Search results for "Control system"
showing 10 items of 971 documents
Micropollutants throughout an integrated urban drainage model: Sensitivity and uncertainty analysis
2017
Abstract The paper presents the sensitivity and uncertainty analysis of an integrated urban drainage model which includes micropollutants. Specifically, a bespoke integrated model developed in previous studies has been modified in order to include the micropollutant assessment (namely, sulfamethoxazole – SMX). The model takes into account also the interactions between the three components of the system: sewer system (SS), wastewater treatment plant (WWTP) and receiving water body (RWB). The analysis has been applied to an experimental catchment nearby Palermo (Italy): the Nocella catchment. Overall, five scenarios, each characterized by different uncertainty combinations of sub-systems (i.e…
Spatial patterns of sediment connectivity in terraced lands: Anthropogenic controls of catchment sensitivity
2017
In recent decades the dynamics of global change in developed countries has led to significant alterations in the hydrological and sediment dynamics of terraced land. Agricultural terraces were built to control overland flow and prevent erosion, acting as buffers and barriers throughout the sediment cascading system. Their abandonment and degradation increase the sensitivity of the catchment, promoting the collapse of dry-stone walls and the reworking of stored sediment. In this study, a geomorphometric Index of Connectivity (IC) –derived from high-resolution LiDAR data (0.9 pt m-2, RMSE Q8). This spatial matching was related to feedback dynamics between structural and functional connectivit…
Reference tracking control of hypersonic vehicles using switched linear parameter-varying approach
2013
This paper is concerned with the control problem of the air-breathing hypersonic vehicle using switched linear parameter-varying (LPV) systems approach. By linearizing the nonlinear model of the hypersonic vehicle at trim points and dividing the velocity scope into several partitions, a switched LPV model for the underlying systems is derived. With aid of multiple Lyapunov-like functions technique, the controllers ensuring the tracking of given commands of the closed-loop system are designed under the mode-independent and mode-dependent switching logics, respectively. Simulation results for the hypersonic vehicle show the effectiveness of the proposed method and the advantages of the mode-d…
Robust H∞ filtering for networked control systems with markovian jumps and packet dropouts
2014
Published version of an article in the journal: Modeling, Identification and Control. Also available from the publisher at: http://dx.doi.org/10.4173/mic.2014.3.3 Open Access This paper deals with the H∞ filtering problem for uncertain networked control systems. In the study, network-induced delays, limited communication capacity due to signal quantization and packet dropout are all taken into consideration. The finite distributed delays with probability of occurrence in a random way is introduced in the network.The packet dropout is described by a Bernoulli process. The system is modeled as Markovian jumps system with partially known transition probabilities. A full-order filter is designe…
Monitoring pH and ORP in a SHARON reactor
2011
This paper analyses the valuable information provided by the on-line measurements of pH and oxidation reduction potential (ORP) in a continuous single high ammonia removal over nitrite (SHARON) reactor. A laboratory-scale SHARON reactor equipped with pH, ORP, electric conductivity and dissolved oxygen (DO) probes has been operated for more than one year. Nitrogen removal over nitrite has been achieved by adding methanol at the beginning of anoxic stages. Time evolution of pH and ORP along each cycle allows identifying the decrease in nitritation rate when ammonia is consumed during the aerobic phase and the end of the denitrification process during the anoxic phase. Therefore, monitoring pH…
Model-based automatic tuning of a filtration control system for submerged anaerobic membrane bioreactors (AnMBR)
2014
This paper describes a model-based method to optimise filtration in submerged AnMBRs. The method is applied to an advanced knowledge-based control system and considers three statistical methods: (1) sensitivity analysis (Morris screening method) to identify an input subset for the advanced controller; (2) Monte Carlo method (trajectory-based random sampling) to find suitable initial values for the control inputs; and (3) optimisation algorithm (performing as a supervisory controller) to re-calibrate these control inputs in order to minimise plant operating costs. The model-based supervisory controller proposed allowed filtration to be optimised with low computational demands (about 5min). E…
Advanced control system for optimal filtration in submerged anaerobic MBRs (SAnMBRs)
2013
The main aim of this study was to develop an advanced controller to optimise filtration in submerged anaerobic MBRs (SAnMBRs). The proposed controller was developed, calibrated and validated in a SAnMBR demonstration plant fitted with industrial-scale hollow-fibre membranes with variable influent flow and load. This 2-layer control system is designed for membranes operating sub-critically and features a lower layer (on/off and PID controllers) and an upper layer (knowledge-based controller). The upper layer consists of a MIMO (multiple-input-multiple-output) control structure that regulates the gas sparging for membrane scouring and the frequency of physical cleaning (ventilation and back f…
The Optimal Aspect Ratio for Plasmonic Bio-Sensing
2012
The sensitivity of plasmonic particles to the immediate dielectric environment allows to monitor the dielectric constant of liquids and binding events of molecules to the gold particle surface. Here, by means of simulations and experiments, I investigate which aspect ratio (AR) of gold nanorods is ideal for plasmonic sensing by employing various measures for “ideal” behavior.
Modelling of a hydro-pneumatic system for heave compensation
2018
This paper presents a mathematical model of the dynamic behaviour of a passive heave compensation system. The main purpose is to develop a model that enables cost-efficient prototyping and testing of the control system in an active heave compensator. The physics are described by first principles, and result in 21 ordinary differential equations. Temperature calculations are included as an option during simulation in order to investigate its effect on the results. Similarly is a non-ideal gas law (Redlich-Kwong equation) implemented and compared to the ideal gas law. Verification against field data shows that the model is in good accordance with real-life drilling operations. It is further s…
Assessment of the integrated urban water quality model complexity through identifiability analysis
2010
Urban sources of water pollution have often been cited as the primary cause of poor water quality in receiving water bodies (RWB), and recently many studies have been conducted to investigate both continuous sources, such as wastewater-treatment plant (WWTP) effluents, and intermittent sources, such as combined sewer overflows (CSOs). An urban drainage system must be considered jointly, i.e., by means of an integrated approach. However, although the benefits of an integrated approach have been widely demonstrated, several aspects have prevented its wide application, such as the scarcity of field data for not only the input and output variables but also parameters that govern intermediate st…