| 1. |
- Åström, Karl Johan, et al.
(författare)
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Analysis of a Scheme for Iterated Identification and Control
- 1994
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Ingår i: IFAC Symposium on System Identification (SYSID'94), Copenhagen, Denmark, 4-6 July. - 1474-6670. ; 27:8, s. 473-478
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Konferensbidrag (refereegranskat)abstract
- This paper presents analysis of a scheme for iterated identification and control design. The approach is based on least squares identification in closed loop and pole placement design. It has previously been shown that the criteria for control and identification are the same provided that the data filters are chosen properly. The iterated scheme may be viewed as a recursion in model parameters. Each step consists of system identification and control design. Interesting questions are then: What are the fix points? Are the fix points stable? These questions are investigated for some simple examples. Relations to other problems like model reduction and adaptive control are also discussed.
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| 2. |
- Medvedev, Alexander, et al.
(författare)
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External model control of a peristaltic pump
- 1994
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Ingår i: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080422292 ; 27:2, s. 519-524
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Tidskriftsartikel (refereegranskat)abstract
- An observer-based approach to perfect disturbance rejection in linear continuous systems with delayed control is presented and exemplified by an application to a peristaltic pump. Disturbance rejection properties of the Smith Predictor are studied. A recently developed technique of continuous deadbeat observation is exploited to predict the disturbance signal which is described by a known dynamic model. It is shown that under certain algebraic conditions a disturbance estimate based control law is able to provide a disturbance-free output signal. The disturbance rejection scheme can be used in combination with any conventional control technique such as stabilizing or servo controller.
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| 3. |
- Medvedev, Alexander
(författare)
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Fault Detection by Continuous Dead-Beat Observation
- 1994
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Ingår i: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080422225 ; 27:5, s. 28-33
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Tidskriftsartikel (refereegranskat)abstract
- An application of continuous-time deadbeat observation to fault analysis in linear dynamic systems is discussed. A finite memory residual chosen as a difference of two deadbeat state vector estimates is shown to be independent of both the state vector and control signal. The mapping of the fault mode to the residual is proven to be intrinsically BIBO-stable. Exploiting a decomposition of the “sliding-window” convolution operator, an upper bound for residual norm is derived and a fault detectability condition is obtained. Due to its simple structure, the deadbeat observer does not create a hard computational burden and can be easily implemented in real-time applications.
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| 4. |
- Mäkilä, Pertti, et al.
(författare)
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Robust identification
- 1994
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Ingår i: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 27:8, s. 45-63
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Tidskriftsartikel (refereegranskat)abstract
- This paper introduces the reader to several recent developments in robust identification motivated by various issues of modelling of systems from data for the purpose of robust control design. Many aspects of identification in H∞ and l1 are covered; including algorithms, convergence and divergence results, control relevancy issues, and objective worst case estimation of uncertainty models
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| 5. |
- Rönnbäck, Stefan, et al.
(författare)
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A design algorithm for anti-windup compensators : polynomial approach
- 1993
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Ingår i: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 008042211X ; 26:2:5, s. 619-624
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Tidskriftsartikel (refereegranskat)abstract
- It is discussed how an LTI ‘polynomial controller’ for a SISO-system with actuator constraints can be designed using conventional linear pole-placement technique. This becomes possible due to the utilization of an ‘anti-windup’ technique in which the effect of control-signal saturation is interpreted as being caused by an equivalent disturbance. The results are summarized into a ‘design algorithm’ which supports a complete separation of 'servo', ‘disturbance-rejection’ and ‘anti-windup’ poles. It also supports the introduction of arbitrary 'specific factors’ into the controller polynomials, and it can be used for both continuous-time and discrete-time controllersIt is discussed how an LTI ‘polynomial controller’ for a SISO-system with actuator constraints can be designed using conventional linear pole-placement technique. This becomes possible due to the utilization of an ‘anti-windup’ technique in which the effect of control-signal saturation is interpreted as being caused by an equivalent disturbance. The results are summarized into a ‘design algorithm’ which supports a complete separation of 'servo', ‘disturbance-rejection’ and ‘anti-windup’ poles. It also supports the introduction of arbitrary 'specific factors’ into the controller polynomials, and it can be used for both continuous-time and discrete-time controllers.
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| 6. |
- Vagenas, Nikos
(författare)
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Prognos : a prototype expert system for fault diagnosis of the transmission system of load-haul-dump vehicles in Kiruna mine, LKAB, Sweden
- 1992
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Ingår i: Expert systems in mineral and metal processing. - Oxford : Pergamon Press. - 1474-6670. - 0080417043 ; , s. 173-178
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Konferensbidrag (refereegranskat)abstract
- As a consequence of the increasing complexity of modern mining machinery and systems, more time is consumed on repair following a breakdown. Equipment breakdowns cause lengthy and costly delays in the operation of mines. PROGNOS is a rule-based expert system for fault diagnosis of the transmission system of load-haul-dump (LHD) vehicles in Kurna mine, Sweden. This paper presents the problem approach and discusses the formulation of the knowledge base and the software implementation. The use of expert systems for fault diagnosis of mining machinery can be a cost and time effective approach of minimizing repairs in the mines
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