基于动力学分析的谷物流量模型

Grain Flow Model Based on Kinematic Analysis

基于运动学原理建立了谷物流量模型,该模型综合考虑了谷物流量测量时的外部因素影响,如升运器转速、机械结构参数、相对位置参数和谷物特性参数等,并且通过引进相关参数来反映谷物外部因素变化影响。为了实现谷物流量模型参数的辨识和模型的精度验证,研制了一种谷物流量实验台。3个称重传感器安装在谷物流量实验台的称重箱上,用于标定和精度检验。进给箱的底部设有一块阀板,通过对阀板开度的调节可控制实验过程中不同进给量大小。在谷物流量实验台上测试结果表明:该模型能够准确描述:冲击力和谷物流量之间的关系,测量的最大误差不超过2.5%,效果要优于常用的经验模型,并具有一定通用性和鲁棒性。

Currently the grain flow models that were used for grain flow estimation were mainly empirical models .These models were difficult to meet the requirements of robust and versatility .A grain flow model was established based on kine-matic analysis to accurately estimate mass flow .The model considered the external factors to grain flow measurement , such as the elevator rotation speed ,the mechanical structure parameters ,the relative positions parameters and grain char-acteristic parameters , and introduced relevant parameters that reflected changes of external factors .The relationship be-tween the impact force and grain flow was nonlinear due to the variation of the external factors , a nonlinear least squares method was used to identify the grain characteristic parameters .An experimental platform was built to for the grain charac-teristic parameters and model validation .Three weighting sensors were mounted on the weighting bin in the experimental platform to calibrate grain flow sensor and verify the accuracy of grain flow sensor .A valve plate was inserted in the bot-tom of the feed bin of the experimental platform .The feed flow could be controlled by adjusting opening of the valve plate .Experimental results showed that the model can accurately describe the relationship between grain flow and impact , the maximum measurement error did not exceed 2 .5%.The model was superior to the empirical models that were usually used , and is with versatility and robustness .