Research On The Key Technology Of Dentate Disc Cotton-stalk Uprooting Machine

As a by-product of cotton production,cotton-stalk is a high-quality biomass resource with high utilization value.In comparison with cutting collection or crushing and then returning to the field,cotton-stalk uprooting has better economic value and agronomic value.Due to the lack of thorough research on the mechanism and technology of cotton-stalk uprooting,the existing cotton-stalk uprooting machinery has low removal rate and unstable operation effect,which affected the promotion and application of cotton-stalk uprooting equipment,and further restricted the cotton-stalk utilization.Aiming at the above problems,the research on cotton-stalk uprooting technology was carried out based on the dentate disc type cotton-stalk uprooting mechanism in this paper,and an electro-hydraulic controlled multi-row cotton-stalk uprooting machine was developed and its working parameters were optimized.The main work is as follows:A typical cotton variety K836 was selected to study the tensile,shearing and bending mechanical properties of cotton-stalk.When the moisture content was between 58.87% and 18.01%,the tensile failure load of cotton-stalk was 2434.0 N-4759.8 N,the bending failure load was 167.89 N-276.33 N,and the shearing failure load is 785.01 N-1618.14 N.The tensile strength of cotton-stalk was positively correlated with the moisture content,while the bending strength was negatively correlated with the moisture content.The shearing strength decreased first and then increased with the decrease of water content.The average tensile failure load of cotton-stalk was 1.81-3.98 times of the average shearing failure load,and the difference was the largest when the moisture content was 28.13%.A platform was designed to measure the uprooting resistance of cotton-stalk.Taking the uprooting angle and uprooting speed as the influencing factors and the peak value of the uprooting resistance and the corresponding displacement as the evaluation index,the testing of the uprooting resistance of cotton-stalk was carried out.The results showed that the peak value of uprooting resistance was positively correlated with the uprooting angle and the uprooting speed.There was a negative correlation between the peak displacement of uprooting resistance and the uprooting angle as a whole,and there was little difference between the peak displacements of uprooting resistance under different uprooting speeds.The tensile failure load of the cotton-stalk was much higher than the peak value of the uprooting resistance.When uprooting the cotton-stalk,it should avoid or reduce the bending or shearing load on the cotton-stalk.The influence of working parameters such as dentate disc speed ratio,cotton-stalk offset and dentate disc inclination angle on the cotton-stalk uprooting distance was emphatically analyzed.It was found that when the dentate disc speed ratio was greater than 0.7963,there was a "pressing down" effect.It was proved that the dentate disc inclined arrangement could reduce or counteract the "pressing down" effect of the dentate disc,and the down tilt effect was better than the up tilt effect.The cotton-stalk uprooting test bench was set up and the laboratory uprooting test was carried out.High speed photography method was used to confirm that there was a "pressing down" effect under specific working parameters,which was related to the moisture content of cotton-stalk and soil properties.A multi-row dentate disc cotton-stalk uprooting machine was designed based on the electro-hydraulic control technology and field experiments were carried on.The influence of the speed ratio of the dentate disc on the cotton-stalk uprooting effect was studied through a single factor test.Test results showed that the speed ratio has a very significant effect on the omission rate and the fracture rate,and the reasonable range of the speed ratio is 0.40-0.75.Response surface method was used to study the influence of the circumferential speed,the forward speed and the inclination angle of the dentate disc on the removal rate,the fracture rate and the omission rate of cotton-stalk.The order of the influence of various factors on the cotton-stalk removal rate was: the forward speed of the dentate disc > the rotation speed of the dentate disc > the inclination angle of the dentate disc.The main reason affecting the removal rate is the fracture of cotton-stalk,and the secondary reason is the omission of cotton-stalk.The significant order of the influence of each factor on the cotton-stalk fracture rate was: the forward speed of the dentate disc > the rotational speed of the dentate disc > the inclination angle of the dentate disc.The significant order of the influence of each factor on the cotton-stalk omission rate was: the rotational speed of the dentate disc > the forward speed of the dentate disc > the inclination angle of the dentate disc.The optimum working parameter combination of the dentate disc cotton-stalk uprooting device was that 16 r/min of the rotation speed of the dentate disc(0.42 m/s of the circumferential speed of the dentate disk),0.86 m/s of the forward speed of the dentate disc,and 10° of the inclination angle of the dentate disc.At this time,the test results showed that the cotton-stalk removal rate was 97.18%,the fracture rate was 1.69%,and the omission rate was 1.13%.In this paper,the mechanical properties,uprooting resistance,motion characteristics,bench test,field test and other aspects of the dentate disc cotton-stalk uprooting mechanism are systematically studied.The operating characteristics of the dentate disc cotton-stalk uprooting mechanism were comprehensively analyzed,which provides a systematic theoretical reference for the design and application of the dentate disc cotton-stalk uprooting machine.