, the usability of our approach is demonstrated.

Keywords: Optimal Path, Combinatorial Optimisation Problem, Heuristic Optimisation, Genetic Algortihm

Conference / Journal: 12th International Conferences on evolutionary  and deterministic methods for design optimization and control with application to industrial and societal problems - EUROGEN 2017

August 2017

Surrogate-Based Multi-Objective Optimization of Electrical Machine Designs Facilitating Tolerance Analysis

Authors: G. Bramerdorfer (JKU-Linz), A-C. Zavoianu (JKU-Linz)

Abstract: Multi-objective optimization algorithms are becoming ever more popular in the field of electrical machine design as they provide engineers with an automated way of efficiently exploring huge design spaces when searching for machines that are simultaneously highly competitive regarding several objectives, such as efficiency, material costs, torque ripple, and others. Apart from exhibiting these good target characteristics, a good design should also be robust, i.e., it should not be very sensitive to slight changes in its design parameters as this would either seriously impact production costs or make the physical machine behave differently than its (optimized) computer simulation model. This paper is focused on describing how global surrogate models (i.e., nonlinear regression models), that are created in order to reduce the dependence on finite-element (FE) simulations during the multi-objective optimization run, can be easily reused to perform very fast local and global tolerance/sensitivity analyses of generated designs. While obtained in a fraction of the time required by the complementary FE-based approach, the surrogate-based sensitivity estimates are able to provide accurate and valuable information regarding the robustness of electrical machine designs. Ultimately, by integrating robustness-related information with Pareto front projections, we aim to provide engineers with much clearer pictures of the specific problem-related trade-off discovered by the automated design optimization procedure.

Keywords: optimal design, surrogate-based optimization, multi-objective optimization, tolerance/sensitivity analysis, efficiency, cogging torque, torque ripple


July 2017

A Federated Enterprise Architecture and MBSE Methodological Framework for integrating Design Automation into a global PLM approach

Authors: T. Vosgien (VRES), E. Rigger (VRES), M. Schwarz (LWN), K. Shea (ETH-EDAC)

Abstract: PLM and Design Automation (DA) are two interdependent and necessary approaches to increase the performance and efficiency of product development processes. Often, DA systems’ usability suffers due to a lack of integration in industrial business environments stemming from the independent consideration of PLM and DA. This article proposes a methodological and modeling framework for developing and deploying DA solutions within a global PLM approach. This framework supports the identification of DA potentials and the definition of the DA task building blocks to support DA task formalization by practitioners. The aim is to make the specification and development of DA solutions more efficient and aligned with the business requirements and with the existing digital environments. This framework combines the usage of two standardized modeling languages to make the captured knowledge re-usable across heterogeneous PLM and DA applications. An industrial case study demonstrating the applicability of the framework is introduced and discussed.

Keywords: Design Automation, Product Lifecycle Management, Enterprise Architecture, Model-Based System Engineering, ArchiMate, SysML

Conference / Journal: IFIP 14th International Conference on Product Lifecycle Management

July 2017

Engineering Knowledge Extraction for Semantic Interoperability between CAD, KBE and PLM systems

Authors: J. Cho (TUW-MIVP), T. Vosgien (VRES), D. Gerhard (TUW-MIVP)

Abstract: For the deployment of both Product Lifecycle Management (PLM) and Knowledge-Based Engineering (KBE) approaches, product and process engineering knowledge needs to be identified, acquired, formalized, processed and reused. While knowledge acquisition is still a bottleneck process, the formalized engineering knowledge is still too often encapsulated in CAD models and in KBE systems developed in vendor-specific environments. To address this issue, this paper introduces a possible solution enabling the enrichment of a CAD-KBE-PLM integration schema that provides a standardized and neutral representation of engineering knowledge for further reuse across heterogeneous CAD, KBE and PLM systems. To enrich this schema, the proposed solution combines the use of a Multi-CAD API library – which allows platformindependent and automatic extraction of engineering knowledge from CAD models into an XML-based representation – and a Knowledge Acquisition and Formalization Assistant (KAFA) which assist domain experts to formalize their procedural knowledge.

