Data-Driven Simulator: Redesign of Chickpea Harvester Reels

Conventional redesign methodologies applied on the grain harvester headers for the mechanical harvesting of chickpeas cause its progress to not be as rapid and technological. This paper presents a hybrid modeling-optimization methodology to design harvester reels for efficient chickpea harvesting. The five fabricated headers were tested in both real and virtual modeling environments to optimize the operational parameters of the reel for minimum losses. Harvesting losses data gathered from chickpea fields over ten years of trials were fed into a fuzzy logic model, which in turn was merged with simulated annealing to develop a simulator. To this end, simulated annealing was used to produce combinations of reel diameter and number of bats, to be fed into the fuzzy model until achieving a minimum harvesting loss. The proposed model predicts the reel structure measured in-field evaluation, which fits well with the previously established mathematical model. A significant improvement in harvesting performance, 71% pod harvesting, validates the benefits of the proposed fuzzy-simulated annealing approach to optimize the design of grain harvester headers

Development of harvesters for traditional orchards based on canopy shakers

El olivar español es el primer productor mundial de aceite (40%) y de aceituna de mesa (25%). La mayor parte del olivar no es rentable y es clave reducir sus costes. Dado que la recolección supone del orden del 50% de su valor, en ella se deben centrar los esfuerzos. No existe una solución única válida para la recolección de todos los tipos de olivar, aunque, en olivares modernos de media y de alta densidad existe un alto grado de mecanización. Sin embargo, el olivar tradicional, que representa casi el 70% del total, no dispone de una cosechadora. Su introducción supondría un cambio tecnológico y una innovación clave para este tipo de olivar. La presente memoria expone los resultados obtenidos en I+D+i con el objetivo principal de desarrollar la primera cosechadora para la recolección integral de olivar tradicional. En una primera fase, se realizó un estudio de un sistema sacudidor de copa procedente de cítricos para su aplicación a olivar, determinando las características de la sacudida y del funcionamiento de la máquina en campo. Posteriormente, se completaron estos estudios, determinado la forma y zona de caída de los frutos. Por último, se desarrolló un sistema de recepción, logística, limpieza y almacenaje del fruto para incorporación de, alcanzándose resultados muy prometedores en la recolección integral del árbol. En fases posteriores, se realizó una caracterización de árboles y plantaciones tradicionales para poder realizar un diseño específico de sistema de derribo adaptado a esta tipología. Tras un proceso de investigación sobre los principios de la sacudida de la copa y el desprendimiento de los frutos, se avanzó en el diseño y fabricación de nuevos sistemas de sacudida de copa, así como en el desarrollo de tecnología para el copiado automático del contorno del árbol. Los nuevos sistemas para derribar las aceitunas alcanzaron resultados prometedores para su aplicación al olivar tradicional, adaptándose a su morfología y a las características singulares de sus árboles. Finalmente, fruto del trabajo realizado en la línea 1 del convenio Mecaolivar, toda la investigación desarrollada se materializó en la fabricación de un prototipo de cosechadora con sistema sacudidor de copa para el olivar tradicional. Estas máquinas demuestran la viabilidad de la cosecha integral de los olivos tradicionales

Vibration analysis of the fruit detachment process in late-season ‘Valencia’ orange with canopy shaker technology

The mechanical harvesting of juice oranges can be achieved by the application of forced vibration to the tree canopy to detach fruit. Among the available harvesting technologies, canopy shaker systems have the advantage of working continuously, with rods that penetrate the tree canopy generating low-frequency, high-amplitude movement. The objective of this work is to analyse the fruit detachment process in order to improve the design and management of canopy shaker systems, reducing the risk of damage to fruit during the mechanical harvesting process. Three different canopy shaker systems were used to remove oranges in a well-adapted intensive orchard during the harvesting period. The fruit detachment process was recorded with a triaxial accelerometer sensor with a datalogger inserted into each tested fruit. Fruit movement displayed a similar frequency value as harvester rods (4.1-4.9 Hz), while the resultant acceleration depended on the interaction of the tree-machine system (38.8-60.4 m s-2). The fruit detachment event occurrence required a vibration time ranging between 1.45-5.75 s, which can limit the machine’s maximum speed. After the detachment event, fruit presented a short mean time (0.28 s) with no interaction with other fruit, branch or machine. The interaction of fruit during the harvesting process was more important, in terms of maximum acceleration, after the detachment event (527.6 m s-2) than before (401.0 m s-2). The use of a catch frame to collect fruit and of padding material in the machinery are fundamental measures to reduce the damage caused to fruit with canopy shaker technologie

