Research Of Variable Spraying And Boom Balance Control System Of Potato Sprayer

The large-scale potato sprayer has become the first choice of potato spraying operation for its good spraying quality,long spraying duration and high spraying efficiency.However,the automation level of large potato sprayer in China is not high,and its variable spraying and spray boom balance technology is poor,resulting in poor spraying quality and low pesticide utilization rate.Therefore,in order to ensure good spraying quality,based on the 3WP-1200potato sprayer with spraying amplitude of 22 meters,variable spraying and spraying boom balance technology are studied in this paper.Its main design contents and conclusions are as follows:(1)Design of variable spraying control system.In order to solve the problems of unreasonable pesticide application methods and relatively simple control methods in the spraying process of large-scale wide-width sprayer,a multi-reflux variable spraying control system was designed.The control system could adjust the proportional control valve according to the running speed of the sprayer,which realized the variable spraying by changing the spray flow rate caused by the opening of the return port.The control system was divided into five paths to control all sprinklers,and each path could be controlled separately.When one or more routes were disconnected,the corresponding return port could be opened,so that the spraying quantity of the other sprinklers would not change without changing the flow rate of the system.Its multi-reflux control method made the system pressure more stable and control precision higher.At the same time,the software and hardware of the system were designed,and the variable spray control system was established.(2)Design of the balance control system of the spray boom.In order to prevent the tilt of spraying boom from affecting spraying effect,scratching crops or causing damage to spraying boom,a spraying boom balance control system of wide potato sprayer was designed to ensure the balance of spraying boom position and posture.Five ultrasonic ranging sensors and one angle sensor were used in the system.By detecting the height of the boom from the target and the rotation angle of the boom around the hinge,the extension and contraction of the hydraulic cylinder are controlled comprehensively to ensure that the height of the spray boom from the target is within a reasonable range to achieve the balance of the spray boom.At the same time,the overall structure of the sprayer,the principle of the spray boom balancing hydraulic system and the mechanical control process were designed and analyzed.The design of the software and hardware of the system was given,and the spray boom balancing control system was established.(3)Based on the above control system research,the performance tests of variable-rate spray and boom balance control system were carried out.Variable spray test mainly includes liquid level calibration test,flow control precision test and spray quantity control precision test.In the liquid level calibration test,the determination coefficient R~2 of liquid volume calibration model was 0.994.In the flow control precision test,the relative error between target flow rate and actual flow rate of a single spray head was not more than 4.1%.In the spray quantity control test,spray quantity can vary with speed.The relative error between the set spraying quantity and the actual spraying quantity was less than 6%.The spray boom balance control test mainly includes height detection and control accuracy test,spray boom lift control test and spray boom balance control test on both sides.In the height detection and control accuracy test,the relative error between the measured height of ultrasonic ranging sensor and the actual height was not more than 2.33%.In the spray boom lift control test and spray boom balance control test,the change of spray boom height can be quickly adjusted.The adjustment process was smooth,which can effectively keep the height of the spray boom in a reasonable range,and the smaller the height adjustment threshold,the higher the control accuracy.