Keywords: Knowledge Acquisition, Semantic interoperability, Computer-Aided Design, KBE-PLM Integration

Conference / Journal: IFIP 14th International Conference on Product Lifecycle Management

May 2017

Simulation-Based Computational Design Synthesis Using Automated Generation of Simulation Models from Concept Model Graphs

Authors: C. Muenzer (ETH-EDAC) and K. Shea (ETH-EDAC)

Abstract: Current approaches in computational design synthesis (CDS) enable the human designer to explore large solution spaces for engineering design problems. To extend this to support designers in embodiment and detail design, not only the generation of solution spaces is needed but also the automated evaluation of engineering performance. Here, simulation methods can be used effectively to predict the behavior of a product. This paper builds on a general approach to automatically generate solution spaces for energy
and signal-based engineering design tasks using first-order logic and Boolean satisfiability. The generated concept model graphs (CMGs) are now in this paper automatically transformed into corresponding bond-graph-based simulation models. To do this, guidelines for creating partial simulation models for the available synthesis building blocks are presented. The guidelines ensure valid causality in the final simulation model. Considering the connections in the concept model graphs, the simulation models are automatically generated and simulated. The simulation results are then used to calculate different objectives, constraints, and performance metrics. The method is validated using automotive powertrains as a case study. One hundred and sixty-two different powertrain concepts are generated and evaluated, showing the advantages of electric powertrains with respect to CO2 emissions and the importance of considering intelligent control strategies in the future for hybrid ones.

Keywords: Computational Design Synthesis, Modeling , Signals , Simulation models , Engines ,Optimization

Conference / Journal: ASME Journal of Mechanical Design

April 2017

3D Model Representations and Transformations in the Context of Computer-Aided Design – a state of the art overview –

Authors: C. Schinko (FhA-VC), U. Krispel (TU-Graz), E. Eggeling (FhA-VC), T. Ullrich (FhA-VC)

Abstract: Within a virtual world, either in virtual reality or in a simulation environment, the digital counterparts of real objects are described by mathematical and computational models. Depending on the purpose, the field of application, and the used toolchain a wide variety of model representations is established. As a consequence, conversion methods and transformation algorithms are becoming increasingly important. This article gives a state of the art overview on model representations and on the most important transformation techniques.

Keywords: 3D Model Representations; 3D Transformations

Conference / Journal: Ninth International Conferences on Advances in Multimedia

February 2017

Multi-Objective Topology Optimization of Electrical Machine Designs using Evolutionary Algorithms with Discrete and Real Encodings

Authors: C. Zavoianu (JKU-Linz), G. Bramerdorfer (JKU-Linz), E. Lughofer (JKU-Linz), S. Saminger-Platz (JKU-Linz)

Abstract: We describe initial results obtained when applying di erent multi-objective evolutionary algorithms (MOEAs) to direct topology optimization (DTO) scenarios that are relevant in the eld of electrical machine design. Our analysis is particularly concerned with investigating if the use of discrete or real-value encodings combined with a preference for a particular population initialization strategy can have a severe impact on the performance of MOEAs applied for DTO.

Keywords: evolutionary algorithms, multi-objective optimization, discrete encoding, real encoding, topology optimization, electrical machine design

Conference / Journal: Sixteenth International Conference on Computer Aided Systems Theory - EUROCAST 2017

February 2017

Search and Retrieval in CAD Databases - a user-centric State-of-the-Art Overview

Authors: C. Schinko (FhA-VC), T. Vosgien (VRES), T. Prante (VRES), T. Schreck (TU Graz), T. Ullrich (FhA-VC)

Abstract: This article presents a state-of-the-art overview on shape, information and design retrieval systems in the context of CAD engineering. In contrast to existing surveys, we classify the different approaches from a CAD application user point of view. As a consequence, we focus on features of surveyed techniques such as: supported shape data types, handling of geometric invariances, support of metadata, supported query types, quality of retrieval results, and the availability of implementations.