Computational Model for the Dynamic Characterisation of a Trunk Shaker

The development of trunk shaker machines over the years has been based on test-error methods in field. Mathematical or computational models have been studied with great simplifications. This paper presents a method for modelling the dynamic behaviour of a trunk shaker with a test bench. Two mass configurations were used on the test bench as well as two different vibration frequencies on the trunk shaker. Acceleration values were recorded at different points of the system. The binomial shaker-post was computationally modelled, and its dynamic response was analysed based on a modal and transient study with a series of proposed simplifications. The results of the simulations were compared with experimentally recorded acceleration values. In both cases, a linear response to mass and frequency variation was observed in the acceleration that the shaker performed. There was a high correlation in the effective accelerations (error < 4%) between experimental and computational studies measured in the trunk shaker. However, there were higher errors when the post was used in the test in the post structure points. The greatest uncertainty in the model may lie in the assumption of contact between the attachment pad and the post, but if this is not carried out, it makes convergence in the computational calculations very difficult. The method has proved its worth in determining the dynamic behaviour of these machines

Estimation of the Cooling Rate of Six Olive Cultivars Using Thermal Imaging

Bringing the olive harvest period forward leads to storing fruit in field temperatures that risk jeopardizing its quality. Knowledge about the bio-thermal characteristics of olives is crucial when considering their cooling, although published research on the subject is limited. In this work, the cooling rate of the fruit of six olive cultivars has been empirically determined by measuring the evolution of their low temperature under controlled conditions by thermal imaging. Based on these data, the cooling time needed to cool the fruit to 22 °C was estimated, considering the biometric characteristics of the individual fruit, a field temperature from 26 to 42 °C, and a room cooling temperature from −8 to −20 °C. The results showed differences among the cultivars and the need to further investigate the specific heat requirements for small varieties and the impact of the conduction factor on the heavier ones. The simulation suggests that between 2 min (for the light Arbequina and Koroneiki cultivars) and 5 min (for the heavier Verdial and Gordal cultivars) suffice to cool the fruit to the desired temperature with a room temperature of −16 °C. These results show the feasibility of developing technological solutions for cooling olives before their industrial processing with industrial applications such as cooling tunnels on individual fruit

Fruit abscission pattern of ‘Valencia’ orange with canopy shaker system

Fruit detachment can occur due to natural causes or be mechanically performed by a combination of mechanical stresses that cause tissue breakage in the plant. Forced abscission should not coincide with natural abscission zones (AZ). Abscission zones are very important in citrus harvesting both in terms of the destination market and of the possible damage caused to the tree or fruit. The objective of this study is to determine the abscission pattern of sweet oranges with a canopy shaker and compare it with other detachment systems. Five plots of Valencia oranges were tested during the 2017 and 2018 harvesting seasons, using a commercial tractor-drawn canopy shaker. The diameter, weight and breakage type were evaluated in the cases of natural fall, snap method, mechanical harvesting with canopy shaker, and pull test. Breakage type AZ-C predominated in natural fall (89.0%) and the snap method (79.5%). Similarly, AZ-A predominated for the canopy shaker (58.8%) and pull test (45.3%). Mechanical action on the fruit produced peel tear by breaking the flavedo, which reached highest frequency in the snap method (7.6%). Peel tear breakage required a mean fruit detachment force value of 99.3 N, higher than the average abscission values for AZ-C (88.7 N) and AZ-A (66.6 N). The fruit that remained on the tree after canopy shaker harvesting showed lower mean values of fruit detachment force (16.3%) than the pre-harvest fruit. The frequency of fruit with calyx with the canopy shaker and snap methods was similar, with a mean value of 36%

Olive Crown Porosity Measurement Based on Radiation Transmittance: An Assessment of Pruning Effect

