System Identification of Complex and Structured Systems

Hjalmarsson, Håkan

doi:10.3166/ejc.15.275-310

Cited by 149 publications

(155 citation statements)

References 48 publications

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“…Since modelling effort is so important in the general control field, and complex models are costly to calibrate accurately, there has been much consideration of "identification-for-control" where the objective is to produce a (simpler) model which is sufficient for its intended purpose, rather than completely identified (Hjalmarsson, 2009). The subject of identification-for-control, or control-relevant identification, has been reviewed by Gevers (2005); Zhu and Butoyi (2002), for example, have investigated the closed-loop identification of some ill-conditioned chemical process plants.…”

Section: Creation Of the Predictive Modelmentioning

confidence: 99%

Model-predictive control for non-domestic buildings: a critical review and prospects

Rockett

Hathway

2016

Building Research & Information

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Model-predictive control (MPC) has recently excited a great deal of interest as a new control paradigm for non-domestic buildings. Since it is based on the notion of optimisation, MPC is, in principle, well-placed to deliver significant energy savings and reduction in carbon emissions compared to existing rule-based control systems. In this paper, we critically review the prospects for buildings MPC and, in particular, the central role of the predictive mathematical model that lies at its heart; our clear emphasis is on practical implementation rather than control-theoretic aspects, and covers the role of occupants as well as the form of the predictive model. The most appropriate structure for such a model is still an open question, which we discuss alongside the development of the initial model, and the process of updating the model during the building's operational life. The importance of sensor placement is highlighted alongside the possibility of updating the model with occupants' comfort perception. We conclude that there is an urgent need for research on the automated creation and updating of predictive models if MPC is to become an economically-viable control methodology for non-domestic buildings. Finally, more evidence through operating full scale buildings with MPC is required to demonstrate the viability of this method.

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Section: Creation Of the Predictive Modelmentioning

confidence: 99%

Model-predictive control for non-domestic buildings: a critical review and prospects

Rockett

Hathway

2016

Building Research & Information

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“…The condition (A10) can be verified using a Taylor expansion around θ 0 , where the expected value of V(θ) for a given θ is approximated by Hjalmarsson (2009) EV ( …”

Section: Disclosure Statementmentioning

confidence: 99%

Least costly closed-loop performance diagnosis and plant re-identification

Mesbah

Bombois

Forgione

et al. 2015

International Journal of Control

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The inherent time-varying nature of dynamics in chemical processes often limits the lifetime performance of model-based control systems, as the plant and disturbance dynamics change over time. A critical step in the maintenance of model-based controllers is distinguishing control-relevant plant changes from variations in disturbance characteristics. In this paper, prediction error identification is used to evaluate a hypothesis test that detects if the performance drop arises from controlrelevant plant changes. The decision rule is assessed by verifying whether an identified model of the true plant lies outside the set of all plant models that lead to adequate closed-loop performance. A unified experiment design framework is presented in the least costly context (i.e., least intrusion of nominal plant operation) to address the problem of input signal design for performance diagnosis and plant re-identification when the performance drop is due to plant changes. The application of the presented performance diagnosis approach to a (nonlinear) chemical reactor demonstrates the effectiveness of the approach in detecting the cause of an observed closed-loop performance drop based on the designed least costly diagnosis experiment.

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“…We will use the application oriented input design framework in [15]. The idea is to define the set of acceptable parameters based on the intended use of the model.…”

Section: Application Oriented Input Designmentioning

confidence: 99%

“…Here, we will consider the excitation design problem using the Application Oriented Input Design framework, [15], where the system identification experiment is designed such that the identified system satisfy some application requirements.…”

Section: Introductionmentioning

confidence: 99%

On optimal input design for networked systems

Hägg

Wahlberg

2015

Automatica

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The topic of this paper is optimal input signal design for identification of interconnected/networked dynamic systems. We consider the case when it is only possible to design some of the input signals, while the rest of the inputs are only measurable. This is most common in industrial applications, where external excitation can only be applied to some subsystems. One example is feed-forward control from measurable disturbances. The optimal input signal will be correlated with the measured signals. The main purpose of this paper is to reveal how to re-formulate the input design problem for networked systems as an input design problem for feedback control systems. We can then use the powerful partial correlation approach for optimal closed loop input design. This means that the corresponding networked optimal input design problem can be formulated as a semi-definite program, for which there are efficient numerical methods. We evaluate this approach using two numerical examples with important applications. The result reveals some non-trivial interesting properties of the optimal input signals.

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System Identification of Complex and Structured Systems

Cited by 149 publications

References 48 publications

Model-predictive control for non-domestic buildings: a critical review and prospects

Model-predictive control for non-domestic buildings: a critical review and prospects

Least costly closed-loop performance diagnosis and plant re-identification

On optimal input design for networked systems

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