| In this paper,aiming at the problem that the domestic air suction seeder fan is driven by the tractor’s power take-off shaft,when the tractor slows down and turns in the field,the negative pressure of the fan is reduced due to the lack of power,which causes the problem of missing seeding.The drive system of the fan is studied.Simulation and test results show that the hydraulic drive and control system of the fan can make the tractor still meet the pressure demand of the air suction seeder even when it is idle,which solves the problem of missing sowing due to the reduced fan pressure when the ground turns,and greatly improves the efficiency of sowing operation.The main research works are as follows:(1)First,the research on the pneumatic system of pneumatic seeders at home and abroad is introduced.The current situation and existing problems of the research on the fan system of the seeder are analyzed,and the entry point of the research is found.The overall scheme of the fan hydraulic drive system has been determined.(2)According to the overall scheme,the specific design has been carried out,the hydraulic schematic diagram of the fan hydraulic drive has been established,and the components of the whole system have been selected through design and calculation.The hydraulic system has been simulated by AMESim software,and the results show that the scheme of the hydraulic motor driving fans can meet the requirements.(3)For the determined overall scheme,the electro-hydraulic proportional control system of fan pressure has been established.The proportional speed control valve has been selected as the control element of the system,and the PID control strategy has been adopted.The simulation results show that the hydraulic drive system with PID control has higher stability and faster system response.(4)Taking Siemens S7-200 SMART PLC as the main controller,the analog acquisition program of speed and pressure and the analog output program of PID control are designed.The configuration interface has been designed with an MCGS touchscreen,and the communication between HMI and PLC has been established.The pressure and speed of the current fan hydraulic drive system can be detected by the touch screen software,and the pressure value can be set according to the need to realize the automatic adjustment of the fan pressure.(5)The sowing experiment has been designed,the pressure of the fan at different speeds of the tractor engine is recorded,and the pressure change range of the fan is determined.It has been found that even when the engine is in the idle state,the pressure of the fan could meet the adsorption requirements of the seed metering device for the seed,that is,the problem of missing sowing has been avoided when the fan is driven by the power output shaft and the tractor is in the idle state due to the decrease of the negative pressure provided by the fan. |
