小株距非圆齿轮行星轮系植苗机构设计与试验

Design and Experiment of Small Plant-spacing Non-circular Planetary Gear Train Planting Mechanism

摘要:

针对现有非圆齿轮行星轮系机构反求设计无法实现单排两级齿轮传动比分配问题，提出一种最优子传动比求解方法，并设计了小株距轻简型非圆齿轮行星轮系植苗机构。在蔬菜小株距移栽理想植苗轨迹上选取植苗机构入土、植苗、出土、接苗4个关键时刻的位姿点，建立了平面2R开链杆组有限分离四位姿求解模型，获取了机构初始设计参数；基于非圆齿轮行星轮系植苗机构运动学模型，确定了优化目标函数，采用改进鲸鱼优化算法对目标函数进行求解，搭建了非圆齿轮行星轮系植苗机构可视化辅助分析软件，最终设计得到一个轨迹较优的非圆齿轮行星轮系植苗机构；完成了非圆齿轮行星轮系植苗机构的三维建模与拓扑优化，并进行了运动学仿真，将仿真轨迹与理论轨迹进行对比，验证了三维设计的正确性。最后，开展了田间移栽试验，当机构转速为30r/min、机器前进速度为120mm/s时，试验株距测量值为120mm，与理论设计株距一致，移栽效率为60株/min，5次试验植苗成功率为95.4%，表明了该植苗机构具备较高的作业性能和实用性。

关键词:小株距移栽;植苗机构;非圆齿轮;优化算法;拓扑优化

Abstract:

Aiming at the problem that the reverse design of the non-circular gear train can not achieve the single-row two-stage gear ratio distribution, an optimal subgear ratio solution method was proposed, and a small plant spacing light simple non-circular gear train planting mechanism was designed. The poses of the planting mechanism at four key moments, namely, embedding, planting, exhuming and grafting, were selected on the ideal seedling trajectory of vegetable small plant distance transplanting. A finite separable four-position kinematic solution model for a planar 2R open-chain linkage assembly was established, and the initial design parameters of the mechanism were obtained. Based on the kinematic model of the seedling planting mechanism with non-circular gear planetary gear train, the optimization objective function was determined, and the improved whale optimization algorithm was used to solve the objective function. A visualization assistant software for the non-circular gear planetary gear train planting mechanism was built, and finally, a seedling planting mechanism with an optimized trajectory was designed. The non-circular gear planetary gear train seedling planting mechanism was three-dimensionally modeled and topology optimized, and kinematic simulations were conducted. The simulated trajectory was compared with the theoretical trajectory to verify the correctness of the three-dimensional design. Finally, field transplanting experiments were conducted. Under the conditions of 30r/min for the mechanism speed and 120mm/s for the machine forward speed, the measured planting spacing was 120mm, which was consistent with the theoretical design spacing. The planting efficiency was 60 seedlings/min, and the average seedling planting success rate over five trials was 95.4%, indicating that the seedling planting mechanism had high operational performance and practicality.

Key words:transplanting with small spacing;planting mechanism;non-circular gear;optimization algorithm;topology optimization