Design And Development Of Measurement And Control System Of Straw Substrate Mulching Machine

In recent years,the intensive planting technology of dwarf apple has been actively introduced into Weibei dry plateau in China.However,the dry and barren soil in the region restricted the technology advantage.At the same time,a lot of crop straw and other agricultural waste resources in the region are not utilized efficiently.Aiming at the above problems,the research group proposed the straw mechanized layered overlay technology,and developed the covering machine.This machine can complete straw substrate mulching and thin soil mulching at a time,but it has low degree of automation,difficulty in operation and unable to realize the operation state parameters and working effect of the cover machine in real time.Therefore,it is necessary to design and develop a measure and control system of straw mulching machine.Setting the STM32 MCU as the core,a measure and control system was designed,developed and tested in this research.The main works and results are as follows:(1)Put forward the overall design scheme of straw substrate mulching machine: based on the analysis of the structure and working process of covering machine,the speed,diesel oil level,hydraulic oil temperature,battery voltage and coverage effect video was set as monitoring objects,the hydraulic motors of discharging roll,scraper device and soil covering mechanism were set as the auxiliary operation control objects.Setting the STM32 MCU as the core,the overall scheme design was carried out by using the upper and lower computer of secondary distributed structure.(2)The hardware circuit design of measure and control system: choose the hardware modules according to the function planning,and hardware modules were designed which include the MCU minimum system,vehicle condition acquisition module,working parameters acquisition module,auxiliary operation control module and serial port communication module.The results of simulation test shows that auxiliary operation control module had a good signal conditioning effect,whose signal conditioning time is less than 0.1s and the error range is less than 0.63%.(3)The software design of measure and control system: the MCU program is programmed based on the Keil uVision5 software,which used the modular programming ideas,including the system main program,vehicle condition acquisition subprogram,working parameters information acquisition subprogram and auxiliary operation controlling subprogram;the man-machine interface was designed by using Kinco HMIware configuration software,mainly include parameter input area,video monitoring area and parameter monitoring area;the serial port communication subprogram was programmed based on the modbus-RTU communication protocol,which realized the communication of the upper and lower computer.(4)Application system integration and test analysis: the auxiliary operation controlling relation chart of the straw mulching machine is established,which according to the relationship between the material thickness and soil thickness with the mechanical parameters and combining with electro-hydraulic proportional speed control valve governor control characteristics;Test results show that the error range of vehicle condition monitoring information acquisition module is not more than 3.3%,which include diesel oil level,hydraulic oil temperature and battery voltage;the error range of operation parameter information acquisition module is not more than 1.4%,which include driving speed,discharging roll speed,scraper device speed and soil covering mechanism speed;the error range of the output rotational speed of auxiliary operation module is not more than 3.3%,and the hardware and software modules had a good performance.The vehicle condition,operation parameter information and coverage effect video could be monitored by measure and control system,which also had an alarm reminding and a certain auxiliary operation function.