ABSTRACT
This paper introduces a Reference System based Model Predictive Controller to the nonlinear transition control problem. The proposed control strategy is based on an online model reference evaluation, called reference system, using a factorization of a locally linearized version of the nonlinear model. The output feed- back problem is addressed using an lp norm as a performance control measurement. The online implementation of the algorithm requires only the solution of an LP or QP problem. By evaluating locally the achievable closed-loop performance, the RS- MPC effects the transition between steady states with enhanced performance over a wide operating region without the necessary retuning of standard MPC algorithms. A chemical reactor example is presented to illustrate the control application.
Keywords. MPC, Transition Control, Reference System.
ABSTRACT
The problem of input.... output Decoupling with simultaneous Disturbance Rejection (DRD) of a Distillation Column is studied. The results reported are first in the field due to the fact that the combined DRD problem is resolved for the case where time delays introduced in the column are taken into account. The controller derived is realistic to implement, while it yields a significant improvement in the system’s performance over other reported distillation column studies.
Key Words. Multivariable Control, Time.... Delay Systems, Decoupling and Disturbance Rejection, Linear Systems, Distillation Column Control.
ABSTRACT
In this paper we propose an energy ow resetting control architecture as a means for achieving enhanced energy dissipation in combustion systems. The overall framework is based on a hybrid controller architecture wherein the closed-loop dynamical system is characterized by impulsive differential equations. The proposed framework is used to design high-performance hybrid controllers for suppressing thermoacoustic oscillations in combustion chambers by eficiently dissipating modal system energy. Key Words. Hybrid resetting controllers, thermoacoustic instabilities, combustion control, energy ow, impulsive dynamical systems.
Key Words. Hybrid resetting controllers, thermoacoustic instabilities, combustion control, energy ow, impulsive dynamical systems
ABSTRACT
In the paper some practical aspects of hybrid modeling application in power plant monitoring are under consideration. In the case of low-rank lignite firing, a numerous problems arise, due to the lack of measurements of the key process variables such as coal main characteristics – mineral composition, caloricity, moisture; flame characteristics – geometry; space distribution of particles, speeds, chemical contents of gases, temperature, pressure; the properties of coal dust after milling system. Inferred variables and hybrid modeling based monitoring of the hard measurable variables is discussed. In the paper the problems with combination of direct and inferred model’s input data are considered. The aggregation of different kind of mathematical models is applied. A number of important cases are presented by applying the inference approach and hybrid modeling: (i) the space position of the flame in combustion chamber, (ii) indirect estimation of the main characteristics of the fired coal, (iii) determination of the admissible control range of the steam boilers. Some of the proposed schemes for monitoring have been applied in 210 MW boilers. The rest of them give promising simulation results and after certain additional engineering will be implemented too.
Key Words. hybrid modeling, inference measurement, low-rank lignite, monitoring, steam boiler
ABSTRACT
In this paper joint control and optimization problems of parallel processing batch reactors are considered. The specific problem addressed is the on-line scheduling of oxidation reactors in Dymethyl terephthalate (DMT) producing plant. Three level hierarchical control system is proposed to coordinates off-line optimization of batch profiles and schedules with on-line multilevel control. A reactive layered multifunctional scheduler is developed to react adequately to the batch processes variability as well as to the operations in the downstream and upstream stages of the whole plant. Results of computer simulation tests as well as some partially applications are presented.
Key Words. Batch process, control, optimization, oxidation, reactor, scheduling.