Development And Performance Test Of Automatic Target Spray Machine For Orchard

In recent years,China’s orchard area and fruit output have increased steadily.Orchard plant protection is an important link in orchard production,which directly affects the yield and quality of fruits.At present,the wind driven sprayer is widely used to carry out orchard plant protection in China.Spray droplets drift seriously,resulting in a large number of soil erosion,and there are still problems such as excessive spraying or ineffective spraying.In order to enhance the permeability of spray machine and reduce the loss of droplet drift,variable spray was applied to improve the utilization rate of pesticide according to the canopy information of fruit trees.The main research contents and results are as follows:(1)Structural design of the whole machine.The spray machine is composed of walking system,spray system and control system.The traveling system is mainly composed of crawler chassis with good trafficability;The spray system mainly includes air assisted spray and electrostatic spray.The control system mainly includes automatic target setting and variable control.(2)Hardware architecture of control system.Considering practicability,cost performance and easy popularization,ultrasonic sensor is selected as target detection;Wi Fi module establishes wireless communication between upper and lower computers;As an actuator,the solenoid valve uses pulse width modulation technology for variable control.(3)Control system software development.The software development of the lower computer is based on STM32 single chip microcomputer,which mainly realizes the driver design of each hardware module;Flow control program design,based on the canopy information collected by ultrasonic sensors,generates PWM signals to control the opening and closing of solenoid valves,and automatically spray the target variables.Wireless communication program design.The software development of upper computer is based on Android application program,establishes TCP communication and realizes the display of information collected by lower computer;Switching of spray mode;Setting of detection range parameters.(4)Prototype trial production and performance test.After the trial production,the performance test was carried out.The results showed that the median particle size of charged droplet was 89.656 when electrostatic spray was applied.μ M,compared with non electrostatic spray,droplet size decreased by 14.07%.When the elevation angle between the upper and lower air outlets and the horizontal is 30°,and the spacing is 1.25 m,the vertical distribution of droplets is the best.In the continuity test of target and non target,the target spray rate is 56.9% compared to the non target target.In the three distance spray test from target 1 m,1.2 m and 1.4 m,the target spray rate was 27.1% higher than that of the non target target.