Design of a Robust Observer with Super-Twisting Algorithm for Simultaneous Concentration Estimation and Faults Reconstruction in a CSTR

2019 ◽  
Vol 17 (8) ◽  
Author(s):  
M. Boudjellal ◽  
R. Illoul
Keyword(s):  
High Gain ◽  
Lyapunov Theory ◽  
Continuous Stirred Tank Reactor ◽  
Nonlinear Observers ◽  
Robust Observer ◽  
Fault Reconstruction ◽  
Concentration Estimation ◽  
Continuous Stirred Tank ◽  
The Stability ◽  
Twisting Algorithm

AbstractThis paper deals with the problem of simultaneous concentration and faults estimations of a continuous stirred tank reactor (CSTR) subject to unknown inputs. We propose a combination of two robust nonlinear observers for state estimation and fault reconstruction without any use of a linear approximation of the CSTR dynamic model. Based on the high-gain observer, the proposed scheme can guarantee the asymptotic estimation of the concentration inside the reactor, while, a robust term is added to the nominal plant on the basis of the super-twisting algorithm for fault reconstruction. The stability analysis is proved mathematically using the Lyapunov theory. The effectiveness and robustness of the proposed scheme are illustrated via simulations.

Position and attitude tracking of uncertain quadrotor unmanned aerial vehicles based on non-singular terminal super-twisting algorithm

2019 ◽  
Vol 234 (3) ◽  
pp. 396-408
Author(s):  
Walid Alqaisi ◽  
Yassine Kali ◽  
Jawhar Ghommam ◽  
Maarouf Saad ◽  
Vahé Nerguizian
Keyword(s):  
Sliding Mode ◽  
Design Procedure ◽  
Lyapunov Theory ◽  
Effective Control ◽  
Attitude Tracking ◽  
Control Scheme ◽  
The Stability ◽  
Terminal Sliding Surface ◽  
Twisting Algorithm ◽  
Twisting Control

This paper proposes an improved non-singular terminal super-twisting control for the problem of position and attitude tracking of quadrotor systems suffering from uncertainties and disturbances. The super-twisting algorithm is a second-order sliding mode known to be a very effective control used to provide high precision and less chattering for uncertain nonlinear electromechanical systems. The proposed method is based on a non-singular terminal sliding surface with new exponent that solves the problem of singularity. The design procedure and the stability analysis of the closed-loop system using Lyapunov theory are detailed for the considered system. Finally, the proposed control scheme is tested in simulations and by experiments on the parrot-rolling spider quadrotor. Moreover, a comparison is made with the standard super-twisting algorithm in the simulation part. The results obtained show adequate performance in trajectory tracking and chattering reduction.

scholarly journals An Adaptive Observer Design for Nonlinear Systems Affected by Unknown Disturbance with Simultaneous Actuator and Sensor Faults. Application to a CSTR

2021 ◽  
Vol 12 (4) ◽  
pp. 4847-4856
Keyword(s):  
Nonlinear Behavior ◽  
Lyapunov Theory ◽  
Observer Design ◽  
Adaptive Observer ◽  
Linear Matrix ◽  
Sensor Faults ◽  
Continuous Stirred Tank Reactor ◽  
Continuous Stirred Tank ◽  
Unknown Disturbance ◽  
Takagi Sugeno

Continuous Stirred Tank Reactor (CSTR) is an important system in the chemical and biological industries. It's characterized by a complex nonlinear behavior and is usually affected by faults and disturbances. Therefore, the states and faults estimation of a CSTR is always a challenging task for automated process researchers and engineers. This paper proposes an adaptive observer. This paper proposes an adaptive observer in order to estimate states and actuator and sensor faults simultaneously under unknown disturbance. Firstly, the approach of the Takagi-Sugeno multi-model is proposed to transform the complex nonlinear model into several simple linear sub-models. However, the states of the considered isotherm CSTR are not completely measurable, so the multi-model is represented with non-measurable premise variables. Then, in order to transform the considered system into a system with an unknown input, a mathematical transformation is introduced to describe the sensor faults as actuator faults. The proposed observer is designed, and the exponential stability conditions are studied with the Lyapunov theory and L2 optimization and formulated in terms of linear matrix inequalities. Finally, to improve the effectiveness of the proposed observer, a numerical simulation is carried out on a CSTR.

