Research On Boom Height Adjustment And Self-balancing System Of Sprayer

With the demand of agricultural operation,agricultural machinery is developing towards large-scale and intelligent.In agricultural plant protection,boom sprayer occupies a leading position.In order to achieve good uniformity of droplet deposition during spray operation,the boom must be maintained in parallel with the crop canopy at a certain height in real time.At present,the domestic large scale boom sprayer is seldom equipped with active balance control.In this paper,the relative height measurement of 24 m sprayed boom sprayer,the pre judgment of the position of the rotor,the adjustment of the boom height and the active balance of the boom are carried out.(1)Revamping the hydraulic system of the spray rod according to the requirements,selecting the hardware for the research content,setting up the height adjustment and self-balancing control system of the spray rod,and making the control cabinet.(2)Aiming at the problem of low accuracy of measuring relative canopy height of spray rod with a single ultrasonic sensor,a new type of measuring device for relative canopy height of spray rod was designed,and data filtering methods for different kinds of crops(wide and narrow leaves)were proposed.In order to evaluate the performance of the measuring device,field experiments were carried out.The results showed that the average errors of relative ground height and relative canopy height of broad-leaved crops were no more than 3 cm and 11.1 cm,and the relative errors were no more than 2% and 17.45%.The average errors of relative canopy height of narrow-leaved crops were no more than 2.3 cm,and the relative errors were no more than 6.63%.(3)Aiming at the problem that the rocking range of the spray rod is large under ground excitation,a model of the body roll angle and the rocking angle of the spray rod is established and simulated.The relationship between the rocking angle of the spray rod and the body roll angle is obtained.The test results show that there is a lagbetween the rocking angle of the spray rod and the body roll angle and the maximum displacement of the spray rod end.The correlation degree is high,which can be used to predict the rocking of the spray rod.(4)Aiming at the hydraulic system of non-linear spray rod,the hydraulic system models of spray rod height control and self-balancing control are established and simulated respectively.The simulation results show that when Kp=400 and Kp=200,the spray rod height control and self-balancing control can quickly reach the target position and meet the requirements of the rapidity and stability of spray rod profile control.(5)The comprehensive test of the position and attitude measurement and control of the spray rod is carried out.The test results show that the spray rod height adjusting system can be adjusted according to the system setting.The error between the actual height and the set height after adjusting is not more than 14 mm,and the accuracy is high.The spray rod self-balancing system can effectively reduce the impact of the ground on the rocking of the spray rod.Compared with the open active balancing system,the displacement of the end of the spray rod is reduced by more than 31.2%.