Study On Chassis Stability And On-line Drug Mixing Technology Of High Gap Plant Protection Machine

According to the research status of high gap plant protection machinery and technology,focusing on the working environment of paddy field in South China,the research on chassis stability and on-line drug mixing technology of high gap plant protection machine is proposed.In order to realize the high-precision plant protection operation in the paddy field in the South and ensure the effect of plant protection spray,the paper analyzes the chassis stability of the highland gap plant protection machine and the related theoretical basis of online mixing technology.Through the study of fuselage leveling control technology,the mechanism of high altitude chassis paddy field subsidence,the slip characteristics and the precise on-line mixing technology,the theoretical derivation and simulation analysis are carried out.Experimental verification and other methods,respectively,from the chassis stability,the sliding characteristics of the running device and the accuracy of mixing,ensure the effect of plant protection spray,improve the efficiency of operation,and reduce the amount of pesticide use.The main research contents and conclusions of this paper are as follows:(1)Taking the high clearance operation chassis used by the high clearance plant protection machine as the research object,using the ground clearance adjustment mechanism of the chassis,this paper focuses on the fuselage leveling technology of the high clearance operation Chassis Based on the four-point leveling theory.Firstly,by establishing the mathematical model of chassis leveling technology,the theoretical basis of four point leveling scheme of chassis based on high clearance operation is analyzed,and the virtual leg of chassis is discussed.At the same time,the matching test of driving and executing components of the leveling system is carried out through relevant tests.On this basis,the static and dynamic tests for the leveling system are carried out.The test data show that the average error angle in the static leveling test is 0.26°,and the maximum error is 0.48°.During the test,the root mean square value is 0.29 °.The average completion time of dynamic leveling response is 0.48 s,the average value of the maximum error of dynamic leveling is 0.83 °,and the maximum error value of root mean square is 0.36.Finally,through the simulation of the actual spray operation on the undulating road surface,and through the droplet deposition comparison test,the test results show that the adjustment of the fuselage posture by the dynamic leveling system ensures the overall level of the boom to be leveled,so the deposition data is improved obviously,and the droplet deposition amount in the working area is improved obviously compared with the closed state.(2)Combined with the special soil environment of paddy field in South China,the paddy field passing performance and settlement mechanism of high gap operation chassis are studied to provide platform guarantee for high gap plant protection operation.Firstly,based on the analysis of paddy soil characteristics,the wheel ground mechanics model of high ground gap operation chassis is established,which provides a model support for the subsequent analysis of high ground gap operation chassis settlement mechanism.Secondly,the original settlement prediction model is established through the force analysis of the wheels of the chassis with high clearance.At the same time,the parameters of the original settlement prediction model of the chassis with high clearance are modified through variable test.On this basis,through the test method,the passing performance of high clearance chassis affected by different tire parameters and different load conditions is compared and analyzed.By analyzing the relationship between spray volume and vehicle speed,a modified compensation relationship based on slip rate and vehicle speed is established.The test results show that the traction characteristics,driving characteristics and settlement of the chassis for high clearance operation are improved.With the increase of wheel diameter,the traction characteristics are improved from 3.16 kn to 3.64 kn,and the performance is improved by15.2%;The driving characteristics(hydraulic motor feedback driving torque)increased from1709 nm to 1824 nm,and the performance increased by 6.7%;The maximum settlement decreased from 432 mm to 375 mm,and the settlement decreased by 13.2%.When the slip rate is 0.5 and the tire width increases from 0.1M to 0.14 m,the cut in angle decreases from34.4 to 30.3,a decrease of 11.9%.When the load increases and the slip rate is 0.5,the traction force increases from 3.76 kn to 4.13 kn,and the traction characteristic increases by9.84%;In addition,the settlement increased from 369 mm to 402 mm,and the settlement increased by 8.94%.When the load changes,the driving coefficient is directly proportional to the traction coefficient,and the tire resistance coefficient is inversely proportional to the traction coefficient.When the slip rate is 0.5,the traction coefficient decreases from 0.57 to0.45,down by 21%.In order to ensure the quality of plant protection operation,the spray volume is corrected in real time by improving chassis passing and slip ratio..(3)By discussing the convection diffusion and jet motion in the mixing process,the basic motion characteristics and theoretical concentration distribution of the injection and jet mixing used in this paper are determined.At the same time,the turbulent diffusion of the internal flow field of the mixer based on the combination of injection and jet is discussed,The turbulent diffusion equation of the flow field in the mixer is determined based on the Euler method.Combined with the advantages and disadvantages of the existing jet mixer and injection mixer,and combined with the actual technical parameter requirements of the project,the three mixers designed by the cylindrical mixer,two-stage jet mixer and ball head cone tail mixer are compared and simulated,the relevant structural parameters are optimized and determined through single factor,orthogonal and other analysis and comparison methods,and the relatively optimal conclusion is put forward,At the same time,the time and space distribution uniformity of the mixing process of the three mixers and supporting mixing systems in the laboratory and field were studied.The laboratory test data show that the three mixers and the supporting mixing system have relatively stable mixing performance.Among them,the laboratory test performance of the ball head cone tail mixer is the best.The field test based on the ball head cone tail mixer shows that the mixing performance is slightly worse than the laboratory performance in some cases due to the influence of factors such as the high clearance chassis and the driving of the mixing system,The field test data carried on3wzg-3000 m multi-functional high clearance chassis showed that when the mixing ratio was1:1200 and 1:2500,the CV values were 12.31% and 9.98% respectively;The field test data carried on 3wp-750 paddy field high gap chassis show that the field test data of paddy field chassis change more greatly than that of dry land chassis.When the mixing ratio is 1:1500,1:250 and 1:3000,the CV values are 11.78%,11.58% and 10.56% respectively,which can meet the actual use needs as a whole.Provide accurate proportioning and uniform mixing at the front end to ensure the quality of subsequent plant protection operations.The platform provides technical support for the quality of the spray operation of the highland gap operation chassis from three aspects,namely,the high floor operation chassis itself,the high ground gap plant protection machine operation parameters matching,and online mixing technology,so as to provide technical support for the realization of high-precision precision plant protection operation,and provide reference for further in-depth study of the high altitude gap plant protection machine and related technologies.