Keywords: Computer-Aided Design, Information Retrieval, Library Services, CAD Search

Conference / Journal: International Joint Conference on Computer Vision and Computer Graphics Theory and Applications - VISIGRAPP17

September 2016

Analysis of Uncertainty in Engineering Design Optimization Problems

Authors: Philipp Fleck (HEAL), Michael Kommenda (HEAL), Michael Affenzeller (HEAL), Thorsten Prante (VRES)

Abstract: In this paper, we analyze popular benchmark instances in the field of engineering design optimization regarding the robustness of published solutions. First, we implement selected benchmark problems with HeuristicLab and show the advantages of having a framework that enables rapid prototyping for optimization and analysis. Then, we show that many solutions quickly become infeasible when considering uncertainty like production inaccuracies. Based on these findings, we motivate why robust solutions for engineering design are important and present methods for measuring, identifying and visualizing robustness. Finally, we present how solutions can be compared and selected using a novel robustness measure.

Keywords: Engineering Design Optimization, Constraint Handling, Uncertainty, Robustness

Conference / Journal: European Modeling and Simulation Symposium (Simulation in Industry) - EMSS 2016

September 2016

Evolution Under Strong Noise: A Self-Adaptive Evolution Strategy Can Reach the Lower Performance Bound - The pcCMSA-ES

Authors: Michael Hellwig (FhV) and Hans-Georg Beyer (FhV)

Abstract: According to a theorem by Astete-Morales, Cauwet, and Teytaud, “simple Evolution Strategies (ES)” that optimize quadratic functions disturbed by additive Gaussian noise of constant variance can only reach a simple regret log-log convergence slope ≥−1/2 (lower bound). In this paper a population size controlled ES is presented that is able to perform better than the −1/2 limit. It is shown experimentally that the pcCMSA-ES is able to reach a slope of −1 being the theoretical lower bound of all comparison-based direct search algorithms.

Keywords: -----

Conference / Journal: International Conference on Parallel Problem Solving from Nature - PPSN 2016

September 2016

A Path Planning Algorithm for a Materials Handling Gantry Robot and its Validation by Virtual Commissioning

Authors: Ruth Fleisch (VRES), Robert Schöch (VRES), Thorsten Prante (VRES), Reinhard Pfefferkorn (Schelling Anlagenbau)

Abstract: Adaptive and intelligent path planning is required to provide fully automated and optimized transportation systems directed at reducing the non-productive time related to materials handling. This paper presents a case study from the machine-tool industry sector: In order to optimize the efficiency of a cut-to-size plant with feedbacks in the material flow, a materials handling gantry robot is employed for transporting panels of largely varying sizes. For each of these panels, a path within spatial limitations, which are partially very tight, is planned so that collisions are prevented. This paper describes the developed path planning algorithm and its integration with the programmable logic controller (PLC) of the robot. Towards improving solution quality and decreasing lead time, first, the integration with the PLC is realized by software components automatically generated based on code developed in a high-level programming language. Second, virtual commissioning of the materials handling robot was performed.

Keywords: Robot Path Planning, Control System, Virtual Commissioning, Gantry Robot.

Conference / Journal: International Conference on Manufacturing Research - ICMR 2016

July 2016

KBE-PLM integration schema for Engineering Knowledge Re-use and Design Automation

Authors: Jullius Cho (TUW), Thomas Vosgien (VRES), Thorsten Prante (VRES), Detlef Gerhard (TUW)

Abstract: This paper addresses the challenges related to KBE-PLM systems integration in order to unlock engineering knowledge from proprietary representations and to manage the lifecycle of KBE models as well as their usage by different design automation applications. Essential constituents of product knowledge are identified and analyzed and the concepts of design intent and design rationale are re-introduced as key enablers to re-use this product knowledge in the appropriate KBE context. The paper introduces a KBE-PLM integration framework including a platform-independent Open KBE repository structured according to the KBE-PLM integration schema. This schema is a multi-layer neutral product and knowledge data model designed for integrating information from parameterized Computer-Aided Design (CAD) models, rule-based KBE systems and PLM systems.

Keywords: Knowledge-Based Engineering, Design Automation, Knowledge re-use, Design Intent, Design Rationale.

