2自由度夹子式水稻穴盘钵苗拔抛机械手设计与试验

Design and Experiment of 2-DOF Clamp-type Manipulator for Transplanting of Rice Potted-seedlings

摘要:

根据2自由度机械手拔抛穴盘钵苗的特点和机理，设计了一种2自由度夹子式机械手，简述了其工作对象特征，主要结构组成及控制电路，对关键部件夹秧机构进行了设计，通过Pro/E建模及虚拟装配对秧夹的开闭合过程进行仿真，保证开闭合运动的精度和可靠性。在试验平台上，进行了不同穴盘类型、不同钵土含水率、不同秧夹弹簧拉伸力以及不同穴盘进给模式对机械手拔秧效果影响的试验研究。试验结果表明：穴盘类型和钵土含水率对拔秧成功率有显著影响（P<0.01），采用红色穴盘育秧或保持钵土含水率大于30%可以提高拔秧成功率；夹秧机构上复位弹簧拉伸力在15N和22N间变化对拔秧成功率没有显著影响；采用自动进给穴盘模式不会对拔秧成功率产生显著影响，秧苗自动输送进给机构的性能满足钵苗行输送进给的要求。

Abstract:

A new kind of 2-DOF clamp-type manipulator was developed relying on the feature and principle of 2-DOF manipulator for automatically pulling up and transplanting multiple cell-tray potted-seedlings. The characteristics of operating targets, main structure and control circuit of the manipulator were described. The key component of seedling clamp mechanism was designed, and 3D structure model was established and virtually assembled by using Pro/E. Dynamics simulation to the seedling clamp mechanism ensured the reliability of its opening and closing process. Preliminary performance experiment was conducted on a program controlled prototype platform. Four related factors were considered, including the type of cell-tray, moisture of soil ball, extending force of clip’s spring and feeding mode of cell-tray. And the effect of above factors on the evaluate index of successful pulling up rate of the manipulator was analyzed. Results showed that type of cell-tray and moisture of soil ball both had very significant effects on successful pulling up rate (P<0.01), while no significant difference for both extending force of clip’s spring (15,22N) and feeding mode of cell-tray (P>0.05). When the extending force of clip’s spring and feeding mode of cell-tray were unchanged, cultivating the potted-seedlings by using red tray or maintaining moisture of soil ball of potted-seedling above 30% can increase successful pulling up rate. And the performance of seedlings automatic transporting and feeding mechanism can meet the requirements of transporting and feeding cell-tray potted-seedlings row-by-row. The results provide a useful reference for subsequent optimization on manipulator’s performance.