Design and optimization of a sugarcane orientation-specific seeding mechanism based on complex spatial offset motion

Abstract Since existing sugarcane planters are unable to ensure the complex spatial motion of cane seeds, it is difficult to achieve orientation-specific and uniform seeding in accordance with agronomic requirements. To address this issue, we propose an innovative rocker-type seeding mechanism driven by a secondary elliptical planetary gear system. By utilizing the periodic non-uniform transmission characteristics of the combined elliptical and helical gears, the terminal seeding arm can stably and orderly grasp the cane seeds, execute complex spatial offset motions, and release them with a specified orientation. Based on the homogeneous transformation relations of spatial position and orientation in the gear-driven rocker mechanism, a forward kinematic model was established. A MATLAB GUI–based auxiliary tool was developed to explore the influence of key parameters on the static seeding trajectory and to determine the boundaries of parameter optimization. Finally, a genetic algorithm was employed to precisely optimize and select the mechanism in order to meet the seeding requirements. Virtual prototype verification shows that the complex motion patterns are generally consistent with the theoretical model. The mean deviations at key trajectory positions are 6.53 mm and 8.07 mm; the differences in seed posture are 2.72° and 3.03°; and the velocity deviations are 6.28 mm s −1 and 10.74 mm/s. These results meet the agronomic requirements for sugarcane planting and confirm the feasibility of the proposed mechanism design.