| 1. |
- Fors, Niklas, et al.
(författare)
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Feature-Oriented Control Programming
- 2020
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Ingår i: 25th IEEE International Conference on Emerging Technologies and Factory Automation. - 9781728189567 - 9781728189574 ; , s. 1043-1046
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Konferensbidrag (refereegranskat)abstract
- Managing variability in control programs often requires code duplication or that all variants are anticipated in advance. In this paper, we present a new approach to obtaining modular functionality reuse across variants. Using the language mechanisms diagram inheritance and connection interception, a feature model and an interactive feature-selection wizard can be automatically derived from the control program.
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| 2. |
- Gerber, Tobias, et al.
(författare)
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Towards a seamless integration between process modeling descriptions at Business and Production levels - work in progress
- 2014
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Ingår i: Journal of Intelligent Manufacturing. - : Springer Science and Business Media LLC. - 0956-5515 .- 1572-8145. ; 25:5, s. 1089-1099
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Tidskriftsartikel (refereegranskat)abstract
- To fulfill increasing requirements in the manufacturing sector, companies are faced to several challenges. Three major challenges have been identified regarding time-to-market, vertical feedback loops and level of automation. Grafchart, a graphical language aimed for supervisory control applications, can be used from the process-planning phase, through the implementation phase and all the way to the phase for execution of the process control logics, on the lower levels of the automation triangle. This work in progress is examining if the same concepts could be used on the higher levels of the automation triangle as well. By splitting the execution engine and the visualization engine of Grafchart various different visualization tools could potentially be used, however connected by the shared Grafchart semantics. Traditional Business languages (e.g. BPMN) could therefore continue to be used for the process-planning phase whereas traditional production languages (e.g. Grafchart or other SFC-like languages) could be used for the execution. Since they are connected through the semantics, advantages regarding the three identified challenges could be achieved; time-to-market could be reduced, the time delays in the vertical feedback loops could be reduced by allowing Key Performance Indicator visualization, and the level of automation could be increased.
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| 3. |
- Gerber, Tobias, et al.
(författare)
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Towards a seamless integration between process modeling descriptions at Business and Production levels - work in progress
- 2012
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Ingår i: 14th IFAC Symposium on Information Control Problems in Manufacturing. - 9783902661982 ; , s. 1537-1542
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Konferensbidrag (refereegranskat)abstract
- To fulfill increasing requirements in the manufacturing sector, companies are faced with several challenges. Three major challenges have been identified regarding time-to-market, vertical feedback loops and level of automation. Grafchart, a graphical language aimed for supervisory control applications, can be used from the process-planning phase, through the implementation phase and all the way to the phase for execution of the process control logics, on the lower levels of the Automation triangle. Work in progress is examining if the same concepts could be used on the higher levels of the Automation triangle as well. By splitting the execution engine and the visualization engine of Grafchart various different visualization tools could potentially be used, however connected by the shared Grafchart semantics. Traditional Business languages, e.g. BPMN, could therefore continue to be used for the process-planning phase whereas traditional production languages, e.g. Grafchart or other SFC-like languages, could be used for the execution. Since they are connected through the semantics, advantages regarding the three identified challenges could be achieved; time-to-market could be reduced, the time delays in the vertical feedback loops could be reduced by allowing KPI visualization, and the level of automation could be increased.
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| 4. |
- Hansson, Jonas, et al.
(författare)
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Next generation relay autotuners—analysis and implementation
- 2021
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Ingår i: Proceedings of the 5th IEEE Conference on Control Technologies and Applications (CCTA) 2021. ; , s. 1075-1982
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Konferensbidrag (refereegranskat)abstract
- In order to produce models for automatic controller tuning, this paper proposes a method that combines a short experiment with a novel scheme for approximating processes using low-order time-delayed models. The method produces models aimed to tune PI and PID controllers, but they could also be used for other model-dependent controllers like MPC. The proposed method has been evaluated in simulations on benchmark processes. It has also been implemented in an industrial controller and tested experimentally on a water-tank process. It is shown that our method is successful in estimating models for a variety of processes such as lag-dominated, delay-dominated, balanced, and integrating processes. We also demonstrate that the experiment time is both shorter and more predictable than currently used autotuners.
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| 5. |
- Hägglund, Tore, et al.
(författare)
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An industrial control loop decoupler for process control applications
- 2022
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Ingår i: Control Engineering Practice. - : Elsevier BV. - 0967-0661. ; 123:June
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Tidskriftsartikel (refereegranskat)abstract
- The paper describes a simple and efficient control loop decoupler for TITO (two inputs, two outputs) control systems. The inverted decoupling approach is used, and the feedforward filters are just static gains. The feedforward gains are determined in two ways, from a static analysis and from optimization. By investigating several cases found in literature, it is found that the two sets of feedforward gains are very close. The control loop decoupler is implemented in an industrial DCS system and simulation experiments as well as laboratory tests show that a significant reduction of the coupling is accomplished. Automatic tuning of the feedforward gains is derived and implemented in the system as well.
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| 6. |
- Lundh, Magnus, et al.
