1,721,051 research outputs found
“Evolutionary adaptation of dispatching agents in heterarchical manufacturing systems”
No full textWe propose a new approach to job flow adaptive operational control in advanced manufacturing systems. The major feature of the method is the distribution of the control tasks among completely autonomous intelligent agents. Namely, agents are implicitly coordinated by a nature-analogous adaptation mechanism, which continuously tunes the free parameters of the control law of each agent. The proposed approach is effective and reactive to severe disturbances and changes in the manufacturing environment. Simulation experiments illustrate the operational distributed approach and its response to fault
Near Optimum Control of a Full Car Active Suspension System
No full textIn this paper, a near-optimum control strategy applied to a full car model equipped with an active suspension system is presented. The control law is based on a reduced order model obtained by means of a modal aggregation method, achieving a compromise between computational effort in deriving the control law and system performances. To assess the controller performances, a virtual prototype of the suspension system is developed by using AMESim, an advanced fluid-mechanic developing tool. The virtual prototype could be assumed as a reliable model of the real system enabling to perform safer and cheaper tests than using the real system. Simulation results show the effectiveness of the approach
Controllability of multi-input positive discrete-time systems
No full textLinear discrete-time positive systems arise in various fields of science, such as economic modelling, behavioural science, stochastic processes, etc. Recently, some authors have examined the problem of the controllability of such systems for the single-input case.This paper provides necessary and sufficient conditionsfor characterizing the controllability properties of multi-input systems. The results here developed show that only a narrow class of these systems enjoys the properties of reachability and controllability
Modeling and Predictive Control of a New Injection System for Compressed Natural Gas Engines
No full textIn internal combustion engines equipped with the common rail injection system the accurate metering of the air/fuel mixture strictly depends on the pressure regulation. Accuracy in metering is difficult to be achieved especially for compressed natural gas (CNG) injection systems, as the gas compressibility makes the fuel delivery process more complex. Since the controller design requires a model of the injection system, this paper presents a physics-based state-space model of an innovative CNG injection system. The model parameters only depend on well defined geometrical data and fuel properties. Comparing simulation and experimental results in different operating conditions validates the model. Further, the proposed model is used for designing a generalized predictive controller for the injection pressure regulation, which is implemented in few steps. Experimental results show the effectiveness of the proposed approac
Una strategia di partizionamento ed ordinamento degli stati delle catene di Markov nell'analisi delle linee di produzione a tre stadi
No full textDeadlock Avoidance in Cellular Manufacturing Systems
No full textWe develop control policies to avoid deadlocks in cellular manufacturing systems (CMSs). We take advantage of the structure of a CMS to develop a distributed control system in which each cell is controlled locally and independently. The controller of each cell is a local agent that adopts his own control law to improve flexibility and performance measures
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