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Vibratory harvesting technology research for fresh market sweet cherry.

机译：新鲜市场甜樱桃的振动收获技术研究。

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摘要

As labor cost keeps rising and labor availability remains increasingly uncertain, growers are seeking for mechanical harvesting solutions for tree fruit production. The goal of this research was to develop suitable vibratory harvesting technologies for fresh market sweet cherry to achieve high harvest efficiency and low fruit damage. The major objectives were to investigate the effect of shaking frequency, duration and excitation position on fruit removal and damage.;To fulfill the goal, different prototypes of vibratory harvesting system were fabricated. The resonant frequencies of cherry trees were identified through analyzing their dynamic response to vibratory excitation. Experiments also showed that the majority of vibratory energy was transmitted to the excitation limbs, which could benefit the fruit catching.;To find out the suitable shaking frequency and duration to achieve high fruit removal efficiency, harvesting tests were conducted in field condition. It was found that different combination of shaking frequency and duration had a big influence on fruit removal efficiency. The maximum fruit removal efficiency of 81% was achieved at 18 Hz with a 5-s shaking duration in total shaking time of 20 s. Among the fruit remaining on trees, over 60% were growing on long and slender twigs, which suggest that a proper pruning could increase the fruit removal efficiency. Additionally, excitation at different positions of a limb also resulted in different fruit removal efficiencies, which varied between 51 and 83% when a limb was excited in one position. It is also estimated that up to 97% of fruit could be removed if limbs were excited at two locations. The damage rates of harvested fruit were approximately 10% higher than that of handpicked fruit, but the rate was not affected by excitation positions.;The fruit trajectory and damage source under vibratory excitation at different shaking frequencies were analyzed using high-speed camera images. It is found that detaching time of each fruit was closely related to its average kinetic energy, which resulted in higher harvesting efficiency at higher shaking frequency. Test results revealed that high fruit damage level at high shaking frequency was mainly caused by repeated high-intensity impacts on limbs.
机译：随着劳动力成本的不断上涨以及劳动力供应的不确定性越来越大，种植者正在寻求用于树果生产的机械收割解决方案。这项研究的目的是为新鲜的市场甜樱桃开发合适的振动收获技术，以实现高收获效率和低水果损害。主要目的是研究振动频率，持续时间和激发位置对水果去除和损伤的影响。为了实现这一目标，制造了不同的振动收获系统原型。通过分析樱桃树对振动激发的动态响应来确定其共振频率。实验还表明，大部分的振动能量传递给了激励肢体，有利于果实的捕获。为了找出合适的摇动频率和持续时间以达到较高的去除水果效率，在田间条件下进行了收获试验。结果发现，不同的振动频率和持续时间的组合对水果的去除效率有很大的影响。在18 Hz的条件下，以5 s的振动持续时间达到20 s的总振动时间，最大去除水果效率为81％。在树上剩余的果实中，超过60％的果实生长在细长的树枝上，这表明适当的修剪可以提高果实的去除效率。另外，在肢体的不同位置激发还导致不同的水果去除效率，当在一个位置中激发肢体时，水果去除效率在51％至83％之间变化。据估计，如果在两个位置兴奋肢体，最多可以去除97％的水果。收获的果实的损伤率比手工采摘的果实高约10％，但损伤程度不受激发位置的影响。;利用高速相机图像分析了不同振动频率下振动激发下的果实轨迹和损伤源。研究发现，每种水果的脱落时间与其平均动能密切相关，从而在较高的振动频率下具有较高的收获效率。测试结果表明，在高振动频率下较高的水果损伤水平主要是由于反复对肢体施加高强度冲击造成的。

著录项

  • 作者

    Zhou, Jianfeng.;

  • 作者单位

    Washington State University.;

  • 授予单位 Washington State University.;
  • 学科 Engineering Mechanical.;Agriculture Horticulture.;Engineering Agricultural.
  • 学位 Ph.D.
  • 年度 2014
  • 页码 128 p.
  • 总页数 128
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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