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- Christiansson, Anna-Karin, 1947-, et al.
(author)
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Mixed continuous/discrete-time output feedback H∞ control : A unified approach
- 1999
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In: European Control Conference, ECC 1999 - Conference Proceedings. - 9783952417355 ; , s. 4077-4082
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Conference paper (peer-reviewed)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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- Hellgren, Anders, 1970, et al.
(author)
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Deadlock Detection and Controller Synthesis for Production Systems Using Partial Order Techniques
- 1999
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In: Proceedings of the 1999 IEEE International Conference on Control Applications, Kohala Coast, Hawaii, USA.
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Conference paper (peer-reviewed)abstract
- Discrete event systems can be used to model the behaviour of production systems. The supervisory control theory is a suitable tool for synthesising controllers that coordinate the resource utilisation of concurrent products in the production system. Due to the combinatorial state space explosion, computations become intractable for most real life systems. To alleviate this problem, methods that do not enumerate the entire state space are needed. One method that has proven valuable for the verification of concurrent systems is based on partial order principles. For a certain class of production systems it is shown how such ideas may be used to synthesise non-blocking discrete event controllers.
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4. |
- Hellgren, Anders, 1970, et al.
(author)
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Synchronised Execution of Discrete Event Models Using Sequential Function Charts
- 1999
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In: Proceedings of the 38th IEEE Conference on Decision and Control, Phoenix, Arizona, USA.
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Conference paper (peer-reviewed)abstract
- The discrepancy between the event based supervisory control theory and its signal based implementation in programmable logic controllers using sequential function charts is explored. Different execution models and the related problems are discussed. Specifically, synchronisation of sequential function charts is treated in the context of modular implementation of the control functions. The supervisory control theory requires that conflicting events are never generated. This is guaranteed by the synchronous execution of events present in all modules. However, in a signal based environment the synchronous “execution of events” is not well defined. We propose an event monitor to resolve this problem.
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- Lindgärde, Olof, 1967, et al.
(author)
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Frequency analysis for mixed continuous-time and discrete-time periodic systems
- 1999
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In: 1999 European Control Conference, ECC 1999; Karlsruhe; Germany; 31 August 1999 through 3 September 1999. - : IEEE. - 9783952417355 ; , s. 4071-4076
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Conference paper (peer-reviewed)abstract
- In this paper mixed continuous-time and discrete-time periodic systems are analyzed in the frequency domain taking the intersample behavior into account. By the presented model structure it is possible to analyze a couple of different control problems in a common framework. The suggested approach is very similar to the one presented by Yamamoto and Khargonekar. The fundamental differences are that the solution is generated, not via the lifted model, but more directly based on the transition matrix of a continuous-time periodic system with jumps. The hybrid model that is analyzed is very clean, but is general compared to model structures considered before. © 1999 EUCA.
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