Design and evaluation of a two-section canopy shaker with variable frequency for mechanical harvesting of citrus

Pu, Yingjun; Toudeshki, Arash; Ehsani, Reza; Yang, Fuzeng

doi:10.25165/j.ijabe.20181105.4445

Cited by 20 publications

(20 citation statements)

References 23 publications

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“…Using this information, they could potentially make modifications to improve the shaking mechanism or shaking pattern to achieve higher fruit removal during harvest. e improved shaking performance also has the potential to reduce branch breakage and bark and tree damage, which often result in decreased production in subsequent years [7,8]. In addition, improving shaking performance will increase the energy efficiency of a mechanical trunk shaker, resulting in lower operating costs.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study and Mathematical Modeling of Vibration Transfer in Pistachio Trees Using an Inertia-Type Trunk Shaker and Field-Adapted Wireless Sensors

Homayouni

Toudeshki

et al. 2022

Shock and Vibration

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Trunk shakers are the most widely used mechanical harvesting machines for harvesting nut trees, including pistachio in California. Improvement of these machines requires a better understanding of the shaking dynamics of the existing trunk shakers during harvest. In this study, the effects of four different shaking patterns on three sizes of pistachio trees of different ages, shapes, and sizes were investigated under field conditions. The vibration acceleration of the real pistachio tree was measured using a wireless network of 3-axis accelerometers installed on the shaker head and different parts of the trees during the shaking harvest. Changes in acceleration and the effect of tree morphology on the magnitude of acceleration in each pattern are presented and discussed. A new location index λ, which is based on the distance of the sensor from the shaking point and diameter of the branch at each sensor location, is introduced. This study focused on mathematical modeling of the variation and distribution of the acceleration throughout the tree canopy. The sensor location index, relative force ratio (RFR), and relative kinetic energy ratio (RKER) were defined to better understand the energy damping in each part of the tree. The results showed that the relationship between the acceleration peaks and the sensor location index could be expressed by a third-degree polynomial function with an acceptable coefficient of determination. Under different shaking patterns, similar changes in the RFR of the tree at different locations and for different trees were observed. This finding indicates that the vibration force is significantly damped as the distance from the shaker clamps increases. However, the RKER values at the same shaking pattern result in different effects at different points on the branches according to tree morphology.

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Section: Introductionmentioning

confidence: 99%

An Experimental Study and Mathematical Modeling of Vibration Transfer in Pistachio Trees Using an Inertia-Type Trunk Shaker and Field-Adapted Wireless Sensors

Homayouni

Toudeshki

et al. 2022

Shock and Vibration

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“…The comb fingers may beat the branches as well, which causes the branches to vibrate and the fruit or flower bud on the branch will vibrate consequently. When the inertia force of the fruits is greater than the binding force, the fruits are detached [26,27] .…”

Section: Figure 5 Force Analysis Diagram Between the Fruit And Fingersmentioning

confidence: 99%

Design and experiment of the comb-brush harvesting machine with variable spacing for oil-tea camellia fruit

Shen

Zhao

et al. 2021

International Journal of Agricultural and Biological Engineering

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Oil-tea camellia tree is an important oil plant in China that has long flexible branches. The most challenging feature for the mechanized harvest of oil-tea fruits is that its flower and fruit grow synchronously. In order to improve the harvesting efficiency and avoid damaging the flower bud, a hand-held fruit harvesting machine with a variable spacing comb brush was proposed. The harvesting machine can generate three kinds of actuation to detach fruit when it runs. The main actuation results from the brushing of multiple comb fingers. The other two kinds of actuation result from the beating of comb fingers on the fruits and the branches. The finger spacing of the comb brush can be adjusted consequently through moving the spacing adjusting crossbar. Hence, when the finger spacing is smaller than the diameter of the oil-tea fruit, the fruit is brushed off, but the flower bud and leaf pass through the finger gap. When the finger spacing is bigger than the fruit diameter, the fruit stuck between the fingers is loosened to ensure the continuous operation of the machine. Nylon was used as the material of the brush finger to avoid damage, which can also reduce the overall weight. The dynamic simulation of the harvesting machine was carried out with ADAMS, and the acceleration of the front end of the comb finger and the variation of the finger spacing were analyzed. The prototype of the harvesting machine was built and tested in the field. Field experiment results showed that when the speed of the comb finger drive shaft was 480 r/min, the average harvesting percentage of oil-tea fruit was 80%, and the flower bud was seldom detached, which met the working requirements of oil-tea fruit harvesting.

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“…Mechanical vibrations can be used as an option for the process of removing the fruit from the rachilla, either in a biofuel plant or during harvesting. Like other fruits, such as coffee, olive and citrus [4][5][6] etc., the modal properties, natural frequencies, and modes of vibration of the fruit-rachilla system are the basic data required to develop equipment employing mechanical vibrations to harvesting.…”

Section: Introductionmentioning

confidence: 99%

Modal properties of fruit-rachilla system of the macaw palm

et al. 2021

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The macaw palm has been domesticated due to its potential use in the production of biofuel, in addition to several co-products that can be generated from its oil and pulp. One of the current challenges in this area is the harvesting, as there are no specific machines for this operation. Therefore, it is necessary to determine the appropriate information regarding the physical properties of the plant, so that it is feasible to develop the technologies necessary for the commercial scale application of macaw palm, allowing it to contribute to the sustainable production of raw material for the biofuel industry and other co-products. The principle of mechanical vibration can be used to shed fruit from trees when ripe, and it can be a method used for harvesting. Thus, as proposed in this study, it was necessary to study the dynamic behavior of the fruit-rachilla system during vibration. Hence, the modal properties of the system were determined. A study on the dynamic behaviors was carried out using a deterministic finite element model, and the natural frequencies were obtained through a frequency-scanning test to evaluate the model. The mean relative error (MRE) between the measured and simulated natural frequencies was also used to evaluate the model. The natural frequencies, determined experimentally, varied from 26.21 to 33.45 Hz on average, whereas the simulated frequencies varied from 24.81 to 39.27 Hz. The overall MRE was 9.08%. Once the model was validated, a sensibility test was carried out, which showed that the density of fruit and the elasticity modulus are the parameters that most influence the natural frequencies of the fruit-rachilla system.

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Design and evaluation of a two-section canopy shaker with variable frequency for mechanical harvesting of citrus

Cited by 20 publications

References 23 publications

An Experimental Study and Mathematical Modeling of Vibration Transfer in Pistachio Trees Using an Inertia-Type Trunk Shaker and Field-Adapted Wireless Sensors

An Experimental Study and Mathematical Modeling of Vibration Transfer in Pistachio Trees Using an Inertia-Type Trunk Shaker and Field-Adapted Wireless Sensors

Design and experiment of the comb-brush harvesting machine with variable spacing for oil-tea camellia fruit

Modal properties of fruit-rachilla system of the macaw palm

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