Design and test of the hydraulic shear-type Caragana korshinskii Kom. coppicing machine

Caragana korshinskii is one species of the flowering plants in western China. This study aims to improve the cutting surface quality of its stems for the high regrowth rate in the following year. While the cutting force and energy consumption were effectively reduced in the stubble-cutting equipment. A hydraulic shear-type stubble-cutting machine was developed specifically for the clustered growth patterns and arid sandy habitats of Caragana korshinskii populations. A systematic investigation was also made on the structural, working, and mechanical configuration of the machine. Particularly, the theoretical analysis was then carried out to determine the technical parameters for the efficient operation in the field. A hydraulic shear-type cutting test bench was constructed to optimize the cutting performance. An accurate simulation was conducted on the field operations in order to measure the cutting forces and power consumption. A single-factor trial was implemented on the three primary operational factors: hydraulic cylinder extension speed, blade wedge angle, and cutting clearance. Multi-factor experiments were conducted with the peak cutting force, cutting energy consumption, and stubble-breaking rate as the evaluation indicators. A regression analysis model was then established to quantitatively analyze the influence of each factor and their interactions on the cutting performance. The test bench consisted of a cutting assembly, a control measurement, and a hydraulic drive system. In experimental material, the Caragana korshinskii shrubs (aged between three to five years with a consistent growth status and free from pest or disease damage) were bundled, and then cut at 5 cm above ground level. A total of 200 groups were collected, labeled, and immediately tested for data accuracy and reliability. The response surface method was utilized to optimize the regression equation. An optimal combination of the working parameters was determined to be a hydraulic cylinder extension speed of 0.09 m/s, a blade wedge angle of 28°, and a cutting clearance of 3.0 mm. The better performance was achieved, where the stubble-breaking rate reached 7.1%, the peak cutting force was measured at 10 467.4 N, and the cutting energy consumption was 1 640.9 J. The relative error between the experimental and the predicted values remained within 5%, indicating the high accuracy and reliability of the regression model and the optimal parameters. The additional field trials were conducted in the typical sandy land shrub environments, in order to verify the field performance of the equipment. The hydraulic shear-type stubble-cutting machine achieved a stubble-breaking rate of 1.8%, a missed cutting rate of 1.5%, and a stubble height non-conformance rate of 3.3%, fully meeting the expected performance. This finding can provide the theoretical and technical references for the mechanical harvesting of the desert shrubs. Some valuable insights can also be offered to integrate the cutting, collecting, and transporting in the arid and semi-arid ecosystems.