Examinando por Autor "Barrero Mendoza, Oscar"
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- PublicaciónSólo datosAgricultural unmanned ground vehicles: A review from the stability point of view(Revista Ciencia Agronomica, 2020-12-20) Fernandes, Hugo Rafacho; Moriones Polania, Edna Carolina; Pontín García, Ángel; Barrero Mendoza, Oscar; Albiero, DanielAgricultural ground vehicles often have to traverse unstructured terrain, i.e., terrain whose conditions cannot be precisely predicted during its displacement. Such characteristics restrict the use of robots in the agricultural field because their stability could be compromised by their interaction with the terrain. As it does not have a human operator capable of observing, predicting, and controlling the interaction of the vehicle with the terrain. Therefore, a robot must deal with the unpredictability caused by this interaction, a task that was previously performed by the human operator. Given the relevance of the topic, this study investigates the literature on agricultural unmanned ground vehicles from the stability point of view, and also presents relevant criteria for dealing with the stability of agricultural robots in terms of their design and selection.
- PublicaciónSólo datosAssimilation of ozone measurements in the air quality model AURORA by using the Ensemble Kalman Filter(2011 50th IEEE Conference on Decision and Control and European Control Conference, 2011-12-12) Barrero Mendoza, OscarThis paper presents the results of using the Ensemble Kalman Filter (EnKF) for improving the ozone estimations of the air quality model AURORA. The EnKF is built around a stochastic formulation of the model, where some of its parameters are assumed to be uncertain. These uncertainties turn out to be the main reason behind the differences between the model predictions and the real measurements. The filter estimates these parameters as well as the ozone concentration field by using ground-based measurements from the Airbase database. The assimilation experiments are carried out over a region that consists of Belgium, Luxembourg, and some small parts of Germany, France and the Netherlands. The simulations results show that the EnKF significantly reduces the error of the ozone estimations.
- PublicaciónAcceso abiertoDesarrollo de un sistema de navegación autónoma para un vehículo eléctrico tipo rover, para aplicaciones de agricultura de precisión(Universidad de Ibagué, 2019) Nova Zamora, Yuli Marcela; Barrero Mendoza, OscarAgriculture is the main economic activity of the department of Tolima and with the use of technologies it is possible to increase productivity, reduce costs and improve the competitiveness of this sector, therefore in this degree work an autonomous navigation system is developed for a land vehicle type Skid-Steering for use in agricultural applications, with the aim of having a technological tool with the ability to track specific trajectories and thus be able to automate tasks such as plowing, planting seeds, fertilize, taking samples located among others . The system implements an extended Kalman filter that integrates sensors to have a reliable geolocation, a trajectory tracking control was designed based on the dynamic model obtained with the identification of linear systems and system monitoring is performed based on telemetry. Presented satisfactory results with errors less than one meter.
- PublicaciónAcceso abiertoDiseño, implementación y validación de un algoritmo de geolocalización de alta precisión para un vehículo de navegación terrestre tipo Rover de la Universidad de Ibagué(Universidad de Ibagué., 2018) Bolívar Marín, Fabián; Barrero Mendoza, OscarThis thesis shows the design, implementation and validation of two high precision geolocation algorithms for a land vehicle of the University of Ibagué. This rover is designed to be used in projects related to precision agriculture, a line of research in which the D + TEC group is currently working. The document illustrates two alternatives that were developed to achieve the implementation of a position and orientation estimator for the aforementioned rover. The first alternative consisted of the design of a two-stage algorithm that integrates a Kalman filter assembled with an adaptive Kalman filter in the first stage and allows merging the data obtained from an Inercial Measurement Unit housed in a navigation card Navio2 with encoder data installed on the axes of the rover wheels. The output of this stage feeds the second stage of the algorithm, developed through a Kalman filter integrating the data of a GPS and magnetometer installed also in the rover. The second alternative that was also implemented was a two-stage algorithm that integrated an extended Kalman filter with an adaptive one in the first stage and a conventional Kalman filter in the second stage merging the same data from the sensors mentioned in the first alternative. Finally, the results obtained are shown and a detailed analysis of what is found in each designed algorithm is made.
