Design and experiment of automatic feeding seedling mechanism and control system for rice pot seedlings

Objective To improve the accuracy and reliability of automatic feeding rice seedlings in the orderly throwing transplanter, and reduce the seedling loss in the seedling feeding link.

Method A rice seedling-row-in-position detecting scheme and its practical program method were proposed, while a belt-type automatic seedling feeding mechanism (BASFM) and related control system were developed. Through prototype test, three kinds of characteristic signals representing the plug-seedling-row-in-position status were received based on direct-on-line detection of seedling stalk, plastic tray and magnetic bulge of ferric tray respectively. The synthetical measure attribute of plug-seedling-row-in-position signal was summarized. An optimal scheme to monitor plug-seedling-row-in-position and associated control circuit was established. The BASFM with functions of detecting seedling-row, transporting and feeding seedling was designed.

Result When body of plastic tray was chosen as a detected target, the success-detect rate was the highest (99.78%), magnetic bulges aside ferric tray was higher (96.64%) and seedling stalk was the lowest. When plastic tray or magnetic bulge of ferric tray was chosen as a row detected target, tray type showed no significant effect on success-detect rate, but significant while seedling stalk was chosen as a row detected target. For three seedling-row-in-position detecting schemes, the variance of transport motor speed also showed no significant impact on the seedling-row-in-position detecting performance between 30-60 r·min^-1.

Conclusion This design of BASFM and affiliated seedling-row-in-position automatic detecting and control system can meet the performance requirements for pot-seedling-row transporting and feeding in the rice seedling orderly throwing transplanter.