基于PLC控制的等径凸轮传动自动变速秸秆粉碎还田装置设计与试验

Design and Experiment of Variable-speed Straw Chopping Machine Based on PLC Control with Equal Diameter Cam Transmission

摘要:

为提高玉米秸秆粉碎还田机具作业质量，解决传统秸秆粉碎还田机械作业参数不可实时调节等问题，基于等径凸轮机构往复运动原理，设计了一种基于PLC控制的自动变速秸秆粉碎还田装置。通过分析地表支撑条件下秸秆粉碎过程中受力变化，确定影响秸秆粉碎效果主要因素，利用LS-Dyna软件确定主要因素取值范围；通过理论计算和动力学仿真分析，优化粉碎刀运动轨迹并确定粉碎机构关键部件参数。为提高玉米秸秆粉碎合格率，建立“泵-阀-马达”调速模型，设计人机交互界面进行作业参数设置，实现不同秸秆覆盖量情况下，秸秆粉碎装置作业参数快速匹配，以机具前进速度、秸秆覆盖量为试验因素，以秸秆粉碎合格率为评价指标进行单因素试验。试验结果表明，当田间秸秆覆盖量一定时，随着主轴转速增加，粉碎合格率呈明显上升趋势；当主轴转速一定时，随着田间秸秆覆盖量的增加，粉碎合格率有所下降；当主轴转速超过200r/min时，秸秆粉碎合格率均达到90%以上，基本保持不变。为进一步验证试验结果，进行变速秸秆粉碎方式与定速秸秆粉碎方式对比试验。试验结果表明，变速秸秆粉碎方式秸秆粉碎合格率为92.17%，优于定速秸秆粉碎方式。该装置实现了秸秆粉碎还田作业参数精准控制，为秸秆粉碎还田机具智能化发展提供了技术支撑。

Abstract:

To enhance the chopping quality of the maize straw chopping machine and address issues such as the inability to adjust traditional straw chopping parameters, a straw variable-speed chopping device based on a programmable logic controller (PLC) controlled mechanism utilizing an equal diameter cam mechanism for reciprocating motion was designed. Through analyzing force variations during straw chopping underground support conditions, the primary factors influencing the effectiveness of straw chopping were identified, and the LS-Dyna software was employed to determine the range of values for these factors. Through theoretical calculations and dynamic simulation analysis, the motion trajectory of the chopping blades was optimized, and key component parameters of the chopping mechanism were determined. To improve the chopping pass rate of maize straw chopping process, a “pump-valve-motor” speed regulation model was established. A human-machine interface was designed for operational parameter settings, facilitating rapid matching of chopping device operational parameters under different straw cover conditions. Experimental trials were conducted, with forward speed and straw cover as test factors and straw chopping pass rate as the evaluation index. The results demonstrated that there was a significant increase in chopping pass rate with the increase of chopping speed when the field straw cover was constant. Conversely, with a constant chopping speed, the chopping pass rate was decreased as field straw cover was increased. Beyond chopping speed of 200r/min, the chopping pass rate reached over 90% and remained relatively constant. To further validate the experimental results, a comparative test was conducted between variable-speed and constant-speed straw chopping methods, revealing straw chopping pass rate of 92.17% for the variable-speed method compared with the constant-speed method. This device achieved precise control of operational parameters for straw chopping, providing technical support for the intelligent development of straw chopping machines.