Study On Height Control Of Corn Harvester In Hilly And Mountainous Area

Corn harvester is a kind of agricultural machinery which can complete the task of harvesting corn in mature period according to harvest requirements.It plays an important role in agricultural production and can effectively improve labor productivity and harvest efficiency.At present,different types of corn harvesters have appeared in the market,which are widely used in most areas such as the plain of our country.However,due to the complex and changeable topography of our country,especially in some hilly and mountainous areas,there are many characteristics,such as high mountains and steep slopes,scattered cultivated land and so on.In addition,people’s lack of understanding of mechanized production and the limitation of physical and geographical conditions have resulted in a serious lack of research and development of corn harvester in this field,especially the harvester can not automatically adjust according to different topography and slope changes.it is very easy to cause the phenomenon of missing cutting,which makes the level of mechanical harvest in hilly and mountainous areas on the low side.In view of the above problems,this paper studies the height control of corn harvester in hilly and mountainous areas,and designs a height control system of corn harvester in hilly and mountainous areas.the system is mainly composed of terrain change detection device,cutting table change detection device,electromechanical hydraulic adjustment mechanism and electronic control unit.The main contents of the study are as follows:(1)A kind of electrohydraulic regulating mechanism of cutting table is designed.based on the hydraulic mechanism of the original car,the mechanical-electro-hydraulic coupling power system is established,which is mainly divided into harvester subsystem,cutting table connecting rod subsystem and wire-controlled hydraulic subsystem and the dynamics of each subsystem is modeled.According to the regulation requirements of the cutting table of the corn harvester in the hilly and mountainous area,the matching design method of each part of the wire-controlled hydraulic system is put forward,including using the three-position four-way proportional solenoid valve as the direct control device for the lifting of the cutting table,the parameters of the hydraulic cylinder and hydraulic gear pump are designed according to the flow characteristics and output characteristics,and the harvesting operation is designed with PWM duty cycle of50%,so that the matching parameters are optimized.(2)A biaxial voltage output inclination sensor is used as the terrain change detection device and the cutting table change detection device to detect the change angle in real time,and the voltage signal is input to the electronic control unit.compared with other types of sensors,the results show that the sensor is not affected by weather,terrain and ground weeds,and the detection angle error is minimum.(3)A cutting table height control system is designed,which is mainly composed of hardware design and software design.The hardware design mainly includes the minimum system module,switch module,analog module,communication module and PCB board design.The software design mainly includes fuzzy PID control algorithm,as the control algorithm of cutting table height adjustment;designed three control strategies of the system with different detection angle range;using keil uvision5 software development platform to develop the main program module,measurement module,serial communication module,other modules and so on.On this basis,the test platform is built by AMESim simulation software,and the test scheme is designed.The simulation results show that the control of the system meets the design requirements.(4)The subject takes the hilly and mountainous area as the test site and the corn harvester as the test object.the test results show that the adjustment time of hydraulic cylinder piston connecting rod reaching balance is 1s in the process of 10 °slope on the harvester,and the adjusting time of hydraulic cylinder piston connecting rod in the process of 5 °slope is 0.6s,and the balance position of hydraulic cylinder is controlled within 0-5cm.The expected design goal has been achieved.