为了实现枸杞机械化采摘，该文研究了枸杞振动采摘机理，并建立振动采摘力学模型，分析求解得到枸杞挂果枝条受迫振动时各节点处枸杞和花朵所受惯性力的通解。运用 MATLAB 对振动式枸杞采摘机工作参数进行优化和仿真试验，优化得到合理的迫振载荷和驱动轮转速组合，仿真试验得到受迫振动枸杞挂果枝条各节点处枸杞与花朵所受采摘惯性力随转速变化规律仿真曲线，对转速取值进行调整。最后进行了枸杞采摘试验，试验得到合理的驱动轮转速为2870 r/min，该转速水平在仿真得到的合理的转速区间为2868.84～2871.21 r/min。试验转速为2870 r/min时，成熟枸杞采摘效率为815颗/min，成熟枸杞采净率为86.70%，未成熟枸杞采摘率为7.36%，花朵采摘率为7.43%，成熟枸杞损伤率为8.62%，机采人采效率比为5.43，试验结果与仿真结论一致。研究结果可为枸杞振动采摘机的研制提供参考。%Recently, as scientific research has been further explored, the health care functions of theLycium barbarum (L. barbarum) in anti-oxidation, anti-aging, anti-fatigue, protecting liver, improving body immunity, eye protection and other aspects have been further confirmed. Its unique and nutrient-rich health function is recognized gradually in western countries, and the market demand of theL. barbarum is expanding each year. TheL. barbarum blooms and bears fruit continuously during the growing season which begins in mid-May. Depending on the picking time around the year, theL. barbarum fruit can be divided into spring, summer and autumn fruit. In order to make driedL. barbarum keep good commodity characters, the L. barbarum is harvested at 80 percent maturity. The full bearing period ofL. barbarum is from May to September every year, which is the picking peak ofL. barbarum. It must be picked once about every 7 days. For centuries, the mechanized harvesting ofL. barbarum has been a tough problem. Its harvesting has been artificial, which brings about low picking efficiency and high harvesting costs. With the continuous expansion ofL. barbarum acreage, fruit picker has been increasingly scarce, which will be followed by rising picking costs. It’s no doubt that the picking has become the bottleneck restricting the development of L. barbarum industry. Aiming at realizing the harvesting mechanization ofL. barbarum and establishing the theoretical guidance and design basis for theL. barbarum picking machine, the vibration picking mechanism ofL. barbarum plant’s fruiting branches in picking was studied, the parameter optimization and simulation analysis was done to determine exciting force vector and rotational speed of driving wheel, and an experiment was conducted to prove the obtained rotational speed of driving wheel in this paper. First, we analyzed the working principle of the picking machine to get the vibration picking mechanism. The fruiting branches’ model was simplified and theL. barbarum plant’s fruiting branches’ physical model and mathematical model were got, which were solved by equation solutions. We then obtained the forced vibration response of the fruiting branch and the forced vibration picking inertia force exerted on ripe and unripe fruits and flowers on each node. Second, 10L. barbarum trees were selected as the test samples. We measured the binding force and mechanical parameters of theL. barbarum and fruiting branches, such as the number of ripe and unripe fruits and flowers, diameter, length, elastic modulus, damping ratio of fruiting branches, and node number. Based on the principle of successful picking which is the ripe can be picked and the other parts wouldn’t be picked, the parameters were optimized, and the inertia force changes of the fruits and flowers with rotational speed were simulated with the MATLAB software. Simulation results showed the reasonable rotational speed was 2 868.84-2 871.21 r/min. Finally, rotational speeds of 7 levels which came from the interval and beyond the interval were selected in the experiment. Using a self-developed experimentalL. barbarum picking machine, the test was conducted at planting base ofL. barbarum of Ningxia Academy of Agriculture and Forestry Sciences, and the fruit distribution before and after picking was compared. Experiment result showed that reasonable rotational speed was 2 870 r/min, which is within the reasonable simulation interval of rotational speed. Under this rotational speed, picking efficiency of ripeL. barbarum was 815 grains per minute, the picking rate of ripe fruit was 86.70%, the picking rate of unripe fruit was 7.36%, and the picking rate of flower was 7.43%. The damage rate of fruit was 8.62%. The efficiency ratio of machine to worker was 5.43. Due to the actual picking environment, this result differs from simulation conclusion that the ripe is picked totally and none of the unripe and flowers is picked. The results can provide a reference for the development ofL. barbarum vibration picking machines.
展开▼
