Robust PID Control Design in CPS-based Batch Distillation Column

Interconnected system between computationand physical process (Cyber-Physical Systems) has been widelyused in industrial processes. In CPS-based industrial process,sensors, controllers, and actuators are connected into acommunication network. The communication network mayintroduce delay time uncertainties due to shared resources andload traffic in the network. Furthermore, the nonlinear timevaryingcharacteristic of batch distillation column may causesanother uncertainties to take into account in control systemdesign. Parameter model and delay process uncertainty isintroduced due to linearized system approximation thatunmodeled high-frequency dynamics. The dynamicuncertainty on both I/O channel are also introduced to thesystem uncertainty. In this paper, robust PI and PID controllerusing AMIGO method with appropriate weighting function isdesigned to guarantee robust stability spesification of batchdistillation column. The impact of system uncertainties toclosed-loop system performances such as peak overshoot andintegral error is investigated. MATLAB/Simulink simulationis used to validate the methods before its implementation inCPS-based batch distillation column. Based on simulation, theproposed robust PI/PID controller can guarantee robuststability of system compared to conventional PID controller.Furthermore, the robust PI/PID controller can improve closedloopsystem performances compared to conventional PID

Adaptive and identification two tanks system in control

The classical approach to system identification is to identify the transfer function on the basis of measured data. The goal of this research, with the aid of Matlab package, is to both identify and adaptively control a laboratory non-linear two tanks system which is simulated in a Simulink model block. Sampling time and model structure selection will be introduced first. Then, concentration will be on the OLS and IV methods of estimating parameters as they will be used in the Matlab identification toolbox. The system accordingly will be identified to obtain both discrete and continuous linear function models at operating points of 3 and 6. Adaptive and self-tuning control is the second part of this report where self-tuning PI control will be implemented based on RLS and phase margin design algorithms. Relay-based auto-tuning PI control is the second part control method, and practical comparison between them is provided at the end of this repor

Tuning Rules for Active Disturbance Rejection Controllers via Multiobjective Optimization - A Guide for Parameters Computation Based on Robustness

[EN] A set of tuning rules for Linear Active Disturbance Rejection Controller (LADRC) with three different levels of compromise between disturbance rejection and robustness is presented. The tuning rules are the result of a Multiobjective Optimization Design (MOOD) procedure followed by curve fitting and are intended as a tool for designers who seek to implement LADRC by considering the load disturbance response of processes whose behavior is approximated by a general first-order system with delay. The validation of the proposed tuning rules is done through illustrative examples and the control of a nonlinear thermal process. Compared to classical PID (Proportional-Integral-Derivative) and other LADRC tuning methods, the derived functions offer an improvement in either disturbance rejection, robustness or both design objectives.This work was supported in part by the Ministerio de Ciencia, Innovacion y Universidades, Spain, under Grant RTI2018-096904-B-I00.Martínez, BV.; Sanchís Saez, J.; Garcia-Nieto, S.; Martínez Iranzo, MA. (2021). Tuning Rules for Active Disturbance Rejection Controllers via Multiobjective Optimization - A Guide for Parameters Computation Based on Robustness. Mathematics. 9(5):1-34. https://doi.org/10.3390/math90505171349

Application of the Correlation Method to the Tuning of Industrial Control Schemes.

The correlation method of finding a system\u27s impulse response weights, based on the Wiener-Hopf integral, was studied for its application to the tuning of feedback, feedforward, and decoupling control elements in closed loop operation using only ordinary operating data. Also included in the work is a thorough study of actual data for eight typical stochastic disturbances taken from a refinery light ends unit. A disturbance signal typical of these actual signals was used throughout the tuning studies to make results obtained more practically meaningful. These actual signals were also used to demonstrate the desirability of differencing input and output data prior to use of the correlation method. The correlation method was applied to the tuning of feedback and decoupling controllers by using it to find the closed loop impulse response of a system\u27s output to set point changes. Given knowledge of the control structure and control elements, equations are derived which use this closed loop response to obtain the open loop impulse response. Many existing methods are available to design feedback controllers or decouplers given open loop responses. The correlation method was applied to the tuning of feedforward controllers by finding the closed loop impulse response of the system\u27s output to disturbance changes. Equations are derived which convert this closed loop response directly into an improved feedforward controller given the control structure and control elements. An approximation of the manipulated variable transfer function is also required. The equations derived for both problems are applicable to a 2 x 2 interactive process such as a distillation column with or without feedback elements, feedforward controllers, and partial or simplified decouplers. Less complex processes and/or control schemes allow the equations to be significantly simplified. A criterion called the Impulse Confidence Ratio (ICR) is proposed which when interpreted properly will allow the determination of the value of a test result. The correlation method of impulse response determination and the tuning techniques were subjected to numerous tests of robustness in the face of various non-ideal situations which might be expected to arise in real application. The tuning techniques are applied successfully to a nonlinear distillation column model

