Electric Drive Control with Rotor Resistance and Rotor Speed Observers Based on Fuzzy Logic

Many scientific researchers have proposed the control of the induction motor without speed sensor. These methods have the disadvantage that the variation of the rotor resistance causes an error of estimating the motor speed. Thus, simultaneous estimation of the rotor resistance and the motor speed is required. In this paper, a scheme for estimating simultaneously the rotor resistance and the rotor speed of an induction motor using fuzzy logic has been developed. We present a method which is based on two adaptive observers using fuzzy logic without affecting each other and a simple algorithm in order to facilitate the determination of the optimal values of the controller gains. The control algorithm is proved by the simulation tests. The results analysis shows the characteristic robustness of the two observers of the proposed method even in the case of variation of the rotor resistance

In vitro vegetative growth and flowering of olive tree in response to GA3 treatment

The phytohormone gibberellin is involved in the regulation of many physiological process including flower induction and shoot growth. In this study, gibberellic acid (GA3) was used in order to induce thereversion of olive tree vegetative buds towards a floral ones in vitro. For this, six varieties (Marsaline, Chemchali, Picholine, Chemlali, Zalmati and Oueslati ) was tested and explants, consisting of a singlenode segments, were grown in media containing three concentrations of GA3 (1, 2 and 10 mg/l). Results show that Marsaline seems to be the most able variety in regenerating floral structures. For this variety,5 cases of reversion were observed mainly on the medium containing 10 mg/l GA3. This same medium was also favorable for this transformation for the other varieties (3 cases on Picholine, one each on Chemchali , Zalmati and Oueslati). The examination of the histological sections confirmed this transformation. In addition, this experiment showed that GA3 can be at the origin of an interestinggrowth rate of vegetative buds, which elongation depend on variety as well as GA3 concentration

The effect of the process on mechanical properties of polylactic acid - date palm leaf fibers composite films produced by extrusion blowing

Biocomposite films prepared with melt compounding and film blowing have become a new trend in plastic research to deliver more eco-friendly packages. Polylactic acid (PLA) was melt compounded with minimally processed date palm leaf fiber (DPLF) and converted into films by blown film extrusion. The compounding was done in order to enhance the film mechanical properties in one hand, and to decrease the film production cost in the other hand. In this present study, a reference PLA film and films with 1%, 2%, and 5% of DPLF (weight %) were produced with different process parameters. The spatial variations in films thickness and lay flat width indicate that the addition of DPLF up to 2% enhances the bubble stability for the tested process parameters. However, the composite with 5% DPLF shows nearly the same processability window as the neat PLA. The structural and mechanical characterizations of films suggest a reinforcing effect of the PLA matrix up to 2% of fiber (with an optimum at 1%). Larger DPLF loading leads to depressed and more anisotropic mechanical properties, related to an increased density of defects at the fiber-PLA fragile interface and to a DPLF-induced enhanced PLA thermal degradation and amorphous phase orientatio

Red light-emitting Carborane-BODIPY dyes: Synthesis and properties of visible-light tuned fluorophores with enhanced boron content

A small library of 2,6- and 3,5-distyrenyl-substituted carborane-BODIPY dyes was efficiently synthesized by means of a Pd-catalyzed Heck coupling reaction. Styrenyl-carborane derivatives were exploited as molecular tools to insert two carborane clusters into the fluorophore core and to extend the π-conjugation of the final molecule in a single synthetic step. The synthetic approach allows to increase the molecular diversity of this class of fluorescent dyes by the synthesis of symmetric or asymmetric units with enhanced boron content. The structural characterization and the photoluminescence (PL) properties of synthesized dyes were evaluated, and the structure/properties relationships have been investigated by theoretical calculations. The developed compounds exhibit a significant bathochromic shift compared to their parent fluorophore scaffolds, and absorption and emission patterns were practically unaffected by the different substituents (Me or Ph) on the Ccluster atom (Cc) of the carborane cage or the cluster isomer (ortho- or meta-carborane). Remarkably, the presence of carborane units at 2,6-positions of the fluorophore produced a significant increase of the emission fluorescent quantum yields, which could be slightly tuned by changing the Cc-substituent and the carborane isomer, as well as introducing ethylene glycol groups at the meso-position of the BODIPY

Enhanced model of gear transmission dynamics for condition monitoring applications: Effects of torque, friction and bearing clearance

Gear transmissions remain as one of the most complex mechanical systems from the point of view of noise and vibration behavior. Research on gear modeling leading to the obtaining of models capable of accurately reproduce the dynamic behavior of real gear transmissions has spread out the last decades. Most of these models, although useful for design stages, often include simplifications that impede their application for condition monitoring purposes. Trying to filling this gap, the model presented in this paper allows us to simulate gear transmission dynamics including most of these features usually neglected by the state of the art models. This work presents a model capable of considering simultaneously the internal excitations due to the variable meshing stiffness (including the coupling among successive tooth pairs in contact, the non-linearity linked with the contacts between surfaces and the dissipative effects), and those excitations consequence of the bearing variable compliance (including clearances or pre-loads). The model can also simulate gear dynamics in a realistic torque dependent scenario. The proposed model combines a hybrid formulation for calculation of meshing forces with a non-linear variable compliance approach for bearings. Meshing forces are obtained by means of a double approach which combines numerical and analytical aspects. The methodology used provides a detailed description of the meshing forces, allowing their calculation even when gear center distance is modified due to shaft and bearing flexibilities, which are unavoidable in real transmissions. On the other hand, forces at bearing level were obtained considering a variable number of supporting rolling elements, depending on the applied load and clearances. Both formulations have been developed and applied to the simulation of the vibration of a sample transmission, focusing the attention on the transmitted load, friction meshing forces and bearing preloads.The authors would like to acknowledge Project DPI 2013-44860 funded by the Spanish Ministry of Science and Technology and Project PRX14/00451 funded by the Spanish Ministry of Education, Culture and Sports

