Development and optimization of an orchard green-manure chopping and incorporation machine using rigid-flexible coupling simulation and field validation

To address inadequate stem chopping, shallow incorporation and multi-pass operation in existing orchard green-manure equipment, a dedicated machine for hairy vetch in dwarf apple orchards was developed to perform stem chopping and incorporation, soil pulverization and firming in a single pass. The overall structure and key components, including the green-manure chopping device, incorporation plow and soil-pulverizing device, were designed through theoretical analysis. ADAMS multibody dynamics models and an ADAMS/OptiStruct rigid-flexible contact model were used to analyze stem fracture during chopping, and finite-element analysis was used to verify structural strength under extreme conditions. Box-Behnken field experiments were then conducted to optimize operating parameters using the qualified stem-length rate and stem incorporation rate as response variables. Simulation results showed that the main load-bearing members of the machine were made of Q345 steel (yield strength 345 MPa) and satisfied the strength requirements under extreme conditions, with a maximum stress of 251 MPa and a minimum safety factor of 1.37. The optimum practical settings were a forward speed of 1.1 m·s–1, gearbox output shaft rotational speed of 450 r·min−1, and incorporation depth of 190 mm; under these settings, the qualified stem-length rate was 91% ± 1.5% and the stem incorporation rate was 91% ± 2.1%.