| 1. |
- Albo, Anton, 1991, et al.
(författare)
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A framework concept for data visualization and structuring in a complex production process
- 2019
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Ingår i: Procedia Manufacturing. - : Elsevier BV. - 2351-9789. ; 38, s. 1642-1651
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Konferensbidrag (refereegranskat)abstract
- This paper provides a concept study for a visual interface framework together with the software Sequence Planner for implementation on a complex industrial process for extracting process information in an efficient way and how to make use of a lot of data to visualize it in a standardized human machine interface for different user perspectives. The concept is tested and validated on a smaller simulation of a paint booth with several interconnected and supporting control systems to prove the functionality and usefulness in this kind of production system. The paper presents the resulting five abstraction levels in the framework concept, from a production top view down to the signal exchange between the different resources in one production cell, together with additional features. The simulation proves the setup with Sequence Planner and the visual interface to work by extract and present process data from a running sequence.
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| 2. |
- Andersson, Alf, et al.
(författare)
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Inline Process Control – a concept study of efficient in-line process control and process adjustment with respect to product geometry
- 2016
-
Ingår i: Swedish Production Symposium 2016 SPS 2016. - Lund, Sweden.
-
Konferensbidrag (refereegranskat)abstract
- All manufacturing processes have variation which may violate the fulfillment of assembly, functional, geometrical or esthetical requirements and difficulties to reach desired form in all areas. The cost for geometry defects rises downstream in the process chain. Therefore, it is vital to discover these defects as soon as they appear. Then adjustments can be done in the process without losing products or time. In order to find a solution for this, a project with the overall scope “development of an intelligent process control system” has been initiated. This project consists of five different work packages: Inline measurement, Process Evaluation, Corrective actions, Flexible tooling and demonstrator cell. These work packages address different areas which are necessary to fulfill the overall scope of the project. The system shall both be able to detect geometrical defects, propose adjustments and adjust simple process parameters. The results are demonstrated in a demo cell located at Chalmers University of Technology. In the demonstrator all the different areas have been verified in an industrial case study – assembly of GOR Volvo S80. Efficient offline programming for robot based measurement, efficient process evaluation based on case base reasoning (CBR) methodology, flexible fixtures and process adjustments based on corrective actions regarding in going part positioning.
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| 3. |
- Andraos, Rama, et al.
(författare)
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Autoantibodies associated with systemic sclerosis in three autoimmune diseases imprinted by type I interferon gene dysregulation: a comparison across SLE, primary Sjogrens syndrome and systemic sclerosis
- 2022
-
Ingår i: Lupus Science and Medicine. - : BMJ PUBLISHING GROUP. - 2053-8790. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveSLE, primary Sjogrens syndrome (pSS) and systemic sclerosis (SSc) are heterogeneous autoimmune diseases with a dysregulated type I interferon (IFN) system. The diseases often show overlapping clinical manifestations, which may result in diagnostic challenges. We asked to which extent SSc-associated autoantibodies are present in SLE and pSS, and whether these link to serum IFN-alpha, clinical phenotypes and sex. Samples with clinical data from patients with SSc and healthy blood donors (HBDs) served as controls. Finally, the diagnostic performance of SSc-associated autoantibodies was evaluated.MethodsSamples from well-characterised subjects with SLE (n=510), pSS (n=116), SSc (n=57) and HBDs (n=236) were analysed using a commercially available immunoassay (EuroLine Systemic Sclerosis Profile (IgG)). IFN-alpha was quantified by ELISA. Self-reported data on Raynauds phenomenon (RP) were available.ResultsWith exceptions for anti-Ro52/SSA and anti-Th/To, SSc-associated autoantibodies were more frequent in SSc than in SLE, pSS and HBDs regardless of sex. IFN-alpha levels correlated with the number of positive SSc-associated autoantibodies (r=0.29, p<0.0001) and associated with Ro52/SSA positivity (p<0.0001). By using data from SLE, SSc and HBDs, RP was significantly associated with topoisomerase I, centromere protein (CENP)-B, RNA polymerase III 11 kDa, RNA polymerase III 155 kDa and PM-Scl100 whereas Ro52/SSA associated inversely with RP. In SLE, CENP-A was associated with immunological disorder, CENP-B with serositis and Ku with lupus nephritis. By combining analysis of ANA (immunofluorescence) with SSc-associated autoantibodies, the diagnostic sensitivity reached 98% and the specificity 33%.ConclusionsThe 13 specificities included in the EuroLine immunoassay are commonly detected in SSc, but they are also frequent among individuals with other diseases imprinted by type I IFNs. These findings are valuable when interpreting serological data on patients with suspected SSc, especially as patients may present with disease manifestations overlapping different rheumatological diseases. In SLE, we observed associations between manifestations and SSc-associated autoantibodies which have not previously been reported.
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| 4. |
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| 5. |
- Bengtsson, Kristofer, 1979, et al.
(författare)
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Aspect-Oriented Programming for Manufacturing Automation Control Systems
- 2009
-
Ingår i: 13th IFAC Symposium on Information Control Problems in Manufacturing Technology, INCOM’09, Moscow, Russia. - 1474-6670. - 9783902661432 ; 13:PART 1, s. 668-673
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Konferensbidrag (refereegranskat)abstract
- The languages defined by the standard IEC 6-1131 for Programm\-able Logic Controllers (PLCs), have both benefits and drawbacks compared to object-oriented programming languages. For example, the current programming approach is good for maintaining the system, since it is easy to program and comprehend for a plant floor personal with limited programming experience. The main drawbacks are reusability, code dependability and flexibility. This paper proposes an aspect-oriented programming (AOP) approach as an alternative solution, which can keep the benefits and eliminate the drawbacks. AOP is an emerging programming methodology in computer science, which helps the programmer by separating different crosscutting concerns in the program. These crosscutting concerns and tangled behavior are especially important issues in PLC programming, which makes AOP a suitable approach. The paper describes how to adapt the AOP methodology into PLC program development and how it can benefit the control design process.
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| 6. |
- Bengtsson, Kristofer, 1979, et al.
(författare)
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Developing control logic using aspect-oriented programming and sequence planning
- 2013
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Ingår i: Control Engineering Practice. - : Elsevier BV. - 0967-0661. ; 21:1, s. 12-22
-
Tidskriftsartikel (refereegranskat)abstract
- A fundamental functionality of a Programmable Logic Controller (PLC) is to control and execute a set of operations. But a large part of the program code is more involved in supporting the user with concerns like alarm, HMI, communication, safety and manual control. Code related to these supporting concerns is often tangled with operation execution code, the core concerns, which makes it hard to reuse.This paper describes a method to reuse code and functionality when developing PLC programs and code libraries. The method proposes that core concerns are planned with a software tool called Sequence Planner, and the supporting concerns are integrated into the core concerns with a tool based on aspect-oriented programming.
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| 7. |
- Bengtsson, Kristofer, 1979, et al.
