无人驾驶替代农药喷雾车机架动静态特性分析

Analysis of Dynamic and Static Characteristics of Unmanned Alternative Pesticide Spraying Vehicle Frame

为保证无人驾驶替代农药喷雾车在复杂的田间环境中安全作业,需要对机架进行有限元分析,确保机架有足够的强度、刚度,避免机架在施药车田间路面行驶时共振。利用CATIA三维软件建立无人驾驶替代农药喷雾车机架模型,导入有限元分析软件Workbench中,通过对机架结构的网格划分,按照实际载荷与约束情况进行应力、应变及模态分析。结果表明,最大应力值66.102 MPa小于屈服强度值290 MPa,最大变形值0.65975 mm,由于机架整体尺寸都比较大,相对于机架最大变形值可忽略不计,得出机架强度、刚度满足设计要求;机架前12阶固有频率最小值71.977 Hz,车轮激励频率(11 Hz)和柱塞泵工作激励频率(50~60 Hz),始终小于机架最小固有频率,避免了喷雾车田间行驶过程中机架共振,为喷雾车后期的结构优化提供依据。

In order to ensure the safe operation of the unmanned alternative pesticide sprayer in the complex orchard environment,finite element analysis of the frame is required to ensure that the frame has sufficient strength and rigidity to avoid resonance of the frame when the pesticide sprayer is driving on the road in the field.Use CATIA three-dimensional software to build a model of the unmanned alternative pesticide spraying vehicle frame,import it into the finite element analysis software Workbench,and conduct stress,strain and modal analysis according to the actual load and constraints by meshing the frame structure.The results show that the maximum stress value of 66.102 MPa is less than the yield strength value of 290 MPa,and the maximum deformation value is 0.65975 mm.Since the overall size of the frame is relatively large,it can be ignored relative to the maximum deformation value of the frame.It is concluded that the frame strength and rigidity meet the design requirements;the minimum natural frequency of the first 12 orders of the frame is 71.977 Hz,the wheel excitation frequency(11 Hz)and the working excitation frequency of the plunger pump(50~60 Hz)are always less than the minimum natural frequency of the frame,which avoids the field driving process of the spray truck.The resonance of the middle frame provides a basis for the structural optimization of the spray truck in the later stage.