| 1. |
- Bennulf, Mattias, 1992-
(författare)
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A Control Framework for Industrial Plug & Produce
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Kundanpassade produkter och korta produktionsserier blir alltmer populärt. Detta har lett till problem för dedikerade tillverkningssystem som är designade för massproduktion. Det krävs ofta långa produktionsserier för att det ska bli en rimlig investering att ställa om produktionen. Därför används människor för tillverkningsuppgifter som ofta ställs om. Denna avhandling fokuserar på konceptet Plug & Produce, som gör det enklare att flytta, lägga till och ta bort resurser från ett tillverkningssystem. Tanken är att resurser placeras i processmoduler som alla har samma fysiska gränssnitt för att kopplas in i tillverkningssystemet. Styrningen av tillverkningssystemet görs av ett multiagentsystem där varje detalj som ska produceras för produkter får en egen agent som representerar detaljen och agerar som styrningsmjukvara. Varje detaljs agent tar hand on sina egna tillverkningsmål genom att kommunicera med resursagenter i systemet som används för styrning av resurserna. I detta arbete, presenteras ett ramverk för Plug & Produce som består av ett konfigurerbart multiagentsystem, samt ett konfigurationsverktyg som kan användas för att definiera agenterna. Arbetet inkluderar metoder för att identifiera inkopplade resurser, kommunikation mellan agenter, schemaläggning som kan undvika konflikter mellan agenter, samt metoder för att automatiskt hitta vägar för transport genom tillverkningssystemet.
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| 2. |
- Bennulf, Mattias, 1992-
(författare)
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A User-Friendly Approach for Applying Multi-Agent Technology in Plug & Produce Systems
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents methods for simplifying the use of multi-agent systems in Plug & Produce. The demand for customized products and low volume production is constantly increasing. The industry has for many years used dedicated manufacturing systems where it is difficult and expensive to adapt to new product designs. Instead, factories are forced to use human workers for certain tasks that demand high flexibility and rapid adaption for new product designs. Several solutions have been proposed over the years to create highly flexible automation systems that automatically handles rapid adaption for new products. A concept called Plug & Produce aims at creating a system where resources and parts can be added in minutes rather than days in dedicated systems. One promising solution for implementing Plug & Produce is the distributed approach called multi-agent systems, where each resource and part get its own controller that communicates with each other to reach manufacturing goals. The idea is that the system automatically handles the adaption for new products. However, still today the use of such systems is extremely limited in the industry. One reason is the lack of mature multi-agent systems that are easy to use and that hides the complexity of the underlying agent system from the users. This is a huge problem since these systems tend to be more complex than traditional approaches. Thus, this thesis focuses on simplifying the use of multi-agent systems by proposing various methods for bringing the multi-agent technology for Plug & Produce closer to the industry.
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| 3. |
- Bennulf, Mattias, 1992-, et al.
(författare)
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Goal-Oriented Process Plans in a Multiagent System for Plug & Produce
- 2021
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Ingår i: IEEE Transactions on Industrial Informatics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1941-0050 .- 1551-3203. ; 17:4, s. 2411-2421
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a framework for Plug & Produce that makes it possible to use configurations rather than programming to adapt a manufacturing system for new resources and parts. This is solved by defining skills on resources, and goals for parts. To reach these goals, process plans are defined with a sequence of skills to be utilized without specifying specific resources. This makes it possible to separate the physical world from the process plans. When a process plan requires a skill, e.g., grip with a gripper resource, then that skill may require further skills, e.g., move with a robot resource. This creates a tree of connected resources that are not defined in the process plan. Physical and logical compatibility between resources in this tree is checked by comparing several parameters defined on the resources and the part. This article presents an algorithm together with a multiagent system framework that handles the search and matching required for selecting the correct resources.
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| 4. |
- Carlsson, Henrik, 1979-, et al.
