Rice transplanting by hand offers advantages such as minimal plant injury and a short recovery period. The key to mechanizing this process lies in replicating the ideal final trajectory of hand-transplanting through mechanical equipment. Based on the motion characteristics of manual transplanting, this study divides the transplanting process into three stages: seedling pickup, seedling transport, and seedling placement. Using the trajectory and posture of the human hand as a reference, an ideal mechanized transplanting trajectory was planned. Manual transplanting was simplified into a 2R open-chain mechanism configuration. A non-circular gear mechanism was employed to constrain the 2R open-chain mechanism to two degrees of freedom, proposing a non-circular gear transplanting mechanism design. Based on normalization principles, the ideal transplanting trajectory and the training trajectory corresponding to the feasible solution domain were normalized and feature-coded. The end-effector trajectory was then represented using a trajectory matrix. By constructing an objective function, a globally optimal mechanism solution was obtained through optimization across the entire solution domain. A test bench for the transplanting machine was developed. High-speed camera analysis of the transplanting mechanism’s working trajectory demonstrated that the optimal mechanism solution reproduces the ideal mechanized transplanting trajectory, meeting the operational requirements for mechanized transplanting.
Zhou et al. (2026) studied this question.