(författare)
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Model optimization for autotuners in industrial control systems
- 2021
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Ingår i: Proceedings of the 26th International Conference on Emerging Technologies and Factory Automation (ETFA). - 9781728129891 ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- Automatic tuning of PID controllers using relay feedback experiments has received attention on and off since it was first proposed and industrially implemented in a control system in the 1980s. While optimal experiment design and modern system identification easily outperform the original automatic tuner, they rely on computational resources that are not always available in industrial control systems. Here we present a combination of experiment and subsequent output-error identification of continuoustime first-order time-delayed (FOTD) system models, that requires very little in terms of computations and memory. The method has been extensively evaluated in simulation, and a prototype has been implemented for the ABB AC 800M controller family.
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| 7. |
- Ollinger, Lisa, et al.
(författare)
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A Reference Architecture for Service-oriented Control Procedures and its Implementation with SysML and Grafchart
- 2013
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Ingår i: IEEE 18th Conference on Emerging Technologies & Factory Automation (ETFA), 2013. - 1946-0759 .- 1946-0740. - 9781479908622 ; , s. 1-8
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Konferensbidrag (refereegranskat)abstract
- Innovative engineering methods are needed to enhance the adaptability and agility of industrial control procedures and concurrently manage their rising complexity. Service-oriented Architecture (SOA) constitutes a promising paradigm to meet these challenges. To apply the rather abstract SOA principles to industrial automation, a model-driven engineering method is presented in this paper. Therefore, a reference architecture is introduced providing a framework to structure and define services for control tasks in a convenient way. The application of the engineering method is supported by an implementation concept. It uses SysML during the design phase and the process modeling and control language Grafchart for the execution of service-oriented control procedures.
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| 8. |
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| 9. |
- Theorin, Alfred
(författare)
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A Sequential Control Language for Industrial Automation
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Current market trends for industrial automation are the need for customizable production, shorter time to market, and powerful global competitive pressure. Based on these trends two challenges have been identified: 1) flexible production systems and 2) integration and utilization of devices and software. Applications from both process automation, manufacturing, and robotics have been considered. More flexible languages and tools are needed to get a flexible production system. The graphical programming language Grafchart, based on the IEC 61131-3 standard language Sequential Function Charts (SFC), is considered with the aim to make both the language and its implementation more flexible. In particular, new constructs have been added to the Grafchart language and modern compiler techniques are evaluated for JGrafchart, a Grafchart implementation, with focus on an extensible language implementation. A first step toward real-time execution of Grafchart applications is also taken to make it possible to use Grafchart for hard real-time control. High execution rates often reveal concurrency issues and thus execution concurrency has also been investigated. Access to more data from industrial devices and software can be used to optimize production. Architectures for factory integration have been considered as this is the foundation to connect all devices and thus address the challenge of integrating and utilizing devices and software. Service Oriented Architecture (SOA) is a flexible software design methodology widely used in IT systems and for business processes. SOA service orchestration is brought to industrial automation by integrating support for both Devices Profile for Web Services (DPWS) and OPC Unified Architecture (OPC UA) in JGrafchart. Looking further, SOA 2.0 is event driven and features extremely loose coupling between components. An architecture based on SOA 2.0 where it is easy to integrate any device or software, in particular legacy devices with limited knowledge and capabilities, has been developed with focus on service choreography in industrial manufacturing. Another step toward real-time execution of Grafchart applications is integrated support for the high performance communication protocol LabComm. Additionally, it is investigated how Grafchart can be connected to Functional Mock-up Interface (FMI) for co-simulation to further address the shorter time to market trend by introducing simulation support. The PID controller is the most common controller for industrial automation. A PID implementation has been added to a Grafchart library and a flaw with the PID algorithm has been discovered. The problem occurs for PID controllers with a derivative part when the process value saturates. The derivative part then backs off which leads to undesired changes in the control signal. This issue has been analyzed and a solution to the problem is proposed.
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| 10. |
- Theorin, Alfred
(författare)
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Adapting Grafchart for Industrial Automation
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Current trends in industrial automation are the need for customizable production, vertical integration, more advanced sensors and actuators, and shorter time to market. The currently used control systems and languages for control were developed with a more static production in mind. More flexible languages and tools are needed to get a more flexible production. The flexible graphical programming language Grafchart, based on the IEC 61131-3 standard language Sequential Function Charts (SFC), is considered with the focus to make it usable in an industrial context. Modern compiler techniques are evaluated for JGrafchart, a Grafchart implementation, with focus on extensible automation language implementations. In particular implementing the High Level Version (HLV) of Grafchart as an extension would make JGrafchart more dynamic and enable further research on HLV. To make Grafchart possible to use at the lowest levels of automation, realtime execution with JGrafchart is considered. For this to be possible the execution engine must be separated from the editor. In the first step the execution engine is still an interpreter, but an order of magnitude faster than before. Finally Service Oriented Architecture (SOA), a highly flexible software design methodology widely used for business processes, is brought to automation by integrating support for Devices Profile for Web Services (DPWS) in JGrafchart.
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