scholarly journals An Analysis of Microbial Population of Chemostat Model in Fuzzy Environment

2019 ◽  
Vol 36 (1-2) ◽  
pp. 1-10
Author(s):  
Harish Chandra Bhandari ◽  
Kanhaiya Jha
Keyword(s):  
Differential Equations ◽  
Microbial Population ◽  
Stirred Tank ◽  
Continuous Stirred Tank Reactor ◽  
Chemostat Model ◽  
Tank Reactor ◽  
Fuzzy Environment ◽  
Research Problems ◽  
Continuous Stirred Tank ◽  
The Stability

Chemostat is a continuous stirred tank reactor used for continuous microbial biomass production in commercial, medical and other research problems. While modeling real world phenomena through differential equations as backbone of practical problems, we need to introduce various parameters. These parameters may be vague, imprecise and uncertain. To incorporate these uncertainties, the notion of fuzzy differential equations is used in chemostat model as one of the tool. In this paper, we discuss some new results for the stability analysis of chemostat model and the results so obtained are justifiable analytically and verified graphically in fuzzy environment.

scholarly journals Comparative genomics in “Candidatus Kuenenia stuttgartiensis” reveal high genomic plasticity in the overall genome structure, CRISPR loci and surface proteins

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Chang Ding ◽  
Lorenz Adrian
Keyword(s):  
Growth Rate ◽  
Genome Structure ◽  
Draft Genome ◽  
Surface Proteins ◽  
Anammox Bacteria ◽  
Continuous Stirred Tank Reactor ◽  
Genes Encoding ◽  
Continuous Stirred Tank ◽  
The Stability ◽  
Genomic Regions

Abstract Background Anaerobic ammonium oxidizing bacteria (anammox bacteria) are contributing significantly to the nitrogen cycle and are successfully used in wastewater treatment. Due to the lack of complete genomes in the databases, little is known about the stability and variability of their genomes and how the genomes evolve in response to changing environments. Results Here we report the complete genome of the anammox bacterium “Candidatus Kuenenia stuttgartiensis” strain CSTR1 which was enriched planktonically in a semi-continuous stirred-tank reactor. A comparison of the genome of strain CSTR1 with the genome of “Ca. Kuenenia stuttgartiensis” MBR1 and the draft genome of KUST showed > 99% average nucleotide identity among all. Rearrangements of large genomic regions were observed, most of which were associated with transposase genes. Phylogenetic analysis suggests that strain MBR1 is more distantly related to the other two strains. Proteomic analysis of actively growing cells of strain CSTR1 (growth rate ~ 0.33 d− 1) failed to detect the annotated cytochrome cd1-type nitrite reductase (NirS) although in total 1189 proteins were found in the proteome. Yet, this NirS was expressed when strain CSTR1 was under stress or starvation (growth rate < 0.06 d− 1). We also observed large sequence shifts in the strongly expressed S-layer protein compared to other “Ca. Kuenenia” strains, indicating the formation of hybrids of genes encoding the surface proteins. Conclusions “Ca. Kuenenia” strains appear to be relatively stable in their basic physiological traits, but show high variability in overall genome structure and surface proteins.

scholarly journals Performance enhancements of DFIG wind turbine using fuzzy-feedback linearization controller augmented by high-gain observer

2020 ◽  
Vol 11 (1) ◽  
pp. 10
Author(s):  
Kada Boureguig ◽  
Abdellah Mansouri ◽  
Ahmed Chouya
Keyword(s):  
Feedback Linearization ◽  
Fuzzy Logic Controller ◽  
Dynamic Performance ◽  
High Gain ◽  
Lyapunov Theory ◽  
Nonlinear Observer ◽  
High Gain Observer ◽  
Rotor Flux ◽  
Doubly Fed ◽  
The Stability

<span>This paper proposes a feedback linearization control of doubly fed induction generator based wind energy systems for improving decoupled control of the active and reactive powers stator. In order to enhance dynamic performance of the controller studied, the adopted control is reinforced by a fuzzy logic controller. This approach is designed without any model of rotor flux estimation. The difficulty of measuring of rotor flux is overcome by using high gain observer. The stability of the nonlinear observer is proved by the Lyapunov theory. Numerical simulations using MATLAB-SIMULINK shown clearly the robustness of the proposed control, particularly to the disturbance rejection and parametric variations compared with the conventional method.</span>

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