Repetitive systems can be characterized by two time variables, namely, the finite time within each repeating cycle and the cycle index, each embodying a distinct connotation of time. Conventional optimal control theor...
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Repetitive systems can be characterized by two time variables, namely, the finite time within each repeating cycle and the cycle index, each embodying a distinct connotation of time. Conventional optimal control theory does not explicitly account for this two dimensional (2D) description of repetitive systems. We propose a new formulation for control of repetitive systems using Model Predictive control (MPC) that explicitly incorporates a 2D representation of the system. The proposed formulation uses a 2D Lyapunov function and the stability requirements are established along each time dimension of the system. The resulting controller synthesis problem is expressed in convex form using Linear Matrix Inequalities (LMIs). The approach allows explicit incorporation of input/output constraints in the controller design. Two examples illustrate the applicability of the proposed approach.
Optimal experiment or input design is the scientific exercise of designing informative excitation signals for the identification of a real-life dynamic system. In the least costly input design framework, the input is ...
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Simulation of recipe driven batch processes is a complex demanding task. It can be performed either with general purpose simulators, causing a high modelling effort, or with specific tools which often lack flexibility...
Simulation of recipe driven batch processes is a complex demanding task. It can be performed either with general purpose simulators, causing a high modelling effort, or with specific tools which often lack flexibility. Neither of these approaches is appropriate in all cases. In this contribution, we outline a software architecture for batch process simulation which is flexible enough to be adapted to meet the particular requirements of the simulation problem at hand. It consists mainly of the elements model creation, output clients, simulator, and user interface. All these components are exchangeable to offer the software solution which is best suited for the specific problem. The software concepts are presented in terms of design patterns.
Simple conceptual or mathematical models have always been used in design of linear SISO processcontrollers. On the other hand the design of nonlinear or MIMO controllers has always been perceived as requiring a detai...
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Simple conceptual or mathematical models have always been used in design of linear SISO processcontrollers. On the other hand the design of nonlinear or MIMO controllers has always been perceived as requiring a detailed dynamic model. This communication aims to show that, the use of simple models, can drastically affect the design of such controllers by suggesting a design framework that centers around the extensive variable of the process instead of the intensive one that are usually measured.
There are significant incentives in controlling the end-use properties in batch reactors to reduce the variability in the final product quality specifications. Here we define an approach for controlling the properties...
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There are significant incentives in controlling the end-use properties in batch reactors to reduce the variability in the final product quality specifications. Here we define an approach for controlling the properties within a desired target region, instead of a set point, with an economic objective and with consideration of the model uncertainty. The approach to handling process-model mismatch is based on determining the uncertainty in the predicted final values of the properties, in the form of elliptical confidence regions. The controller then ensures that the complete confidence region is within the target set. A semi-infinite programming problem is solved to find the input values for the rest of the batch, utilizing techniques that reduce the complexity of the problem. An emulsion polymerization process for styrene is chosen as a case study and the methods developed here are demonstrated on this challenging example process.
We propose to use the Izhikevich single neuron model to represent a motor cortex neuron for studying a control-theoretic perspective of a neuroprosthetic system. The problem of estimating model parameters is addressed...
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Very often one needs to know the current values of reaction rates in chemical reactors in order to control them effectively or in order to avoid unsafe operating conditions. ln this work state estimation techniques ar...
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Very often one needs to know the current values of reaction rates in chemical reactors in order to control them effectively or in order to avoid unsafe operating conditions. ln this work state estimation techniques are used to estimate on-line reaction rates in well mixed isothermal batch reactors. The proposed scheme assumes the availability of on-line measurements of overall concentrations of the reactants, and the lack of knowledge on the reaction rate dependence with those concentrations. The state estimator used in this application is a Kalman filter based estimator. Relationships between the continuous and the discrete versions of the filter as well as a Laplace domain analysis were considered. The estimation scheme is applied to two examples of semi-continuous emulsion co-polymerization.
There are economic incentives in controlling the end-use properties in batch reactors to reduce the variability in the final product quality specifications. Here we define an approach for controlling the properties wi...
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There are economic incentives in controlling the end-use properties in batch reactors to reduce the variability in the final product quality specifications. Here we define an approach for controlling the properties within a desired target region, instead of a set point, with an economic objective and with consideration of the model uncertainty. The approach to handling process-model mismatch is based on determining the uncertainty in the predicted final values of the properties, in the form of elliptical confidence regions. The controller then ensures that the complete confidence region is within the target region. A semi-infinite programming problem is solved to find the input values for the rest of the batch. The methods developed here are demonstrated on an emulsion polymerization example.
Presents a general methodology for the identification of average linear low order models (ALLOM) from data collected from detailed nonlinear models. While there are many methods available in the literature for identif...
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Presents a general methodology for the identification of average linear low order models (ALLOM) from data collected from detailed nonlinear models. While there are many methods available in the literature for identifying linear models, these methods tend to produce inaccurate and ill-conditioned models when used on nonlinear data sets. The method in this paper differs from traditional linearization methods in that it better approximates the dynamic characteristics over a wider area around the reference steady state.
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