The Product-Assembly Co-Design (PACo) project aims at bridging the gap between product design and assembly system design by front-loading of assembly knowledge into the early stages of the product development. Currently, most companies consider assembly aspects later in the design process, often in a manual way, solely relying on the experience of assembly engineers. This leads to numerous design changes causing signi cant extra costs. PACo user companies expect that applying these co-design methods and tools will lead to improved designs, internal cost reduction (up to 25%), and will allow them to strengthen their market position and keep their production. One of the innovative goals of this project is a software environment for the formalization of assembly knowledge e.g. Design-for-Assembly (DFA) rules, assembly complexity metrics. This paper presents a general overview of the project and is speci cally focused on the formalization of assembly knowledge, in the scope of workpackage 3 of the project. The goal of this workpackage is the development of a platform for the formalization and quanti cation of assembly knowledge such as product and assembly designs as well as DFA rules and assembly complexity metrics. This platform will transform the qualitative de nitions of such rules and metrics into a mathematical form, allowing an objective comparison and ranking of di erent conceptual designs with respect to assembly complexity. Based on this platform, a framework will be developed for the co-design of the product and its assembly system in a semi-automated work ow.
The Product-Assembly Co-Design (PACo4) project is an ongoing national project in Flanders region, Belgium. It is a collaborative research projects between researchers and industry which is funded by Flanders Make in the scope of design and optimization cluster. Flanders Make is the strategic research centre for the manufacturing industry. The main goal of Flanders Make is realising a top-level research network in Flanders that delivers full support to the innovative projects for manufacturing companies. In this way, it contributes to the new products and production processes that help to realise the vehicles, machines and factories of the future.
PACo project is a SBO (Strategic Basic Research) project and it aims at
bridging the gap between product design and assembly system design by
frontloading of assembly knowledge into the early stages of the product development
[
All companies involved in the user group of this project indicate a clear need to support their engineers with methods and software tools enabling assessment of assembly complexity in an early design stage, allowing co-optimization of product performance with ease-of-assembly in a quantitative way, and allowing trade-o analysis of various solutions. As these software tools are beyond the state-of-the-art, the research partners will join forces to shift the state-of-the-art in product-assembly co-design. The results of the project will be evaluated with the industrial use cases.
The project duration is 4 years (started in September 2018). It has 5 corelab partners, see Table 1, from Belgian universities (KULueven, University of Antwerp and University of Ghent) and research-center (Flanders Make) which play the role of research group in the project. Also, it has 9 industrial partners as the user group of the project. While the user group provides the industrial use cases and industrial challenges in the scope of the project (via 6-monthly user group meetings), the research group addresses these cases and challenges with their innovative research studies and technologies. FM-CoDesignS Flanders Make Core Lab Research Center PraonjdecWtcPo1orldeaindaetror FM-ProductS Flanders Make Core Lab Research Center WP2 leader AnSyMo/CoSys Univ. of Antwerp Core Lab University WP3 leader DMMS-D KULeuven-PMA Core Lab University WP4 leader EEDT Univ. of Ghent Core Lab University WP5 leader Atlas Copco Atlas Copco Airpower NV Industrial partner Use Case provider Borit Borit NV Industrial partner Industrial user CNHi CNHi Industrial Belgium Industrial partner Use Case provider Noesis Noesis Solutions Industrial partner Industrial user Reynaers Reynaers Aluminium Industrial partner Industrial user Siemens Siemens PLM Software Industrial partner Industrial user Tenneco Tenneco Inc. Industrial partner Industrial user VHA Van Hoecke Automation Industrial partner Industrial user Vitalo Vitalo Global Termoforming Industrial partner Use Case provider
The project has 7 workpackages which are shown in Figure 1 demonstrating their interactions with each other. There are 3 managemental workpackages namely WP1-Management, WP2-Use Cases, and WP-7 Vaporization and Dissemination in the project. Also, there are 4 technical workpackages namely WP3-Formalization of assembly knowledge, WP4-Product optimization, WP5Assembly system optimization, and WP6-Semi-automated product-assembly codesign. Here, we give a brief description of each technical workpackage.
