| With the rapid construction and development of facilities and agricultural economy,the development trend of agricultural economic and industrial structure has become more sophisticated and efficient in China.Facilities agriculture is another major upgrade after the transformation of agricultural mechanized production,and brings more challenges to traditional plant protection machinery.To ensure that job tasks are completed in a limited space,plant protection machinery has a higher requirement for maneuverability and smoothness of the chassis.Based on the Design theory of the crawler chassis,a cross-type independent suspension mobile crawler system was designed.With the aid of Matlab and a new generation of Recurdyn multi-body dynamics simulation software,the chassis designed in this paper was comprehensively implemented.The track is simulated for dynamics and kinematics with the software and using Recurdyn to optimize the main parameters of the suspension assembly design.First of all,based on the full consideration of the narrow row spacing conditions of the greenhouse and the full study of the structure and function principle of the crawler-type mobile chassis,the subject has carried out a detailed analysis of the overall layout of the chassis,crawler system,wheel system,transmission system and suspension assembly.The theoretical analysis and structural design have determined the main parameters of the chassis.The analysis of the cornering performance of the chassis was performed in detail,theoretically ensuring the model maneuverability of the entire chassis.At the same time,a mathematical model was established for the cross independent suspension assembly,and the mathematical relationship between the installation angle and the dynamic stroke of the suspension was calculated and analyzed,which provided a basic theory for the dynamic study of the crawler chassis.The Matlab/simulink module was used to build the three-dimensional random road surface of the greenhouse and the simulation results were verified by the Matlab/simulink module.The spectrum function of the road was obtained.The road surface power spectrum function was also obtained to verify the road surface model.Based on the characteristics of the chassis mechanism,the greenhouse chassis model was reasonable Simplified,the approximate dynamics mathematical model of the chassis was obtained,and the dynamic simulation of the mathematical model was performed using Matlab.The initial simulation value of the vertical acceleration of the chassis was obtained,which provided the theoretical basis for the later optimization and verified the rationality of the simplified model.According to the design requirements,the constraints of each component were added.After the commissioning,the experimental simulation was performed according to the driving relationships among the various subsystems.The entire chassis model was refined and the chassis traction performance,steering stability,and climbing performance were simulated.The drive was obtained.Wheel drive torque,vertical displacement of the center of mass of the chassis,and turning radius,and other important simulation data,verify the theoretical design and provide a theoretical basis for prototype testing.At the same time,based on the Recurdyn multi-body dynamics simulation technology,using the meta-model optimization algorithm of the DOE module,the main parameters of the suspension system are optimized and the better vibration reduction effect is obtained.In summary,this paper designs a tracked mobile chassis based on the special conditions of greenhouse environment,and it verified by simulation software to meet the design requirements of the chassis's dynamic performance and kinematics performance.At the same time,the mathematical model of the cross-type independent suspension assembly is established.The main parameter design and optimization provide full theoretical preparation for the follow-up sample prototype. |
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