A New Robust Sliding-Mode Observer Design for Monitoring in Chemical Reactors

2004 ◽  
Vol 126 (3) ◽  
pp. 473-478 ◽  
Author(s):  
Rafael Martı´nez-Guerra ◽  
Ricardo Aguilar ◽  
Alexander Poznyak
Keyword(s):  
Sliding Mode ◽  
Industrial Applications ◽  
Observer Design ◽  
Temperature Measurements ◽  
Model Description ◽  
Chemical Reactors ◽  
Stirred Tank Reactors ◽  
Robust Observer ◽  
Continuous Stirred Tank ◽  
Algebraic Technique

The robust observer design for the online estimation of heat in continuous stirred tank reactors, containing nonstructured uncertainties within its model description as well as noisy temperature measurements, is addressed. The proposed observer contains a sliding-mode term and is designed based on Differential Algebraic technique. The concept of the algebraic observability for a given class of model uncertainty is introduced. It is applied to the uncertainty estimation from noisy temperature measurements providing a simple observer structure which turns out to be robust against output (sensors) noises as well as sustained disturbances. The performance of this observer is shown to be calculated numerically. The obtained results look promising for possible industrial applications.

Sliding-mode Observer for Uncertainty Estimation in a Class of Chemical Reactor: A Differential-Algebraic Approach

2007 ◽  
Vol 2 (3) ◽  
Author(s):  
Ricardo Aguilar-López
Keyword(s):  
Sliding Mode ◽  
Algebraic Approach ◽  
Chemical Reactor ◽  
Uncertainty Estimation ◽  
Temperature Measurements ◽  
Continuous Stirred Tank Reactor ◽  
Reaction Heat ◽  
On Line ◽  
Continuous Stirred Tank ◽  
Noisy Measurements

The problem of the on-line estimation of the reaction heat in a continuous stirred tank reactor from temperature measurements is addressed in this paper. The proposed uncertainty observer is based on differential algebraic techniques, such that the algebraic observability condition of the uncertainty from noisy temperature measurements is easily verified and the observer structure is very simple, which lead to feasible implementation. The observer proposed is robust against noisy measurements and sustained disturbances. The good performance of the observer is shown by means of numerical simulations and is compared with a nonlinear Luenberger-type observer.

scholarly journals A Path Tracking Strategy for Car Like Robots with Sensor Unpredictability and Measurement Errors

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3077 ◽  
Author(s):  
Madan Mohan Rayguru ◽  
Mohan Rajesh Elara ◽  
Balakrishnan Ramalingam ◽  
M. A. Viraj J. Muthugala ◽  
S. M. Bhagya P. Samarakoon
Keyword(s):  
Motion Control ◽  
Measurement Errors ◽  
Feedback Linearization ◽  
Closed Loop ◽  
Sliding Mode ◽  
Observer Design ◽  
Sliding Mode Controller ◽  
Control Input ◽  
Robust Observer ◽  
Uncertain Dynamics

This work is inspired by motion control of cleaning robots, operating in certain endogenous environments, and performing various tasks like door cleaning, wall sanitizing, etc. The base platform’s motion for these robots is generally similar to the motion of four-wheel cars. Most of the cleaning and maintenance tasks require detection, path planning, and control. The motion controller’s job is to ensure the robot follows the desired path or a set of points, pre-decided by the path planner. This control loop generally requires some feedback from the on-board sensors, and odometry modules, to compute the necessary velocity inputs for the wheels. As the sensors and odometry modules are prone to environmental noise, dead-reckoning errors, and calibration errors, the control input may not provide satisfactory performance in a closed-loop. This paper develops a robust-observer based sliding mode controller to fulfill the motion control task in the presence of incomplete state measurements and sensor inaccuracies. A robust intrinsic observer design is proposed to estimate the input matrix, which is used for dynamic feedback linearization. The resulting uncertain dynamics are then stabilized through a sliding mode controller. The proposed robust-observer based sliding mode technique assures asymptotic trajectory tracking in the presence of measurement uncertainties. Lyapunov based stability analysis is used to guarantee the convergence of the closed-loop system, and the proposed strategy is successfully validated through numerical simulations.

scholarly journals Tracking unmodelled signals of nonlinear systems via robust sliding mode observer: Application to reacting systems

