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Volume 141
Issue 2
IEE Proceedings - Control Theory and Applications
Volume 141, Issue 2, March 1994
Volumes & issues:
Volume 141, Issue 2
March 1994
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- Author(s): S. Bittanti and L. Piroddi
- Source: IEE Proceedings - Control Theory and Applications, Volume 141, Issue 2, p. 57 –69
- DOI: 10.1049/ip-cta:19949877
- Type: Article
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p.
57
–69
(13)
A nonlinear extension of minimum variance and generalised minimum variance control strategies is developed. The plant is modelled with a linear autoregressive part and a nonlinear dependency on the input. A neural network based implementation of the control law is discussed. This results in a nonlinear controller constituted by a few linear blocks complemented with not more than two neural networks. The weights of the networks are estimated off-line and the learning is carried out with input-output data provided by suitable open loop identification experiments. The performance of the time-invariant neuro-control system is compared with the one achievable by adaptive controllers based on linear models of the plant. - Author(s): D.A. Linkens and M. Mahfouf
- Source: IEE Proceedings - Control Theory and Applications, Volume 141, Issue 2, p. 70 –82
- DOI: 10.1049/ip-cta:19949875
- Type: Article
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p.
70
–82
(13)
S0ingle-input/single-output generalised predictive control (GPC) has been applied successfully to muscle-relaxant anaesthesia in both simulations and clinical trials. This work was extended later to the multivariable case involving simultaneous control of muscle relaxation through EMG measurements, and unconciousness using blood-pressure monitoring in a series of simulation studies. To achieve even higher degrees of automation, a fault detection isolation and accommodation layer has been superimposed on top of the multivariable GPC strategy. The performance of the overall supervisory control scheme has been evaluated in a series of simulation runs on a work station. The results are encouraging in the sense that the algorithm has proved very effective in detecting, diagnosing and eventually compensating for various simulated faults normally encountered in the operating theatre. The experiments used two versions of GPC: the multivariable GPC (using a P-canonical form for the process model) and GPC with feedforward, and were conducted in noise-free and noise-corrupted situations since operating theatres can be electrically dirty environments. The study forms the basis for an experiment protocol which will be followed in clinical trials. - Author(s): C.-H. Wang ; W.-Y. Wang ; T.-T. Lee
- Source: IEE Proceedings - Control Theory and Applications, Volume 141, Issue 2, p. 83 –92
- DOI: 10.1049/ip-cta:19949874
- Type: Article
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p.
83
–92
(10)
A study is made of the sampling-time effects of higher-order digitisations (i.e. the Madwed and Boxer-Thaler digitisations) to convert a continuous-time system into a discrete-time system. A general expression for the denominator and numerator of the digitised system is proposed, and used to predict precisely the computational stability and sampling-time effects of these types of digitisation. The 'polynomial root locus' is introduced to describe the pole variations of the digitised system when the sampling time is varied from zero to infinity. The maximum sampling time of a particular digitisation can also be found by a new algorithm which is proposed. The transient behaviour of the digitised system is further studied by defining a new set of transient terms for discrete-time systems. In this way, the effects of sampling-time can be studied thoroughly. It is shown that the appropriate sampling times obtained via these approximate methods play a meaningful role in selecting appropriate sampling times for real problems. Several examples are illustrated. - Author(s): H.-Y. Chung and W.-J. Chang
- Source: IEE Proceedings - Control Theory and Applications, Volume 141, Issue 2, p. 93 –98
- DOI: 10.1049/ip-cta:19949973
- Type: Article
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p.
93
–98
(6)
An approach for the constrained variance control of nonlinear stochastic systems, which uses the theory of covariance control of linear stochastic systems, is proposed. The nonlinear stochastic systems are linearised by the use of describing functions. Two cases of nonlinear systems are considered: zero-mean nonlinear stochastic systems and nonzero-mean nonlinear stochastic systems. The application of this approach to a position servomechanism is illustrated by a numerical example. - Author(s): D. Czarkowski and M.K. Kazimierczuk
- Source: IEE Proceedings - Control Theory and Applications, Volume 141, Issue 2, p. 99 –103
- DOI: 10.1049/ip-cta:19949972
- Type: Article
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p.