WP3 aims to keep the knowledge of the product and production system in a systematic way and transform this data to meet the system requirements. This WP, as the information management center of the project, uses software engineering techniques and extende them to apply on PACo project. WP3 has a software-intensive role in the project which is the focus of this paper.
The goal of WP4 is the development of one or more optimization algorithms for the (multi-objective) optimization of early-stage product designs. These designs will be optimized with respect to product performance and/or one or more assembly complexity metrics resulting in a set of (Pareto-)optimal designs.
The aim of WP5 is the development of algorithms for (i) the derivation of assembly steps from the product description, (ii) the optimization of the assembly process (the order in which the di erent steps will be performed) and (iii) the optimization of the assembly system (the resources performing these steps), all for a given product.
Finally, WP6 intends to develop semi-automated work ows to perform productassembly co-design. A comparative study will be performed to compare their performance (speed, ease of use, and so on) for the di erent generic use cases. This allows design teams to select the work ow most suited to their product class. Due to the variety of the interacting components and stakeholders in the project, the system is complex (structural complexity) and we need for a systematic way to handle this complexity and to provide: (I) Data integration (II) Data exchange between design tools (Product design and Assembly process design) and analysis/optimization tools (III) Interaction between the designer and the tools (IV) a Standard interface for a third party integration. WP3 addresses this problem with formalizing the assembly knowledge in this project.
In general, WP3 aims the development of a platform for the formalization
and quanti cation of assembly knowledge such as Design for Assembly (DFA) [
Assembly knowledge-base aims to keep the all data required for a product and its assembly process to be analyzed and optimized later, see Figure 2. This data will be provided/used by the other components such as CAD tools (e.g. FreeCAD and/or optimization tools such as Minizinc and Julia .
To provide a formal and systematic approach to keep the knowledge in the
system and provide the aforementioned requirements, it is decided to provide the
data model using Model-driven Engineering (MDE) techniques to later
analysis and optimisation. This will be realized by developing 3 Domain-speci c
Languages (DSL) [
To implement the above-mentioned DSLs, the concept dictionary is provided by doing commonality and variability analysis collaboratively with all partners. This concept dictionary paves the way for developing the domain-speci c metamodel. The metamodel will be used to instantiate some of the user case studies to evaluate the comprehensiveness and expressiveness of the metamodel. The metamodel can be used directly or can be transformed to a context-free grammar to play the role of abstract syntax of the DSLs. Based on this abstract syntax, text/graphical concrete syntaxes will be provided to develop the editors for the DSLs. These editors can be extended by adding domain rules as constraint checking feature of the languages. Later, the semantics of the languages will be de ned by providing the transformation rules for each language to transform the models to the target tool speci cations (such as Minizinc).
The potential innovative results of the PACo project can be characterized as follows: { a software environment for the formalization of assembly knowledge (e.g.
DFA rules, assembly complexity metrics). { tools and algorithms for automated multi-objective optimization of the earlystage design of a product, taking into account the product performance and its assembly complexity. { tools and algorithms to automatically nd the optimal assembly process (order of steps) and assembly system (resources allocation), for a given earlystage product design { a framework for the co-design of both product and its assembly system in a semi-automated work ow.
The proposed approach will provide a semi-automatic mechanism for design of the product by considering both, product performance and the assembly process, see Figure 3. In the resulting methodology, the users (design engineers) will interact with the algorithms while designing the product or after nalizing the design. Then, the methodology will be able to evaluate the performance of the product as well as assess the assembly process required to produce the product. It is foreseen that the user can interact with the algorithm in this evaluation process in order to provide input when required. Later, the system can suggest optimized product design and assembly sequence considering the already adjusted evaluation criteria. Finally, the user will select/con rm the suggested choice(s) and continue the design iterations. By employing the proposed methodology, the trade-o analysis between product performance and assembly process will be formally and consistently addressed.
The companies expect that applying this methodology, empowered by
codesign [
This research was supported by Flanders Make, the strategic center for the manufacturing industry within the framework of the PACo SBO project.