(författare)
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Emergency department overview - Improving the dynamic capabilities using an event-driven information architecture
- 2016
-
Ingår i: IEEE International Conference on Emerging technologies and factory automation (ETFA) 2016.
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Konferensbidrag (refereegranskat)abstract
- It is challenging to get an overview and understand- ing of what is going on at an emergency department (ED). This is due to the sometimes turbulent work environment and a large variation in patient processes. To increase the dynamic capability and responsiveness of an ED, it is important that the staff and patients have an overview of what is going on and what will happen in the coming hours. This paper presents a smart online support software that shows the current state of the ED as well as a prediction of the coming hours. The software has been developed as a case study of using agile development ideas when developing new systems for hospitals. The result shows that the use of the event-driven information architecture for healthcare (EVAH) enabled a rapid development of a successful running application, helping the nurses getting an overview of current situation and the coming hours.
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| 8. |
- Bengtsson, Kristofer, 1979
(författare)
-
Flexible design of operation behavior using modeling and visualization
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The behavior of a system can be described by a set of operations. The process of designing and developing these operations poses a real challenge in various situations, for example, when designing automation systems or keeping track of work in an emergency department. This thesis focuses on designing and developing the logical behavior of operations, for example, when they start, when they finish, and how they interact with the rest of the system. Being flexible during design and development entails coping with uncertainty. However, the practice of designing operation behavior is often fairly inflexible because every possible execution route is explicitly specified. This thesis suggests an operation design approach that does not explicitly specify operation routes. This is achieved in the proposed modeling method by only declaring current execution restriction using transition conditions in each operation, together with models representing entities, resources, and variables. A main benefit of the proposed modeling framework is the possibility it offers of creating multiple projections of operation relations to enable better understanding. This is accomplished by automatically generating a multiplicity of sequences showing various operation relations. The key discoveries that accomplish this are the state-based operation methods for relation identification and visualization. These methods make it possible to use the presented research not only when designing automation systems, but also in other applications, such as keeping track of all the patients in an emergency department. Some of the tools and methods presented here have been implemented in a prototype software called Sequence Planner.
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| 9. |
- Bengtsson, Kristofer, 1979, et al.
(författare)
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Flexible Specification of Operation Behavior Using Multiple Projections
- 2014
-
Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 11:2, s. 504 - 515
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Tidskriftsartikel (refereegranskat)abstract
- The execution behavior of a system or a product can often be specified by a set of operations (sometimes called tasks, actions or activities). The process to specify these operations seems to be a real challenge in various situations, for example when designing automation systems or keeping track of the work at an emergency department. To be flexible during design and development, is about coping with uncertainty. However, in practice, specifying operation behavior is often quite inflexible because every possible execution route is explicitly defined. This approach is sometimes refereed to as point-based engineering, which is characterized by the early selection and approval of a single "best" specific solution. This approach can result in neither a robust nor a flexible design process with many rework iterations.
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| 10. |
- Bengtsson, Kristofer, et al.
(författare)
-
Framtidens skadeplats : intervjuer med landstingens beredskapssamordnare
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med föreliggande studie var att genom intervjuer med beredskapssamordnare från Sveriges landsting försöka skapa en bild av hur uppfattningen var att skadeplatsen såg ut idag och skulle kunna kommat att förändras på sikt. Vidare önskade intervjustudien söka svar på frågor som rörde komplexiteten på skadeplatsen genom att diskutera ledningsförhållanden, samverkan med andra aktörer, alarmerings- och dirigeringsfunktionernas roll i det svenska sjukvårdsystemet samt hur ett möjligt arbete med ett återtagande av förmågan till ett civilt försvar skulle påverka systemet i sin helhet. Överlag har detta syfte uppnåtts genom ett rikt material kring relevanta frågeställningar som belyst ett flertal kritiska aspekter både i dagens situation men även för framtiden.Resultatet ger en relativt entydig bild av hur situationen uppfattas på landstingsnivå idag av personalen som behandlar beredskapsfrågorna. Den bild som målas upp fokuserar kanske främst på en upplevd avsaknad av centrala och nationellt övergripande styrningar vilket menligt påverkar förmågan att lyfta ledningsförmågan från regional till nationell nivå vid en större händelse som överstiger den regionala förmågan. Den svenska modellen för att hantera samhällsstörningar av idag är väl anpassad för att hantera händelser inom ramen för det egna länets geografiska område. Befintliga koncept för samverkan och samordning bedöms fungera bra i vardagen, exempelvis vid de vanligaste fallen av skadeplatser: trafik och brand. Detta innebär dock att systemet fungerar väl under förutsättning att händelsen är begränsad i såväl tid och rum som vad avser antalet drabbade. En större händelse eller flera händelser samtidigt på olika platser, särskilt om det finns försvårande faktorer såsom utsläpp av farliga ämnen eller en högre hotbild, skapar försvårande omständigheter som upplevs svårhanterliga idag. I ett framtida scenario upplevs även risken för dessa händelser och terrorattacker att öka. Avhängigheten av IT samt ett samhälle som i allt högre grad förlitar sig på ”just in time”-leveranser gör att sårbarheten har ökat och upplevs fortsätta göra det även i framtiden. Andra viktiga områden som lyfts är nuvarande och befarad framtida brist på kompetent personal samt att utbildnings- och övningsverksamhet inte kan bedrivas i önskvärd utsträckning, delvis på grund av personalbrist och –omsättning.Vidare syns den generella uppfattningen vara att det saknas ett tydligt ledarskap på nationell nivå då det sällan, om alls, utkommer några direkta styrningar rörande vad som skall uppnås och i vilken utsträckning. Detta har också påvisats i avsnittet ovan rörande före-, under- och efterperspektivet där det finns en klart övervägande del synpunkter på de två förstnämnda perspektiven. Nationell styrning är alltså något som uppfattas vara efterfrågat och då inte bara avseende ledning under insats utan även i frågor rörande enhetlig utrustning och metodik samt utbildnings- och övningsfrågor. Få respondenter har tagit upp efterperspektivet i någon större utsträckning men då det har förekommit har det framförallt berört erfarenhetshanteringsfrågor och den brist som upplevs finnas inom detta specifika område idag. Erfarenheter från den egna verksamheten, såväl i vardagen som vid insatser vid allvarliga händelser, behöver tas om hand, följas upp och sedan utgöra grund för ett levande utvecklingsarbete.
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| 11. |
- Bengtsson, Kristofer, 1979, et al.
(författare)
-
Operation Behavior Modeling using Relation Identification and Visualization Algorithms
- 2013
-
Ingår i: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. ; , s. 368 - 373
-
Konferensbidrag (refereegranskat)abstract
- The behavior of a system can be described by a set of operations - sometimes called activities or tasks. The process to specify these operation seems to be a real challenge in various situations, for example when designing automation systems or keeping track of the work at an emergency department. In practice, operation behavior specification is often quite inflexible because every possible execution route is explicitly defined. In this paper, a modeling method and a relation identification and visualization algorithm is introduced that does not explicitly specify operation routes, where instead the operation behavior is specified using the execution restrictions in transition conditions for each operation. This enables the possibility to create multiple projections of the operation relations to enable better understanding.