99
–103
(5)
The well-known state feedback with integral control is applied to the multioperating point pulse-width modulated push-pull DC-DC convertor. A new large-signal circuit model of the power stage is modified so that the load resistance is eliminated from the system matrix. Two closed-loop continuous-conduction mode push-pull convertors are designed using a pole-placement technique: (a) a conventional convertor with a diode rectifier; and (b) a convertor with a small inductor and a bidirectional power flow. The large-signal dynamic performance of these convertors is investigated by simulations in the time domain. It was found that the state feedback with integral control in the bidirectional power-flow convertor is suitable for switched-load applications, e.g. radar systems, dot-matrix printers, and power supplies for random-access computer memories. - Author(s): P. Fessas and C. Parisses
- Source: IEE Proceedings - Control Theory and Applications, Volume 141, Issue 2, p. 104 –106
- DOI: 10.1049/ip-cta:19949990
- Type: Article
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p.
104
–106
(3)
The paper investigates the relationship between the problems of stabilisation with static output feedback and with feedback of the local state vectors, in an interconnected system. A sufficient condition for the stabilisation of system (F, G, H) with the output feedback u=Ly is given. When this condition is satisfied, the decentralised and the output feedback controls are equivalent, and allow realisation of the feedback of the local state vectors as a static output feedback. - Author(s): L. Wang and W.R. Cluett
- Source: IEE Proceedings - Control Theory and Applications, Volume 141, Issue 2, p. 107 –110
- DOI: 10.1049/ip-cta:19949971
- Type: Article
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p.
107
–110
(4)
This paper presents a new identification algorithm for processes operating in closed-loop. The algorithm involves fitting two Laguerre models directly to the control signal and the process output signal generated by a step change in the setpoint. The algorithm does not require any prior assumptions about the structure of the process model. The method generates an estimate of the process model in the frequency domain, and then transforms this frequency domain estimate into a continuous-time Laguerre model. Simulation results are used to illustrate the accuracy of the algorithm. - Author(s): M. Zhuang and D.P. Atherton
- Source: IEE Proceedings - Control Theory and Applications, Volume 141, Issue 2, p. 111 –120
- DOI: 10.1049/ip-cta:19949977
- Type: Article
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p.
111
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The paper presents some approaches for the design of a diagonal proportional-integral-derivative (PID) controller for a two-input two-output (TITO) system. First, a new autotuning procedure is given for a TITO system and from the results of this a design method is developed based on moving the critical point to a desired position on the compensated characteristic loci. Second, an optimisation method using integral performance criteria is presented. Examples are given to illustrate both design methods. - Author(s): A.V. Medvedev and T. Toivonen
- Source: IEE Proceedings - Control Theory and Applications, Volume 141, Issue 2, p. 121 –129
- DOI: 10.1049/ip-cta:19949974
- Type: Article
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p.
121
–129
(9)
The paper investigates the possibilities of using a feedforward time-delay structure for state estimation and smoothing in linear continuous dynamic systems. A fixed-lag finite-memory smoother and a continuous deadbeat observer are shown to be described by a linear combination of delayed measurements of the system inputs and outputs. To facilitate implementation of the observer-based controllers an infinite-memory deadbeat observer is introduced. Design methods are illustrated by numerical examples. - Author(s): D.J. Leith
- Source: IEE Proceedings - Control Theory and Applications, Volume 141, Issue 2, p. 130 –136
- DOI: 10.1049/ip-cta:19949989
- Type: Article
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p.
130
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(7)
Identification techniques have been widely used in the rotorcraft community for some time, but despite good progress, difficulties are often encountered, particularly in the estimation of flight mechanics models. Results are presented on the identifiability of a theoretical six degree-of-freedom flight mechanics model of the SA-330 Puma, in particular on the effect of the control axis used, on the estimation of coupling parameters, and on the importance of low-frequency information. These results form the basis of a proposal that the difficulties encountered in recent AGARD WG18 work can be largely attributed to insufficiently long test records.
GMV technique for nonlinear control with neural networks
Supervisory generalised predictive control and fault detection for multivariable anaesthesia
Sampling-time effects of higher-order digitisations and their applications in digital redesign
Extension of the covariance control principle to nonlinear stochastic systems
Application of state feedback with integral control to pulse-width modulated push-pull DC-DC convertor
When can the decentralised state feedback be realised as a static output feedback?
System identification based on closed-loop step response data
PID controller design for a TITO system
Feedforward time-delay structures in state estimation: finite memory smoothing and continuous deadbeat observers
Identification of the SA-330 Puma helicopter
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