(författare)
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Automated Generation of Discrete Event System Simulation Models for Flexible Automation
- 2011
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Ingår i: The 21st International Conference on Flexible Automation and Intelligent Manufacturing. - 9789868729100 ; , s. 825-832, s. 825-832
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Konferensbidrag (refereegranskat)abstract
- Flexible automation cells with rapid product changes are an important competitive advantage for industries today. These cells can increase a company’s productivity and thereby increase their profits. A flexible cell shall be able to handle different products with none or minimal changes to the cell itself. A powerful tool, which can be used to analyse and verify such cells, is discrete event system simulation. Problems such as potential bottlenecks, deadlocks, answers to "what-if" questions and the level of resource utilisation can be gathered. The drawback of discrete event system simulation is that the modelling task is both time consuming and difficult to accomplish. Furthermore, state-of-the-art discrete event system simulation tools that are used in the industry today are not suitable for flexible automation. If the production scenario is changed, e.g. introduction of a new product, the simulation and modelling has to be redone and this is both time consuming and tedious. In this paper a new approach will be presented that enables discrete event simulation models to be generated automatically. The models are generated from information retrieved from a PLM/PDM database system, which is shared among other engineering tools such as robot simulation, CAD and process planning. Hence, when the cell and the database are updated a new model can easily be generated. The database is also connected to the real cell so up-to-date data can be retrieved from the real cell. The model generator described in this paper was implemented and tested in a discrete event system simulation tool and showed promising results. With this approach it is possible to handle flexible automation cells more effectively in a process planning stage.
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| 5. |
- Carlsson, Henric, 1979-, et al.
(författare)
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General Time Synchronisation Method for PLC Programs Aiming at Virtual Verification and Development
- 2008
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Ingår i: 17th IFAC World. - 9783902661005 ; , s. 4440-4445
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The latest state-of-the-art Computer Aided Production Engineering (CAPE) simulation technology offers OPC integration for PLC verification. A critical drawback with this technology has been identified and described within this paper. A new time synchronisation method and a simulation architecture are therefore presented and proposed. The time synchronisation method together with the architecture can be used when verifying and developing real-time dependent control logic for industrial control system, e.g. PLC with CAPE tools. The method described in this paper is general and should work on any PLCs that are compatible with the IEC 61131-3 standard. A test case was also carried out, showing that by disregarding time synchronisation it is impossible to verify real-time dependent PLC functions together with CAPE tools in a reliable way. However, the test case also shows that by applying the proposed time synchronisation method together with the described simulation architecture a successful industrial verification method is achieved
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| 6. |
- Carlsson, Henrik, 1979-, et al.
(författare)
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Methods for Reliable Simulation-Based PLC Code Verification
- 2012
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Ingår i: IEEE Transactions on Industrial Informatics. - 1941-0050 .- 1551-3203. ; 8:2, s. 267-278
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Tidskriftsartikel (refereegranskat)abstract
- Simulation-based programmable logic controller (PLC) code verification is a part of virtual commissioning, where the control code is verified against a virtual prototype of an application. With today's general OPC interface, it is easy to connect a PLC to a simulation tool for, e. g., verification purposes. However, there are some problems with this approach that can lead to an unreliable verification result. In this paper, four major problems with the OPC interface are described, and two possible solutions to the problems are presented: a general IEC 61131-3-based software solution, and a new OPC standard solution.
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| 7. |
- Christiansson, Anna-Karin, 1947-, et al.
(författare)
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Low order sampled-data H∞ control
- 2003
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Ingår i: Decision and Control, 2003. Proceedings. 42nd IEEE Conference on. ; 3, s. 2308 - 2313
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Konferensbidrag (refereegranskat)abstract
- A method for obtaining low order sampled-data H∞ controllers is presented. The method is mainly based on a parametric static feedback controller for a plant that is augmented with the controller dynamics. The design of a full-order controller is a convex problem, while the optimisation problem for lower order controllers is non convex. The proposed method starts with design of a full-order sampled-data controller using Riccati equations. Then this controller is reduced by an ordinary model reduction technique, and the reduced controller is used as an initial value for an iterative procedure using linear matrix inequalities (LMIs) in the search for an optimal controller. The matrix inequalities are in fact linear in either the Lyapunov matrix or the static controller matrix, why the solution to the non convex problem fundamentally is given by a bilinear matrix inequality (BMI). The order of the controller is reduced until the closed loop performance degrades too much. Simulations are shown for the control of a time delayed SISO-plant where the controller order can be reduced from 8th to 3rd order. Results are also shown from control of a MIMO-model of a jet engine where the reduction is successful from 15th to 4th order. It is argued that the non convexity is handled efficiently since the procedure uses a model reduction of the full-order controller as initial value.
