Robust control of ill-conditioned plants: high-purity distillation

Using a high-purity distillation column as an example, the physical reason for the poor conditioning and its implications on control system design and performance are explained. It is shown that an acceptable performance/robustness tradeoff cannot be obtained by simple loop-shaping techniques (using singular values) and that a good understanding of the model uncertainty is essential for robust control system design. Physically motivated uncertainty descriptions (actuator uncertainties) are translated into the H∞/structured singular value framework, which is demonstrated to be a powerful tool to analyze and understand the complex phenomena

Global self-optimizing control for uncertain constrained process systems

Self-optimizing control is a promising control strategy to achieve real-time optimization (RTO) for uncertain process systems. Recently, a global self-optimizing control (gSOC) approach has been developed to extend the economic performance to be globally acceptable in the entire uncertain space spanned by disturbances and measurement noise. Nevertheless, the gSOC approach was derived based on the assumption of no change in active constraints, which limits the applicability of the approach. To address this deficiency, this paper proposes a new CV selection approach to handle active constraint changes. It ensures that all constraints are within their feasible regions when the selected CVs are maintained at constant setpoints for all expected uncertainties. In particular, constraints of interest are linearized at multiple operating conditions to get better estimates of their values and then incorporated into the optimization formulation when solving the globally self-optimizing CVs. The new CV selection approach is able to ensure an improved operational economic performance without potential constraint violations, as illustrated in an evaporator case study

PENERAPAN PENDEKATAN MATEMATIKA REALISTIK UNTUK MENINGKATKAN PEMAHAMAN KONSEP OPERASI HITUNG PERKALIAN SISWA KELAS 2C SD

Penelitian ini dilatar belakangi oleh banyaknya siswa kelas 2C SDN SKJ I mengalami kesulitan dalam memahami konsep operasi hitung perkalian untuk mengatasi masalah tersebut, peneliti menerapkan Pendekatan Matematika Reaslistik (PMR). Penelitian Tindak Kelas (PTK) ini bertujuan untuk mendeskripsikan : 1) Rencana Pelaksanaan Pembelajaran (RPP) dengan menerapkan Pendekatan Matematika Realistik (PMR) untuk meningkatkan pemahaman konsep operasi hitung perkalian siswa kelas 2SDN SKJ I, Bandung. 2)Pembelajaran dengan menerapkan Pendekatan Matematika Realistik (PMR) untuk meningkatkan pemahaman konsep operasi hitung perkalian siswa kelas 2C SDN SKJ I, bandung. 3) Peningkatan pemahaman konsep operasi hitung perkalian siswa kelas 2C SDN SKJ I Bandung setelah menerapkan Pendekatan Matematika Realistik (PMR). Metode yang digunakan adalah penelitian tindak kelas (PTK) model Kemmis dan Taggart. Pengumpulan data dilakukan dengan observasi dan tes. Data klasifikasi diolah melalui reduksi data, klasifikasi data, display data, penapsiran dan penarikan simpulan, data kuantitatif diolah dengan menggunakan statistik rata-rata dan presentase, temuan penelitian menunjukan bahwa Penerapan Matematika Realistik (PMR) dapat meningkatkan pemahaman konsep operasi hitung perkalian siswa 2C SDN SKJ I. Hal ini ditunjukan dengan nilai rata-rata kelas pada siklus I sebesar 63,75 dan siklus II 85,75. Padahal nilai rata-rata pra siklus sebesar 57,7. Pada pra siklus presentase 16,6 % siswa yang dapat mencapai KKM, sedangkan pada siklus I menjadi 20% dan siklus II 90%.;---The study was based on the number of students in grade 2C SDN SKJ I that have difficulty in understanding of multiplication arithmetic operations concept. to overcome the problem, researchers applied realistic mathematics education. This Classroom Action Research is intended to describe: 1)Learning Implementation Plan by applying the approach Realistic Mathematics Education (RME) to improve understanding of the arithmetic operations of multiplication concept in graders 2 C SDN SKJ I, Bandung. 2) Learning to apply the approach Realistic Mathematics Education (RME) to improve understanding of the operations calculated concept by multiplying grade 2 C SDN SKJ I Bandung. 3) Improved understanding of the arithmetic operations concept of multiplication grade 2 C SDN SKJ I Bandung after applying Approach Realistic Mathematics Education (RME). The method was used Classroom Action Research with model Kemmis and Taggart. The data collection was done by observation and tests. Data classification is processed through data reduction, data classification, data display, interpretation and drawing conclusions, quantitative data were processed using average statistics and percentages, the research findings indicate that the adoption of Realistic Mathematics Education to enhance understanding of the arithmetic operations concept of multiplication students 2 C SDN SKJ I. This is evidenced by the average value of the class in the first cycle of 63.75 and 85.75 second cycle. Where as the value of pre-cycle average of 57.7. In the pre-cycle percentage of 16.6% of students who can be reached KKM, while the first cycle to the second cycle of 20% and 90%

Two-degree-of-freedom controller design for an ill-conditioned distillation process using µ-synthesis

The structured singular value framework is applied to a distillation benchmark problem formulated for the 1991 IEEE Conference on decision and control (CDC). A two degree of freedom controller, which satisfies all control objectives of the CDC problem, is designed using /spl mu/-synthesis. The design methodology is presented and special attention is paid to the approximation of given control objectives into frequency domain weights

Model predictive control for the self-optimized operation in wastewater treatment plant : analysis of dynamic issues

[EN] This paper describes a procedure to find the best controlled variables in an economic sense for the activated sludge process in a wastewater treatment plant, despite the large load disturbances. A novel dynamic analysis of the closed loop control of these variables has been performed, considering a nonlinear model predictive controller (NMPC) and a particular distributed NMPC-PI control structure where the PI is devoted to control the process active constraints and the NMPC the self-optimizing variables. The well-known self-optimizing control methodology has been applied, considering the most important measurements of the process. This methodology provides the optimum combination of measurements to keep constant with minimum economic loss. In order to avoid non feasible dynamic operation, a preselection of the measurements has been performed, based on the nonlinear model of the process and evaluating the possibility of keeping their values constant in the presence of typical disturbances.[ES] Este trabajo describe un procedimiento eficiente para encontrar las mejores variables para el proceso de lodos activados en una planta de tratamiento de aguas residuales, a pesar de las grandes perturbaciones de carga. Se ha realizado un nuevo análisis dinámico del control en bucle cerrado de estas variables, considerando un controlador predictivo de modelo no lineal (NMPC) y una estructura de control NMPC-PI distribuida. Se ha aplicado la conocida metodología de control de auto-optimización, considerando las mediciones más importantes del proceso. Esta metodología proporciona la combinación óptima de mediciones para mantener constante con pérdidas económicas mínimas. Para evitar un funcionamiento dinámico no factible, se ha realizado una preselección de las mediciones, basándose en el modelo no lineal del proceso y evaluando la posibilidad de mantener constantes sus valores en presencia de perturbaciones típicas

Control of steam bottoming cycles using nonlinear input and output transformations for feedforward disturbance rejection

publishedVersio

Two-degree-of-freedom controller design for an ill-conditioned distillation process using µ-synthesis

The structured singular value framework is applied to a distillation benchmark problem formulated for the 1991 IEEE Conference on decision and control (CDC). A two degree of freedom controller, which satisfies all control objectives of the CDC problem, is designed using /spl mu/-synthesis. The design methodology is presented and special attention is paid to the approximation of given control objectives into frequency domain weights