Harvesting technologies for Chinese jujube fruits: A review

Vibratory harvesting is the primary method used to harvest red jujubes. This study aimed to improve the efficiency of vibratory harvesting for red jujubes and identify the optimal parameters for harvesting at different jujube tree diameters. A model for the forced vibration dynamics of jujube trees was established, and a three-dimensional model was constructed for different diameter variations. A kinematic simulation analysis was then conducted to determine the inherent frequency and modal vibration patterns of jujube trees. Harmonic response analysis was performed to study the displacement and acceleration responses of jujube trees with different diameters to different vibration factors. Subsequently, vibration tests were carried out on the jujube trees. The results showed that the vibration characteristics of trees with different diameters were distinct at each vibration order, and the maximum number of vibrating branches differed at different orders of vibration. The vibration frequency ranges for vibration harvesting of jujube trees with 30 mm, 50 mm, and 70 mm diameters were determined as 4–30 Hz, 6–25 Hz, and 17–29 Hz, respectively. Furthermore, the study obtained the optimal vibration parameters for jujube trees by establishing the regression equations of harvest rate and each vibration factor. For jujube trees with a diameter of 30 mm, the optimal parameters included a vibration frequency of 30 Hz and a vibration amplitude of 15 mm. For jujube trees with a diameter of 50 mm, the optimal parameters included a vibration frequency of 18.55 Hz and a vibration amplitude of 12.52 mm. Lastly, for jujube trees with a diameter of 70 mm, the optimal parameters included a vibration frequency of 6 Hz and a vibration amplitude of 15 mm. This study provides a theoretical foundation and technical support for improving the efficiency of vibratory harvesting and identifying the optimal vibration harvesting parameters for jujube trees with different diameters.

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“…The differential equation for the forced vibration of the jujube tree, Equation (8), is obtained by collapsing Equation (7):…”

Section: Principle Of Vibration Harvesting Of Red Jujubementioning

confidence: 99%

“…Vibratory harvesting is a method of harvesting crops that involves applying mechanical vibrations to the branches of fruit trees to cause them to vibrate and facilitate fruit removal [8]. This method has been widely adopted for harvesting various crops.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Vibration Parameters for Red Jujube Trees with Different Diameters

Chen

Qiao

Feng

et al. 2023

Forests

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“…Still with the aim of keeping a high-quality level of the harvested fruits, another crucial operation is the correct execution of storing operations [51], which are seen as inseparable from the harvesting process as a whole. Contextually, the separated foreign materials have to follow a different flow [52], and some of them need restoring in correct waste management practices.…”

Section: Definition Of the Industrial Domain And Presentation Of The ...mentioning

confidence: 99%

From the Extraction of Currently Fulfilled Requirements to Value Curves: A Case Study in the Field of Harvesting Machines for Shell Fruits and Lessons Learnt in Engineering Design

2020

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The market for agricultural machinery is characterized by products with a high degree of maturity in the product life cycle. Consequently, current improvements in new machinery are predominantly incremental and new projects basically use solutions that are already consolidated. This makes this domain appropriate for benchmarking existing systems and envisioning new value propositions. The present paper deals primarily with the former and uses the value curves as a means to structure the comparison among different families of technical systems; in particular, harvesting machines for shell fruits from the ground surface, e.g., chestnuts, walnuts, and hazelnuts, were investigated here. The process of building value curves requires the identification of currently fulfilled requirements. Despite the attention paid by engineering design research to requirements, a structured process is lacking to extract relevant information and create value curves or other representations useful for benchmarking. The present paper approaches this problem and presents how the authors have individuated relevant knowledge for characterizing different categories of harvesting machines. Namely, after an extensive search of the scientific literature and patents, a critical review of existing machines, aimed at individuating their functioning principles, architecture, and attitude in fulfilling specific design requirements, was performed. Then, existing machines were classified in 8 main categories, and their strengths and weaknesses were identified with reference to 11 competing factors. The consequent construction of value curves enabled the identification of possible points of intervention by hypothesizing possible future evolutions of such machinery, both in a structural and in a value-based perspective. Limitations about the repeatability of the followed approach and possible repercussions on design research are discussed.

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“…Vibratory harvesting machines are efficient and stable, which makes them suitable for harvesting jujubes in large areas. However, they can also cause damage to the tree trunks [10]. On the other hand, air-suction harvesting machinery uses the negative pressure effect generated by airflow to adsorb and collect jujubes from the trees into the machine's container.…”

Section: Introductionmentioning

confidence: 99%

Research and Validation of Vibratory Harvesting Device for Red Jujube Based on ADAMS and ANSYS

Feng

Qiao

et al. 2023

Agriculture

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The mechanization of red jujube industry is a high-potential agricultural research field in China. In this study, a vibration harvesting device has been developed for jujube trees that features adjustable vibration frequency and amplitude. The device is designed to make jujube trees vibrate with varying diameters by utilizing different vibration frequencies and amplitudes according to the tree’s size such that jujubes can be harvested efficiently. The study completed the structural design of excitation and fruit collection mechanisms based on the working principle of vibration harvesting. The red jujube excitation mechanism was dynamically simulated using ADAMS, and it was found that the acceleration at the end of the vibration rod of the mechanism had a tendency to sharply increase and decrease, which was conducive to the vibration shedding of red jujube. A collision model between the red jujubes and the fruit collection umbrella was constructed, and the fruit collection mechanism was structurally simulated using ANSYS. The tests showed that the device effectively harvested red jujubes from nine types of jujube trees with diameter ranges of 29.15–31.26 mm, 49.56–52.34 mm, and 65.23–73.25 mm. The average net harvesting rates were 93.98%, 94.71%, and 94.33%, and the average fruit collection efficiencies were 95.78%, 89.43%, and 85.04%, respectively. These results demonstrate the effectiveness of the excitation and collection mechanisms and provide a theoretical basis for the development of vibratory harvesting devices for red jujubes.

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Harvesting technologies for Chinese jujube fruits: A review

Cited by 9 publications

References 15 publications

Optimization of Vibration Parameters for Red Jujube Trees with Different Diameters

Optimization of Vibration Parameters for Red Jujube Trees with Different Diameters

From the Extraction of Currently Fulfilled Requirements to Value Curves: A Case Study in the Field of Harvesting Machines for Shell Fruits and Lessons Learnt in Engineering Design

Research and Validation of Vibratory Harvesting Device for Red Jujube Based on ADAMS and ANSYS

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