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Enrique C.L.H.,National Research Center y Desarrollo Tecnologico | Jorge B.H.,Apizaco Institute of Technology | Dariusz S.W.,National Research Center y Desarrollo Tecnologico
RIAI - Revista Iberoamericana de Automatica e Informatica Industrial | Year: 2015

It presents a method of multi-objective optimization, applied to energy consumption of open kinematic chains, analyzing the case of the movement of an extremity of a walking electro- hydraulic robot. To demonstrate the effectiveness of the proposed method, it is applied in two cases of displacement. The first case shows the movement of the extremity without obstacles in its workspace and the second includes the evasion of an obstacle. The minimization of angular displacement of the links with higher energy consumption and the minimization of the maximum absolute value of the angular acceleration of the links are used as optimization criteria. In both cases a trajectory that reduces energy consumption by more than 25% over the other methods proposed in the literature, at the same time the dynamic behavior of the system by avoiding variations in the speed and the acceleration is improved during the phase of transference, besides increasing the precision and accuracy of the foot position. © 2015 CEA. Publicado por Elsevier Espaa, S.L.U. Todos los derechos reservados.

Peregrina-Barreto H.,National Institute of Astrophysics, Optics and Electronics | Morales-Hernandez L.A.,Autonomous University of Queretaro | Rangel-Magdaleno J.J.,National Institute of Astrophysics, Optics and Electronics | Avina-Cervantes J.G.,University of Guanajuato | And 2 more authors.
Computational and Mathematical Methods in Medicine | Year: 2014

Thermography is a useful tool since it provides information that may help in the diagnostic of several diseases in a noninvasive and fast way. Particularly, thermography has been applied in the study of the diabetic foot. However, most of these studies report only qualitative information making it difficult to measure significant parameters such as temperature variations. These variations are important in the analysis of the diabetic foot since they could bring knowledge, for instance, regarding ulceration risks. The early detection of ulceration risks is considered an important research topic in the medicine field, as its objective is to avoid major complications that might lead to a limb amputation. The absence of symptoms in the early phase of the ulceration is conceived as the main disadvantage to provide an opportune diagnostic in subjects with neuropathy. Since the relation between temperature and ulceration risks is well established in the literature, a methodology that obtains quantitative temperature differences in the plantar area of the diabetic foot to detect ulceration risks is proposed in this work. Such methodology is based on the angiosome concept and image processing. © 2014 H. Peregrina-Barreto et al.

Valles-Novo R.,National Institute of Astrophysics, Optics and Electronics | Rangel-Magdaleno J.,National Institute of Astrophysics, Optics and Electronics | Ramirez-Cortes J.,National Institute of Astrophysics, Optics and Electronics | Peregrina-Barreto H.,National Institute of Astrophysics, Optics and Electronics | Morales-Caporal R.,Apizaco Institute of Technology
Conference Record - IEEE Instrumentation and Measurement Technology Conference | Year: 2014

Induction motors are an ubiquitous machine. In industrial settings, online monitoring of motors' health status in order to schedule maintenance operations with the goal of damage prevention has become an essential necessity. Broken rotor bar is one of the most common failures in the rotor of a squirrel cage motor. Motor current signature analysis (MCSA) has become a popular method for its detection due to its high reliability. Recent works perform MCSA with a combination of different signal processing techniques to identify the presence of broken bars. In this work, MCSA is done with Empirical Mode Decomposition (EMD) from which a set of Intrinsic Mode Functions (IMF) is obtained. The extracted features of the arithmetical sum of the obtained IMFs form the basis of the proposed classification criteria. Unlike other works, the only employed signal processing technique in our methodology is EMD. Experimental results using our method show high accuracy in the detection of one broken rotor bar. © 2014 IEEE.

Bonilla Huerta E.,Apizaco Institute of Technology | Duval B.,University of Angers | Hao J.-K.,University of Angers
Neurocomputing | Year: 2010

In supervised classification of Microarray data, gene selection aims at identifying a (small) subset of informative genes from the initial data in order to obtain high predictive accuracy. This paper introduces a new embedded approach to this difficult task where a genetic algorithm (GA) is combined with Fisher's linear discriminant analysis (LDA). This LDA-based GA algorithm has the major characteristic that the GA uses not only a LDA classifier in its fitness function, but also LDA's discriminant coefficients in its dedicated crossover and mutation operators. Computational experiments on seven public datasets show that under an unbiased experimental protocol, the proposed algorithm is able to reach high prediction accuracies with a small number of selected genes. © 2010 Elsevier B.V.

Szwedowicz D.,CENIDET | Bedolla J.,Apizaco Institute of Technology
DYNA (Colombia) | Year: 2012

Stress concentrations at the ends of a flat contact including frictional sliding are analyzed in this article by using the finite element (FE) method. The numerical studies are conducted with a shaft coupled to the hub by conical rings. The applied mesh refinement at the contact ends assures the reliability of the FE results, which show significantly higher stress peaks than those obtained from the conventional analytical solution recommended in the design guidelines of the frictional conical joints. These notch stresses result in low cycle fatigue (LCF) failures of the shaft-hub connection in service, since the yield point of the shaft material can be locally exceeded. The effect of clearances among the joint components and magnitudes of the friction coefficient on variations of the maximum stress in the contact are considered as well. The paper's findings and conclusions are applicable to the design and manufacturing process of the frictional conical joints with regard to assembly tolerances.

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