The introduction of tighter drinking water quality standards and economic considerations has focused attention on ways to improve control systems for water treatment, and for the disinfection process in particular. Th...
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The introduction of tighter drinking water quality standards and economic considerations has focused attention on ways to improve control systems for water treatment, and for the disinfection process in particular. This control problem has, however, proved difficult to tackle with automatic control systems, due to the long contact time between the water and the disinfectant needed to ensure reliable disinfection, and hence the long delay between a control action and its measurement. The variable quality of raw water, together with the large effect that seasonal changes in ambient temperature and pH have on the dissociation, and thus the disinfecting capability, of dosed chlorine-based disinfectants, compound the problem. This paper describes a simple and cost-effective approach to the control of water chlorination that is being implemented for a large UK water treatment works.
A multi-loop control scheme for a state-of-the-art section mill is described. The basis of the system is the set-up calculation which uses complex, non-linear models of the rolling process to predict the optimum setti...
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A multi-loop control scheme for a state-of-the-art section mill is described. The basis of the system is the set-up calculation which uses complex, non-linear models of the rolling process to predict the optimum settings for the mill stands. To obtain maximum performance from the system, adaptive control loops are included on three levels: piece-by-piece, pass-by-pass and in-pass. These loops use various techniques for identification of piece state and model parameters, including square root information filtering and extended Kalman filtering. The paper describes some of the problems of applying these methods to an online system and shows how these problems are addressed in practice.
The primary objective of QUO VADIS is to establish how Variable Message Signs (VMS) are best managed to give high quality information and guidance to drivers and to improve the capacity of a road network. Four alterna...
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The primary objective of QUO VADIS is to establish how Variable Message Signs (VMS) are best managed to give high quality information and guidance to drivers and to improve the capacity of a road network. Four alternative approaches are being investigated within QUO VADIS. They include: a plan selection approach based on a pre-established library of plans identified by rule of thumb;a plan selection approach that utilizes the MCONTRAM network traffic model to develop a library of plans;a feedback approach derived from automatic control theory and leading to traffic responsive control based on current traffic measurements;and an expert system approach OPERA combining real time forecasting and pre-established expert rules.
The Statemate range of tools from i-Logix is presented as an alternative approach to hardware/software codesign. Statemate provides automatic code generation that can speed up both the hardware and software aspects of...
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The Statemate range of tools from i-Logix is presented as an alternative approach to hardware/software codesign. Statemate provides automatic code generation that can speed up both the hardware and software aspects of the design. It also allows the quick modeling and verification of function algorithms, continuation of parallel hardware and software development, and the condensation of a huge amount of information into easy to use panel display space.
Experimental results on a laboratory micromachine illustrate how the presence of a supervisory expert system can enhance the robustness and performance of a self-tuning controller. The system provides bumpless startup...
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Experimental results on a laboratory micromachine illustrate how the presence of a supervisory expert system can enhance the robustness and performance of a self-tuning controller. The system provides bumpless startup of an adaptive controller, eliminating induced transient oscillations while maintaining closed-loop operation. Injection of appropriate PRBS inputs, moving parameter boundaries, etc. maintain stability of the adaptive estimator and the controller output, although instability detection algorithms ensure that if the self-tuner could fail it is switched out. The settings for a PID controller are regularly retuned, so that the back-up controller can successfully replace the self-tuning regulator, thus maintaining stable operation.
This paper addresses the problem of designing guidance, navigation and control systems for Autonomous - Unmanned -Underwater Vehicles (AUVs) to achieve accurate tracking of reference paths defined in a universal refer...
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This paper addresses the problem of designing guidance, navigation and control systems for Autonomous - Unmanned -Underwater Vehicles (AUVs) to achieve accurate tracking of reference paths defined in a universal reference frame. The theoretical framework adopted is illustrated with a design example in which recent developments in multivariable control theory and classical results in navigation and guidance were applied to the design of a trajectory following system for the AUV MARIUS (Marine Utility Vehicle System). The key ideas in the design methodology are to clearly state performance specifications in the frequency domain, and to use design tools that explicitly address these types of specifications. Thus, the natural constraint that the navigation, control and guidance systems have decreasing bandwidths, can be directly incorporated in the initial phase of the project. Analysis of the integrated system is performed using a simulation package that allows the user to assess the impact of the navigation, guidance, and control algorithms on the dynamic behaviour of the vehicle.
The stone processing industries produce different types of material for use in the construction industries. Two major types are stone aggregates used for production of asphalt and concrete, and polished stone slabs us...
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The stone processing industries produce different types of material for use in the construction industries. Two major types are stone aggregates used for production of asphalt and concrete, and polished stone slabs used for a range of products including floor and wall tiles. Traditionally, the stone processing industries have relied on manual and subjective methods of plant set up, monitoring and control. The increasing demand for better quality products and lower costs is creating a trend towards process optimization and automatic control. Due to the non-linear nature of the involved processes, the introduction of automation in these industries is often problematic. Variation in stone properties, in particular, presents a major problem which causes a drift in plant performance in terms of tool wear, system efficiency, and product characteristics. The paper describes the use of adaptive and intelligent control strategies to overcome this problem in both stone polishing and aggregate industries.
The United Kingdom Military Satellite Communications System (UKMSCS) provides access to the Skynet 4 satellites for the UK Armed Forces. Access is obtained through a configuration of fixed and transportable ground sta...
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The United Kingdom Military Satellite Communications System (UKMSCS) provides access to the Skynet 4 satellites for the UK Armed Forces. Access is obtained through a configuration of fixed and transportable ground stations with routing and control of terrestrial information managed by Network control Centres. The paper identifies and describes a mechanism for handling the results of stress as exhibited by the UKMSCS. Stress is defined as anything which reduces the capacity of the network to carry communications. This can take the form of weather conditions, interference, deliberate jamming, or, more commonly, faults. When there is a stress condition within the network (either caused through equipment failure or deliberate action), the effects are difficult to predict. When the symptoms of stress conditions are exhibited, therefore, diagnosing the cause is not simple. The stress management system (SMS) is able to monitor the UKMSCS, detecting, isolating and diagnosing any stress affecting the network. The combination of advanced artificial intelligence techniques and a high fidelity modelling/simulation system allow the SMS to cope with the problems caused by the distributed and dynamic nature of the UKMSCS. Also, by including a modelling system within the SMS, several other benefits could be available, such as validation of plans and operator training.
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