Form trimming is an important practice in horticulture. Currently, handheld trimming tools are the most commonly used in China, which presents certain disadvantages including high human labor input, low productivity and inconsistent performance. In this work, a wheeled form trimming machine was designed for shrub plants with the aim of reducing labor input, increasing efficiency and improving trimming performance. The machine was mainly composed of three parts: a supporting frame, a rotary base and a knife system. The design and construction of the key components of the machine were introduced. The knife system was a combination of multiple cutter units with reciprocating motions. The number of units and their connecting angles could be adjusted to realize different trimming shapes. The knife system was carried by the rotary base and could realize 360° rotations to cut the plants into a desired form. Experiments were performed to determine the optimal working parameters (cutting frequency of the cutter unit and rotating speed of the rotary base). The similarity between the plant profile after trimming and the profile of the knife system and the consumed time in each operation were chosen as two evaluation indexes. Results showed that when the cutting frequency was 16.7 Hz and the rotating speed of the rotary base was 13.5 r/min, the trimming operation could be completed by two circles, and the time consumption was 8.89 s. Furthermore, to test the adaptability of the machine, five different shrub plants were chosen and trimmed by the machine, and results showed that the overall similarity was above 93%. Therefore, the form trimming machine developed could meet the requirements of shrub trimming in horticulture with desirable precision and adaptability.

To address the problems of threshing loss and high impurity rate during sunflower oil harvesting, a vertical axial flow sunflower oil threshing device was designed. To reduce severe breakage of the sunflower plate and high entrainment loss rate when threshing by the traditional grating gravure sieve, a circular tube-type gravure screen was designed, and a contact model describing the grain rod, sunflower pan, and gravure screen was analyzed. The results show that reducing the diameter of the gravure screen round tubes can effectively reduce breakage of the sunflower pan. The range of the threshing gap, drum speed, and feed amount were determined by a single-factor test. Design-Expert software was used to design a response surface experiment: threshing gap, drum rotation speed, and feed amount were used as test factors, and the threshing loss rate of grains and the grain mass ratio of undersize grains were used as evaluation indicators. A regression model between test factors and evaluation indexes was established by variance analysis of the test results. A software-based numerical optimization function was used to reduce the loss rate of grains and increase the grain mass ratio of undersize grains. The optimal parameters of the threshing device were obtained by multi-objective optimization of all factors: the separation gap was 24.90 mm, drum speed was 244.14 r/min, feed amount was 2.95 kg/s, the threshing loss rate grains was 2.35%, and the grain mass ratio of undersized grains was 81.34%. This study can provide a reference for the design of a combined sunflower oil harvester threshing device.

The stationary thresher machines are widely used worldwide in threshing and separating many crops; they proved to have a high performance, especially in small spaces. The threshing drum is the essential working device of the thresher and plays a fundamental role in threshing efficiency, consumed specific energy, machine productivity, and seeds loss. In this study, a structure of sunflower thresher (open style drum with 45 incline degree loop teeth) was tested, and evaluated for performance under different drum rotational speeds (150, 200, 250, and 300 rpm) and different concave clearances ( 10, 15 and 20 mm). The thresher structure and operating parameters were assessed and optimized concerning damaged and unthreshed seed percentage, threshing efficiency, consumed specific energy, and machine productivity. The obtained results revealed that increasing cylinder rotating speed positively related to threshing efficiency, power requirements, and machine productivity while increasing concave negatively related to threshing efficiency, power requirements, and machine productivity. The highest efficiency of 97.40 %, the maximum productivity of 434.50 kg/h, and the lowest consumed specific energy of 6.85 kW.h/t were obtained at the operational condition of 300 rpm drum rotational speed 10 mm concave clearance. Buckingham's π theorem was followed to find an equation to predict the threshing efficiency theoretically, resulting in an equation with an R2 value of 0.8892. These developments were an excellent choice to uprising the performance of the original thresher drum.