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| 12. |
- Bengtsson, Kristofer, 1979, et al.
(författare)
-
Operation-Oriented Specification for Integrated Control Logic Development
- 2009
-
Ingår i: 2009 IEEE Conference on Automation Science and Engineering, CASE 2009, Bangalore, India. - 9781424445783 ; , s. 183-90
-
Konferensbidrag (refereegranskat)abstract
- In order to develop a manufacturing automation system, it is necessary to understand the manufacturing operations and their relationship, the sequence of operations, which is the basis for control logic design. The operations have preconditions that define when they are allowed to start executing, which also defines the sequence relations among them. Requirements and demands throughout the development will add and change these conditions, which also changes the sequence of operations. This paper studies how an operation-oriented development approach better can handle the operations and manufacturing sequences from early product design to detailed control engineering. An operation is defined by an extended finite automaton, with an initial, executes and finished location. The start event is enabled by a precondition, the stop event is enabled by a postcondition and the reset event is enabled by a reset condition. This representation together with a resource and product description enables the possibility to integrate control logic in the complete development process.
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| 13. |
- Bengtsson, Kristofer, 1979
(författare)
-
Operation Specification for Sequence Planning and Automation Design
- 2010
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- When designing an automation system, an important challenge is to specify the different tasks, or operations, of the system. This has become a problematic bottle-neck in industry, since the rising needs on manufacturing flexibility increases the complexity of the entire manufacturing system, as well as its control function. This thesis studies how to specify the manufacturing operations when developing an automation system, especially how to plan the operations and the relations among them, called sequence planning, and how to implement them in a programmable logic controller (PLC).To manage the complete automation development process, a formal language called sequences of operations, SOP, is introduced. This language, together with a set of methods, are used to represent, identify and visualize complex operation relations, so that the behavior of the system can be understood. By the use of different views or perspectives, the sequence of operations related to e.g the part flow, robot operations or operator tasks can be visualized. These different perspectives help the user to easier understand the relation between the control of a cell and the mechanical design, as well as the product design and the total system behavior. The proposed language is based on a formal model, thus formal verification, optimization and synthesis are available. This is necessary since it is hard to find errors in complex system specifications.When implementing the control of manufacturing operations, much of the code is related to supporting concerns like alarm handling, logging, user interface, etc. These parts tend to be hard to fully reuse and implement, since they are tangled with other functionalities, and are located at many places in the program. An aspect-oriented programming (AOP) approach is proposed, to reuse and implement these concerns. AOP is an emerging programming methodology in computer science, which helps the programmer by separating crosscutting and tangled concerns in a program. The approach is focused on how to adapt the AOP methodology for PLC program development, and how it can benefit the control design process.
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| 14. |
- Bengtsson, Kristofer, 1979, et al.
(författare)
-
Patient coordination in emergency departments using an event-based information architecture
- 2014
-
Ingår i: The 19th IEEE International Conference on Emerging Technologies and Factory Automation. - 9781479948451 ; , s. 1-6
-
Konferensbidrag (refereegranskat)abstract
- It is challenging to get an overview and understanding of the activities and their relations at an emergency department (ED). This is due to the complicated relations among activities - called operations in this paper - and the always changing system behavior. Two key enablers to get this overview are the transformation of real-time events into understandable information and an operation-based behavior description. This paper presents an event-based information architecture for healthcare (EVAH) for gathering state changing events in real-time at an ED and how these are transformed into an operation-based representation. EVAH together with the tool Sequence Planner, will be used for visualization, online prognosis and optimization.
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| 15. |
- Bengtsson, Kristofer, 1979, et al.
(författare)
-
Patient coordination in emergency departments using visualization of operation behavior
- 2013
-
Ingår i: Proceedings of the 2013 IEEE Symposium on Computational Intelligence in Healthcare and e-Health, CICARE 2013 - 2013 IEEE Symposium Series on Computational Intelligence, SSCI 2013. - 9781467358835 ; , s. 58-63
-
Konferensbidrag (refereegranskat)abstract
- It is challenging to get an overview and understanding of the activities and their relations at an emergency department (ED). This is due to the complicated relations among activities called operations in this paper and the always changing system behavior. This paper presents a method to represent and visualize operations during the actual work at the ED that enables flexibility during modeling and actual care. By specifying operation behavior using only execution restrictions in transition conditions for each operation instead of fixed sequences, the method and related visualization tool can describe the ever changing and complex ED flows. Using the proposed approach, the ED staff will therefore have the possibility to in a better way coordinate the operations due to the increased overview.
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| 16. |
- Bengtsson, Kristofer, 1979, et al.
(författare)
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Relations Identification and Visualization for Sequence Planning and Automation Design
- 2010
-
Ingår i: In Proc. IEEE Conference on Automation Science and Engineering, Toronto. - 9781424454471 ; , s. 841 - 848
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Konferensbidrag (refereegranskat)abstract
- The sequential behavior of a manufacturing system results from a number of constraints introduced both in product, manufacturing and control logic development. Sequence planning is therefore an important activity throughout the complete development process. This paper proposes a sequence planning approach using self-contained manufacturing operations that model actions and relevant execution conditions. These operations can have temporal relations with each other, due to execution constraints expressed by operation pre- post- and reset conditions. The operation relations can for example be parallel, sequence, arbitrary order, alternative or hierarchy. Based on a formal operation model, the relations among operations are identified and visualized with a graphical language called Sequences of Operations, SOP.
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| 17. |
- Bengtsson, Kristofer, 1979, et al.
(författare)
-
Sequence Planning Using Multiple and Coordinated Sequences of Operations
- 2012
-
Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 9:2, s. 308-319
-
Tidskriftsartikel (refereegranskat)abstract
- The sequential behavior of a manufacturing system results from several constraints introduced during the product, manufacturing, and control logic development. This paper proposes methods and algorithms for automatically representing and visualizing this behavior from various perspectives throughout the development process. A new sequence planning approach is introduced that uses self-contained operations to model the activities and execution constraints. These operations can be represented and visualized from multiple perspectives using a graphical and formal language called Sequences of Operations (SOPs). The operations in a manufacturing system are related to each other in various ways, due to execution constraints expressed by operation pre- and post-conditions. These operation relations include parallel, sequence, arbitrary order, alternative, and hierarchy relations. Based on the SOP language, these relations are identified and visualized in various SOPs and sequences. A software tool, Sequence Planner, has been developed, for organizing the operations into SOPs that visualize only relevant operations and relations. Note to Practitioners-This paper proposes methods and algorithms for a new sequence planning approach in which sequences are automatically created based on the relations among operations instead of having to be manually constructed. Using various views, the sequences of operations related to, for example, part flow, robot operations, and operator tasks, can be visualized. The use of various views helps the user better understand the relations between cell control and mechanical design, and between product design and total system behavior.
