The relative gain for non-square multivariable systems

Chang, Jin Wen; Yu, Cheng

doi:10.1016/0009-2509(90)87123-a

Cited by 124 publications

(81 citation statements)

References 17 publications

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“…B(s)d * (s) is the so called net load effect (Chang and Yu, 1992) and y net s (s) the augmented form considering references and disturbances changes (Nieto Degliuomini et al, 2012). In the latter work only a "sparse suboptimal control policy" was evaluated in a decentralized context.…”

Section: Sparse Controllers: Improvements Via Nlementioning

confidence: 99%

“…General topics involved in these proposals include stability and/or controllability assessments (Yuan et al, 2011a,b), input-output pairing problems (Bristol, 1966;Chang and Yu, 1990;McAvoy et al, 2003;He et al, 2009;Assali and McAvoy, 2010), operating cost and self-optimizing (Skogestad, 2000;Alstad and Skogestad, 2007;Downs and Skogestad, 2011), performance and/or robustness indicators (Grosdidier et al, 1985;Skogetad and Morari, 1987;Skogestad and Postlethwaite, 2005), and deviation-based indexes or some combination of these into a multi-objective criteria (Downs and Skogestad, 2011;Sharifzadeh and Thornhill, 2012). Usually, the suggested design framework considers all possible degrees of freedom in a classical control structure (centralized/full or decentralized/diagonal).…”

Section: Introductionmentioning

confidence: 99%

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Oversizing analysis in plant-wide control design for industrial processes

Zumoffen

2013

Computers & Chemical Engineering

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In this work, an alternative plant-wide control design approach based on oversizing analysis is presented.The overall strategy can be divided in two main sequential tasks: 1-defining the optimal decentralized control structure, and 2-setting the controller interaction degree and its implementation. Both problems represent combinatorial optimizations based on multi-objective functional costs and were solved efficiently by genetic algorithms. The first task defines the optimal selection of controlled and manipulated variables simultaneously, the input-output pairing, and the overall controller dimension in a sum of square deviations context. The second task analyzes the potential improvements by defining the controller interaction degree via the net load evaluation approach. In addition, some insights are given about the feasibility (implementation load) of these control structures for a decentralized or centralized framework. The well-known Tennessee Eastman (TE) process is selected here for sake of comparison with other multivariable control designs.

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Section: Sparse Controllers: Improvements Via Nlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Oversizing analysis in plant-wide control design for industrial processes

Zumoffen

2013

Computers & Chemical Engineering

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“…The RGA was applied by Machado et al (2009) to a similar WWTP using square configurations but, when the number of inputs and outputs is not the same, a non-square relative gain array (NSRGA) approach is recommended The NSRGA was proposed by Chang and Yu (1990) and it is an extension of the RGA to non-square systems. The NSRGA matrix is calculated using the formula:…”

Section: Control Methodsmentioning

confidence: 99%

Development and economic assessment of different WWTP control strategies for optimal simultaneous removal of carbon, nitrogen and phosphorus

Ostace

Baeza

Guerrero

et al. 2013

Computers & Chemical Engineering

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This paper presents the comparison of four control strategies for the A 2 /O WWTP configuration for simultaneous C, N and P removal. The control strategies: i) external COD-P control; ii) external recycle flow-P control; iii) nitrate control in the last anoxic reactor; iv) ammonia control in the last aerobic reactor, were combined with other common control loops to build different control structures and were simulated in Matlab/Simulink under different influent conditions. A systematic approach was conducted with all the strategies to assess their potential effectiveness, according to the following steps: theoretical design, setpoint optimization and, finally, a detailed comparison of the control results against a reference operation and an optimized reference scenario. The optimization of the reference operation presented a 7 % reduction of the total operational cost. The simulation results showed that some control strategies further reduced 3-7.5% the WWTP operational costs while the effluent quality is greatly improved.

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“…As shown in , Chang and Yu (1990), and Skogestad and Postlethwaite (1996, Section 10.5), to some extent the RGA may be used for a direct approach to IO selection. Consider P corresponding to the full IO set and suppose N S ON W .…”

Section: The Relative Gain Arraymentioning

confidence: 99%

“…* a denoting element-by-element multiplication (Hadamard or Schur product). For a nonsquare P, the inverse in (19) is again replaced by the pseudo-inverse (Chang & Yu, 1990). The RGA is independent of the scaling of the plant's inputs and outputs if n S "n W , while it is independent of output scaling if n S 'n W and independent of input scaling if n S (n W .…”

Section: The Relative Gain Arraymentioning

confidence: 99%

A review of methods for input/output selection

2001

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Control system design involves input/output (IO) selection, that is, decisions on the number, the place, and the type of actuators and sensors. The choice of inputs and outputs a!ects the performance, complexity, and costs of the control system. Due to the combinatorial nature of the selection problem, systematic methods are needed to complement one's intuition, experience, and physical insight. This paper reviews the currently known IO selection methods, which aids the control engineer in picking a suitable method for the problem at hand. The methods are grouped according to the control system property that is addressed and applications are grouped according to the considered control systems. A set of criteria is proposed that a good IO selection method should possess. It is used to assess and compare the methods and it could be used as a guideline for new methods. The state of the art in IO selection is sketched and directions for further research are mentioned.

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The relative gain for non-square multivariable systems

Cited by 124 publications

References 17 publications

Oversizing analysis in plant-wide control design for industrial processes

Oversizing analysis in plant-wide control design for industrial processes

Development and economic assessment of different WWTP control strategies for optimal simultaneous removal of carbon, nitrogen and phosphorus

A review of methods for input/output selection

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