Power fluctuations of the rolling mill may cause the instability of electric power systems, and increase the cost of the electric power facility and electricity charges. Therefore, in order to compensate the power flu...
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This paper addresses the dissolved oxygen tracking problem in multi-zone bioreactor. The proposed approach utilizes decentralized control system incorporating fuzzy multiregional PI controllers so that satisfactory co...
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ISBN:
(纸本)9783902661913
This paper addresses the dissolved oxygen tracking problem in multi-zone bioreactor. The proposed approach utilizes decentralized control system incorporating fuzzy multiregional PI controllers so that satisfactory controller performance can be robustly and reliably achieved over a whole process operating range. A fuzzy supervisor of the completely decentralized control system is introduced in order to meet a global actuator capacity constraint. An overall control system can be implemented by using fairly standard equipment that is commonly available at a plant site.
Sewer systems are large-scale systems that collect and transport stormwater and sanitary sewage out of urban areas. Sewer systems are mainly operated using pumping stations and pollutants are removed from sewage by tr...
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ISBN:
(纸本)9783902661913
Sewer systems are large-scale systems that collect and transport stormwater and sanitary sewage out of urban areas. Sewer systems are mainly operated using pumping stations and pollutants are removed from sewage by treatment plants before water is released into the environment. When a sewer overflow occurs, e.g., caused by a strong rainfall, sewage is discharged directly into the environment without any treatment. An efficient use of storage capacities and pumping stations can help to minimize the environmental pollution caused by sewer overflows. In this paper a nonlinear predictive control approach is presented to improve the operation of sewer systems. To deal with the nonlinear and non-differentiable features of the prediction model used, a pattern search method is proposed to solve the underlying optimization problem. The technique proposed is implemented on a part of the sewer system of Bogotá, Columbia. Simulation results illustrate the potential of the approach.
作者：
Tran, Vu NamBrdys, Mietek A.School of Electronic
Electrical and Computer Engineering College of Engineering and Physical Sciences University of Birmingham Birmingham B15 2TT United Kingdom Department of Control Systems Engineering
Faculty of Electrical and Control Engineering Gdansk University of Technology ul. Narutowicza 11/12 80 - 233 Gdansk Poland
This paper presents a modeling technique and considers the water network distribution under three typical operating scenarios. Robustly feasible model predictive control structure and algorithms are applied to the con...
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ISBN:
(纸本)9783902661913
This paper presents a modeling technique and considers the water network distribution under three typical operating scenarios. Robustly feasible model predictive control structure and algorithms are applied to the control problem. The computing time issue of optimization solvers is addressed and improved by supplying the corresponding gradients. The analytical method of finding the required gradients intensively utilizes the Hamiltonian function. Comparisons between two different optimization solvers as well as between control strategies are verified by computer simulation under MATLAB-EPANET environment.
The aeration is used in different operations at wastewater treatment plants. The biological processes that are carried out at require sufficiently high dissolved oxygen concentration in order to maintain microorganism...
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In a general nonlinear control system a stabilizing control strategy is often possible if complete information on external inputs affecting the system is available. Assuming that measurements of persistent disturbance...
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ISBN:
(纸本)9781424474264
In a general nonlinear control system a stabilizing control strategy is often possible if complete information on external inputs affecting the system is available. Assuming that measurements of persistent disturbances are available it is shown that the existence of a smooth uniform control Lyapunov function implies the existence of a stabilizing state feedback with feedforward control which is robust with respect to measurement errors and external disturbances. Conversely, using differential inclusions parameterized as nonlinear systems with state and disturbance measurement errors, it is shown that there exists a smooth uniform control Lyapunov function if there is a robustly stabilizing state feedback with feedforward. This paper demonstrates that if there exists a smooth control Lyapunov function for a general nonlinear system with persistent disturbances for which one has previously designed a feedback controller, a feedforward always exists to be augmented for stability.
Reducing tool differences is one of the important tasks to improve the yield of semiconductor device manufacturing. Various kinds of methods have been proposed to solve this problem. These methods enable us to find pr...
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Reducing tool differences is one of the important tasks to improve the yield of semiconductor device manufacturing. Various kinds of methods have been proposed to solve this problem. These methods enable us to find problematic tools from numbers of process tools. However, finding problematic tools is not always enough to work out the problem of tools. Visualization of the transition profile of tool differences provides us additional information to help finding the unknown control parameters. It helps us to find corresponding events such as maintenance, repair, and adjustment. We design a profiling algorithm based on the maximum likelihood estimation. This algorithm introduces a new constraint that “tools are stable at each process step for a short period”, and recursively uses a regression method by employing previous results of the estimation. Simulation results show that our algorithm extracts the transition profile of tool differences more precisely than existing regression methods.
To maintain stable operation of semiconductor fabrication lines, statistical process control (SPC) methods are recognized to be effective. In semiconductor fabrication lines, there exist a huge number of process state...
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To maintain stable operation of semiconductor fabrication lines, statistical process control (SPC) methods are recognized to be effective. In semiconductor fabrication lines, there exist a huge number of process state signals to be monitored, and these signals contain both normally and non-normally distributed data, which make the application of SPC difficult. The authors have already proposed an SPC method “ESCM” which can solve these problems. However, this method has a problem that it is highly sensitive to outliers contained in the reference data. In this paper, we propose a new outlier removal method to solve this problem. This method uses the “effective standard deviation” we used in the ESCM to deal with a wide range of non-normal distributions. Basic performances of this method are demonstrated by comparing abilities to detect outliers correctly, and to mistakenly detect non-outlier data with conventional methods. In the demonstration, we use various kinds of artificially generated data and real data observed in process tools in a semiconductor fabrication line. Usefulness of this method is demonstrated by studying the effects of this method when used with ESCM.
This paper addresses the dissolved oxygen tracking problem in multi-zone bioreactor. The proposed approach utilizes decentralized control system incorporating fuzzy multiregional PI controllers so that satisfactory co...
详细信息
This paper addresses the dissolved oxygen tracking problem in multi-zone bioreactor. The proposed approach utilizes decentralized control system incorporating fuzzy multiregional PI controllers so that satisfactory controller performance can be robustly and reliably achieved over a whole process operating range. A fuzzy supervisor of the completely decentralized control system is introduced in order to meet a global actuator capacity constraint. An overall control system can be implemented by using fairly standard equipment that is commonly available at a plant site.
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