scholarly journals Improved predictive functional control for ethylene cracking furnace

2019 ◽  
Vol 52 (5-6) ◽  
pp. 526-539
Author(s):  
Han Song ◽  
Cheng-li Su ◽  
Hui-yuan Shi ◽  
Ping Li ◽  
Jiang-tao Cao
Keyword(s):  
Control System ◽  
State Space ◽  
Control Method ◽  
Balance Control ◽  
State Space Model ◽  
Industrial Process ◽  
Outlet Temperature ◽  
Extended State ◽  
Predictive Functional Control ◽  
Functional Control

The objective of this paper is to show the design and application of pass temperature balance control system using an improved predictive functional control method in eight 800 tone/year USC ethylene cracking furnaces. The advanced pass temperature balance controller is developed using the proposed method and implemented in proprietary APC-ISYS software, which is connected to Yokogawa distributed control system via an OPC server. The advantage of it lies in the fact that the dynamics of pass temperature with nonlinearity and time delay are described by Takagi–Sugeno model and transformed into time-varying extended state space model, and thus, the proposed controller can regulate pass temperature based on the extended state space formulation. In addition, the control law with a linear iterative form, easily applied to industrial process, is derived. The robust analysis for the set point, input disturbance and output disturbance to the output verifies the ability of tracking and disturbance rejection of the proposed method. Application results from an industrial furnace are shown to be markedly better in terms of lower variability in the outlet temperature of both the passes compared to the current proportional–integral–derivative control scheme.

scholarly journals Fractional-Order Predictive Functional Control of Industrial Processes with Partial Actuator Failures

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-26
Author(s):  
Min-Ying Li ◽  
Kang-Di Lu ◽  
Yu-Xing Dai ◽  
Guo-Qiang Zeng
Keyword(s):  
Fractional Order ◽  
Control Method ◽  
Industrial Process ◽  
Batch Process ◽  
Industrial Processes ◽  
Smoothing Factor ◽  
Extremal Optimization ◽  
Actuator Failures ◽  
Predictive Functional Control ◽  
Functional Control

As the actuator faults in an industrial process cause damage or performance deterioration, the design issue of an optimal controller against these failures is of great importance. In this paper, a fractional-order predictive functional control method based on population extremal optimization is proposed to maintain the control performance against partial actuator failures. The proposed control strategy consists of two key ideas. The first one is the application of fractional-order calculus into the cost function of predictive functional control. Since the knowledge of analytical parameters including the prediction horizon, fractional-order parameter, and smoothing factor in fractional-order predictive functional control is not known, population extremal optimization is employed as the second key technique to search for these parameters. The effectiveness of the proposed controller is examined on two industrial processes, e.g., injection modeling batch process and process flow of coke furnace under constant faults, time-varying faults, and nonrepetitive unknown disturbance. The comprehensive simulation results demonstrate the performance of the proposed control method by comparing with a recently developed predictive functional control, genetic algorithm, and particle swarm optimization-based versions in terms of four performance indices.

CONTROL SYSTEM SYNTHESIS FOR THE ETHYLBENZENE DEHYDROGENATION PROCESS BASED ON THE PREDICTIVE FUNCTIONAL CONTROL METHOD

2021 ◽  
pp. 7-14
Author(s):  
С.Л. Подвальный ◽  
А.П. Попов ◽  
С.Г. Тихомиров ◽  
О.Г. Неизвестный
Keyword(s):  
Control System ◽  
System Analysis ◽  
Dynamic Models ◽  
Control Method ◽  
Reaction Medium ◽  
Automated System ◽  
Process Equipment ◽  
Catalytic Layer ◽  
Predictive Functional Control ◽  
Functional Control

