Analytic applications of tsypkin's method relay with hysteresis and dead zone

Previous studies of the effects of manholes on longitudinal dispersion has concentrated on the spreading of solutes. This papers presents new data describing the influence of a surcharged and free-flowing manhole structure on the longitudinal dispersion of a fine suspended material. The effects of benching within the manhole structure are also illustrated. Laser Induced Fluorescence (LIF) techniques have been used to provide a qualitative description of the mixing processes present within a surcharged manhole. Nephelometric results have provided estimates of the parameters required to simulate the mixing effects using either increase in variance or aggregated dead zone techniques. A preliminary attempt at describing these observations using available software is discussed and recommendations for future developments are made.

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LIFE IN THE DEAD ZONE: A DIVERSE MIOCENE ICHNOFAUNA PRESERVED IN VOLCANIC ASH, ASHFALL FOSSIL BEDS STATE HISTORICAL PARK, NEBRASKA, USA

10.1130/abs/2018am-318389 ◽

2018 ◽

Author(s):

Jon J. Smith ◽

◽

R.M. Joeckel ◽

Rick E. Otto ◽

Shane T. Tucker

Keyword(s):

Volcanic Ash ◽

Dead Zone ◽

The Dead

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Temperature control in a chemical reactor through variable area of the heat transfer surface. Experimental verification

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19820446 ◽

1982 ◽

Vol 47 (2) ◽

pp. 446-453

Author(s):

Josef Horák ◽

František Jiráček ◽

Libuše Ježová

Keyword(s):

Batch Reactor ◽

Exothermic Reaction ◽

Chemical Reactor ◽

Open Loop ◽

Heat Transfer Surface ◽

Laboratory Reactor ◽

Hysteresis Control ◽

Relay With Hysteresis ◽

Rate Of Response ◽

The Ideal

A possibility has been tested in the paper of the feed back control of temperature of the reaction mixture in a batch reactor with an exothermic reaction through the variable area of the cooling surface. The measurement were carried out in a laboratory reactor with a retractable cooler which was being immersed into the reaction mixture. The speed of motion of the cooler was sufficiently high permitting the process of immersion to be regarded as practically instantaneous. The aim of the control was to stabilize the set point temperature of the reaction mixture by a two-point controler. In dependence on the rate of response of the system to a change of the section variable either the ideal relay or the relay with hysteresis control algorithmus were used. The results of measurements showed that with the aid of a retractable cooler the temperature could be controlled safely even in those cases, in which the control by the variable flow rate of the coolant was unfeasible. The verification was carried out in the open-loop instable operating point of the reactor.

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Temperature control in a chemical reactor through variable area of the heat transfer surface. Simulation analysis

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19820430 ◽

1982 ◽

Vol 47 (2) ◽

pp. 430-445

Author(s):

Josef Horák ◽

Zina Valášková

Keyword(s):

Heat Exchange ◽

Simulation Analysis ◽

Batch Reactor ◽

Chemical Reactor ◽

Rate Of Change ◽

Action Variable ◽

Heat Exchange Surface ◽

Relay With Hysteresis ◽

Exchange Surface

An algorithm has been developed and on a mathematical model analyzed to stabilize the reaction temperature of a batch reactor. The reaction has been a zero-order one and the reactor has been operated in a instable operating point. The action variable is the heat exchange surface whose area is increased if the temperature is above, or decreased if the temperature is below the set point. The following two-point regulators have been studied: An ideal relay, a relay with hysteresis and an asymmetric PD relay. The effect has been discussed of the parameters of the regulators on the quality of regulation. Stability analysis has been made of the stationary switching cycles and the domains of applicability have been determined for individual regulators with respect to the rate of change of the area of heat exchange surface.

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A Robust Observer—Based Adaptive Control of Second—Order Systems with Input Saturation via Dead-Zone Lyapunov Functions

Computation ◽

10.3390/computation9080082 ◽

2021 ◽

Vol 9 (8) ◽

pp. 82

Author(s):

Alejandro Rincón ◽

Gloria M. Restrepo ◽

Fredy E. Hoyos

Keyword(s):

Lyapunov Functions ◽

Dead Zone ◽

Tracking Error ◽

Input Saturation ◽

Chemical Reactor ◽

Second Order ◽

Control Law ◽

Compact Set ◽

State Variables ◽

Robust Observer

In this study, a novel robust observer-based adaptive controller was formulated for systems represented by second-order input–output dynamics with unknown second state, and it was applied to concentration tracking in a chemical reactor. By using dead-zone Lyapunov functions and adaptive backstepping method, an improved control law was derived, exhibiting faster response to changes in the output tracking error while avoiding input chattering and providing robustness to uncertain model terms. Moreover, a state observer was formulated for estimating the unknown state. The main contributions with respect to closely related designs are (i) the control law, the update law and the observer equations involve no discontinuous signals; (ii) it is guaranteed that the developed controller leads to the convergence of the tracking error to a compact set whose width is user-defined, and it does not depend on upper bounds of model terms, state variables or disturbances; and (iii) the control law exhibits a fast response to changes in the tracking error, whereas the control effort can be reduced through the controller parameters. Finally, the effectiveness of the developed controller is illustrated by the simulation of concentration tracking in a stirred chemical reactor.

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Uniformly ultimately bounded tracking control of sandwich systems with nonsymmetric sandwiched dead-zone nonlinearity and input saturation constraint

Journal of Vibration and Control ◽

10.1177/1077546320987940 ◽

2021 ◽

pp. 107754632098794

Author(s):

Meysam Azhdari ◽

Tahereh Binazadeh

Keyword(s):

Dead Zone ◽

Input Saturation ◽

Closed Loop System ◽

Unknown Parameters ◽

External Disturbances ◽

Uniformly Ultimately Bounded ◽

Output Tracking ◽

Saturation Constraint ◽

Two Phases ◽

Practical Constraints

This article studies the uniformly ultimately bounded output tracking problem of uncertain nonlinear sandwich systems with sandwiched dead-zone nonlinearity in the presence of some practical constraints such as nonsymmetric input saturation, model uncertainties, time-varying external disturbances, and unknown parameters. Due to the existence of both dead-zone and saturation nonlinearities, the design process is more complicated; therefore, to solve the design complexities, the designing process is divided into two phases. The proposed method leads to output tracking with acceptable accuracy. Moreover, all signals in the closed-loop system are ultimately bounded. Simulation results illustrate the applicability and effectiveness of the proposed method by its application on two practical sandwich systems (robotic system and electrohydraulic servo press system).

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