Search results for "Control system"
showing 10 items of 971 documents
Multi-rate PID Controller for a Networked Control System
2007
In networked control systems several devices (controller, process and others) share a common communication bus. This feature can suppose delays when those devices try to transmit information through the unique bus, leading to a non- regular behaviour, that is, different variables are sampled and updated in a non-uniform way along the time. As a result, if the control system is designed by means of classical design techniques, control performance can be degraded, since these techniques used not to consider those delays. In order to undertake this problem, a solution based on a PID controller's parameters readjustment is proposed. This approach permits to retune these parameters depending on …
Criticality and sensitivity analysis of the components of a system
2000
Abstract In the design of complex systems there is a great interest to know the relative importance of each of their elements. In this paper, we define a new method for measuring the relative importance of each element of the system. We have to specify that this paper concerns only non-repairable systems and components. We present a way of calculating the criticality of each component for a complex system no matter what the random distribution of the life of the component is. The paper also demonstrates a simple way of calculating how the system life improves when the life of a component is improved.
Electronics for Application of Ion Beams in Nanoscience
2009
The breadth of ion-beam nanoscience methods discussed in the proceeding chapters implies that the control and readout systems also span a wide range of techniques. For many nanoscience and technology applications the need to process or characterise a batches of samples has lead to a convergence of data acquisition systems and control systems. This coupled with the development of high-performance lowcost computing over the past decades has lead to a progressive evolution in data acquisition technology. Historically, much of the electronics used in nanoscience and technology using ion beams is based on nuclear analogue pulse counting and spectrometry where NIM (Nuclear Instrumentation Modules…
Experimental investigation on high efficiency real-time control algorithms for IPMSMs
2014
This paper describes an experimental investigation on the power losses variations occurring in an Interior Permanent Magnet Synchronous Motor (IPMSM) with respect to the direct axis current component. Such investigation can be useful to determine a mathematical model accounting for copper, iron and mechanical friction losses, and for the arrangement of a speed control drive system equipped with a real-time power losses minimization algorithm. In particular, a test bench has been set up in order to carry out all measurements and the final power loss identification. The test bed is composed by a IPMSM drive with a field oriented control (FOC) strategy, a power analyzer, a dynamometric brake a…
Life cycle assessment of Italian citrus-based products. Sensitivity analysis and improvement scenarios
2009
Though many studies concern the agro-food sector in the EU and Italy, and its environmental impacts, literature is quite lacking in works regarding LCA application on citrus products. This paper represents one of the first studies on the environmental impacts of citrus products in order to suggest feasible strategies and actions to improve their environmental performance. In particular, it is part of a research aimed to estimate environmental burdens associated with the production of the following citrus-based products: essential oil, natural juice and concentrated juice from oranges and lemons. The life cycle assessment of these products, published in a previous paper, had highlighted sign…
Variance-based sensitivity analysis for wastewater treatment plant modelling.
2014
Global sensitivity analysis (GSA) is a valuable tool to support the use of mathematical models that characterise technical or natural systems. In the field of wastewater modelling, most of the recent applications of GSA use either regression-based methods, which require close to linear relationships between the model outputs and model factors, or screening methods, which only yield qualitative results. However, due to the characteristics of membrane bioreactors (MBR) (non-linear kinetics, complexity, etc.) there is an interest to adequately quantify the effects of non-linearity and interactions. This can be achieved with variance-based sensitivity analysis methods. In this paper, the Extend…
Global sensitivity analysis in wastewater applications: A comprehensive comparison of different methods
2013
Three global sensitivity analysis (GSA) methods are applied and compared to assess the most relevant processes occurring in wastewater treatment systems. In particular, the Standardised Regression Coefficients, Morris Screening and Extended-FAST methods are applied to a complex integrated membrane bioreactor (MBR) model considering 21 model outputs and 79 model factors. The three methods are applied with numerical settings as suggested in literature. The main objective considered is to classify important factors (factors prioritisation) as well as non-influential factors (factors fixing). The performance is assessed by comparing the most reliable method (Extended-FAST), by means of proposed…
Energy saving in the aeration process by fuzzy logic control
1998
An aeration fuzzy logic based control system has been developed and tested in the main aerobic reactor of a BARDENPHO process pilot plant. This system has been compared with two ordinary aeration process controllers: one- and two-aeration-level on/off controllers. Energy savings of about 40% over the one-level on/off controller and a more stable closed-loop response have been obtained. Thus, an improvement of about 60% in average deviation can be accomplished by the use of an AFLBC.
A systematic approach for fine-tuning of fuzzy controllers applied to WWTPs
2010
A systematic approach for fine-tuning fuzzy controllers has been developed and evaluated for an aeration control system implemented in a WWTP. The challenge with the application of fuzzy controllers to WWTPs is simply that they contain many parameters, which need to be adjusted for different WWTP applications. To this end, a methodology based on model simulations is used that employs three statistical methods: (i) Monte-Carlo procedure: to find proper initial conditions, (ii) Identifiability analysis: to find an identifiable parameter subset of the fuzzy controller and (iii) minimization algorithm: to fine-tune the identifiable parameter subset of the controller. Indeed, the initial locatio…
Capacity and safety analysis of hard-shoulder running (HSR). A motorway case study
2016
Abstract Operational motorway conditions can be improved by introducing traffic flow management and control systems, such as ramp metering (RM), high occupancy vehicle (HOV) lanes, real-time variable speed limits (VSLs), reversible lanes (RL), automated highway systems (AHS) and hard-shoulder running (HSR). The effects of such devices need to be examined in terms of capacity and safety. This paper examines the case study of the Italian motorway A22, which is supposed to be equipped with an HSR system implemented along 128 km in order to reduce congestion with consequent improvement in levels of service (LOS). We studied the traffic processes (capacity, flow distribution between lanes, relia…