装载机工作装置载荷识别模型与载荷测取方法

为了研究装载机铲装作业时所受外载荷大小及变化特性,根据铲斗铰点力与斗尖力关系建立工作装置外载荷识别模型。以国产LW900K装载机为试验样机,提出了三向力销轴传感器法和动臂截面弯矩法两种载荷制取方法,进行典型作业姿态下的载荷验证和铁矿粉物料下的载荷测试试验。结果表明:提出的三向力销轴传感器法和动臂截面弯矩法都能够准确获取外载荷识别所需要的铰点载荷,销轴传感器法结果精度高于动臂截面弯矩法;试验样机工作装置所受大载荷出现在物料铲掘和卸载时刻,测得卸料时的惯性冲击载荷峰值约为400kN;通过雨流计数得到外载荷合力的均值服从正态分布,幅值服从三参数威布尔分布。载荷测试和分析结果能够有效解决装载机工作装置外载荷难以获取的问题,为载荷谱编制和疲劳特性分析提供依据。

Load Identification Model and Measurement Method of Loader Working Device

The characteristics of the load and the change of the external load of the loader working device are studied. First, the external load identification model is established according to the relationship between the bucket hinge point force and the bucket tip force. Then, the three direction force pin sensor method and the boom section moment method are proposed. The load verification and dynamic load test of iron ore material are carried out on the prototype of the LW900K loader. The results show that the hinge point force could be gained accurately by these two methods, and the accuracy of the boom section moment test results is lower than that of the pin shaft sensor. Under the test equipment of iron ore material, the load of the working device appears in the time of digging and unloading materials. For the first time, the inertial impact load of LW900K loader is obtained through the test, and the peak load is about 400kN. The relationship between the mean, amplitude and frequency of the resultant force of the working device is obtained by the rain flow counting method. It is found that the distributions of load mean and amplitude obey normal distribution and Weibull distribution with three-parameter respectively. The load identification model could effectively solve the problem of the external load acquisition difficulty of loader working device, and the load time history data could be used as reference for the load spectrum and the analysis of the structural fatigue characteristics.