Conference / Journal: IFIP International Conference on Product Lifecycle Management - PLM16

May 2016

Estimating the Potential of State of the Art Design Automation - Tasks, Methods, and Benefits

Authors: Eugen Rigger (VRES-ETH), Clemens Münzer (ETH), Kristina Shea (ETH).

Abstract: In this study, multiple methods for categorization and characterization of design tasks are analyzed and a mapping of design task characteristics to methods is presented. Further, approaches from literature regarding estimation of potential and success validation are investigated. Due to the lack of an unambiguous categorization of design tasks as well as a general distinct mapping of tasks to methods, based on analysis of multiple recently published design automation methods, this paper introduces an approach that allows mapping of design task characteristics to design automation methods. Additionally, an implicit mapping of automation methods to potential benefits is performed. Therefore, it is expected to improve the understanding of opportunities and potential benefits of design automation in industry.

Keywords: Design Automation, Task Specification, Task Categorization, Computational Design Synthesis (CDS), Evaluation of benefits

Conference / Journal: International Design Conference - DESIGN 2016

April 2016

Mutation strength control via meta evolution strategies on the ellipsoid model

Authors: Michael Hellwig (FhV), Hans-Georg Beyer (FhV)

Abstract: In this paper, The ability of a hierarchical organized evolution strategy (Meta-ES) to optimally control its mutation strength is investigated on convex-quadratic functions (referred to as ellipsoid model). Applying the dynamical systems analysis approach a first step towards the analysis of the Meta-ES behavior is conducted considering isolation periods of length = 1. A nonlinear system of difference equations is derived to describe the mean-value evolution of the Meta-ES. In the asymptotic limit case of large search space dimensions this system is suitable to derive closed-form solutions which describe the longterm behavior of the Meta-ES. The steady state mutation strength is bracketed within an interval depending on the mutation strength control parameter . Compared to standard settings in cumulative steplength adaptation (CSA) evolution strategies the Meta-ES realizes almost similar normalized mutation strengths. The performance of the Meta-ES turns out to be more robust to the choice of its control parameters. The results allow for the derivation of the expected running time of the algorithm.

Keywords: Evolution strategies, Meta-ES, ellipsoid model, mutation strength adaptation

Conference / Journal: Theoretical Computer Science, Volume 623 Pages 160-179.

March 2015

Effizienzoptimierte Konstruktion von Kranen und deren Komponenten: Lösungswege und Ergebnisse

Authors: Gerald Frank (VRES), Thorsten Prante (VRES), Vaheh Khachatouri (VRES), Martin Schwarz (LWN), Klara Fink (LWN)

Abstract: Dieser  Beitrag zeigt, dass die Möglichkeiten des automatisierten Erstellens von CAD-Modellen und ihrer Derivate nicht vom Komplexitätsgrad der jeweiligen Baugruppe abhängen. Sowohl bei Detail-, Haupt- als auch bei Gesamtbaugruppen ist es möglich, die Effizienz des Konstruktionsprozesses mittels Konstruktionsautomatisierung erheblich zu steigern. Abhängig von den Charakteristiken und dem Einsatzziel (Vertrieb oder Konstruktion bzw. Produktion) der zu automatisierenden Baugruppe stehen, wie erläutert, unterschiedliche Herangehensweisen zur Verfügung, die in einen allgemeinen Lösungsansatz eingebettet sind und durch Software-Frameworks unterstützt werden. Auf Basis der diskutierten Faktoren kann die Anwendbarkeit der beschriebenen Ansätze aufgrund des jeweils resultierenden Kosten-Nutzen-Verhältnisses bzgl. Umsetzungsaufwand und Kostenersparnis bewertet und gewählt werden. Die Anwendung des vorgestellten Ansatzes ist nicht auf einzelne CAD-Systeme begrenzt. Er wurde so konzipiert, dass jedes CAD-System, das eine entsprechende Schnittstelle zur Verfügung stellt, eingebunden werden kann.

Event: 23. Kranfachtagung: Krane - Herausforderungen im Zeichen von Industrie 4.0. Technische Universität Dresden