Safflower is one of the key specialty cash crops in Xinjiang of western China. It can serve multiple purposes, including medicinal, edible, dye, oil, and feed use. However, the filaments have relied mainly on manual harvesting, due to the labor-intensive, costly, and seasonal labor shortages. Furthermore, fresh safflower fruit balls are characterized by the scattered spatial distribution and varying heights. Existing harvesting equipment can also be limited to low efficiency, a high miss rate of fruit balls, or fruit damage. It is often required for the high throughput and picking rate during harvesting. Therefore, there is an urgent need to develop efficient and well-adapted mechanical harvesters for safflowers. This study aims to develop a safflower harvesting device with the parallel multi-picking-heads. A gathering first and picking later strategy was proposed to enhance harvesting efficiency during continuous mechanical operation. High efficient, low-damage, and continuous blind harvesting of fresh safflower was achieved to coordinate a feeding/gathering mechanism with multiple picking units. A continuous dynamic envelope was formed around the plant canopy. Firstly, a feeding and gathering mechanism was designed in the device, according to the physical properties of safflower plants and the mechanics of their branches. The structural parameters were determined as a channel width of 200 mm, a divider plate angle of 66°, and an installation height of 580 mm. An orderly picking interface was constructed to significantly compress the lateral distribution width of the fruit balls by 47.62%. Subsequently, a parallel picking unit was centered on three sets of counter-rotating rollers. The geometrical parameters of the roller were set as follows: diameter 30 mm, gap 1.8 mm, length 300 mm, and center distance 85 mm. Mass property analysis was conducted to determine the kinematic constraints. The minimum reciprocating cycle of the unit was obtained greater than 2.45 s. A spatial motion trajectory was established to couple the forward speed, the reciprocating cycle of the picking units, and thee phase difference. Multiple picking heads were complemented the phase differences to form the continuous dynamic envelope in the full coverage of the harvesting area. Taking the filament net picking rate and the fruit ball miss rate as the evaluation metrics, single-factor tests were conducted to optimize the parameter ranges. Box-Behnken response surface method (RSM) was employed to optimize the operational parameters: a phase difference of 0.54π, a reciprocating cycle of 2.9 s, and a forward speed of 0.46 km/h. Field tests were implemented to validate these optimal parameters. The results show that the better performance was achieved in a filament net picking rate of 90.27% and a fruit ball miss rate of 10.93%. The relative error between the experimental and the predictions was less than 5%, fully meeting the industry standards for mechanized safflower harvesting. Simple operation was effectively integrated with the gathering and multi-head coordinated picking for the efficient continuous blind harvesting of fresh safflower. The labor intensity and production costs were reduced significantly, suitable for the large-scale cultivation in arid regions like Xinjiang. This finding can also provide the theoretical and technical reference for the harvesting equipment of fresh safflower.

Safflower is one of the dominant characteristic economic crops in Xinjiang, which is used in medicinal materials, oil, dye and feed. At present, the harvesting of safflower filaments still relies on manual labor. With the increase of safflower planting area and the shortage of labor force, many fresh safflower filaments have no time to harvest into dry-safflower filaments. Both the natural dried safflower filaments in the field and the dried safflower filaments collected during opening and then dried by air meet the national pharmacopoeia standards in terms of medicinal ingredients. But the safflower filaments gradually become hard and brittle after drying, which makes it difficult to pinch the filaments when picking by hand, and the filaments are fragile and easy to fall. It makes farmers reluctant to collect dry-safflower filaments, resulting in serious waste. Therefore, it is urgent to develop a dry-safflower harvester. At present, there have been some related research reports on the mechanical harvesting of dry-safflower, all of which are concept machines or ideas for brush-roller picking dry-safflower. However, there are no relevant reports on the theoretical and practical research on how to separate the safflower filaments from the fruit ball and improve the picking rate without damaging the fruit ball. The vertical brush-roller harvester is designed for dry-safflower filaments in dry land, which are generally planted in arid and barren land. Safflower is a top crop, which has the characteristics of one safflower in one branch, different opening time of filaments, and different spatial distribution of fruit balls. The safflower plants are relatively short, and one plant grows 3-7 fruit balls. When safflower filaments bloom from the neck of the fruit ball, safflower seeds are not yet mature. Therefore, when harvesting safflower filaments, it is necessary not to destroy the fruit balls that wrap the immature seeds and the branches that provide nutrients, but only to harvest the filaments threads located at the top of the fruit balls. Aiming at the problems such as low efficiency, high drop rate and no mechanization, a vertical brush-roller harvester was designed based on the physical characteristics