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| 18. |
- Bengtsson, Kristofer, 1979, et al.
(författare)
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The Origin of Operations: Interactions Between the Product and the Manufacturing Automation Control System
- 2009
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Ingår i: 13th IFAC Symposium on Information Control Problems in Manufacturing Technology, INCOM’09, Moscow, Russia. ; , s. 40-5
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the interaction and relationship between the product design and the control logic design for manufacturing automation system. One important challenge during the development of a manufacturing automation system, is to handle the information related to the manufacturing control system (i.e PLC), since it influences almost every part of the manufacturing design and process. Therefore it is crucial to know when and how this information is created, to be able to increase the development quality and efficiency. This is especially true for the product related information that impacts the design of the control system. This paper studies the liaisons, the interfaces among parts and features in the product design, and its relationship with operations and resources in the manufacturing system. These liaisons must be considered in both product and manufacturing development since the inter-relation between liaisons and operations establishes the direct mapping of constraints and demands between the two domains. This paper further proposes how the manufacturing operations can be described during the development and how they are realized by resources in the manufacturing system. An example from automotive industry is included in this paper, to demonstrate the proposed concept.
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| 19. |
- Bengtsson, Kristofer, 1979, et al.
(författare)
-
Towards Sequence Planning Based on Configurable Product and Manufacturing System Platforms
- 2010
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Ingår i: Proceedings of the 8th International Conference NordDesign 2010. - 9789163370649 ; Vol. 2, s. 467-476
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Konferensbidrag (refereegranskat)abstract
- Operation sequences are central in the interaction between product and manufacturing development. This is because the sequences create an understanding of how a product is manufactured. The high degree of complexity in managing and planning manufacturing operations during the development of a configurable product and manufacturing platform requires a new and more flexible sequence planning approach. By integrating configurable product and manufacturing system platform descriptions, product variance, manufacturing system flexibility, and product and manufacturing system complexity can all be efficiently adapted to each other by considering interrelated constraints. Such an integrated platform system also provides the information required to describe the operations needed to manufacture an instantiated product variant. This paper proposes an approach in which sequences are viewed based on the relations among self-contained operations, thus saving engineers from manually constructing sequences for each product variant. The sequences of operations related to, for example, the part flow for a specific platform configuration, robot operations or operator tasks can be automatically visualized through the use of different perspectives.
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| 20. |
- Bengtsson, Rhodel, et al.
(författare)
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A basic orthotropic viscoelastic model for composite and wood materials considering available experimental data and time-dependent Poisson's ratios
- 2020
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Ingår i: IOP Conference Series. - : IOP Publishing. - 1757-8981 .- 1757-899X. ; 942
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Tidskriftsartikel (refereegranskat)abstract
- Long-term deformation in creep is of significant engineering importance. For anisotropic materials, such as wood, composites and reinforced concrete, creep testing in several axial directions including shear is necessary to obtain a creep model which is able to predict deformation in the basic orthotropic case. Such a full set of experimental data is generally not available, and simplifying assumptions are typically made to conceive a useful 3D model. These assumptions should preferably be made based on the material behaviour and sound engineering arguments. This problem appears to be addressed in many different ways and sometimes the assumptions are not well justified. In the present study, we examine 3D creep of wood and composite materials. Particular emphasis is made on explaining the choices made in developing the model, considering practicality, incomplete material data and the specific behaviour of wood and composites. An orthotropic linear viscoelastic model is implemented as a material model in a commercial FE software. The constitutive equations are derived in the 1D case using a hereditary approach, then later generalized to the 3D formulation. Guidelines are shown how to implement it into the FE software to predict creep of components and structures. Although the model itself is conventional, the effect of considering time-dependent Poisson's ratios is investigated here, as well an optimization approach when inserting inevitably asymmetric experimental creep data into the model. As far as the authors know, creep of wooden materials have not been defined using this approach before. The model of interest is calibrated against experimental data. Examples using experimental results from solid wood data and a unidirectional fiber composite are demonstrated. The results show that the model is able to capture the orthotropic behaviour adequately. Orthotropy requires symmetry of the creep compliance matrix, which typically is not the case experimentally. It is shown that in rendering the matrix symmetric, one needs to decide which direction is more important. It is also shown that the frequently employed assumption of constant Poisson's ratios should be made with caution.
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| 21. |
- Bengtsson, Rhodel, et al.
(författare)
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An applicable orthotropic creep model for wood materials and composites
- 2022
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Ingår i: Wood Science and Technology. - : Springer Nature. - 0043-7719 .- 1432-5225. ; 56:6, s. 1585-1604
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Tidskriftsartikel (refereegranskat)abstract
- Despite the engineering importance of creep of composite materials and other fibrous anisotropic load-carrying materials like wood, there is an apparent lack in useful experimental data in 3D. Proposed creep models are generally not commensurate with realistic data from experimental characterization. In the present study, an orthotropic linear viscoelastic model is presented and examined on its performance of predicting the time-dependent nature of wood and composite materials. The constitutive equations are presented using the hereditary approach. A clear description of the finite element implementation of the material model is given. Since constant Poisson's ratios are a common assumption for viscoelastic composites due to lack of data, this study presents the effects of time-dependent Poisson's ratio in the study. The model is calibrated against inevitably asymmetric experimental creep data using an optimization approach. With time-dependent Poisson's ratios, the results show that the model is able to simultaneously capture the time-dependent behaviour in three material axis of orthotropic materials such as European beech wood and a fibre-reinforced composite. However, a relatively poor match was found when the Poisson's ratios were set to be constant. Thus, the frequently employed assumption of constant Poisson's ratios should be made with caution.
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| 22. |
- Bengtsson, Rhodel, et al.
(författare)
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Comparison of measured creep in a wooden beam with finite element predictions based on orthotropic viscoelastic material model
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Creep is of concern for long-term deformations of wooden structures. Since wood is anisotropic and creeps in several material directions, it may not be sufficient to include only axial creep along the grain even for deformations in beam-like components. A bottle-neck is that creep characterisation in all material directions is both costly and complicated. Multiscale modelling from cell-wall creep including the main contributing features (density, ray content, microfibrillar angle) can contribute to fill to complete material models for wood creep. In the present study, we have chosen a four-point bending test of a Norway spruce beam to represent a loaded wooden component in a structure. Digital image correlation was used to gather data on strain and displacement fields during the creep test. The experimental results were compared with finite element predictions based on a 3D orthotropic viscoelastic model obtained by multiscale homogenisation. There was generally good agreement in the strain fields between the finite element simulations and experimental observations. However, the numerical predictions exhibits slightly greater stiffness in terms of displacement, suggesting the need for further refinement of the multiscale model or a combination of materials creep charactrisation and multiscale modelling.
