ROBUST CONTROL OF WIENER SYSTEMS: APPLICATION TO A pH NEUTRALIZATION PROCESS

Biagiola, Silvina Ines; Agamennoni, Osvaldo; Figueroa, José Luis

doi:10.1590/0104-6632.20160331s00002846

Cited by 9 publications

(10 citation statements)

References 31 publications

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“…The structure from Figure 3 suggests that, for an accurately identified nonlinearity, the nonlinear closed-loop characteristics will be those of the linear element (Biagiola et al, 2016). In a frequency domain context, and considering that uncertainty d f s is small, the controlled process Bode plot will remain bounded withing a certain region with respect to the linear frequency domain plot in Figure 8.…”

Section: Frequency Domain Evaluationmentioning

confidence: 99%

Turbojet direct-thrust control scheme for full-envelope fuel consumption minimization

Villarreal-Valderrama

Delgado

Zambrano‐Robledo

et al. 2020

AEAT

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Purpose Reducing fuel consumption of unmanned aerial vehicles (UAVs) during transient operation is a cornerstone to achieve environment-friendly operations. The purpose of this paper is to develop a control scheme that improves the fuel economy of a turbojet in its full operating envelope. Design/methodology/approach A novel direct-thrust linear quadratic integral (LQI) approach, comprised by an optimal observer/controller satisfying specified performance parameters, is presented. The thrust estimator, based in a Wiener model, is validated with the experimental data of a micro-turbojet. Model uncertainty is characterized by analyzing variations between the identified model and measured data. The resulting uncertainty range is used to verify closed-loop stability with the circle criterion. The proposed controller provides stable responses with the specified performance in the whole operating range, even with after considering plant nonlinearities. Finally, the direct-thrust LQI is compared with a standard thrust controller to assess fuel economy and performance. Findings The direct-thrust LQI approach reduced the fuel consumption by 2.1090% in the most realistic scenario. The controllers were also evaluated using the environmental effect parameter (EEP) and transient-thrust-specific fuel consumption (T-TSFC). These novel metrics are proposed to evaluate the environmental impact during transient-thrust operations. The direct-thrust LQI approach has a more efficient fuel consumption according to these metrics. The results also show that isolating the thrust dynamics within the feedback loop has an important impact in fuel economy. Controllers were also evaluated using the EEP and T-TSFC. These novel metrics are proposed to evaluate the environmental impact during transient-thrust operations. The direct-thrust LQI approach has a more efficient fuel consumption according to these metrics. The results also show that isolating the thrust dynamics within the feedback loop has an important impact in fuel economy. Originality/value This study shows the design of an effective direct-thrust control approach that minimizes fuel consumption, ensures stable responses for the full operation range, allows isolating the thrust dynamics when designing the controller and is compatible with classical robustness and performance metrics. Finally, the study shows that a simple controller can reduce the fuel consumption of the turbojet during transient operation in scenarios that approximate realistic operating conditions.

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Section: Frequency Domain Evaluationmentioning

confidence: 99%

Turbojet direct-thrust control scheme for full-envelope fuel consumption minimization

Villarreal-Valderrama

Delgado

Zambrano‐Robledo

et al. 2020

AEAT

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“…The general representation of a pH system is given by (Alina & Madalina, 2016;Bharathi et al, 2007;Biagiola et al, 2016;Darab et al, 2012;Elameen et al, 2014;Rodriguez & Loparo, 2004), (5)…”

Section: System Modelingmentioning

confidence: 99%

Real-time implementation of QFT, GA, and BFTPSO controller for pH neutralization system

Aparna¹,

Jamal²

2021

JART

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The control of a pH process is complex because of severe nonlinearities in its behavior. A continuous pH neutralization process is usually represented as a first-order plus dead time system, but its gain varies for different operating points. Therefore, a conventional linear controller cannot be used, and the pH system was thus represented as a linear state-space model around an equilibrium point. This linear model was then used to compute the PID controller gains using robust and optimization techniques like quantitative feedback theory, bacterial foraging technique-based particle swarm optimization algorithm, and genetic algorithm. The corresponding controller gains resulting from the three algorithms were used to control the pH using a reconfigurable I/O device, NI myRIO-1900. Finally, the output time domain specifications and the servo and regulatory responses, resulting from the three algorithms, were compared in simulation and in real-time to deduce the appropriate tuning algorithm for this system.

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“…Compared with the existing results using the normal nonlinearity inversion method, 37–39 the proposed control design is based on the polynomial structure nonlinearity inversion approximation. As a consequence, we appeal the T-S fuzzy representation to decompose the existing nonlinearities into linear parts and facilitate the stability analysis and control synthesis.…”

Section: Introductionmentioning

confidence: 99%

“…Compared to the existing results regarding the identification 8–10,12–14,17 and the control 12,37–40 problems of MIMO Hammerstein models, we consider not only stability but also other control performances such as speed of response, tracking control, and attenuation of the disturbances effect.…”

Section: Introductionmentioning

confidence: 99%

Robust stabilization and tracking control schemes for disturbed multi-input multi-output Hammerstein model in presence of approximate polynomial nonlinearities

Ghorbel

Rayouf

Braïek

2020

Proceedings of the Institution of Mechanical Engineers, Part I:

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This article presents robust stabilization and tracking control problems for multi-input multi-output Hammerstein model with external disturbances. This model is characterized by static nonlinear elements followed by a linear dynamic block. Moreover, the unknown parameters of the identified mathematical model are estimated using the multivariable output error state space subspace algorithm. Unlike the general control strategy that used the nonlinearity inversion method, the nonlinearities are supposed not bijective. In this context, inverse nonlinear functions of polynomial structure are suggested in this article. Furthermore, the composition of the static nonlinear elements and their approximate inverses in series with the linear dynamic block are then decomposed into a set of linear parts using the Takagi–Sugeno fuzzy representation. Consequently, new sufficient stability conditions with decay rate and disturbance attenuation using the [Formula: see text] criterion and linear matrix inequality tools are discussed. Finally, simulation studies are provided to illustrate the merit of our purpose.

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ROBUST CONTROL OF WIENER SYSTEMS: APPLICATION TO A pH NEUTRALIZATION PROCESS

Cited by 9 publications

References 31 publications

Turbojet direct-thrust control scheme for full-envelope fuel consumption minimization

Turbojet direct-thrust control scheme for full-envelope fuel consumption minimization

Real-time implementation of QFT, GA, and BFTPSO controller for pH neutralization system

Robust stabilization and tracking control schemes for disturbed multi-input multi-output Hammerstein model in presence of approximate polynomial nonlinearities

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