Juli Romera

Predictive optimal control of sewer networks using CORAL tool: application to Riera Blanca catchment in Barcelona

This paper deals with the global control of the Riera Blanca catchment in the Barcelona sewer network using a predictive optimal control approach. This catchment has been modelled using a conceptual modelling approach based on decomposing the catchments in subcatchments and representing them as virtual tanks. This conceptual modelling approach allows real-time model calibration and control of the sewer network. The global control problem of the Riera Blanca catchment is solved using a optimal/predictive control algorithm. To implement the predictive optimal control of the Riera Blanca catchment, a software tool named CORAL is used. The on-line control is simulated by interfacing CORAL with a high fidelity simulator of sewer networks (MOUSE). CORAL interchanges readings from the limnimeters and gate commands with MOUSE as if it was connected with the real SCADA system. Finally, the global control results obtained using the predictive optimal control are presented and compared against the results obtained using current local control system. The results obtained using the global control are very satisfactory compared to those obtained using the local control.

Fault Diagnosis of Wind Turbines using a Set-membership Approach

Abstract In this paper, the problem of fault diagnosis in wind turbines will be addressed applying a set-membership approach. Fault detection is based on the use of parity equations and unknown but bound description of the noise and modelling errors. Fault detection test is based on checking consistency between measurements and the model by finding if there is parameter in the feasible parameter set (approximated by a zonotope) that is compatible with modelling and noise bounds. The fault isolation algorithm is based on analyzing the observed fault signatures on-line and matching them with the theoretical ones obtained using structural analysis. Finally, the proposed approach will be tested using the wind turbine benchmark proposed in the context of the WT FDI competition.

A Fault-Hiding Approach for the Switching Quasi-LPV Fault-Tolerant Control of a Four-Wheeled Omnidirectional Mobile Robot

This paper proposes a reference model approach for the trajectory tracking of a four-wheeled omnidirectional mobile robot. In particular, the error model is brought to a quasi-linear-parameter-varying (LPV) form suitable for designing an error-feedback controller. It is shown that, if polytopic techniques are used to reduce the number of constraints from infinite to finite, a solution within the standard LPV framework could not exist due to a singularity that appears in the possible values of the input matrix. Adding a switching component to the controller allows solving this problem. Moreover, a switching LPV virtual actuator is added to the control loop in order to obtain fault tolerance within the fault-hiding paradigm, keeping the stability and some desired performances under the effect of actuator faults without the need of retuning the nominal controller. The effectiveness of the proposed approach is shown and proved through simulation and experimental results.

Leak detection and isolation in water distribution networks using principal component analysis and structured residuals

Leaks are present to some extent in all waterdistribution systems. This paper proposes a leakage localization method based on pressure measurements and the application of principal component analysis to the fault diagnosis in water distribution systems. First, some theoretical basics are introduced, from model building and modeling the fault effects to monitoring. Then a simple hydraulic case study is presented to illustrate the proposed methodology, its particularities and the detection results.

Optimal predictive control of water transport systems: Arrêt-Darré/Arros case study

This paper proposes the use of predictive optimal control as a suitable methodology to manage efficiently transport water networks. The predictive optimal controller is implemented using MPC control techniques. The Arrêt-Darré/Arros dam-river system located in the Southwest region of France is proposed as case study. A high-fidelity dynamic simulator based on the full Saint-Venant equations and able to reproduce this system is developed in MATLAB/SIMULINK to validate the performance of the developed predictive optimal control system. The control objective in the Arrêt-Darré/Arros dam-river system is to guarantee an ecological flow rate at a control point downstream of the Arrêt-Darré dam by controlling the outflow of this dam in spite of the unmeasured disturbances introduced by rainfalls incomings and farmer withdrawals.

Model predictive control of combined irrigation and water supply systems: Application to the Guadiana river

In this paper, a methodology for the optimal management of a combined irrigation and water supply system based on model predictive control (MPC) is proposed. A control-oriented modelling methodology for this type of systems is presented as well. MPC is used to generate flow control strategies from the sources to the consumer and irrigation areas to meet future demands with appropriate flows, optimizing operational goals such as network safety volumes in dams and flow control stability in actuators (valves, gates and pumps). The case study of Guadiana river is used to exemplify and verify the proposed optimal management methodology. Results have shown the effectiveness of the proposed modelling and control methodologies.

Low level control of an omnidirectional mobile robot

This paper presents the low level control of an holonomic robot with four omnidirectional wheels. A robust control technique named Quantitative Feedback Theory (QFT), based on an uncertain linear model has been selected to design the PID speed controllers for the four-wheeled robot. A piecewise model has been estimated by means of the least squares estimation approach based on experimental results of the robot in closed loop. In particular, the control is designed using this piecewise model. The performances of the proposed approach are analyzed in real time domain.

Identification and switching quasi-LPV control of a four wheeled omnidirectional robot

This paper presents the quasi-Linear Parameter Varying (quasi-LPV) modeling, identification and control of a four wheeled omnidirectional robot. The unknown nonlinear model parameters of the four wheeled robot have been calibrated by means of the nonlinear least squares identification approach and validated against real data. Introducing a reference model that generates the desired trajectory, the resulting nonlinear error model is brought to a quasi-LPV form suitable for designing a controller using Linear Matrix Inequalities (LMIs). In particular, the controller is obtained within the switching LPV framework. The effectiveness of the proposed approach is shown and proved through experimental results.

Model Predictive Control of Water Networks Considering Flow and Pressure

This chapter proposes a nonlinear model predictive control (NMPC) strategy for WDNs including both flow and pressure constraints. A WDN might be regarded as a nonlinear system described by differential-algebraic equations (DAEs), when flow and hydraulic head equations are considered in the model. The main operational goal of WDNs is the minimization of the economic costs associated with pumping. In addition to the minimization of costs, the optimal operation of WDNs should guarantee water supply with required flows and pressures at all the control/demand nodes in the network. Other operational goals related to safety and reliability are usually sought. From a control point of view, NMPC is a suitable control strategy for WDNs, since the optimal operation of the network cannot be established a priori by fixing reference volumes in the tanks. Alternatively, the NMPC strategy should determine the optimal filling/emptying sequence of the tanks taking into account that electricity price varies between day and night and that the demand also follows a 24-h repetitive pattern. On the other hand, as a result of the ON/OFF operation of pumps in pumping stations, a two-layer control scheme has been utilized: the NMPC strategy at the hourly sampling timescale is chosen in the upper layer while the pump scheduling approach at the minutely sampling timescale dealing with pumps in the ON/OFF manner is proposed in the lower layer. Finally, results of applying the proposed control strategy to a portion of the Barcelona WTN are provided in simulation.

Optimal Design of a Wastewater Treatment Plant using Advanced Technologies

In this paper, a methodology and software tool for the optimal design of advanced waste treatment plants is presented. The problem of the design of the WWTP is translated into a discrete optimization problem. As a result, an optimal sequence of treatment technologies to obtain the output water quality from a given inlet water containing a certain input contaminant concentrations is provided. The discrete optimization problem is solved using Genetic and Pattern Search Algorithms available at the Global Optimization Toolbox of MATLAB. A typical design scenario is used to illustrate the validity and performance of the proposed approach and tool.