Nanjing Research Institute of Agricultural Mechanization Ministry of Agriculture

Nanjing, China

Nanjing Research Institute of Agricultural Mechanization Ministry of Agriculture

Nanjing, China

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Ni Y.,Nanjing Research Institute of Agricultural Mechanization Ministry of Agriculture | Jin C.,Nanjing Research Institute of Agricultural Mechanization Ministry of Agriculture | Liu J.,Nanjing Research Institute of Agricultural Mechanization Ministry of Agriculture
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015

Plug seedlings transplanting, which has comprehensive benefits including high and stable yield, climate compensation and improving land utilization, is an important part in the process of dry land crops production. At present, the crops, such as maize, sugar beet, rapeseed, cotton, tobacco and vegetables, apply dry land seedlings transplanting in China, with total planting area of nearly 50 million hm2 in 2014 which goes in advance in the world. At the same time, semi-automatic transplanting machine is the main equipment for dry land crops transplanting domestically, and the work of picking up and delivering seedlings is finished manually. It results in high-intensive labor and high producing cost. Aiming at some existing problems in China, such as low level of automation in vegetable transplanter and high rate of injuries during picking up and delivering seedlings, a system for picking up and delivering seedlings in automatic transplanter is designed in this paper. In this tester, step mechanism is used to realize the vertical and horizontal movement of plug seedlings, row type of seedlings pushing up mechanism and clamps are adopted to implement the work of pushing up and clamping plug seedlings, and seedlings catching, seedlings stirring up, seedlings delivering, seedling dropping mechanism, etc. are applied to finish the task of delivering plug seedling from bowl plate to transplant instruments. During the whole operation all actions of the system are finished through the programmable logic controller (PLC), which controls pneumatic cylinders and hydraulic motors. Theoretical analysis and MATLAB simulation have been done, and the results show optimum working pressures of 2 drive cylinders which drive seedlings pushing up mechanism and control the opening-closing of clamps' clamping piece are 0.2-0.4 and 0.1-0.3 MPa respectively for pepper seedlings. In order to verify optimization results, single-factor experiment is carried out respectively. The results show that the optimal working pressure of the drive cylinder driving seedlings pushing up mechanism is 0.4 MPa and that of the drive cylinder controlling the opening-closing of clamps' clamping piece is 0.25 MPa. The functional relationship among 3 parameters which are the frequency of picking up seedlings, the speed of delivering seedlings, and the forward speed of transplanting machine are obtained through theoretical analysis. Besides, levels of these 3 factors are optimized, the 4 groups of best combinations of the factors are achieved, and orthogonal experiment is conducted, in which experimental indices are missing ratio of seedling transplanting, seedling repeated planting ratio, seedling lodging ratio, and seedling damage ratio. Using an experimental automatic vegetable high-speed transplanting machine cooperatively developed by College of Mechanical Transportation of Xinjiang Agriculture University, the experiment is conducted in the farm of Regiment 22, Division 2 of Xinjiang construction Corps in Hejing County, Xinjiang. Pepper seedlings which come from the farm of Toudun river, Urumqi, Xinjiang serve as the test sample. The age of seedlings is 52 days, and their plant height is 142 mm. Through analysis on the experiment result, it reflects that the system achieves the best quality of seedlings picking up and delivering when the frequency of picking up seedlings is 7 times/min, the speed of delivering seedlings is 42 m/min, and the forward speed of transplanting machine is 20 m/min. © 2015, Chinese Society of Agricultural Engineering. All right reserved.


Zhang Z.,Nanjing Research Institute of Agricultural Mechanization Ministry of Agriculture | Xiao H.,Nanjing Research Institute of Agricultural Mechanization Ministry of Agriculture | Ding W.,Nanjing Research Institute of Agricultural Mechanization Ministry of Agriculture | Mei S.,Nanjing Research Institute of Agricultural Mechanization Ministry of Agriculture
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015

Recently, as scientific research has been further explored, the health care functions of the Lycium 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 the L. barbarum is expanding each year. The L. barbarum blooms and bears fruit continuously during the growing season which begins in mid-May. Depending on the picking time around the year, the L. barbarum fruit can be divided into spring, summer and autumn fruit. In order to make dried L. barbarum keep good commodity characters, the L. barbarum is harvested at 80 percent maturity. The full bearing period of L. barbarum is from May to September every year, which is the picking peak of L. barbarum. It must be picked once about every 7 days. For centuries, the mechanized harvesting of L. 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 of L. 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 of L. barbarum and establishing the theoretical guidance and design basis for the L. barbarum picking machine, the vibration picking mechanism of L. 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 the L. 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, 10 L. barbarum trees were selected as the test samples. We measured the binding force and mechanical parameters of the L. 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 2868.84-2871.21 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 experimental L. barbarum picking machine, the test was conducted at planting base of L. 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 2870 r/min, which is within the reasonable simulation interval of rotational speed. Under this rotational speed, picking efficiency of ripe L. 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 of L. barbarum vibration picking machines. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.

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