COMPARACIÓN DEL GRADIENTE DE TEMPERATURA EN ESPACIOS CÚBICOS CONTROLADOS CON CELDA PELTIER EN FUNCIÓN A DOS AISLANTES TÉRMICOS. (COMPARISON OF THE TEMPERATURE GRADIENT IN CUBIC SPACES CONTROLLED WITH PELTIER CELL ACCORDING TO TWO THERMAL INSULATORS.)

ResumenEste trabajo estudia el gradiente de temperatura en espacios cúbicos de dimensiones pequeñas utilizando dispositivos de enfriamiento peltier. Se demuestra que el material, el volumen, potencia y temperatura exterior afecta la eficiencia de un elemento termoeléctrico.  Los materiales seleccionados en la construcción de los espacios cúbicos cuentan con baja conductividad térmica, a fin de evitar que la temperatura exterior afecte a la medición. Se tomaron periódicamente valores de temperatura en espacios cúbicos. El banco de prueba consiste en microcontrolador, disipadores de calor en lado frio y caliente y módulos peltier. Se realizó la comparación de los valores que obtienen en cada volumen. Se determina el uso de mayor cantidad de celdas peltier, optimizando el tiempo de enfriamiento y la potencia necesaria que se requiera. Según las ecuaciones que se obtienen el comportamiento del enfriamiento en espacios cúbicos es semejante, la eficiencia que se presenta en enfriamiento a espacios es reflejada en material, volumen, potencia de enfriamiento y temperatura externa. Palabras Claves: Peltier, Modelado, temperatura, Gradiente, Optoelectrónica.AbstractThis paper studies the temperature gradient in cubic spaces of small dimensions using peltier cooling devices. The dependency of the material, volume, power and external temperature was studied, which it affects the efficiency of a thermoelectric element. The materials selected for the cubic spaces elaboration were chosen with low thermal conductivity, since this avoid the room temperature affecting the measurement. The internal temperature of the cubic spaces was taken at periodic    intervals to observe its behavior. The characterization was carried out using a microcontroller, heat sinks on cold and hot sides, and peltier modules. The temperature was compared between each volume used to obtain an optimization as a function of peltiers cells, in a minimal time of set point of cooling temperature and the power required. The equiation obtain in According to the equations that are obtained the behavior of movement in cubic spaces is similar, the efficiency that is presented in space limitations is reflected in material, volume, cooling power and external temperature.Keywords: Peltier, Modeling, Temperature, Gradient, Optoelectronics

CARACTERIZACIÓN DE UN INCLINÓMETRO ÓPTICO PARA DESPLAZAMIENTO VERTICAL DE ESTRUCTURAS CIVILES (CHARACTERIZATION OF AN OPTICAL INCLINOMETER FOR VERTICAL DISPLACEMENT OF CIVIL STRUCTURES)

ResumenEn este artículo, se presenta un sensor de inclinación de fibra óptica basado en la modulación de intensidad, la cual se relaciona experimentalmente en función de pérdidas provocadas por macrocurvaturas en una fibra multimodo. El inclinómetro utiliza un engrane-cremallera, que cuando el eje principal del mecanismo sufre una inclinación, se modifica la trayectoria de la luz debido al cambio de curvatura en la fibra óptica. Para la caracterización del sensor se empleó una fuente de luz y un medidor de intensidad para pruebas de laboratorio. Se observó en la configuración experimental propuesta, que a mayor ángulo de inclinación mayor pérdida de intensidad óptica experimenta. Los resultados experimentales mostraron que el inclinómetro proporcionaba un rango de medición de 0 ° a 10° con una sensibilidad de 0.232 nW/°.Palabras Claves: Fibra multimodo, inclinómetro, macrocurvatura. AbstractIn this article, an optical fiber inclination sensor based on intensity modulation is presented, which is experimentally related to losses caused by macrocurvatures in a multimode fiber. The inclinometer uses a gear-rack, which when the main axis of the mechanism suffers an inclination, the light path is modified due to the change in curvature in the optical fiber. For the characterization of the sensor, a light source and an intensity meter were used for laboratory tests. It was observed in the proposed experimental configuration, that the greater the inclination angle the greater the loss of optical intensity it experiences. Experimental results showed that the inclinometer provided a measuring range of 0 ° to 10 ° with a sensitivity of 0.232 nW/°.Keywords: Inclinometer, macro-curvature, multimode fiber

Robust sensor fault estimation for descriptor-LPV systems with unmeasurable gain scheduling functions: Application to an anaerobic bioreactor

This paper addresses the design of a state estimation and sensor fault detection, isolation and fault estimation observer for descriptor-linear parameter varying (D-LPV) systems. In contrast to where the scheduling functions depend on some measurable time varying state, the proposed method considers the scheduling function depending on an unmeasurable state vector. In order to isolate, detect and estimate sensor faults, an augmented system is constructed by considering faults to be auxiliary state vectors. An unknown input LPV observer is designed to estimate simultaneously system states and faults. Sufficient conditions to guarantee stability and robustness against the uncertainty provided by the unmeasurable scheduling functions and the influence of disturbances are synthesized via a linear matrix inequality (LMI) formulation by considering H∞ and Lyapunov approaches. The performances of the proposed method are illustrated through the application to an anaerobic bioreactor model