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| 23. |
- Bengtsson, Rhodel
(författare)
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Creep aspects of softwood from the cell-wall level to structures
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis addresses the intricate mechanical behaviour of natural materials, with a particular focus on wood. Despite millennia of use, understanding the mechanical behaviour of wood materials remains challenging due to their complex microstructures. For instance, they exhibit variations in properties among samples, nonlinear behaviour under elevated loads, and are sensitive to alterations in moisture content.Wood and related natural biobased materials hold immense potential due to their renewability, cost-effectiveness, eco-friendliness, and ease of use in sustainable construction. Wood boasts remarkable stiffness and strength along its primary axis, surpassing many man-made materials in strength-to-weight ratios. However, its anisotropic and heterogeneous nature gives rise to challenges, necessitating the consideration of multiple parameters for accurate characterization to be used in design.Wood is intrinsically heterogeneous, leading to considerable variations in local stresses and deformations during loading. To address these microstructural effects on macroscopically measurable phenomena, mathematical homogenization methods, established since the 1970s, have found applications in material mechanics, including both fibre composites and wood.In recent years, there has been a growing focus on the viscoelastic behaviour of composites and timber structures, given their increased long-term use in load-carrying applications. While numerous investigations have explored the relationship between the microstructure of wood and its elastic properties, few studies have explored the connection between microstructure and viscoelastic properties.The thesis focuses on the static and, more notably, on the time-dependent mechanical properties of wood, bridging the gap from cell-wall creep to structures. It includes experiments and numerical work, culminating in the development of a material model suitable for orthotropic materials like wood. The multiscale model establishes a link between microstructural parameters and macroscopic properties, potentially applicable to various softwood species. Given the lack of shear creep data in the literature, the thesis introduces straightforward methods to characterize shear creep properties, addressing a significant knowledge gap.Furthermore, the thesis progresses from material-level experiments to higher length scales, demonstrating how the results can be applied to larger wooden structures, such as the tower for a counter-rotating axis tilted turbine. While these results require further validation in the absence of experimental data for wooden wind turbine structures, they offer useful insights into simulating creep behaviour in such applications.In conclusion, this thesis highlights the multifaceted nature of a natural material like wood, its mechanical challenges, and the promising research avenues for comprehensive understanding and practical use. The outcome provides contributions to the efficient utilization of wood in load-carrying structures and underlines the importance of ongoing research in this field.
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| 24. |
- Bengtsson, Rhodel, et al.
(författare)
-
Evaluating the viscoelastic shear properties of clear wood via off-axis compression testing and digital-image correlation
- 2023
-
Ingår i: Mechanics of time-dependant materials. - 1385-2000 .- 1573-2738.
-
Tidskriftsartikel (refereegranskat)abstract
- Highly anisotropic materials like wood and unidirectional polymer composite structures are sensitive to shear deformations, in particular close to fixed joints. Large wooden structures in buildings and, e.g. wind-turbine blades, are designed to last for decades, and hence are susceptible to unwanted creep deformations. For improved structural design, the shear-creep properties of the material are needed. These are rarely available in the literature, possibly because of technical difficulties to achieve a well-defined shear-stress state in test specimens. For cost-efficient testing, this goal of a pure stress state necessarily needs to be compromised. In the present study, we propose a simple test method based on uniaxial compression on wooden cubes, but is equally applicable for fibre composites. The viscoelastic shear properties of Norway spruce (Picea abies) under off-axis creep compression tests have been characterised in all three directions. The tests are performed in a controlled climate chamber and the creep strains are captured using digital-image correlation.
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| 25. |
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| 26. |
- Bengtsson, Rhodel, et al.
(författare)
-
Feasiblity of wooden towers for offshore wind turbines: Creep and fatigue predictions
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Long-term experiences with vertical axis wind turbines constructed with wood are positive, and show that wood towers are a viable alternative to conventional steel towers on land. Wood is a renewable material in contrast to steel and concrete and could steer a more sustainable use of raw material for future wind farms. The obvious drawback of moisture-induced softening and degradation in off-shore settings can be mitigated by efficiently sealing the tower using a barrier coating. In that case, fatigue sensitivity and creep deformations are the main design concerns. In this paper through finite element simulations of a floating tilted vertical-axis wind turbine, it was shown that fatigue issues can be resolved with proper design of the mast and the blade joints keeping the stress concentrations at bay. The numerical results also indicated that creep displacements are negligible. The review and calculations reinforce the assumption that the fast developments seen in timber high-rise building can also be expected for off-shore wind turbine towers.
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| 27. |
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| 28. |
- Bengtsson, Rhodel, et al.
(författare)
-
Viscoelastic behavior of softwood based on a multiscale computational homogenization
- 2023
-
Ingår i: Mechanics of materials. - : Elsevier. - 0167-6636 .- 1872-7743. ; 179
-
Tidskriftsartikel (refereegranskat)abstract
- In the present study, a numerical multiscale model is made to show how the hierarchical structure of softwood affect its macroscopic viscoelastic properties. The performance of the model is demonstrated for two softwood species — Norway spruce and Japanese cypress, whose creep behavior has been characterized experimentally. The results show that by using the same transversely isotropic viscous properties of the cell wall for both species, it is possible to predict creep deformation relatively close to experimental creep measurements for both species. Assuming that the variability is larger on the microstructural level (density, cell-wall geometry, microfibril angle, composition of wood tissues) than on the cell-wall level, it is possible to predict the macroscopic creep behavior based on the microstructural parameters alone. Such predictions can potentially save cost and time, since creep characterization in all material directions is demanding.
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| 29. |
- Bohlin, Robert, 1972, et al.
(författare)
-
Data Flow and Communication Framework Supporting Digital Twin for Geometry Assurance
- 2018
-
Ingår i: ASME 2017 International Mechanical Engineering Congress and Exposition. ; 2
-
Konferensbidrag (refereegranskat)abstract
- Faster optimization algorithms, increased computer power and amount of available data, can leverage the area of simulation towards real-time control and optimization of products and production systems. This concept — often referred to as Digital Twin — enables real-time geometry assurance and allows moving from mass production to more individualized production. To master the challenges of a Digital Twin for Geometry Assurance the project Smart Assembly 4.0 gathers Swedish researchers within product development, automation, virtual manufacturing, control theory, data analysis and machine learning. The vision of Smart Assembly 4.0 is the autonomous, self-optimizing robotized assembly factory, which maximizes quality and throughput, while keeping flexibility and reducing cost, by a sensing, thinking and acting strategy. The concept is based on active part matching and self-adjusting equipment which improves geometric quality without tightening the tolerances of incoming parts. The goal is to assemble products with higher quality than the incoming parts. The concept utilizes information about individual parts to be joined (sensing), selects the best combination of parts (thinking) and adjust locator positions, clamps, weld/rivet positions and sequences (acting). The project is ongoing, and this paper specifies and highlights the infrastructure, components and data flows necessary in the Digital Twin in order to realize Smart Assembly 4.0. The framework is generic, but the paper focuses on a spot weld station where two robots join two sheet metal parts in an adjustable fixture.
