At the Boliden's concentrator in Aitik, bulk flotation constitutes an important part of the process for extracting valuable minerals from the ore. A series of flotation cells consists of five tanks connected in ca...
详细信息
At the Boliden's concentrator in Aitik, bulk flotation constitutes an important part of the process for extracting valuable minerals from the ore. A series of flotation cells consists of five tanks connected in cascade with control valves between the tanks and a slowly varying flow of mineral slurry into the first tank. This paper deals with a comparative study of control strategies for level control in a flotation series in Aitik. The aim is to show the potential performance improvements taking into account couplings between the process state variables. Two control strategies are considered;a decoupling controller and a Linear quadratic (LQ) optimal multivariable, controller. Experiments with both structures show a significant enhancement of the level control performance as compared to the original SISO design. (C) 2002 Elsevier Science Ltd. All rights reserved.
control of a coupled drives apparatus laboratory model as a two inputs - two outputs system is presented. Two control algorithms based on polynomial theory and pole - placement are proposed. The algorithms in adaptive...
详细信息
ISBN:
(纸本)0780373863
control of a coupled drives apparatus laboratory model as a two inputs - two outputs system is presented. Two control algorithms based on polynomial theory and pole - placement are proposed. The algorithms in adaptive version are then used for control of the model. The results of the real-time experiments are also given.
In Mexico, the largest share of the nation's agricultural production comes from agricultural zones designated as irrigation districts and units. Increasingly limited availability and competition for water have mad...
详细信息
In Mexico, the largest share of the nation's agricultural production comes from agricultural zones designated as irrigation districts and units. Increasingly limited availability and competition for water have made it necessary to implement integrated technification programs, in order to improve both efficiency of water use and productivity in these zones. Through these programs, over the past 7 years, roughly 700,000 hectares have benefited from high- and low-pressure irrigation systems. Additionally, in several irrigation districts, collective low-pressure networks have been built on surfaces ranging from 500 to 4, 000 hectares. This transformation in small parcel irrigation systems and interparcel distribution now demands a corresponding change in the control of main canals, in order to provide users with irrigation services in a flexible, reliable, equitable, and efficient manner In many areas of the country, the secondary canals have been substituted by collective low-pressure networks and pumping stations when the head in the main canals has been small. The control of irrigation canals consists of optimizing the conveyance and distribution process to satisfy the evapotranspiration demands of the crops in an irrigation district. This optimization implies the application of gate operation controls to adapt the transport and distribution of water in the canal to the volumes extracted through the laterals. Although the control of canals can be viewed from different perspectives, the proposed method is easily adapted to canal networks with configurations that vary over time. In fact, the general rationale used to model the canals, determine and identify the parameters, and prepare the control commands, can be applied to most open channel networks. The results of this work lead to the conclusion that the application of the control theory to the control of canals is an alternative that will reduce water losses and improve irrigation services in the irrigation distric
The aim of this paper is to present approximated model of pH process applicable for simulation and control. The highly nonlinear dynamical properties of the pH value to the addition of acid or base make the pH control...
详细信息
The aim of this paper is to present approximated model of pH process applicable for simulation and control. The highly nonlinear dynamical properties of the pH value to the addition of acid or base make the pH control very difficult. Changes in process sensitivity with pH makes difficult to design conventional controllers. Proposed pH model approximation allows formulating advanced control algorithm in relatively simple way.
In this paper an algorithm is proposed to solve the problem of time-optimal bang–bang control of nonlinear systems from a given initial state to a given terminal state. The problem is reduced to the problem of minimi...
详细信息
In this paper an algorithm is proposed to solve the problem of time-optimal bang–bang control of nonlinear systems from a given initial state to a given terminal state. The problem is reduced to the problem of minimising a Lagrangian subject to an equality constraint defined by the terminal state. Then a solution is obtained by solving a system of nonlinear equations. Examples are given so as to illustrate the algorithm presented.
The formation control of multiple vehicles using a perceptive frame is studied in this paper. The method is applied to multiple mobile robots. The controller design and lab experiments are shown in the paper. Some use...
详细信息
The formation control of multiple vehicles using a perceptive frame is studied in this paper. The method is applied to multiple mobile robots. The controller design and lab experiments are shown in the paper. Some useful strategies of coordination are implemented in a perceptive frame by reference projections. The feature of the coordination is illustrated by experiments of three mobile robots.
作者：
J.M. SousaC.A. SilvaJ.M. Sá da CostaTechnical University of Lisbon
Instituto Superior Técnico Dept. of Mechanical Engineering/GCAR - IDMEC Av. Rovisco Pais 1049-001 Lisbon Portugal Phone: +351-21-8417313 Siemens AG
Corporate Technology Information and Communications Neural Computation Department 81730 Munich Germany
The design of active noise control has been developed in the last two decades based on linear identification and control tools. However, acoustic processes present nonlinearities coming both from the characteristics o...
详细信息
The design of active noise control has been developed in the last two decades based on linear identification and control tools. However, acoustic processes present nonlinearities coming both from the characteristics of the actuator and from the nature of the process. Recent research has emphasized the importance of nonlinear model-based controllers, which increase the performance of several types of systems. Direct and inverse multivariable fuzzy models can be identified directly from data using fuzzy clustering. Inverse models can then be applied directly as controllers, which can be included in an active noise control scheme. This paper proposes the use of fuzzy techniques in active noise control. The performance of the proposed control schemes is compared to classical FIR active noise control in an experimental setup. Model-based fuzzy controllers clearly outperform classical active noise controllers.
The transmission matrix, introduced by Friedland in 1957, can be used to characterize a linear, time invariant system having an emprically-determined impulse response. The Wiener-Kalman filter can be determined by Cho...
详细信息
The transmission matrix, introduced by Friedland in 1957, can be used to characterize a linear, time invariant system having an emprically-determined impulse response. The Wiener-Kalman filter can be determined by Cholesky factorization of a covariance matrix formed from the transmission matrix. An analogous result is given for linear, quadratic control. The method is illustrated by several examples.
First we show that continuous piecewise-affine systems are equivalent to max-minplus-scaling systems (i.e., systems that can be modeled using maximization, minimization, addition and scalar multiplication). Next, we c...
详细信息
First we show that continuous piecewise-affine systems are equivalent to max-min-plus-scaling systems (i.e., systems that can be modeled using maximization, minimization, addition and scalar multiplication). Next, we ...
详细信息
First we show that continuous piecewise-affine systems are equivalent to max-min-plus-scaling systems (i.e., systems that can be modeled using maximization, minimization, addition and scalar multiplication). Next, we consider model predictive control for these systems. In general, this leads to nonlinear non-convex optimization problems. However, we present a method based on canonical forms for max-min-plus-scaling functions to solve these optimization problems in a more efficient way than by just applying nonlinear optimization as was done in previous research.
暂无评论