Numerical and experimental characterisation of polylactic acid (PLA) processed by additive manufacturing (AM): bending and tensile tests

In additive manufacturing (AM), one of the most popular procedures is material extrusion (MEX). The materials and manufacturing parameters used in this process have a significant impact on a printed product’s quality. The purpose of this work is to investigate the effects of infill percentage and filament orientation on the mechanical properties of printed structures. For this reason, the characterisation of polylactic acid (PLA) was done numerically using the finite element method and experimentally through mechanical tests. The experiments involved three-point bending and tensile tests. The results showed that mechanical performance is highly dependent on these processing parameters mainly when the infill percentage is less than 100%. The highest elastic modulus was exhibited for structures with filament align at 0◦ and 100% infill, while the lowest one was verified for specimen filament aligned at 0◦ and 30% infill. The results demonstrated that the process parameters have a significant impact on mechanical performance, particularly when the infill percentage is less than 100%. Structures with filament aligned at 0◦ and 100% infill showed the maximum elastic modulus, whereas specimens with filament oriented at 0◦ and 30% infill showed the lowest. The obtained numerical agreement indicated that an inverse method based only on the load–displacement curve can yield an accurate value for this material’s elastic modulus.National Innovation Agency (ANI) for MSc grant of Mariana Salgueiro nº POCI-01-0247- FEDER-039733 and Portuguese Foundations for Science and Technology. This project was co-financed by European Regional Development Fund (ERDF) through SI&IDT Projects in the framework of co-hosting—Competitiveness and Internationalisation Operational Programme (CIOP)—COMPETE 2020, Portugal 2020, with the National Innovation Agency (ANI) as the Intermediate Partner. Fabio Pereira acknowledges the Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020. Mariana Salgueiro and Andrea Zille acknowledge the European Commission and the National Innovation Agency (ANI) for the financial support through the project “ARCHKNIT: Innovative smart textile interfaces for architectural applications”, Ref.: POCI-01-0247-FEDER-039733. This project was co-financed by European Regional Development Fund (ERDF) through SI&IDT Projects in the framework of co-hosting—Competitiveness and Internationalisation Operational Programme (CIOP)—COMPETE 2020, Portugal 2020, with the National Innovation Agency (ANI) as the Intermediate Partner. Nuno Dourado acknowledges FCT for the conceded financial support through the reference project UID/EEA/04436/2019 and “Programa bilateral de Portugal com a Tunísia”. Charii Fakher acknowledges the « Fondation pour la Recherche Scientifique” for the conceded financial support through “Programa bilateral de Portugal com a Tunísia”

Deep convolutional neural network with 2D spectral energy maps for fault diagnosis of gearboxes under variable speed.

For industrial safety, correct classification of gearbox fault conditions is necessary. One of the most crucial tasks in data-driven fault diagnosis is determining the best set of features by analyzing the statistical parameters of the signals. However, under variable speed conditions, these statistical parameters are incapable of uncovering the dynamic characteristics of different fault conditions of gearboxes. Later, several deep learning algorithms are used to improve the performance of the feature selection process, but domain knowledge expertise is still necessary. In this paper, a combination domain knowledge analysis and a deep neural network is proposed. By using the input acoustic emission (AE) signal, a two-dimensional spectrum energy map (2D AE-SEM) is created to form an identical fault pattern for various speed conditions of gearboxes. Then, a deep convolutional neural network (DCNN) is proposed to investigate the detailed structure of the 2D input for final fault classification. This 2D AE-SEM offers a graphical depiction of acoustic emission spectral characteristics. Our proposed system offers vigorous and dynamic classification performance through the proposed DCNN with a high diagnostic fault classification accuracy of 96.37% in all considered scenarios

Coupling dynamics of a geared multibody system supported by Elastohydrodynamic lubricated cylindrical joints

A comprehensive computational methodology to study the coupling dynamics of a geared multibody system supported by ElastoHydroDynamic (EHD) lubricated cylindrical joints is proposed throughout this work. The geared multibody system is described by using the Absolute-Coordinate-Based (ACB) method that combines the Natural Coordinate Formulation (NCF) describing rigid bodies and the Absolute Nodal Coordinate Formulation (ANCF) characterizing the flexible bodies. Based on the finite-short bearing approach, the EHD lubrication condition for the cylindrical joints supporting the geared system is considered here. The lubrication forces developed at the cylindrical joints are obtained by solving the Reynolds’ equation via the finite difference method. For the evaluation of the normal contact forces of gear pair along the Line Of Action (LOA), the time-varying mesh stiffness, mesh damping and Static Transmission Error (STE) are utilized. The time-varying mesh stiffness is calculated by using the Chaari’s methodology. The forces of sliding friction along the Off-Line-Of-Action (OLOA) are computed by using the Coulomb friction models with a time-varying coefficient of friction under the EHD lubrication condition of gear teeth. Finally, two numerical examples of application are presented to demonstrate and validate the proposed methodology.National Natural Science Foundations of China under Grant 11290151, 11221202 and 11002022, Beijing Higher Education Young Elite Teacher Project under Grant YETP1201