and planting patterns of safflower. Firstly, the brush wires arrangement scheme was analyzed theoretically in combination with the structure of the machine, and it was determined that the brush wires arrangement scheme was helix, the helix angle was 30°, the rotation direction was right rotation. Secondly, the mechanical analysis of picking dry-safflower filaments by brush-roller was carried out, in order to find that the key force of the safflower filaments from the fruit balls was the normal force F_N. Furthermore, Hertz elastic contact theory was used to analyze the contact mechanics of normal force F_N, and the contact mechanics model of brush wires and fruit balls was established, which clarified the picking principle and the main factors affecting the picking quality, such as the material, diameter, length of the brush wires and the rotational speed of the brush-roller. Finally, the structural parameter design and kinematic analysis of the vertical brush-roller were carried out, and the main parameters of the picking device were obtained as follows: the length of the brush-roller was 300 mm, the diameter of the brush-roller was 100 mm, the material of the brush wires was polyamide 610 (PA-610), the length of the brush wires was 30 mm, the rotational speed of the brush-roller was 360 r/min, and the diameter of the brush wires was 0.3 mm. The clearance between the vertical brush-roller and the grid rack was determined to be 12 mm through the plant passing rate test. The field picking test showed that the picking rate and fruit damage rate of the vertical brush-roller harvester were 87.04% and 4.19%, respectively. The picking efficiency of harvester was 7.71-10.92 times that of manual picking. The research results can provide reference for the design and optimization of brush-roller harvester and dry-safflower harvester.

The straw checkerboard is one of the most effective engineering sand fixations in Xinjiang of western China. Reed straw can often be utilized to produce the sand barriers of straw checkerboard, according to the regional conditions. Sand break and water conservation can be expected to serve as excellent ecological benefits. However, manual paving protocols of the reed straw checkerboard cannot fully meet the large-scale production at present, due to the high labor intensity and cost during straw-pressing operation. Alternatively, mechanical paving of the reed straw checkerboard can be expected to ensure the performance of its sand fixation. However, the existing research focuses mainly on the paving machinery in the longitudinal column of the straw checkerboard. By contrast, the transverse straw-pressing mechanism can be required for a certain spacing distance to press the straw. Among them, the straw is firstly tied in the shape of squares on the desert surface, and then interlaced by the equally spaced longitudinal and transverse columns. A grid of straw checkerboard is often formed to be generally laid first in the longitudinal columns in the same direction, as the forward direction of the machine, and then in the transverse columns. The existing transverse paving machinery usually combines the straw-pressing and straw-laying machine for instantaneous speed matching to realize the transverse column of the paving straw checkerboard. It is still lacking in the response relationship among the operating parameters of the transverse column straw-pressing mechanism on the quality of straw-pressing operation, as well as the motion and mechanical models. The paving quality of the straw checkerboard can dominate in the evaluation of the performance of a transverse straw-pressing mechanism. Taking the transverse paving of the reed straw checkerboard as the research object, this study aims to propose a "T" type straw checkerboard of the transverse and longitudinal synergistic paving mode. The transverse intermittent and longitudinal continuous straw-pressing were combined during paving. Two technical requirements were fully met in the paving mode. Specifically, the transverse straw-pressing was required to avoid the first longitudinal and the adjacent molded transverse reed sand barriers, as well as the intermittent zero-speed straw-pressing. The institutional kinematic model was constructed for the transverse straw-pressing, according to the manual action and motion trajectory. The agronomical requirements of the reed straw checkerboard were combined to determine the optimization objective of the transverse intermittent straw-pressing mechanism using the MATLAB and ADAMS platforms. The auxiliary optimization interface was written to optimize the parameters of the mechanism; The mechanical model was also constructed to explore the relationship between the straw-pressing cutter and the sand/reed straw. Particularly, the reed straw was often broken during pressing and extruding, indicating the large resistance in the stage of entering the sand. The structural parameters of the straw-pressing cutter were determined after optimization. The results show that there was relative consistency in the actual, ADAMS simulation and theoretical trajectory of the transverse intermittent straw-pressing mechanism. The qualified rates were 86.4% and 84.9%, respectively, for the transverse column depth and the edge thickness of the reed straw checkerboard. The relatively stable and reliable performance of transverse intermittent straw-pressing has verified the correctness of the theoretical design and the feasibility of the mechanism. The finding can provide a strong reference to optimize the transverse straw-pressing mechanism of the reed straw checkerboard paying machine.