- PublicaciónAcceso abiertoEstrategia para el control de convertidores de potencia conectados en paralelo orientados a la carga rápida de vehículos eléctricos(Universidad de Ibagué, 2023) Salas Castaño, Maria Claudia; López Santos, Oswaldo; Barrero Mendoza, Oscar; Suárez Sierra, Oscar JavierEl desarrollo de estrategias de control para convertidores conectados en paralelo es de importancia para la investigación en aplicaciones como la carga rápida de vehículos eléctricos. Este trabajo se enfoca en el análisis de la conexión en paralelo de convertidores Ćuk como una topología simple y robusta, conveniente para la aplicación deseada. Para ello, se define una función de transferencia que describe el comportamiento de los convertidores teniendo en el sistema de control propuesto. Este sistema consiste en controladores proporcional-integral (PI) dispuestos así: un lazo interno, que controla la corriente de entrada de cada convertidor individualmente, garantizando su estabilidad. Un lazo externo, que controla la corriente de salida de cada convertidor, buscando el intercambio de corriente homogéneo en el sistema y un lazo de balance de potencia que se encarga de obtener una adecuada distribución de corriente entre los convertidores. Se propone un diseño para el convertidor Ćuk y, con base en la función de transferencia, se realiza la sintonización de los controladores usando el lugar geométrico de las raíces. Finalmente, se implementan los convertidores con los respectivos controladores en PSIM para efectuar pruebas de estabilidad, de rechazo a perturbaciones y de distribución de corriente. Los resultados muestran que con el sistema de control propuesto se garantiza la estabilidad del sistema y se logra una distribución de corriente balanceada entre los convertidores, lo que es importante para aplicaciones de carga rápida de vehículos eléctricos.
- PublicaciónSólo datosRGB and multispectral UAV image fusion for Gramineae weed detection in rice fields(Precision Agriculture, 2018-09-02) Barrero Mendoza, Oscar; Perdomo Ospina, Sammy AlejandroIn this paper, a new method to fuse low resolution multispectral and high resolution RGB images is introduced, in order to detect Gramineae weed in rice fields with plants at 50 days after emergence (DAE).The images are taken from a fixed-wing unmanned aerial vehicle (UAV) at 60 and 70 m altitude. The proposed method combines the texture information given by a high resolution red–green–blue (RGB) image and the reflectance information given by a low resolution multispectral (MS) image, to obtain a fused RGB-MS image with better weed discrimination features. After analyzing the normalized difference vegetation index (NDVI) and normalized green red difference index (NGRDI) for weed detection, it was found that NGRDI presents better features. The fusion method consists of decomposing the RGB image using the intensity, hue and saturation (IHS) transformation, then, a second order Haar wavelet transformation is applied to the intensity layer (I) and the NGRDI image. From this transformation, the low–low (LL) coefficients of the NGRDI image are replaced by the LL coefficients of the I layer. Finally, the fused image is obtained by transforming the new wavelet coefficients to RGB space. To test the method, a one hectare experimental plot with rice plants at 50 DAE with Gramineae weeds was selected. Additionally, to compare the performance of the method, two indices were used, specifically, the M/MGT index which is the percentage of detected weed area, and the MP index which indicates the precision of weed detection. These indices were evaluated in four validation zones using three Neural Networks (NN) detection systems based on three types of images; namely, RGB, RGB + NGRDI, and fused RGB-NGRDI. The best weed detection performance was obtained by the NN with the fused image, with M/MGT index between 80 and 108% and MP between 70 and 85%.
- PublicaciónSólo datosRGB and multispectral UAV image fusion for Gramineae weed detection in rice fields(Precision Agriculture, 2018-10-01) Barrero Mendoza, Oscar; Perdomo Ospina, Sammy AlejandroIn this paper, a new method to fuse low resolution multispectral and high resolution RGB images is introduced, in order to detect Gramineae weed in rice fields with plants at 50 days after emergence (DAE).The images are taken from a fixed-wing unmanned aerial vehicle (UAV) at 60 and 70 m altitude. The proposed method combines the texture information given by a high resolution red–green–blue (RGB) image and the reflectance information given by a low resolution multispectral (MS) image, to obtain a fused RGB-MS image with better weed discrimination features. After analyzing the normalized difference vegetation index (NDVI) and normalized green red difference index (NGRDI) for weed detection, it was found that NGRDI presents better features. The fusion method consists of decomposing the RGB image using the intensity, hue and saturation (IHS) transformation, then, a second order Haar wavelet transformation is applied to the intensity layer (I) and the NGRDI image. From this transformation, the low–low (LL) coefficients of the NGRDI image are replaced by the LL coefficients of the I layer. Finally, the fused image is obtained by transforming the new wavelet coefficients to RGB space. To test the method, a one hectare experimental plot with rice plants at 50 DAE with Gramineae weeds was selected. Additionally, to compare the performance of the method, two indices were used, specifically, the M/MGT index which is the percentage of detected weed area, and the MP index which indicates the precision of weed detection. These indices were evaluated in four validation zones using three Neural Networks (NN) detection systems based on three types of images; namely, RGB, RGB + NGRDI, and fused RGB-NGRDI. The best weed detection performance was obtained by the NN with the fused image, with M/MGT index between 80 and 108% and MP between 70 and 85%. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
- PublicaciónAcceso abiertoSistemas de control digital(Ediciones Unibagué, 2021-04) Barrero Mendoza, Oscar