Research And Development On The Chassis Of Fully Hydraulic Multifunctional Vegetable Working Machinery

China is a major vegetable production and consumption country in the world,with many types of vegetables,large planting differences,complex operation links and low mechanization level,and the comprehensive mechanization rate of vegetable cultivation harvest is only 20%.The existing research mainly focuses on single vegetables,specific planting patterns,and mechanization operations in a certain link,resulting in low mechanical versatility and high production costs of vegetable operations.In order to solve the problem,aiming at the agronomy and operation requirements of hilly and mountainous vegetable production,according to the modular idea,this paper develops a fully hydraulic multifunctional operating machine that can carry out field operation in the whole life cycle of vegetables,and carries out the development of hydraulic system,the matching of functional modules and the in-depth study of the steering theory of the chassis of the operating car.Specific study contents are as follows:(1)Development of complete machine structure and verification of frame strength.Based on the research objectives,the structure,advantages and disadvantages of the walking device of common agricultural operation machinery are compared and analyzed,the wheel distance adjustable scheme is selected for the whole machine development in combination with the operating environment and functional needs,the working parameters of the whole machine of operation machinery are determined,the three-dimensional modeling is completed using the virtual prototype technology,and the structural principle of key components is studied;the strength and stability of the working machinery frame are checked with the help of finite element simulation tools,and the stress and strain of the off-frame under three limiting operating conditions are studied and analyzed.The results show that the strength and stiffness of the frame meet the design requirements.(2)Development of hydraulic system of the whole machine and theoretical study of steering.On the basis of virtual prototype,based on the functional requirements of operating machinery,the schematic diagram of the hydraulic system of the whole machine is constructed to match the wireless remote control scheme for the hydraulic system of the whole machine,and the relevant components of the hydraulic system are calculated and selected;based on Ackermann steering theory,a three-degree of freedom dynamic model of four-wheel steering with proportional virtual rotation angle of the front and rear wheels is established,and the lateral deviation performance parameters of four-wheel steering(4WS)and front wheel steering(2WS)are compared and simulated at high and low speeds using visual system modeling and simulation tools.The comparison shows that 4WS can obviously improve the maneuverability and stability of the operating vehicle.(3)Simulation analysis of the synchronization of the whole walking hydraulic motor and the supporting scheme of the functional module.Based on the walking hydraulic system circuit,the hydraulic simulation technology is used to simulate the synchrony of the hydraulic motor of the hydraulic walking system,the virtual prototype technology is used to evaluate the quality attributes of the operating machinery,the operating machinery is counterbalanced according to the offset of the mass center,based on different counterweight loads,the simulation circuit is used to compare and analyze the rotation speed of each hydraulic motor by whether it is connected to the shunt collector valve,verifying that the shunt collector valve can significantly improve the synchrony of each hydraulic motor;on the basis of the mechanical chassis of vegetable operation,the preliminary matching scheme of the operating machinery of functional modules such as transplanting,spraying,and harvesting is completed.