Crown porosity influences radiation interception, air movement through the fruit orchard, spray penetration, and harvesting operation in fruit crops. The aim of the present study was to develop an accurate and reliable methodology based on transmitted radiation measurements to assess the porosity of traditional olive trees under different pruning treatments. Transmitted radiation was employed as an indirect method to measure crown porosity in two olive orchards of the Picual and Hojiblanca cultivars. Additionally, three different pruning treatments were considered to determine if the pruning system influences crown porosity. This study evaluated the accuracy and repeatability of four algorithms in measuring crown porosity under different solar zenith angles. From a 14 to 30 solar zenith angle, the selected algorithm produced an absolute error of less than 5% and a repeatability higher than 0.9. The described method and selected algorithm proved satisfactory in field results, making it possible to measure crown porosity at different solar zenith angles. However, pruning fresh weight did not show any relationship with crown porosity due to the great differences between removed branches. A robust and accurate algorithm was selected for crown porosity measurements in traditional olive trees, making it possible to discern between different pruning treatments

Effect of temperature and time on oxygen consumption by olive fruit: Empirical study and simulation in a non-ventilated container

Fermentation processes within olive fruit jeopardize the quality of the extracted oil. Aera-tion, temperature, and time play a crucial role in attaining the critical threshold at which an aerobic respiration shifts towards anaerobic. In this work, the O2 consumption and CO2 production of olive fruit kept in a closed container at different temperatures (5–45◦ C) were measured over 7 h. The data allowed us to describe the relationship between the temperature and the respiration rate as an Arrhenius function and simulate the oxygen consumption in the inner part of a container full of fruit with low aeration, considering the generated respiration heat over time. The simulation revealed that olives risk shifting to anaerobic respiration after 3 h at 25◦ C and less than 2 h at 35◦ C when kept in a non-ventilated environment. The results underline the irreversible damage that high day temperatures can produce during the time before fruit processing, especially during transport. Lowering, as soon as possible, the field temperature thus comes to the fore as a necessary strategy to guarantee the quality of the olives before their processing, like most of the fruit that is harvested at excessive temperatures

In-Field Estimation of Orange Number and Size by 3D Laser Scanning

The estimation of fruit load of an orchard prior to harvest is useful for planning harvest logistics and trading decisions. The manual fruit counting and the determination of the harvesting capacity of the field results are expensive and time-consuming. The automatic counting of fruits and their geometry characterization with 3D LiDAR models can be an interesting alternative. Field research has been conducted in the province of Cordoba (Southern Spain) on 24 ‘Salustiana’ variety orange trees—Citrus sinensis (L.) Osbeck—(12 were pruned and 12 unpruned). Harvest size and the number of each fruit were registered. Likewise, the unitary weight of the fruits and their diameter were determined (N = 160). The orange trees were also modelled with 3D LiDAR with colour capture for their subsequent segmentation and fruit detection by using a K-means algorithm. In the case of pruned trees, a significant regression was obtained between the real and modelled fruit number (R2 = 0.63, p = 0.01). The opposite case occurred in the unpruned ones (p = 0.18) due to a leaf occlusion problem. The mean diameters proportioned by the algorithm (72.15 ± 22.62 mm) did not present significant differences (p = 0.35) with the ones measured on fruits (72.68 ± 5.728 mm). Even though the use of 3D LiDAR scans is time-consuming, the harvest size estimation obtained in this research is very accurate

Gamificación como instrumento para mejorar los indicadores docentes en asignaturas de ingeniería agroforestal

En cursos iniciales de asignaturas de ingeniería aplicada se produce una reducida asistencia y participación del alumnado en clase, minorando el rendimiento de este y promoviendo el absentismo en el examen final. El fomento de la motivación del alumno puede ser un factor determinante en dicho problema, pudiendo presentarse la gamificación como herramienta útil para tal fin. En este trabajo, como respuesta ante esta cuestión, se muestra el uso de una herramienta on-line que ofrece la posibilidad de realizar una prueba tras cada unidad didáctica. Con ello, el alumno puede autoevaluar su proceso de aprendizaje y, al mismo tiempo, el profesorado tiene la posibilidad de conocer la evolución individual de cada estudiante. Para incentivar su uso, se ofrece la opción de superar contenidos de la asignatura para mantener la calificación de parte de la nota, previa a su evaluación en la prueba final de la asignatura. La práctica docente se ha llevado a cabo en una asignatura troncal con 126 alumnos, de los que han participado 87. Los resultados indican que se ha incrementado la asistencia a clase y la retroalimentación y proactividad de los alumnos a través de tutorías, foros y preguntas con relación a los tres cursos académicos anteriores. La práctica propuesta no aumenta sustancialmente la carga de trabajo del profesorado y mejora la compresión y el aprendizaje del alumno, así como la superación de las pruebas escritas de la asignatura