基于柔性梳脱的酿酒葡萄脱粒机理与装置的研究

发布时间：2018-01-18 09:46

本文关键词：基于柔性梳脱的酿酒葡萄脱粒机理与装置的研究　出处：《中国农业大学》2017年博士论文　论文类型：学位论文

【摘要】：针对我国酿酒葡萄完全依赖人工采摘,效率低、成本高的问题,为实现酿酒葡萄机械化采收,本文深入研究了葡萄串梳脱机理,以优化脱粒装置,提高脱净率和降低破损率。通过对葡萄动力学参数的测试分析,建立了葡萄串脱粒的仿真模型,通过脱粒仿真为脱粒装置设计和分析提供参考。通过在试验台上进行正交试验、对比试验和高速摄影观察分析,研究各参数对脱粒效果的影响,获得了柔性梳脱的最优方案。本文主要结论如下:1.针对葡萄果实静摩擦系数、动摩擦系数和葡萄碰撞恢复系数、果肉粘弹性参数、葡萄果实与果梗之间断裂特性,搭建试验台并进行了测试分析,为建立葡萄仿真模型提供基础物理参数。2.建立了果实的粘弹性碰撞仿真模型,进行了仿真与实际碰撞试验对比分析,结果表明,碰撞速度不大于1 m/s时,仿真模型误差较小。建立了葡萄果实与果梗之间断裂的FBM模型,仿真断裂与实际断裂数据进行对比,仿真模型结果误差在可接受范围内,且随着拉断角度增加而增加。基于Python对葡萄串模型进行快速和批量建模,提高建模效率。3.进行了柔性脱粒装置的台架试验研究。研制了柔性梳脱式酿酒葡萄脱粒试验台,进行以对辊转速、对辊间距和弯曲刚度为三因素的正交试验,试验结果表明,对于指标脱粒时间和破损率,弓齿抗弯刚度是唯一的显著性因素,最佳对辊转速为160r/min,抗弯刚度为0.067 N·m2,对辊中心距离为280 mm,该条件下脱粒时间为1.73 s,破损率为3.51%。在以上试验基础上,研制了酿酒葡萄篱架梳脱运动试验台,进行对辊转速、行进速度和弓齿螺旋角三因素的正交试验,试验结果确定了影响脱净率的显著因素为对辊转速和行进速度,对辊转速从200 r/min增加到300 r/min时,脱净率从75%提升到92.3%,行进速度从0.4 m/s提升到0.7 m/s时,脱净率从93%降低到78%,3个因素对于葡萄破损率均不显著,破损率约为20%左右。研发了板齿式和锯齿式酿酒葡萄脱粒装置,通过弓齿式、板齿式和锯齿式3种脱粒装置性能对比试验,在0.4 m/s和0.5 m/s的行进速度下,3种脱粒装置的脱粒能力依次增强,锯齿式则脱粒能力最强,弓齿式和板齿式的破损率随着进行速度的增加而增加,且板齿式较弓齿式的破损率要低,锯齿式的破损率最低,保持在较低的7.5%左右。通过对3种脱粒装置脱粒过程高速摄影分析,结果表明,锯齿式脱粒装置的脱粒能力最强,为将来的柔性脱粒装置研究提供了更优的方案。4.研制了脱粒试验台的基于PLC的自动对行避障系统,试验证明可以稳定可靠地进行对行避障,上位机能够实现对脱粒过程的各个参数的监控和手动操作。
[Abstract]:In order to realize the mechanization of wine-grape harvesting, this paper studied the off-line principle of grape string in order to optimize the threshing device in order to solve the problem that wine-grape is totally dependent on artificial picking, low efficiency and high cost in order to realize the mechanization of wine-grape harvesting. By testing and analyzing the dynamic parameters of grape, the simulation model of grape string threshing was established. Through threshing simulation to provide a reference for the design and analysis of threshing device. Through orthogonal test on the test bench, contrast test and high-speed photographic observation and analysis, study the effect of each parameter on threshing effect. The main conclusions are as follows: 1. Aiming at the static friction coefficient of grape fruit, the dynamic friction coefficient and the coefficient of grape collision recovery, and the visco-elastic parameters of pulp. In order to provide the basic physical parameters for grape simulation model, a viscoelastic collision simulation model of grape fruit was established. The results showed that the error of the simulation model was small when the impact velocity was less than 1 m / s. The FBM model of grape fruit and stem fracture was established. Compared with the actual fracture data, the error of the simulation model is within the acceptable range and increases with the increase of the breaking angle. Based on Python, the grape string model is modeled quickly and in batches. To improve the modeling efficiency. 3. The bench test of flexible threshing device was carried out. The flexible comb-de-wine grape threshing test bench was developed, and the roll speed was checked. The results show that the bending stiffness of arch teeth is the only significant factor for the threshing time and breakage rate. The optimum rolling speed is 160 r / min, the bending stiffness is 0.067 N 路m ~ 2, the distance to the center of the roll is 280 mm, and the threshing time is 1.73 s. The breakage rate is 3.51. On the basis of the above tests, a wine-making grape hedgerow carding motion test bench was developed. The orthogonal test was carried out on the three factors of roll speed, travel speed and spiral angle of arch teeth. The experimental results show that the significant factors affecting the removal rate are the rotation speed and travel speed of the opposite roll, when the rotation speed of the opposite roll is increased from 200 r / min to 300 r / min. When the removal rate increased from 75% to 92.3am, and the travel speed increased from 0.4 m / s to 0.7 m / s, the removal rate decreased from 93% to 787.The three factors were not significant for the grape breakage rate. The breakage rate is about 20%. The bead gear and sawtooth threshing device were developed. The performance of three kinds of threshing units were compared by bow tooth type, plate tooth type and saw tooth type threshing device. At the speed of 0.4 m / s and 0.5 m / s, the threshing ability of the three kinds of threshing devices increased in turn, while the sawtooth type was the strongest. The breakage rate of bow tooth type and plate tooth type increases with the increase of speed, and the damage rate of plate tooth type is lower than that of bow tooth type, and that of sawtooth type is the lowest. The results showed that the sawtooth threshing device had the strongest threshing ability. It provides a better scheme for the research of flexible threshing device in the future. 4. The automatic obstacle avoidance system based on PLC has been developed on the threshing test bench, and it has been proved that the system can avoid obstacles stably and reliably. The upper computer can realize the monitoring and manual operation of each parameter of threshing process.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S225.93

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