On the Analysis and Design of Disturbance Rejecter

In this thesis, the impact of the disturbance rejecter concept and the enforced plant has been explored. In order for the active disturbance rejection controller (ADRC) to provide a reasonable alternative to the industry standard PID controller, it is necessary to develop tuning procedures capable of providing adequate performance with reasonable stability margins. A focus should be placed upon the disturbance rejecter, as it is the heart and soul of ADRC. In this thesis, transfer function analysis of the enforced plant has been performed to connect ADRC with the tools from classical control. The relationship between the gain parameter and observer bandwidth is studied to understand why higher bandwidths are attainable with smaller gains. A root locus technique demonstrates how the enforced plant poles change with observer bandwidth. The Nyquist stability criterion is used to offer tuning methods that satisfy gain and phase margins and ensures a transient that satisfies a given damping requirement. A technique is offered to display the infinite radius encirclements of the Nyquist plot within a finite graph. Analysis is performed on why the controlled response is typically slower than desired and how to correct i

On the Analysis and Design of Disturbance Rejecter

In this thesis, the impact of the disturbance rejecter concept and the enforced plant has been explored. In order for the active disturbance rejection controller (ADRC) to provide a reasonable alternative to the industry standard PID controller, it is necessary to develop tuning procedures capable of providing adequate performance with reasonable stability margins. A focus should be placed upon the disturbance rejecter, as it is the heart and soul of ADRC. In this thesis, transfer function analysis of the enforced plant has been performed to connect ADRC with the tools from classical control. The relationship between the gain parameter and observer bandwidth is studied to understand why higher bandwidths are attainable with smaller gains. A root locus technique demonstrates how the enforced plant poles change with observer bandwidth. The Nyquist stability criterion is used to offer tuning methods that satisfy gain and phase margins and ensures a transient that satisfies a given damping requirement. A technique is offered to display the infinite radius encirclements of the Nyquist plot within a finite graph. Analysis is performed on why the controlled response is typically slower than desired and how to correct i

On the Analysis and Design of Disturbance Rejecter

In this thesis, the impact of the disturbance rejecter concept and the enforced plant has been explored. In order for the active disturbance rejection controller (ADRC) to provide a reasonable alternative to the industry standard PID controller, it is necessary to develop tuning procedures capable of providing adequate performance with reasonable stability margins. A focus should be placed upon the disturbance rejecter, as it is the heart and soul of ADRC. In this thesis, transfer function analysis of the enforced plant has been performed to connect ADRC with the tools from classical control. The relationship between the gain parameter and observer bandwidth is studied to understand why higher bandwidths are attainable with smaller gains. A root locus technique demonstrates how the enforced plant poles change with observer bandwidth. The Nyquist stability criterion is used to offer tuning methods that satisfy gain and phase margins and ensures a transient that satisfies a given damping requirement. A technique is offered to display the infinite radius encirclements of the Nyquist plot within a finite graph. Analysis is performed on why the controlled response is typically slower than desired and how to correct i

Robust tuning procedures of dead-time compensating controllers

This paper describes tuning procedures for dead-time compensating controllers (DTC). Both stable and integrating processes are considered. Simple experiments are performed to obtain process models as well as bounds on the allowable bandwidth for stability. The DTC's used have few parameters with clear physical interpretation so that manual tuning is possible. Furthermore, it is shown how the DTC's can be made robust towards dead-time variations. </p