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| 8. |
- Christiansson, Anna-Karin, 1947-, et al.
(författare)
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Mixed continuous/discrete-time output feedback H∞ control : A unified approach
- 1999
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Ingår i: European Control Conference, ECC 1999 - Conference Proceedings. - 9783952417355 ; , s. 4077-4082
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Konferensbidrag (refereegranskat)abstract
- A Riccati equation (RE) based solution to the H∞ optimal control problem for mixed continuous/discrete-time systems is presented. The results unify a number of recently penetrated H∞ control problems. In the infinite-horizon case a periodic behaviour is assumed, and it is shown how the related continuous RE with jumps can be replaced by an equivalent discrete periodic RE. A related algebraic RE, which involves the system behaviour during one period, then can be formulated and solved by standard methods. Typical applications are control of continuous-time or discrete-time periodic systems, as well as multirate and sampled-data control, including mixed continuous and sampled-data measurements. © 1999 EUCA.
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| 9. |
- Glorieux, Emile, et al.
(författare)
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A Constructive Cooperative Coevolutionary Algorithm Applied to Press Line Optimisation
- 2014
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Ingår i: Proceedings of the 24th International Conference on Flexible Automation and Intelligent Manufacturing. - Lancaster, PA, USA : DEStech Publications, Inc.. - 9781605951737 ; , s. 909-916
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Konferensbidrag (refereegranskat)abstract
- Simulation-based optimisation often considers computationally expensive problems. Successfully optimising such large scale and complex problems within a practical time frame is a challenging task. Optimisation techniques to fulfil this need to be developed. A technique to address this involves decomposing the considered problem into smaller subproblems. These subproblems are then optimised separately. In this paper, an efficient algorithm for simulation-based optimisation is proposed. The proposed algorithm extends the cooperative coevolutionary algorithm, which optimises subproblems separately. To optimise the subproblems, the proposed algorithm enables using a deterministic algorithm, next to stochastic genetic algorithms, getting the flexibility of using either type. It also includes a constructive heuristic that creates good initial feasible solutions to reduce the number of fitness calculations. The extension enables solving complex, computationally expensive problems efficiently. The proposed algorithm has been applied on automated sheet metal press lines from the automotive industry. This is a highly complex optimisation problem due to its non-linearity and high dimensionality. The optimisation problem is to find control parameters that maximises the line’s production rate. These control parameters determine velocities, time constants, and cam values for critical interactions between components. A simulation model is used for the fitness calculation during the optimisation. The results show that the proposed algorithm manages to solve the press line optimisation problem efficiently. This is a step forward in press line optimisation since this is to the authors’ knowledge the first time a press line has been optimised efficiently in this way.
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| 10. |
- Glorieux, Emile, 1989-, et al.
(författare)
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Constructive cooperative coevolution for large-scale global optimisation
- 2017
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Ingår i: Journal of Heuristics. - : Springer Science and Business Media LLC. - 1381-1231 .- 1572-9397. ; 23:6, s. 449-469
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the Constructive Cooperative Coevolutionary ( C3C3 ) algorithm, applied to continuous large-scale global optimisation problems. The novelty of C3C3 is that it utilises a multi-start architecture and incorporates the Cooperative Coevolutionary algorithm. The considered optimisation problem is decomposed into subproblems. An embedded optimisation algorithm optimises the subproblems separately while exchanging information to co-adapt the solutions for the subproblems. Further, C3C3 includes a novel constructive heuristic that generates different feasible solutions for the entire problem and thereby expedites the search. In this work, two different versions of C3C3 are evaluated on high-dimensional benchmark problems, including the CEC'2013 test suite for large-scale global optimisation. C3C3 is compared with several state-of-the-art algorithms, which shows that C3C3 is among the most competitive algorithms. C3C3 outperforms the other algorithms for most partially separable functions and overlapping functions. This shows that C3C3 is an effective algorithm for large-scale global optimisation. This paper demonstrates the enhanced performance by using constructive heuristics for generating initial feasible solutions for Cooperative Coevolutionary algorithms in a multi-start framework.
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