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| 30. |
- Dahl, Martin, 1984, et al.
(författare)
-
Application of the sequence planner control framework to an intelligent automation system with a focus on error handling
- 2021
-
Ingår i: Machines. - : MDPI AG. - 2075-1702. ; 9:3
-
Tidskriftsartikel (refereegranskat)abstract
- Future automation systems are likely to include devices with a varying degree of autonomy, as well as advanced algorithms for perception and control. Human operators will be expected to work side by side with both collaborative robots performing assembly tasks and roaming robots that handle material transport. To maintain the flexibility provided by human operators when introducing such robots, these autonomous robots need to be intelligently coordinated, i.e., they need to be supported by an intelligent automation system. One challenge in developing intelligent automation systems is handling the large amount of possible error situations that can arise due to the volatile and sometimes unpredictable nature of the environment. Sequence Planner is a control framework that supports the development of intelligent automation systems. This paper describes Sequence Planner and tests its ability to handle errors that arise during execution of an intelligent automation system. An automation system, developed using Sequence Planner, is subjected to a number of scenarios where errors occur. The error scenarios and experimental results are presented along with a discussion of the experience gained in trying to achieve robust intelligent automation.
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| 31. |
- Dahl, Martin, 1984, et al.
(författare)
-
Automatic modeling and simulation of robot program behavior in integrated virtual preparation and commissioning
- 2017
-
Ingår i: Procedia Manufacturing. - : Elsevier BV. - 2351-9789. ; 11, s. 284-291
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a method where the behavior of a robot cell is automatically modeled based on existing robot programs and a simulation model of the cell. Robot programs from the shop floor are uploaded into a virtual manufacturing tool, and a formal model is then generated from the robot programs. Then, control logic is automatically calculated, and the fastest possible execution order is found by using the generated model to formulate an optimization problem. The result is continuously analyzed and validated by simulation in the virtual manufacturing tool.
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| 32. |
- Dahl, Martin, 1984, et al.
(författare)
-
Control components for Collaborative and Intelligent Automation Systems
- 2019
-
Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA. - 1946-0759 .- 1946-0740. ; 2019-September, s. 378-384
-
Konferensbidrag (refereegranskat)abstract
- Collaborative and intelligent automation systems need intelligent control systems. Some of this intelligence exist on a per-component basis in the form of vision, sensing, motion, and path planning algorithms. To fully take advantage of this intelligence, also the coordination of subsystems need to exhibit intelligence. While there exist middleware solutions that eases communication, development, and reuse of such subsystems, for example the Robot Operating System (ROS), good coordination also requires knowledge about how control is supposed to be performed, as well as expected behavior of the subsystems. This paper introduces lightweight components that wraps ROS2 nodes into composable control components from which an intelligent control system can be built. The ideas are implemented on a use case involving collaborative robots with on-line path planning, intelligent tools, and human operators.
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| 33. |
- Dahl, Martin, 1984, et al.
(författare)
-
Guard extraction for modeling and control of a collaborative assembly station
- 2020
-
Ingår i: IFAC-PapersOnLine. - : Elsevier BV. - 2405-8963. ; 53:4, s. 223-228
-
Konferensbidrag (refereegranskat)abstract
- A transition system represented by guards and actions can be amended by new guards computed in order to satisfy some specification. If the transition system is the result of composing smaller state machines, guard extraction can be used to put the new guards onto the guards the original state machines. Planning and verification can then be performed directly on the system with additional guards. In this paper we discuss the benefits of applying guard extraction as part of the modeling work in a modular control architecture, where reusable resources are composed using specifications. We show with an example from the development of an industrial demonstrator that even if the specification language is limited to invariant propositions, in practice many common safety specifications can be expressed when combined with a notion of which transitions are allowed to be restricted.
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| 34. |
- Dahl, Martin, 1984, et al.
(författare)
-
Integrated Virtual Preparation and Commissioning: supporting formal methods during automation systems development
- 2016
-
Ingår i: IFAC-PapersOnLine. - : Elsevier BV. - 2405-8963. ; 49:12, s. 1939-1944
-
Konferensbidrag (refereegranskat)abstract
- Virtual commissioning – the development and validation of industrial control systems against a simulation model – is attracting interest in the automotive industry. The main motivation for its use is that control systems can start to be integrated and tested before the construction of the physical system. In addition to this, the ability to continuously test can lead to increased reliability and enables better coping with late changes. At the same time, using formal methods during production preparation and control system design promise similar benefits. Formal methods however, are not seeing the same surge in interest – they are rarely used in the automotive industry. In this paper a framework is proposed, Integrated Virtual Preparation and Commissioning, where virtual commissioning models are used as a base for preparation and control system implementation assisted by formal methods. The extensive use of simulation in virtual commissioning allows computation results from formal methods to be continuously validated by visual inspection and using existing analysis tools (e.g. collision detection methods). The framework is applied in a case study, where the combination of a simulation model and a formal model is used as an aid in generating operation sequences for validation during production preparation. The resulting formal model can be used to study the behavior of the production system before a control system has been implemented.
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| 35. |
- Dahl, Martin, 1984, et al.
(författare)
-
Interactive formal specification for efficient preparation of intelligent automation systems
- 2022
-
Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 38, s. 129-138
-
Tidskriftsartikel (refereegranskat)abstract
- The automation system of the future will consist of an increasing amount of complex resources, such as collaborative robots and/or autonomously roaming robots for material handling. To control these devices in an environment shared with human operators require state of the art computer perception and motion planning algorithms to be used as part of the automation system. This new type of intelligent automation system, where intelligent machines and learning algorithms are replacing more traditional automation solutions, requires new methods and workflows to keep up with the increase in complexity. This paper presents an interactive and iterative framework for solving some of these new challenges. The framework supports model-based control system preparation performed simultaneously to preparation of 3D geometries, positioning of robots, and tool design. The workflow enables an interactive preparation process, where new resources and constraints can be added to a live (real or simulated) automation system and control system failures can be analyzed in familiar tools for virtual preparation. Additionally, the paper describes how the integrated preparation process was applied to reconfiguring an industrial use case that includes a collaborative robot working side by side with a human operator, smart tools, and a vision system for localizing both work objects and tools.
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| 36. |
- Dahl, Martin, 1984, et al.
(författare)
-
Sequence Planner: A Framework for Control of Intelligent Automation Systems
- 2022
-
Ingår i: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417. ; 12:11
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents a framework that tackles the challenges met in the development of automation systems featuring collaborative robotics and other machines that have some degree of autonomy. These machines rely on online algorithms for both sensing and acting in order to achieve a very high level of flexibility. To take advantage of these new machines and algorithms, control systems must also be increasingly flexible. In this paper, we present a framework for control of this new class of intelligent automation systems called Sequence Planner (SP), which helps with control of both traditional automation equipment and machines with autonomy. To aid the complex task of developing automation control solutions, SP relies on supporting algorithms for control logic synthesis and online planning. SP has been implemented with plug-in support for the Robot Operating System (ROS) and applied to an industrial demonstrator. We present our findings on how SP performed as a control system for this demonstrator, where we show that it is an adequate approach to implement automation for a highly flexible single station system. As a standardized way of automating such systems is missing, we hope that our contribution will provide a foundation for how to develop intelligent automation systems.