2007 ◽  
Vol 5 (01) ◽  
Author(s):  
R. Aguilar-López ◽  
G. Soto-Cortés ◽  
M.I. Nerí­a-González ◽  
R. Escarela-Pérez
Keyword(s):  
Sliding Mode ◽  
Temperature Measurements ◽  
Stirred Tank ◽  
Continuous Stirred Tank Reactor ◽  
Reaction Heat ◽  
Tank Reactor ◽  
On Line ◽  
Continuous Stirred Tank ◽  
Reacting Systems ◽  
Noisy Measurements

The problem of the on-line estimation of the reaction heat in a continuous stirred tank reactor from temperature measurements is addressed in this paper. The proposed uncertainty observer is based on differential algebraic techniques, such that the algebraic observability condition of the uncertainty from noisy temperature measurements is easily verified and the observer structure is very simple, which lead to feasible implementation. The observer proposed is robust against noisy measurements and sustained disturbances. The good performance of the observer is shown by means of numerical simulations.

Minimum time controller in a class of chemical reactors based on Lagrangian approach

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ricardo Aguilar-López ◽  
Juan L. Mata-Machuca
Keyword(s):  
Sliding Mode ◽  
Chemical Kinetic ◽  
Minimum Time ◽  
Continuous Stirred Tank Reactor ◽  
Chemical Reactors ◽  
Chemical Kinetic Model ◽  
Finite Time Convergence ◽  
Brachistochrone Problem ◽  
Convergence Performance ◽  
Continuous Stirred Tank

Abstract The main goal of this work is the construction of a class of controller, which employs directly a Lagrangian formulation to resolve the classical brachistochrone problem, this allows to obtain an optimal controller which reaches in a minimum time the stabilization of an isothermal continuous stirred tank reactor, whose chemical kinetic model is based on the power law. The proposed methodology is compared with an input/output linearizing which achieve asymptotic and exponential closed-loop convergence, sliding-mode controller with a finite time convergence and an exact gradient optimal control to compare the time convergence performance. Numerical experiments show the satisfactory performance of the proposed controller, despite sustained disturbances in the concentration input feed.

Removal of lead by sulfate-reducing bacteria in anaerobic continuous stirred tank reactors

2016 ◽  
Vol 14 (3) ◽  
pp. 557-561
Author(s):  
Nguyễn Thị Yên ◽  
Kiều Thị Quỳnh Hoa
Keyword(s):  
Sulfate Reducing Bacteria ◽  
Stirred Tank ◽  
Synthetic Wastewater ◽  
Terminal Electron Acceptor ◽  
Stirred Tank Reactors ◽  
Sulfate Reducing ◽  
Sulfide Production ◽  
Continuous Stirred Tank ◽  
Continuous Stirred Tank Reactors ◽  
Reducing Bacteria

Lead contaminated wastewater negatively impacts to living organisms as well as humans. In recent years, a highly promising biological process using the anaerobic production of sulfide ions by sulfate-reducing bacteria has presented itself as an alternative option for the removal of lead. This process is based on microbial utilization of electron donors, such as organic compounds (carbon sources), and sulfate as the terminal electron acceptor for sulfide production. The biogenic hydrogen sulfide reacts with dissolved heavy metals to form insoluble metal sulfide precipitates Removal of lead by an enriched consortium of sulfate-reducing bacteria (DM10) was evaluated sulfate reduction, sulfide production and lead precipitation. Four parallel anaerobic continuous stirred tank reactors (CSTR, V = 2L) (referred as R1 - R4) were fed with synthetic wastewater containing Pb2+ in the concentrations of 0, 100, 150 and 200 mg L-1 of lead and operated with a hydraulic retention time of 5 days for 40 days. The loading rates of each metal in R1- R4 were 0, 20, 30 and 40 mg L-1 d-1, respectively. The results showed that there was no inhibition of SRB growth and that lead removal efficiencies of 99-100% for Pb2+ were achieved in R2 (100 mg L-1) and R3 (150 mg L-1) throughout the experiment. For the highest lead concentration of  200 mg L-1, a decrease in efficiency of removal (from 100 to 96%) was observed at the end of the experiment. The obtained result of this study might help for a better control operation and performance improvements of reactors.

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