基于ADAMS的油菜割晒机顺向侧铺装置参数优化与试验

针对常规立式油菜割晒机多采用侧边铺放方式,茎秆铺放方向与机组前进方向垂直,油菜茎秆铺放角差异大、姿态各异,易导致后续捡拾作业喂入量波动和捡拾不彻底等现实问题,提出了一种油菜割晒机顺向侧铺装置,分析了关键部件作业参数,基于ADAMS开展了铺放质量的仿真优化试验。利用运动学与动力学分析了割台排禾口处茎秆的平抛运动过程及其落地后的定轴转动过程,结合茎秆铺放角形成机理,计算得出拨禾星轮齿数为7、转动角速度为6.27rad/s,确定了排禾导向板曲线参数方程;基于ADAMS构建了油菜茎秆顺向侧铺装置的多体运动学仿真模型,以机组前进速度、横向输送链速比、割台倾角为因素,以茎秆铺放角为评价指标,开展了Box-Behnken仿真试验,以铺放角最小为目标构建了优化目标函数,运用Design-Expert软件求解得到最佳参数组合并开展了仿真和田间验证试验。Box-Behnken试验结果表明,最佳参数组合为机组前进速度0.93m/s、横向输送链速比1.11、割台倾角117.93°,理论最优铺放角为15.25°。仿真验证试验结果表明,在最佳参数组合条件下,铺放角仿真值为14.42°,与理论值相对误差为5.4%。田间试验结果表明,油菜顺向侧铺装置作业顺畅、无堵塞,油菜茎秆平均铺放角为17.25°、平均铺放宽度为752mm、平均铺放层高度为323mm,可满足实际生产需求。该研究可为立式油菜割晒机铺放装置结构改进和优化提供参考。

Parameter Optimization and Experiment of Forward Laying Device for Rape Windrower Based on ADAMS

The conventional vertical rape windrower, whose laying direction of the rape plants is perpendicular to the forward direction of the windrower, still has the challenge to guarantee stable feeding rate of the following pick-up operation due to the inconsistent laying angle, highlighting a need to change the way of laying. As a solution, a forward laying device for rape windrower, whose operation parameters were analyzed, was proposed and the simulation experiments was carried out to optimize the laying quality based on ADAMS. Focusing on the moving of the rape plant at the outlet of the header, the horizontal throwing movement of the plant and its following fixed axis rotation after landing at the ground were analyzed based on kinematics and dynamics, indicating that the laying angle was related to the initial velocity and fixed axis rotation time of the plant. It was found that the main factors affecting the laying quality were forward speed of the windrower, speed ratio of transverse conveyor chain, and inclination angle of the header. Furthermore, the laying process under the coordination of the wheel and the guide plate was analyzed. The number of wheel teeth was 7 while the rotational angular velocity was 6.27rad/s. In addition, the curve parameter equation of the guide plate was also determined, and a four-bar mechanism was designed. Based on ADAMS, a multi-body kinematic simulation model of the forward laying device was constructed. By taking the forward speed of the windrower, transverse transmission chain speed ratio and inclination angle of the header as factors, the laying angle was utilized to evaluate the laying quality in the Box-Behnken simulation experiment with three factors and three levels. The mathematical relationship model between the laying angle and every factor was obtained to figure out the optimization objective function to minimize the laying angle. With the assistance of the Design Expert software, the optimal parameter combination was obtained, and then it was validated by simulation and field experiment. The results of the Box-Behnken experiment indicated that the optimal parameter combination was forward speed of 0.93m/s, transverse conveying chain speed ratio of 1.11, and inclination angle of 117.93°. The theoretical optimal laying angle was 15.25° under this condition. The results of the simulation experiment illustrated that the simulation value of laying angle was 14.42° under the optimal combination of parameters, and the relative error was 5.4% when compared with the theoretical value. The field experiment showed that the forward laying device could work smoothly without blockage. The average laying angle, average laying width and average laying height were 17.25°, 752mm and 323mm, respectively, which could meet the demand of actual production. The research could provide a reference for the structural improvement and optimization of the laying device for vertical rape windrower.