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| 37. |
- Dahl, Martin, 1984, et al.
(författare)
-
Sequence Planner: Supporting Integrated Virtual Preparation and Commissioning
- 2017
-
Ingår i: IFAC-PapersOnLine. - : Elsevier BV. - 2405-8963. ; 50:1, s. 5818-5823
-
Konferensbidrag (refereegranskat)abstract
- It is essential to understand the operation sequences of a production system when designing or changing it. This paper will demonstrate how the software tool Sequence Planner (SP) not only supports this understanding by sequence visualization, but also improves the solution using optimization and verification. SP is a tool for modeling and analyzing automation systems. The tool has been developed since 2007 with an initial focus on supporting engineers when developing control code for programmable logical controllers. Today, SP is a micro-service architecture, usable in various areas like runtime control, online monitoring, energy optimization, and even emergency department patient planning. This paper presents a use case at an automotive company, where the operation sequences in a large number of automated robot stations, need to be modified. SP, together with virtual commissioning tools, automates this modification by identifying, optimizing, verifying and simulating operation sequences, and then updates the robot and control programs. This use case demonstrates the strength of SP and its architecture and how it is used for integrated virtual preparation and commissioning.
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| 38. |
- Ebrahimi, Amir Hossein, 1976, et al.
(författare)
-
Managing product and production variety - A language workbench approach
- 2014
-
Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 17, s. 338-344
-
Konferensbidrag (refereegranskat)abstract
- Product platforms are commonly used in industries with complex products and high competition like the car and truck industry to allow a customer to order a product that satisfy its unique needs. A consequence of product variety is that manufacturing and assembly processes need to deal with this variety as well. If the variety is low and changes of the product occur infrequently then the variety may be handled by designing the production system for a small set of typical products. But as the variety increases and changes become frequent the necessity for integrated product and production information model is high, to partially solve this problem Product Life Cycle Management (PLM) systems aim at providing an integrated model to all categories of users, e.g. product designers, product preparation engineers, line builders and shop-floor workers. All users need to access the information in the platform and refine and modify the information to reflect new knowledge that has been acquired. Today, most often multiple systems are used where some systems may store information in a structured way but often unstructured text documents are also used. This easily results in redundant information models and automated analysis is not feasible or not event possible because of issues regarding cohesion and traceability of information. The contribution in this paper is to discuss how a new type of tool for building domain specific languages and editors using language workbench approach can be used to support the different user categories in their tasks working with variability of a product and production system while at the same time provide cohesion and traceability of information.
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| 39. |
|
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| 40. |
- Erös, Endre, 1990, et al.
(författare)
-
Development of an Industry 4.0 Demonstrator Using Sequence Planner and ROS2
- 2021
-
Ingår i: Studies in Computational Intelligence. - Cham : Springer International Publishing. - 1860-9503 .- 1860-949X. ; 895, s. 3-29
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In many modern automation solutions, manual off-line programming is being replaced by online algorithms that dynamically perform tasks based on the state of the environment. Complexities of such systems are pushed even further with collaboration among robots and humans, where intelligent machines and learning algorithms are replacing more traditional automation solutions. This chapter describes the development of an industrial demonstrator using a control infrastructure called Sequence Planner (SP), and presents some lessons learned during development. SP is based on ROS2 and it is designed to aid in handling the increased complexity of these new systems using formal models and online planning algorithms to coordinate the actions of robots and other devices. During development, SP can auto generate ROS nodes and message types as well as support continuous validation and testing. SP is also designed with the aim to handle traditional challenges of automation software development such as safety, reliability and efficiency. In this chapter, it is argued that ROS2 together with SP could be an enabler of intelligent automation for the next industrial revolution.
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| 41. |
- Erös, Endre, 1990, et al.
(författare)
-
Evaluation of high level methods for efficient planning as satisfiability
- 2021
-
Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA. - 1946-0740 .- 1946-0759. - 9781728129891 ; 26
-
Konferensbidrag (refereegranskat)abstract
- Fast planning algorithms play a key role in intelligent automation systems where control sequences are constantly calculated. In order to determine which algorithms increase planning performance, we evaluate and compare several high level planning methods on a set of standard benchmarks. We focus on planning as satisfiability as the leading approach for solving difficult planning problems.
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| 42. |
- Erös, Endre, 1990, et al.
(författare)
-
Fault localization for intelligent automation systems
- 2023
-
Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA. - 1946-0740 .- 1946-0759. ; 2023-September
-
Konferensbidrag (refereegranskat)abstract
- Conventional programming of explicit control code is unsuitable for flexible and collaborative production systems. A model-based approach, which focuses on defining capabilities of a system, instead of specifying how to achieve them, provides an alternative for creating complex, scalable, and reliable systems. This is accomplished through the use of behavior models, and tools such as planning, synthesis, verification, and testing. However, developing such models is not without challenges, as it is possible to overlook or incorrectly specify potential behavior and constraints. This can result in unsolvable planning problems or plans that are invalid for other reasons. When plans are unobtainable, developers receive no feedback, which makes model adjustments a difficult and time-intensive task. This paper recognizes these challenges as crucial barriers for adopting model-based development of intelligent automation systems. To facilitate the development of such systems, an approach for detecting and localizing faults in behavior models is presented. Drawing inspiration from software fault localization techniques, the proposed method involves identifying suspicious resources, variables, and operations. The effectiveness of this approach is illustrated with an example use case.
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| 43. |
|
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| 44. |
- Erös, Endre, 1990, et al.
(författare)
-
Structural Coverability for Intelligent Automation Systems
- 2023
-
Ingår i: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. ; 2023-August
-
Konferensbidrag (refereegranskat)abstract
- In order to be flexible and handle complex scenarios, intelligent automation systems might benefit from automated planning techniques which rely on specifications and models describing their behavior. However, due to the presence of message passing, latency, jitter, timeouts, failures, and error handling, the verification of such behavior models using formal methods is often unfeasible. Therefore, testing has emerged as an approach to evaluating the behavior of intelligent automation systems. This paper presents a way to analyze structural coverability of behavior models for intelligent automation systems, which is inspired by the modified condition/decision coverage (MC/DC) criterion. This is paired with a testing procedure that enables each test case to influence both the controller and the simulated environment by injecting some specific state. As a result, the proposed coverability criterion can effectively identify segments of the behavior model that have not been adequately tested and suggest additional test cases to improve coverability. An example use case is presented to demonstrate the effectiveness of this approach.
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| 45. |
- Erös, Endre, 1990, et al.
