Research On Cntrolling System Of Orchard Automatic Spray Machine Based On Infrared Scanning

With the rapid development of economy, People's demands for fruit keep increasing, as well as the quality requirements of fruit. However, the backward orchard spray machine and spraying technology limit the development of fruits, which brings along with a great contradiction between the high quality requirement and the low spraying technology. The behindhand spraying technology also leads to high labor intensity,low efficiency,much harm and even pesticide squandered,high residual volume,water and soil pollution. In conclusion, it is necessary to conduct the research on controlling system of orchard automatic spray machine to improve the development of spraying technology in our country.This thesis aims to design a controlling system of orchard automatic spray machine, so as to realize the function of targeted spraying in orchard, reducing the volume of pesticide, improving utilization ratio of spraying and decreasing pollution. The mechanical drive was chosen as the infrared scanning method. The AT89S52 SCM was used as microcontroller. The hardware circuit,control software,mechanical transmission part and hydraulic circuit of the controlling system were designed respectively in this thesis.(1)System scheme was designed. The controlling system of orchard automatic spray machine was made up with fruiter information monitoring system,Control Unit,hydraulic circuit system and power take-off system.(2)The design of fruiter information monitoring system was finished. The crank mechanism which was used to realize vertical alternate motion of the infrared light electric switch was designed based on the minimum transmission angle 45°.The scan path of the switch was similar with sine curve. The stepping motor provided power for the whole mechanism. Speed control circuit of the stepping motor was designed and the scanning speed could be controlled.(3)Hardware circuit and control software of Control Unit were designed. The AT89S52 SCM was used as microcontroller. Solenoid valve was controlled by the output signal of infrared detection switch. Solenoid valve was driven by solid-state relay. The electrical isolation between SCM system and electromagnetic valve load was realized. Control software comprised initializer,main program,delay subroutine and delay measurement procedure etc. Delay procedure was used to avoid the frequent movement of solenoid valve, so as to increase the service life.(4)Hydraulic circuit system was designed. Hydraulic circuit was the basis hardware system of automatic spray machine, which was made up with liquid pump,solenoid valve,spray lances,sprayers,channels and joint etc.(5)Sub-experiment and overall test of controlling system were conducted. The results showed:The distance that ensured normal work of stitch between trees and infrared light electric switch was 70~80cm; The solenoid valve could work normally if pressure in the hydraulic circuit system was less than 1Mpa. Scanning cycle was 0.5s. The speed of advance is 1m/s. The minimum separation distance of trees which could be detected was 15cm~20cm if the delayed time was 0.5s and closed delayed time was 0.1s; The system could meet the spraying requirement in the orchard.