高级检索+

梳齿耦合驱动式菊花采摘装置设计与试验

Design and experiment of comb-type coupled drive Chrysanthemum harvesting device

  • 摘要: 针对现有梳齿梳刷式菊花采摘设备存在漏摘严重、机具通过性不高、易损伤菊花等问题,该研究设计了一种梳齿耦合驱动式菊花采摘装置。该装置主要由旋转平动多排梳齿采摘机构、气缸驱动龙门升降系统和橡胶履带行走底盘等组成,通过脉宽调制(pulse width modulation)信号实时远程遥控前进速度与工作转速,并可实现无极调速,采摘动作顺序为植株分列插入-梳齿平动梳刷-旋转抛花收集。利用 Ansys-Adams对菊花-采摘装置进行联合仿真,探究了菊花破损机理,并求解菊花采摘脱落及机采破损的加速度阈值。通过三元二次回归组合田间试验建立试验因素与试验指标间数学模型,得出采摘装置最优参数组合为:梳齿间隙8.0 mm、前进速度0.13 m/s、工作转速21 r/min,此时采摘率为73.55%,含杂率为4.51%,破损率为2.88%,与原有样机相比,采摘率提升了2.55个百分点,含杂率、破损率分别降低了6.56和0.1个百分点,该梳齿耦合驱动式菊花采摘装置采摘效果良好,研究结果可为菊花机械化采摘提供理论及技术支撑。

     

    Abstract: Chrysanthemums (Chrysanthemum morifolium R.) can serve as one of the primary dual-purpose Chinese herbal medicines for both medicinal and edible applications. It is often the pressing demand for mechanical harvesting during production. The harvesting can directly determine both the quality and yield of chrysanthemum flowers. However, existing comb-brushing harvesters are limited to high missed-picking rates, low terrain adaptability, and flower damage. In this study, a comb-tooth drive device was designed for chrysanthemum harvesting. A systematic evaluation was also implemented on the chrysanthemum biomechanical properties using a universal testing machine. The results show that the chrysanthemums broke first at the stem under tensile or shear action. The tensile failure load of the stem was less than the shear load. Chrysanthemum picking machinery was required to minimize the damage and impurities for the high picking rate. A biomimetic structure was developed to compare the manual picking. The device consisted of a multi-row comb picking mechanism with the rotary-translational motion, a cylinder-driven gantry lifting, and a rubber crawler chassis with high soil viscosity in the chrysanthemum fields. Theoretical analysis and calculation showed that the structure and working parameters of the key components were obtained, such as the eccentric wheel transmission mechanism and picking comb teeth, as well as the required power for picking. The structural parameters of the picking comb teeth were verified after static simulation. The relationship between picking, working, and forward speed was determined in the picking trajectory. Real-time remote control of the forward and working rotation speed was realized using pulse-width modulation signals. The harvesting action was decomposed into three procedures: "plant separating and inserting, comb translational brushing, rotating flower throwing, and collecting". The better performance of this device was twofold. 1) Its comb teeth shared less impact, and then effectively reduced the collision damage to chrysanthemums, when inserted into the plants, compared with the existing comb-tooth circular rotation and shearing picking mechanisms; 2) Its picking trajectory also exhibited a larger longitudinal range, in order to effectively reduce the missed picking. A lifting system was equipped to improve the adaptability of the picking mechanism. The picking height was adjusted for the different chrysanthemum heights in order to effectively reduce the missed harvesting. There was a minimal forward thrust exerted by the picking component on the plant. The low-impact force was also generated by the comb teeth penetrating into the chrysanthemum plant. The Ansys-Adams module was used to simulate the interaction between chrysanthemums and machines. A systematic investigation was carried out to determine the damage mechanism of chrysanthemum harvesting. The critical acceleration was 4.49×106 mm/s2 for the chrysanthemum picking and shedding. While the damage acceleration threshold was 1.125×107 mm/s2. Simulation test showed that the optimal working speed was conducive to chrysanthemum picking. The optimal range of working speed was determined for the selection. Quadratic regression orthogonal models were established between field experimental and performance indicators. The optimal combination of the parameters was identified: comb tooth clearance of 8.0 mm, forward speed of 0.13 m/s, and picking speed of 21 r/min. The better performance was achieved in a picking rate of 73.55%, an impurity content of 4.51%, and a damage rate of 2.88%. This comb-tooth drive device can provide the theoretical and technical support for the mechanical chrysanthemum harvesting.

     

/

返回文章
返回