204 research outputs found

    State and unknown input estimation in a CSTR using higher-order sliding mode observer

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    The aim of this paper is to design and analyze an observer based on high-order sliding mode to estimate states and unknown inputs in a continuous stirred tank reactor (CSTR). Additionally, the designed HOSM allows to reduce the chattering. The performance of HOSM observer is compared with a 1-order sliding mode observer.ColcienciasUniversidad Nacional de ColombiaCinvesta

    Robust Estimation for a CSTR Using a High Order Sliding Mode Observer and an Observer-Based Estimator

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    This paper presents an estimation structure for a continuous stirred-tank reactor, which is comprised of a sliding mode observer-based estimator coupled with a high-order sliding-mode observer. The whole scheme allows the robust estimation of the state and some parameters, specifically the concentration of the reactive mass, the heat of reaction and the global coefficient of heat transfer, by measuring the temperature inside the reactor and the temperature inside the jacket. In order to verify the results, the convergence proof of the proposed structure is done, and numerical simulations are presented with noiseless and noisy measurements, suggesting the applicability of the posed approach.ITESO, A.C.Universidad Nacional de Colombi

    Robust Estimation for a CSTR Using a High Order Sliding Mode Observer and an Observer-Based Estimator

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    This paper presents an estimation structure for a continuous stirred-tank reactor, which is comprised of a sliding mode observer-based estimator coupled with a high-order sliding-mode observer. The whole scheme allows the robust estimation of the state and some parameters, specifically the concentration of the reactive mass, the heat of reaction and the global coefficient of heat transfer, by measuring the temperature inside the reactor and the temperature inside the jacket. In order to verify the results, the convergence proof of the proposed structure is done, and numerical simulations are presented with noiseless and noisy measurements, suggesting the applicability of the posed approach.ITESO, A.C.Universidad Nacional de Colombi

    State and Parameter Estimation of a CSTR

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    In the continuation of authors’ studies on estimation and control for Continuous Stirred-Tank Reactors (CSTR), a new structure to estimate the concentration of reactive state, the global heat transfer coefficient, and the heat of reaction parameters is proposed here. This scheme consist of an Observer Based Estimator (OBE) connected in cascade with a High Order Sliding Mode Observer (HOSMO). The OBE estimates the global heat transfer coefficient, and the HOSMO estimates the heat of reaction, and the concentration of reactive. Numerical simulations show that the whole structure presents a good performance in presence of parametric variations, which often are presented in chemical processes.Universidad Nacional de ColombiaCINVESTA

    HOSM State Estimation and Robust PID Control of a Chemical Process

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    This paper presents some results of the authors’ studies on robust estimation and control for chemical processes. Here, an observer-based controller is designed for a chemical process. A High Order Sliding Mode Observer (HOSMO) for state and parameter estimation is synthesized and, a Multi-Variable PID (MV-PID) controller is calculated using the estimated variables. The HOSMO presents insensitivity and robustness against a class of uncertainties in the system, and the MV-PID allows the tracking of slow-varying and piecewise constant references, which are often proposed to drive chemical processes. Numerical simulations show that the observer-based controller presents a good performance in presence of parametric variations, which often are presented in chemical processes; the proposed structure is compared with a First Order Sliding Mode Observer (FOSMO) coupled with a MV-PID.CinvestavUniversidad Nacional de Colombi

    A Robust Extended State Observer for the Estimation of Concentration and Kinetics in a CSTR

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    This paper presents a state estimation structure for a Continuous Stirred Tank Reactor (CSTR), by means of an Asymptotic Observer jointly with a disturbance high order sliding mode-based estimator. The proposed estimation scheme allows the asymptotic reconstruction of the concentration inside the reactor based on the measures of the temperature inside the reactor and the temperature inside the jacket, in presence of changes in the global coefficient of heat transfer UA, the Arrhenius constant k0 and the activation energy E. Additionally, the structure is able to estimate UA and the kinetics term k0e−ERT. The properties of the proposed scheme are proved mathematically and verified through numerical simulations.ITESO, A.C.CINVESTAV-IP

    Smooth non linear high gain observers for a class of dynamical systems

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    High-gain observers are powerful tools for estimating the state of nonlinear systems. However, their design poses several challenges due to the need of dealing with phenomena such as peaking and chattering. To address these issues, we propose a differentiator operator design based on a non linear second order high-gain observer, which is suited to a class of dynamical systems. Our method includes a procedure to determine high gains in order to avoid chattering in the case of noise-free models, and cut-off frequency based gain design in the case of noisy measurements. Complementary, we suggest performing observability analyses to ensure a priori the feasibility of the estimation. The main strengths of our approach are its simplicity and robustness. We demonstrate the performance of the proposed method by applying it to two processes (chemical and biological).Xunta de Galicia | Ref. ED431F 2021/003MCIN/AEI/10.13039/501100011033 | Ref. RYC-2019-027537-

    Disturbance observer design for nonlinear systems represented by input-output models

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    A new approach to the design of nonlinear disturbance observers for a class of nonlinear systems described by inputoutput differential equations is presented in this paper. In contrast with established forms of nonlinear disturbance observers, the most important feature of this new type of disturbance observer is that only measurement of the output variable is required, rather than the state variables. An inverse simulation model is first constructed based on knowledge of the structure and parameters of a conventional model of the system. The disturbance can then be estimated by comparing the output of the inverse model and the input of the original nonlinear system. Mathematical analysis demonstrates the convergence of this new form of nonlinear disturbance observer. The approach has been applied to disturbance estimation for a linear system and a new form of linear disturbance observer has been developed. The differences between the proposed linear disturbance observer and the conventional form of frequency-domain disturbance observer are discussed through a numerical example. Finally, the nonlinear disturbance observer design method is illustrated through an application involving a simulation of a jacketed continuous stirred tank reactor syste

    Introduction to State Estimation of High-Rate System Dynamics

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    Engineering systems experiencing high-rate dynamic events, including airbags, debris detection, and active blast protection systems, could benefit from real-time observability for enhanced performance. However, the task of high-rate state estimation is challenging, in particular for real-time applications where the rate of the observer’s convergence needs to be in the microsecond range. This paper identifies the challenges of state estimation of high-rate systems and discusses the fundamental characteristics of high-rate systems. A survey of applications and methods for estimators that have the potential to produce accurate estimations for a complex system experiencing highly dynamic events is presented. It is argued that adaptive observers are important to this research. In particular, adaptive data-driven observers are advantageous due to their adaptability and lack of dependence on the system model

    State observer using high order sliding modes to nonlinear process

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    Este trabajo presenta una estructura de estimación de estados y parámetros basada en modos deslizantes de alto orden y en el estimador basado en observador. Los modos deslizantes de alto orden permiten reducir notablemente el castañeo que es propio del modo deslizante de primer orden. La estructura propuesta es aplicada a un caso de un proceso químico al que también se le diseña un observador por modos deslizantes de primer orden, con el propósito de comparar los resultados obtenidos para el proceso en lazo abierto y en lazo cerrado. Para estructurar lo anterior, aspectos teóricos de los modos deslizantes son presentados. También se presenta una reseña sobre las soluciones dadas al problema del castañeo / Abstract: This survey presents a structure of states and parameters estimation based on high order sliding mode and the observer-based estimator. High order sliding mode can reduce significantly the chattering which is characteristic of first order sliding mode. The proposed structure is applied to a case of chemical process which is also designing a first order sliding mode observer, in order to compare the results obtained for the process in open loop and closed loop. To structure above, theoretical aspects of sliding mode are presented. Also, an overview of solutions given to the chattering problem is presentedMaestrí
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