Описывается применение метода предиктивного управления при синтезе автоматизированной системы программного управления производством стирола. На основе результатов системного анализа объекта управления обоснован способ управления технологическим процессом, проведены обзор и оценка возможности использования различных видов регулирующих устройств. В рамках концепции модельно-ориентированного проектирования синтезирована автоматизированная система, реализующая предсказательное функциональное управление (Predictive functional control (PFC)) концентрацией стирола на выходе из первой ступени реакторного блока. Выполнен структурный синтез и разработан алгоритм функционирования управляющей системы. В качестве структурного элемента, выполняющего построение прогнозной траектории изменения управляющего и управляемого параметров, использован комплекс динамических моделей, описывающих теплообменные процессы и физико-химические превращения, протекающие в исследуемой системе. Расчет оптимального значения управляющего воздействия производился с учетом инерционности технологического оборудования, параметров состояния каталитического слоя реактора, энергетических потоков и компонентов реакционной среды в соответствии со сформированным комплексным интегральным критерием энергоэффективности процесса при одновременном обеспечении максимальной производительности. Приведен сравнительный анализ результатов расчета переходных процессов по основному каналу системы управления, полученных при использовании регулятора ПИД-структуры и управляющего устройства, реализующего метод PFC-управления The article describes the application of the predictive control method in the synthesis of an automated system for software control of styrene production. Based on the results of the object system analysis, the method of process control is justified, the review and evaluation of the possibility of using various types of control devices is carried out. Within the framework of the model-oriented design concept, an automated system is synthesized that implements predictive functional control (PFC) of the concentration of styrene at the outlet of the reactor unit first stage. A structural synthesis was performed, and the control system operation algorithm was developed. A set of dynamic models describing heat exchange processes and physical and chemical transformations occurring in the system under study is used as a structural element that performs the construction of a predictive trajectory of changes in the controlling and controlled parameters. The calculation of the optimal value of the control action was carried out taking into account the inertia of the process equipment, the parameters of the state of the catalytic layer of the reactor, energy flows and components of the reaction medium in accordance with the formed complex integral criterion of the energy efficiency of the process while ensuring maximum productivity. A comparative analysis of the results of calculating transient processes for the main channel of the control system, obtained using a PID structure controller and a control device that implements the PFC control method

scholarly journals Adaptive Model Predictive Vibration Control of a Cantilever Beam with Real-Time Parameter Estimation

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Gergely Takács ◽  
Tomáš Polóni ◽  
Boris Rohal’-Ilkiv
Keyword(s):  
Control System ◽  
Vibration Control ◽  
State Space ◽  
Real Time ◽  
Cantilever Beam ◽  
State Space Model ◽  
Model Parameters ◽  
Extended Kalman Filtering ◽  
Space Model ◽  
Continuous State

This paper presents an adaptive-predictive vibration control system using extended Kalman filtering for the joint estimation of system states and model parameters. A fixed-free cantilever beam equipped with piezoceramic actuators serves as a test platform to validate the proposed control strategy. Deflection readings taken at the end of the beam have been used to reconstruct the position and velocity information for a second-order state-space model. In addition to the states, the dynamic system has been augmented by the unknown model parameters: stiffness, damping constant, and a voltage/force conversion constant, characterizing the actuating effect of the piezoceramic transducers. The states and parameters of this augmented system have been estimated in real time, using the hybrid extended Kalman filter. The estimated model parameters have been applied to define the continuous state-space model of the vibrating system, which in turn is discretized for the predictive controller. The model predictive control algorithm generates state predictions and dual-mode quadratic cost prediction matrices based on the updated discrete state-space models. The resulting cost function is then minimized using quadratic programming to find the sequence of optimal but constrained control inputs. The proposed active vibration control system is implemented and evaluated experimentally to investigate the viability of the control method.

Analysis of a Hydrofoil Craft with a Suspension System

2020 ◽  
Author(s):  
Michel Touw ◽  
Jacob Lotz ◽  
Ido Akkerman
Keyword(s):  
Experimental Data ◽  
Control System ◽  
State Space ◽  
State Space Model ◽  
Suspension System ◽  
Future Research ◽  
Passive System ◽  
Height Control ◽  
Space Model ◽  
Front Wing

In this paper we investigate the efficacy of augmenting, or replacing, an active height control system for a submerged hydrofoil with a passive system based on springs and dampers. A state-space model for submerged hydrofoils is formulated and extended to allow for a suspension at the front wing, aft wing or both wings. The model is partially verified by obtaining results in the fixed-wing limit and comparing these with experimental data from the MARIN Foiling Future Demonstrator. In the current study we limit ourselves to translational springs, only allowing suspension motion in the heave direction. This results in unfavorable behavior: either the motions increased or the system becomes unstable. It is therefore recommended for future research to try rotational springs.

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