装载机外载荷识别模型的载荷特性

The load characteristics of the wheel loader the load identification model

轮式装载机在作业过程中工作装置所受外载荷复杂,目前研究大多基于动力学仿真和理论分析来确定外载荷,所得结果与真实情况有较大差距.以装载机铲斗为研究对象,根据力学平衡方程,推导斗尖外载荷与铲斗铰点力之间的力学关系,建立铲斗外载荷识别理论模型.基于铲斗各铰点处结构特点,设计铰点载荷采集传感器,并结合信号采集仪器,搭建基于铲斗外载荷识别理论模型的载荷测试系统.而后对工作装置进行静态加载实验,发现载荷大小的相对误差在5%以内,角度偏差在3°以内.选取大石方工况进行铲掘实验,对测得载荷进行了不同作业段下的载荷特性分析,发现铲掘段载荷的均幅值最大,均值达到了265kN;重载运输段和卸料段载荷载荷水平接近,其中重载运输段的大载荷比例和载荷频次要高于卸料段;轻载运输段载荷水平最低,其中约90%的载荷均值在50kN以下.该方法可以有效地解决装载机外载荷获取问题,所得载荷特性数据可以为装载机的结构设计和优化提供数据支撑.

In the working process,the external load on the wheel loader is complex.However,in order to determine the external load,most of the researches are based on dynamic simulation and theoretical analysis,and there is a big gap between the results and the real situation.In order to obtain the precise external load,the wheel loader bucket was as the object of study in this paper.Based on the mechanical balance equation,the mathematical relationship between the external load of bucket tip and the point force of bucket was deduced,and a load identification theoretical model was established.Based on the load identification model and the structural features of bucket’s hinge point,a load test system was designed.Then the static loading experiment of the working device was carried out to verify the accuracy of the external load identification model.It is found that the relative size of the load error within 5%,the angle deviation within 3°.The excavation tests were carried out under the conditions of the rock condition.The load characteristics under different operating sections were analyzed.The results show that the average amplitude of the loads in the shoveling section are the largest and the maximum value is 265 kN.The loading level of the heavy-duty transport section is similar to that of the unloading section.The load ratio and load frequency of the heavy-duty transport section are higher than that of the unload section.The load level of the light load section is the lowest,about 90%of which is below 50 kN.The method can effectively solve the problem of the external load determination in wheel loader design,and provide data support for structural design and optimization of the wheel loader.