An FPGA Correlation-Edge Distance approach for disparity map

International audience—This paper describes an FPGA Correlation-Edge Distance approach for real time disparity map generation in stereo-vision. The proposed method calculates the disparity map for the input and disparity map for Edge Distance images of a stereopair. In both cases the approximation algorithm of disparity map SAD (Sum of Absolute Differences) is used. The final disparity map is determined from the previously generated maps, considering a homogeneity parameter defined for each point in the scene. Due to low complexity when implementing stereo-vision algorithms in FPGA devices, the proposed method was implemented in a Cyclone II EP2C35F672C6 FPGA assembled in an Altera DE2 breadboard. The developed module can process stereo-pairs of 1280×1024 pixel resolution at a rate of 75 frames/s and produces 8-bit dense disparity maps within a range of disparities up to 63 pixels. The presented architecture provides a significant improvement in regions with uniformed texture over correlation based stereo-vision algorithms in the reported literature and an accelerated processing rate

Optical Method for Estimating the Chlorophyll Contents in Plant Leaves

This work introduces a new vision-based approach for estimating chlorophyll contents in a plant leaf using reflectance and transmittance as base parameters. Images of the top and underside of the leaf are captured. To estimate the base parameters (reflectance/transmittance), a novel optical arrangement is proposed. The chlorophyll content is then estimated by using linear regression where the inputs are the reflectance and transmittance of the leaf. Performance of the proposed method for chlorophyll content estimation was compared with a spectrophotometer and a Soil Plant Analysis Development (SPAD) meter. Chlorophyll content estimation was realized for Lactuca sativa L., Azadirachta indica, Canavalia ensiforme, and Lycopersicon esculentum. Experimental results showed that—in terms of accuracy and processing speed—the proposed algorithm outperformed many of the previous vision-based approach methods that have used SPAD as a reference device. On the other hand, the accuracy reached is 91% for crops such as Azadirachta indica, where the chlorophyll value was obtained using the spectrophotometer. Additionally, it was possible to achieve an estimation of the chlorophyll content in the leaf every 200 ms with a low-cost camera and a simple optical arrangement. This non-destructive method increased accuracy in the chlorophyll content estimation by using an optical arrangement that yielded both the reflectance and transmittance information, while the required hardware is cheap

Lamb Behaviors Analysis Using a Predictive CNN Model and a Single Camera

Object tracking is the process of estimating in time N the location of one or more moving element through an agent (camera, sensor, or other perceptive device). An important application in object tracking is the analysis of animal behavior to estimate their health. Traditionally, experts in the field have performed this task. However, this approach requires a high level of knowledge in the area and sufficient employees to ensure monitoring quality. Another alternative is the application of sensors (inertial and thermal), which provides precise information to the user, such as location and temperature, among other data. Nevertheless, this type of analysis results in high infrastructure costs and constant maintenance. Another option to overcome these problems is to analyze an RGB image to obtain information from animal tracking. This alternative eliminates the reliance on experts and different sensors, yet it adds the challenge of interpreting image ambiguity correctly. Taking into consideration the aforementioned, this article proposes a methodology to analyze lamb behavior from an approach based on a predictive model and deep learning, using a single RGB camera. This method consists of two stages. First, an architecture for lamb tracking was designed and implemented using CNN. Second, a predictive model was designed for the recognition of animal behavior. The results obtained in this research indicate that the proposed methodology is feasible and promising. In this sense, according to the experimental results on the used dataset, the accuracy was 99.85% for detecting lamb activities with YOLOV4, and for the proposed predictive model, a mean accuracy was 83.52% for detecting abnormal states. These results suggest that the proposed methodology can be useful in precision agriculture in order to take preventive actions and to diagnose possible diseases or health problems

Design of an MPPT Technique for the Indirect Measurement of the Open-Circuit Voltage Applied to Thermoelectric Generators

This paper presents the design of a maximum power point-tracking (MPPT) technique for DC–DC converters that are used in energy-harvesting systems based on thermoelectric generators. This technique is based on the analysis of the characteristics of the converter to measure the open-circuit voltage indirectly. The main contribution of this article is that the algorithm measures the voltage at the maximum power point without the need to disconnect the source of the circuit, as happens when the fractional open-circuit voltage (FOCV) technique is used. The algorithm is based on a predetermined initial duty cycle, which is applied to the circuit, and the input voltage and input current are read. With these values, the open-circuit voltage and short-circuit current are calculated with equations obtained from the circuit. Then, it calculates the duty cycle at the maximum power point and applies it to the circuit. If this duty cycle does not obtain the maximum power from the circuit, the algorithm starts a second stage based on fuzzy logic to calculate an increase or decrease in the duty cycle. The designed technique was evaluated using a topology based on a DC–DC flyback converter variant and was compared with the P&O technique and obtained better results. The designed technique provides between 3.9% and 5.6% more power to the load than the P&O technique in a 20 W system