To date, mechanized picking of famous tea (bud, one bud one leaf) causes a lot of damage. Manual picking results in high-quality tea but the process is inefficient. Therefore, in order to improve the quality of mechanically harvested tea buds, the study of bionic picking is beneficial to reduce the damage rate of mechanical picking. In this paper, the manual flexible picking process is studied, and a bionic bladeless mechanical picking mechanics model is developed. The relationship between the mechanical properties and structural deformation of tea stalks is obtained by microstructural observation and mechanical experimental analysis and determination of the bud bionic picking mechanics flow by combined loading tests is carried out. The results show that the key factor for low damage in tea picking is the precise flexible force applied to different parts of the shoot tip during pinching, upward, and picking. The biological force of tea stalks is closely related to the stalk diameter and maturity of stalk tissue development. The larger the xylem of the tea stalk, the stronger its resistance to bending, stretching, and deformation. The stalks at the tender end of the tea are more resilient than the lower stalks and will not break under the action of large angle bending. Additionally, the stalks at the shoot tip have significantly lower pull-off force than the stalks at other places. By simulating the manual picking process, the mechanical picking mechanical parameters were determined to be a clamping pressure of 340 kPa, bending force of 0.134 N, and pull-off force of 5.1 N. These findings help the design of low-damage pickers for famous tea and provide a reference for low-damage bionic picking of tea.

The performance of existing rice-paddy weeding machines is not optimal. In this study, the influence of the installation angle of the weeding-wheel blade on cutting resistance and soil-slippage ability was analyzed. The optimal blade angle of the weeding wheel (i.e., the angle at which the resistance to the weeding wheel is minimal and the disturbance speed of the soil maximal) was shown to be< 20°; numerical simulation showed the actual optimal value to be 0°. Different weeding depths (30, 40, and 50 mm), rotation speed of weeding wheel (120, 180, and 240 r/min), and weeder forward speeds (0.3, 0.6, and 0.9 m/s) were used as test factors, and the rates of seedling injury and weeding were used as performance-evaluation criteria to optimize the machine in a secondary orthogonal-rotation combination test. Field experiments showed that the weeding wheel can exhibit optimal working performance under the operating conditions of weeding depth of 39 mm, rotation speed of 175 r/min, and forward speed of 0.6 m/s. The seedling injury and weeding rates were 4.4% and 88.2%, respectively, which were consistent with the numerically predicted results and met the agronomic requirements. This study provides a technical reference for the improvement of paddy-field weeding components.

Design and test of post-seat weeding machine for paddy

Conventional winnowing machines rely on manual operation and adjust their parameter settings based on experience. These problems have led to poor wind sorting results. In order to improve the sorting accuracy and efficiency of the tea winnowing machine, a double-layer automatically controlled winnowing machine has been designed in this study. Firstly, an automatic control system based on a programmable logic controller is established. Secondly, the AC motor control technology is used to achieve the automatic adjustment of the baffle position. The prototype tests show that the control input voltage of the vibrating feeder is 2 V for Lan tea and 1.5 V for pan-fried green tea material. The frequencies of the upper fan are 30 Hz and 25 Hz, respectively, while those of the lower fan are 35 Hz and 30 Hz, respectively. For Lan tea, the No. 3 baffle moves to the right by 5 cm, and the positions of the No. 5 and No. 6 baffles remain unchanged. The main outlet of the double-layer winnowing machine contains 3.72% impurities. As for pan-fried green tea, the position of the No. 3 baffle remains unchanged, the No. 5 baffle moves 5 cm to the right, and the No. 6 baffle moves 4.5 cm to the right. The main outlet of the winnowing machine contains 4.28% impurities. The experiments indicate that the double-layer winnowing machine is more effective than the single-layer one and can provide a reference for an efficient and accurate winnowing machine.