# Multibody Dynamics Simulation and Vibration Test for High Clearance Orchard Sprayer
## 5 Conclusions  
The high-clearance orchard sprayer work across-rows, which has the advantages of high efficiency and no harm to crops, making it the trend in plant protection machinery. In this paper, to ensure the operational safety of high clearance sprayers, the model is simplified by using shell cells instead of solid cells, and a simplified model of the tire-ground contact was proposed. The static and dynamic mechanical properties of high clearance sprayer frame were investigated by means of finite element simulation, and the static and dynamic simulation results were analyzed. Modal simulations were carried out to obtain the frame frequencies, and vibration tests were carried out to obtain the vibration law of the frame of the high clearance sprayer. The following conclusions are obtained:  
1. Static simulation test results show that, when a load was applied 1.5 times, the maximum concentrated stress of the frame under static full load condition was 214.31 MPa, and the maximum concentrated stress of the frame under ultimate torsion condition was 309 MPa. The values are all less than the permissible stress of 345 MPa for the frame material, indicating that there are no strength defects in the whole vehicle. 2. The results of the dynamics simulation tests show that, under the combined effect of 1.5 times the load and step excitation, the maximum concentrated stress in the frame is 266.2 MPa, which is also less than the permissible stress in the frame material. The overall displacement variation of the spray bar shows a gradual decrease in peak value, which is consistent with the law of spray boom displacement variation under step excitation. This proves that the simplified model of tire and ground is correct. In the X, Y, and Z directions, the displacement pattern at the end of the spray bar is similar to that of a sine, but the peak of the displacement is gradually decreasing. 3. The modal simulation test results show that the inherent frequency of the whole vehicle is closely distributed (2.1-14.35 Hz), through the vibration test measurement to obtain the high clearance sprayer's engine vibration frequency mainly at 30 Hz and 80 Hz, the whole machine inherent frequency and engine vibration frequency difference is large, which means that the sprayer will not occur resonance phenomenon. According to the above conclusions, it is proven that the high clearance sprayer design meets the safety requirements. The variation law in displacement at the end of the spray  
Figure 16: Displacement results for the left endpoint of the spray boom. (**a**) is the X-direction displacement of the left endpoint; (**b**) is the Y-direction displacement of the left endpoint; (**c**) is the Z-direction displacement of the left endpoint. bar will continue to be studied and which provide a reference for the attitude control of the spray boom. In addition, the stress concentration areas that appear in the finite element simulation results will be optimized, providing an optimization direction for the subsequent design of the high clearance sprayer. Conceptualization, H.C., S.D., M.O. and W.J. ; methodology, H.C., S.D., S.L., C.W., Z.L., G.W. and Y.C. ; software, H.C. and S.D. ; validation, M.O. and W.J. ; formal analysis, H.C. and S.D. ; investigation, H.C. and S.D. ; resources, M.O. and W.J. ; data curation, H.C. and S.D. ; writing--original draft preparation, H.C. and S.D. ; writing--review and editing, H.C., S.D., M.O. and W.J. ; project administration, M.O. ; funding acquisition, W.J. All authors have read and agreed to the published version of the manuscript. This work was funded by the Project of the Ningxia Hui Autonomous Region science and technology key R&D project (Grant No. 2018 BBF02020). Not applicable. The data presented in this study are available on request from the corresponding author. The author thanks Faculty of Agricultural Equipment of Jiangsu University and High-tech Key Laboratory of Agricultural Equipment and Intelligence of Jiangsu Province for the facilities and supports.