Ofelia Begovich

Takagi-Sugeno fuzzy scheme for real-time trajectory tracking of an underactuated robot

This paper presents an approach to achieve trajectory tracking for nonlinear systems. Combining the linear regulator theory with Takagi-Sugeno (T-S) fuzzy methodology; an algorithm is described for the trajectory tracking. The main contribution of the paper includes a real-time application of this algorithm to a specific two-rigid-link underactuated robot, called the Pendubot.

Application of a leak detection algorithm in a water pipeline prototype: Difficulties and solutions

The main aim of this paper is to comment about the difficulties encountered during the implementation of a well known analytic leak detection algorithm on a short length water pipeline prototype. In addition, the proposed solutions to overcome these difficulties are described. To improve the algorithm, extra filtering to all input signals is added and a freezing-method for the friction coefficient estimation is proposed. Real data are obtained from flow and head pressure sensors installed upstream and downstream of the pipe, then they are supplied to the algorithm. The estimation of the leak size and leak position are presented.

T-S scheme for trajectory tracking of an underactuated robot

This paper presents a novel approach to achieve trajectory tracking for nonlinear systems. Combining linear regulator theory with the Takagi-Sugeno (TS) fuzzy methodology a new algorithm is proposed, which is able to handle complex nonlinear systems such as under-actuated mechanisms. The paper includes a description of the algorithm as well as real time results for the application to an specific under-actuated robot-the Pendubot.

Comparison of two Detection Algorithms for Pipeline Leaks

The aim of this paper is to compare two analytic detection algorithms for pipeline leaks in order to assess their effectivity. Parameters such as precision and velocity to detect and locate a leak, algorithm complexity, and application facilities are evaluated, with the purpose of finding the most useful algorithm for a future real-time implementation on a Mexican aqueduct.

Greenhouse Modeling Using Continuous Timed Petri Nets

This paper presents a continuous timed Petri nets (ContPNs) based greenhouse modeling methodology. The presented methodology is based on the definition of elementary ContPN modules which are designed to capture the components of a general energy and mass balance differential equation, like parts that are reducing or increasing variables, such as heat, CO2 concentration, and humidity. The semantics of ContPN is also extended in order to deal with variables depending on external greenhouse variables, such as solar radiation. Each external variable is represented by a place whose marking depends on an a priori known function, for instance, the solar radiation function of the greenhouse site, which can be obtained statistically. The modeling methodology is illustrated with a greenhouse modeling example.

Calibration of Fitting Loss Coefficients for modelling purpose of a plastic pipeline

Motivated by the sensitivity of model-based monitoring algorithms to the so-called Equivalent Straight Length (ESL) of a pipeline, this paper proposes an experiment-based calibration of this parameter and also for the values of the Fitting Loss Coefficients (FLC). This comes as an alternative to achieve a better description of the real flow behavior in a pipeline than the modelling obtained by using the FLC from the manufacturer data-sheet. The proposed calibration method relies on a flow modelling, and Kalman observer-based estimation of the FLC of a pipeline. The friction coefficient in the model is estimated by the explicit so-called Swamee-Jain equation. The approach only assumes sensors of flow and pressure at the ends of the duct. Experimental results are presented.

Real-time nonlinear system regulation via TS fuzzy control

Regulator lineal theory and a Takagi-Sugeno (TS) fuzzy control methodology are used to design a new fuzzy control scheme for nonlinear system regulation. This approach is applied in real time to the level control of two water-storage tanks connected in a cascade manner.

Optimal sensor choice for observability in free-choice Petri nets

This paper studies the optimal sensor choice for observability problem in discrete event systems (DES) modeled by interpreted free-choice Petri nets (IFCN). Taking advantage of the fact that, event-detectability is a necessary and sufficient condition for observability in live, cyclic and bounded IFCN, a structural characterization of event-detectability and a simple polynomial algorithm to choose a minimal cost sensor configuration for observability in this claw of nets are provided. This algorithm is successfully applied to an illustrative example.

DSP application of a water-leak detection and isolation algorithm

In this paper we present an application of a Digital Signal Processor (DSP) system to detect and isolate a water-leak. The programmed algorithm is based on a Sensitivity Model-Based Approach. The DSP system is tested on-line in a water pipeline prototype. The model used to design the algorithm to isolate the leak is obtained from a Preissmann Scheme. An adaptive estimation of the friction factor is incorporated to attain real-time isolation. Comments about the implementation are given. The estimation results of the leak size and leak position are presented.

Leak isolation based on Extended Kalman Filter in a plastic pipeline under temperature variations with real-data validation

The present work is motivated by the purpose of considering a more realistic scenario than in former studies on the problem of leak isolation within a plastic pipeline, when the water can be affected by temperature changes. In order to address this situation, a state observer approach based on a model including temperature effect and an Extended Kalman Filter is proposed. Noting indeed that temperature affects some equivalent straight length of the pipe, which is used in the model, the observer estimates it together with the leak coefficients. This approach only considers head pressure and flow rate measurements coming from pipeline ends, likewise, water temperature measurement at upstream tank. Results with real data obtained from a pipeline prototype are shown in two different ways in order to illustrate the performance of proposed leak isolation system, as compared to the traditional approaches found at literature.