Dairy industry is an economic and efficient livestock husbandry, and it is also an important component of modern agriculture. The healthy development of dairy industry is of great significance for improving the structure of agriculture, for improving the living standards of the people and for promoting the development level of animal husbandry and breeding industry. In recent years, with the rapid development of all sectors of society, people's living standards are improved; the demand for dairy products and quality requirements are increasing. However, the traditional way of artificial feeding has been unable to meet the needs of rapid development of large scale dairy farms, and scientization, intelligence and automation for cow feeding process have become an inevitable trend. Therefore, for the feeding status of concentrate for dairy cattle, a feeding device based on equal diameter and dual-spiral precision feeding is designed in this paper, which can achieve the accurate supply of concentrate according to the demand of individual cow feeding. The device is mainly composed of a storage bunker, a dual-spiral feeding device and a control system, and the 2 kinds of screw pitches of the dual-spiral feeding device are 40 and 70 mm, respectively. The screw auger device of 70 mm pitch is used to improve the feeding efficiency of the device. And the screw auger device of 40 mm pitch is used to improve the feeding accuracy. By combining the screw auger devices of big pitch and small pitch, the feeding of pellet feed can be quickly and accurately completed within a specified time. The specific work process is as follows: When feeding the target quantity, start both of the material supply ways at the same time; when 80% is completed, stop the screw auger device of big pitch (70 mm pitch), and the screw auger device of small pitch (40 mm pitch) continues to feed until achieving target feed delivery. In the process of design and research, the main structure parameters of the pellet feed feeding device are designed. The dual-spiral feeding device is modeled by using Solidworks software, and EDEM (enhanced discrete element method) software is used to simulate the feeding process of the screw auger devices of 40 and 70 mm at different rotating speeds (80, 100 and 120 r/min) respectively. The results showed that the variation coefficient of the screw auger device of 40 mm pitch was 0.0522 when the rotation speed was 120 r/min, the variation coefficient of the screw auger device of 70 mm pitch was 0.1052 when the rotation speed was 100 r/min. In order to further verify the simulation results, a cow feeding device based on equal diameter and dual-spiral precision feeding was set up. Feeding speed stability index was described by variation coefficient, relative error was used to evaluate feeding precision index, and feeding performance test of the screw auger devices of 40 and 70 mm pitch was carried out. The feeding speed was measured at 5, 8 and 10 s in different rotation speeds, and the repetition experiment was carried out 10 times. The results showed when the rotation speed of the screw auger device of 40 mm pitch was 120 r/min and that of the screw auger device of 70 mm pitch was 100 r/min, the feeding stability was the best. The experimental results are consistent with the simulation results. On the basis of the feeding stability of the verification device, the feeding accuracy was tested. The screw auger devices of 40 and 70 mm pitch cooperate in different working speeds, feeding accuracy is not less than 95%; when the rotation speed of the screw auger device of 40 and 70 mm pitch is 120 and 100 r/min, respectively, the feeding time is 14.1 s, the actual feeding quantity is 6.009 kg, and the device feeding accuracy is not less than 99.835%. The results conform to the requirements of the cow precise feeding for efficiency and precision.%奶牛精确饲喂技术的实施不仅能够促进奶牛业健康发展,而且还能够提高牛场经济效益.基于牛场现状,该文在设计的等径双螺旋精确给料的奶牛饲喂装置基础上,理论分析了物料输送速度与给料时间,通过Solidworks对双螺旋给料装置进行了三维建模,并利用EDEM软件分别对40 mm搅龙和70 mm搅龙不同转速(80、100及120 r/min)的给料过程进行了离散元仿真,分析了装置给料稳定性,结果表明,40 mm搅龙在转速为120 r/min时变异系数为0.0522,70 mm搅龙在转速为100 r/min时变异系数为0.1052,给料稳定性最优.为进一步验证仿真结果,在搭建的双螺旋给料饲喂装置上,对40 mm搅龙和70 mm搅龙进行了给料试验,试验结果显示,40 mm螺距搅龙转速120 r/min和70 mm搅龙转速100 r/min时给料稳定性最优,试验结果与仿真结果吻合.在验证装置给料稳定性基础上,对给料精度进行了试验,结果显示:40 mm搅龙和70 mm搅龙在80、100、120 r/min等不同工作转速组合下,给料精度均大于95%,当40 mm搅龙转速为120 r/min,70 mm搅龙转速为100 r/min时,给料时间为14.1 s,给料量为6.009 kg,装置给料精度不低于99.835%,符合奶牛精确饲喂效率与精度要求.
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