| 1. |
- Balluchi, A., et al.
(författare)
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Hybrid control of networked embedded systems
- 2005
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Ingår i: European Journal of Control. - : LAVOISIER. - 0947-3580 .- 1435-5671. ; 11:4-5, s. 478-508
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid systems that involve the interaction of continuous and discrete dynamics have been an active area of research for a number of years. In this paper, we start by briefly surveying the main theoretical control problems that have been treated in the hybrid systems setting and classify them into stabilization, optimal control and language specification problems. We then provide an overview of recent developments in four of the most prominent areas where these hybrid control methods have found application: control of power systems, industrial process control, design of automotive electronics and communication networks.
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| 2. |
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| 3. |
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| 4. |
- Freidovich, Leonid, et al.
(författare)
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Discussion on: ``Robustness of PID-controlled manipulators vis-a-vis actuator dynamics and external disturbances''
- 2007
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Ingår i: European Journal of Control. - 0947-3580 .- 1435-5671. ; 13:6, s. 755-759
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Tidskriftsartikel (refereegranskat)abstract
- The paper by Chaillet, Loría, and Kelly is devoted to study robustness of mechanical systems controlled by proportional integral-differential (PID) regulators. These control strategies are classical and are the most frequently used in industrial applications of robotic manipulators despite various other available techniques. There is a number of results on properties of PID-controlled mechanical systems, see references in the paper and [1,2,5–7,11–13] to mention a few.
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| 5. |
- Hjalmarsson, Håkan, 1962-
(författare)
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System Identification of Complex and Structured Systems
- 2009
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Ingår i: European Journal of Control. - 0947-3580 .- 1435-5671. ; 15:3-4, s. 275-310
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Tidskriftsartikel (refereegranskat)abstract
- A key issue in system identification is how to cope with high system complexity. In this contribution WE stress the importance of taking the application into account in order to cope with this issue. We define the concept "cost of complexity" which is a measure of the minimum required experimental effort (e.g., used input energy) as a function of the system complexity, the noise properties, and the amount, and desired quality, of the system information to be extracted from the data. This measure gives the user a handle on the tradeoffs that must be considered when performing identification with a fixed experimental "budget". Our analysis is based on the observation that the identification objective is to guarantee that the estimated model ends up within a pre-specified "level set" of the application objective. This geometric notion leads to a number of useful insights: Experiments should reveal system properties important for the application but may also conceal irrelevant properties. The latter, dual, objective can be explored to simplify model structure selection and model error assessment issues. We also discuss practical issues related to computation and implementation of optimal experiment designs. Finally, we illustrate some fundamental limitations that arise in identification of structured systems. This topic has bearings on identification in networked and decentralized systems.
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| 6. |
- Peni, T., et al.
(författare)
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Induced L2 norm improvement by interpolating controllers for discrete time LPV systems
- 2009
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Ingår i: European Journal of Control. - 0947-3580. ; 15:5, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- The paper shows an interpolation-based control solution asapossible technique to formulate the constrained H∞ control problem for discrete-time linear parameter varying (LPV) systems. The control policy is constructed by interpolating amongapriori designed, unconstrained, constant, state feedback controllers. Invariant set theory is used to introduce the measure of the domain of applicability. It is shown that the `trade-off' between the performance and the size of the domain of applicability can be significantly reduced by controller interpolation. Hence, the interpolation-based controller becomes applicable overamuch larger region than any other single state feedback. The proposed method gives stabilizing solution not only under hard constraints, but also allows the online modification of the induced L² norm from the generalized disturbance input to the predefined performance output. Moreover, the suggested method can be applied in real-time environment.
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| 7. |
- Svärd, Carl, 1981-, et al.
(författare)
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An Observer-Based Residual Generation Method for Linear Differential-Algebraic Equation Systems
- 2009
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Ingår i: European Journal of Control. - 0947-3580 .- 1435-5671.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Residual generation for linear differential-algebraic systems is considered. A new systematic method for observer-based residual generation is presented. The proposed design method places no restrictions on the system to be diagnosed. If the fault of interest can be detected in the system, the output from the design method is a residual generator in state-space form that is sensitive to the fault of interest. The method is iterative and relies only on constant matrix operations such as multiplications, null-space calculations and equivalence transformations, and thereby straightforward to implement. An illustrative numerical example is included, where the design method is applied to a nonobservable model of a robot manipulator.
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| 8. |
- Årzén, Karl-Erik, et al.
(författare)
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A component-based approach to the design of networked control systems
- 2007
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Ingår i: European Journal of Control. - : Elsevier BV. - 1435-5671 .- 0947-3580. ; 13:2-3, s. 261-279
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Tidskriftsartikel (refereegranskat)abstract
- Component-based techniques revolve around composable, reusable software objects that shield the application level software from the details of the hardware and low-level software implementation and vice versa. Components provide many benefits that have led to their wide adoption it software and middleware developed for embedded systems: They are well-defined entities that can be replaced without affecting the rest of the systems, they can be developed and tested separately and integrated later, and they are reusable. Clearly such features are important for the design of large-scale complex systems more generally, beyond software architectures. We propose the use of a component approach to address embedded control problems. We outline a general coponent-based framework to embedded control aid show how it can be instantiated inspecific problems that arise in the control over/of sensor networks. Building on the middleware component framework developed under the European project RUNES, we develop a number of control-oriented components necessary for the implementation of control applications and design their integration. The paper provides the overview of the approach, discusses a real life application where the approach has been tested and outlines a number of specific control problems that arise in this application.
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