(författare)
-
Towards compositional automated planning
- 2020
-
Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA. - 1946-0759 .- 1946-0740. ; 2020-September, s. 416-423
-
Konferensbidrag (refereegranskat)abstract
- The development of efficient propositional satisfiability problem solving algorithms (SAT solvers) in the past two decades has made automated planning using SAT-solvers an established AI planning approach. Modern SAT solvers can accommodate a wide variety of planning problems with a large number of variables. However, fast computing of reasonably long plans proves challenging for planning as satisfiability. In order to address this challenge, we present a compositional approach based on abstraction refinement that iteratively generates, solves and composes partial solutions from a parameterized planning problem. We show that this approach decomposes the monolithic planning problem into smaller problems and thus significantly speeds up plan calculation, at least for a class of tested planning problems.
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| 46. |
- Farooqui, Ashfaq Hussain, 1990, et al.
(författare)
-
From factory floor to process models: A data gathering approach to generate, transform, and visualize manufacturing processes
- 2019
-
Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 24, s. 6-16
-
Forskningsöversikt (refereegranskat)abstract
- The need for tools to help guide decision making is growing within the manufacturing industry. The analysis performed by these tools will help operators and engineers to understand the behaviour of the manufacturing stations better and thereby take data-driven decisions to improve them. The tools use techniques borrowed from fields such as Data Analytics, BigData, Predictive Modelling, and Machine Learning. However, to be able to use these tools efficiently, data from the factory floor is required as input. This data needs to be extracted from two sources, the PLCs, and the robots. In practice, methods to extract usable data from robots are rather scarce. The present work describes an approach to capture data from robots, which can be applied to both legacy and current state-of-the-art manufacturing systems. The described approach is developed using Sequence Planner - a tool for modelling and analyzing production systems - and is currently implemented at an automotive company as a pilot project to visualize and examine the ongoing process. By exploiting the robot code structure, robot actions are converted to event streams that are abstracted into operations. We then demonstrate the applicability of the resulting operations, by visualizing the ongoing process in real-time as Gantt charts, that support the operators performing maintenance. And, the data is also analyzed off-line using process mining techniques to create a general model that describes the underlying behaviour existing in the manufacturing station. Such models are used to derive insights about relationships between different operations, and also between resources.
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| 47. |
- Farooqui, Ashfaq Hussain, 1990, et al.
(författare)
-
Real-time Visualization of Robot Operation Sequences
- 2018
-
Ingår i: IFAC-PapersOnLine. - : Elsevier BV. - 2405-8963. ; 51:11, s. 576-581
-
Konferensbidrag (refereegranskat)abstract
- Evaluation of manufacturing systems requires large amounts of accurate data from the factory floor. This data is then processed to calculate Key Performance Indicators (KPIs), evaluation metrics used within the manufacturing industry by engineers and managers in order to make data-driven decisions. Mechanisms to capture large scales of usable data, which is both reliable and scalable is, more often than not, scarce. In this paper, we provide an approach to capture data from robot actions, which can be applied to both legacy and current state-of-the-art manufacturing systems. By exploiting the robot code structure, robot actions are converted to event streams that are transformed into a higher usable abstraction of data. Applicability of this data is demonstrated, primarily, by visualizations. The described approach is developed in Sequence Planner - a tool for modeling and analyzing production systems - and is currently implemented at an automotive company as a pilot project to visualize and examine what goes on on the factory floor.
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| 48. |
- Farooqui, Ashfaq Hussain, 1990, et al.
(författare)
-
Towards data-driven approaches in manufacturing: an architecture to collect sequences of operations
- 2020
-
Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 58:16, s. 4947-4963
-
Tidskriftsartikel (refereegranskat)abstract
- Published by Informa UK Limited, trading as Taylor & Francis Group. The technological advancements of recent years have increased the complexity of manufacturing systems, and the ongoing transformation to Industry 4.0 will further aggravate the situation. This is leading to a point where existing systems on the factory floor get outdated, increasing the gap between existing technologies and state-of-the-art systems, making them incompatible. This paper presents an event-based data pipeline architecture, that can be applied to legacy systems as well as new state-of-the-art systems, to collect data from the factory floor. In the presented architecture, actions executed by the resources are converted to event streams, which are then transformed into an abstraction called operations. These operations correspond to the tasks performed in the manufacturing station. A sequence of these operations recount the task performed by the station. We demonstrate the usability of the collected data by using conformance analysis to detect when the manufacturing system has deviated from its defined model. The described architecture is developed in Sequence Planner–a tool for modelling and analysing production systems–and is currently implemented at an automotive company as a pilot project.
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| 49. |
- Hanna, Atieh, et al.
(författare)
-
Industrial Challenges when Planning and Preparing Collaborative and Intelligent Automation Systems for Final Assembly Stations
- 2019
-
Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA. - : Institute of Electrical and Electronics Engineers Inc.. - 9781728103037 ; 2019-September, s. 400-406
-
Konferensbidrag (refereegranskat)abstract
- During the last five decades, automation and robotics have transformed the automotive industry by increasing efficiency and improving the product quality. However, future trucks that will be autonomous, electrical and connected will require a completely new type of flexibility and intelligence in the production systems, especially in the final assembly. To handle the increased complexity of the products, production processes and logistic systems, final assembly must be transformed into collaborative and intelligent automation systems. These systems will include collaborative and deliberative robots (cobots), advanced vision-based control, adaptive safety systems, online optimization and learning algorithms and connected and well-informed human operators. But it will be a huge undertaking to transform current trucks industry such that they can design, implement and maintain large scale collaborative and intelligent automation systems. This paper presents the challenges with current planning and preparation processes for final assembly as well as the requirement and possible solutions for the future processes. An industrial use case at Volvo Trucks based on Sequence Planner and ROS2 is used to evaluate the proposed planning and preparation processes.
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| 50. |
- Hanna, Atieh, et al.
(författare)
-
Requirements for designing and controlling autonomous collaborative robots system-an industrial case
- 2018
-
Ingår i: Advances in Transdisciplinary Engineering. - : IOS Press BV. ; 8, s. 139-144, s. 139-144
-
Konferensbidrag (refereegranskat)abstract
- Automation and Robotics have been described as two of the enabling technologies for the Industry 4.0 paradigm, especially the use of autonomous and collaborative robot systems that can work together with humans and other machines. In manual assembly for example, these so-called co-bot systems (that also includes autonomous transportation and specialized machines) can improve the automation level, product quality, as well as human working conditions. However, in order to fully benefit from co-bot systems, many challenges need to be addressed before it can be introduced in complex industries e.g. the truck industry. This paper presents a number of challenges and requirements identified during an industrial use case, where autonomous co-bot systems have been introduced into an existing manual assembly station. These requirements are related to safe and intuitive interactions, smart tools, the need to manage variability as well as the need for highly flexible communication and control. During the use case, a number of initial solutions was developed where the implemented control architecture was based on the framework Robot Operation System (ROS) and Sequence Planner (SP).
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