| Due to Rapeseed Stalk multi-purpose development of the food demand,lack of existing Rapeseed Stalk harvest machinery,artificial picking efficiency is low,the cost is high,the comprehensive analysis of stems leaf vegetables to harvest technology and equipment at home and abroad research status quo,on the basis of combining the material properties of Rapeseed Stalk and agronomic requirements,developed a kind of Rapeseed Stalk self-propelled harvester,which can realize the walk,automatic lifting,stem leaf unified collection,Finish cutting,conveying and collecting of Rapeseed Stalk in one time.The research contents and conclusions are as follows:(1)The phenotype and mechanical and physical characteristics of Rapeseed Stalk were tested and analyzed.The phenotypic of Rapeseed Stalk test results indicated that the average plant height was 539.60 mm,the average density was 38 plants/m~2,and the average moisture content was 90.77%.The results of mechanical and physical properties showed that the shear strength of stem ranged from 0.31 to 6.53 MPa,and the bending strength ranged from 2.04 to 16.16 MPa,indicating that Rapeseed Stalk was weak and vulnerable,and flexible devices should be used as far as possible during harvest.The lawn pattern conveyor belt with large friction angle was preferred,and the minimum angle of Rapeseed Stalk without sliding was 36.1°.(2)The overall design and parameter of Rapeseed Stalk self-propelled harvester were analyzed and determined.Based on the agronomic requirements and material characteristics of Rapeseed Stalk,the overall structure,technological flow and main technical parameters of harvester were determined;Rapeseed Stalk self-propelled harvester mainly includes walking device,rotary wheel device,cutting device,conveying device and cutting table double lifting device,it can realize self-walking,automatic lifting,unified collection of stems and leaves,and complete the cutting,transportation and collection of Rapeseed Stalk at once;The machine cutting table lifting height adjustment range was150～600 mm,the working width was 1800 mm,the maximum up and down slope angle was 21°,the theoretical turning radius was 750～1650 mm.(3)The structure and parameters of key parts of Rapeseed Stalk self-propelled harvester were designed and analyzed.It mainly includes:(1)Crawler type high gap chassis was used as the walking device,the width of the crawler was 180mm,the height of the frame from the ground was 500 mm,and the adjustable range of the center distance of the crawler was 1500mm～2300 mm;(2)The cutting device was a reciprocating double-action cutter driven by a double eccentric mechanism,the eccentric speed was 200～1000 r/min;(3)By analyzing the process and the movement track of the eccentric wheel,determined the rotary wheel radius was 260 mm,rotary speed ratio was 2,the number of rod was 3,the installation height was 250～450 mm;The impact analysis was carried out,which reached a conclusion that increasing the impact time could reduce the force on Rapeseed Stalk plant and then reduce the damage of Rapeseed Stalk;(4)The belt inclined conveying device is adopted.PVC material and lawn pattern structure were selected as conveying belt,and the rotational speed of active roller was 44.6～223 r/min;(5)Adopting the form of"tilt lifting+rotary lifting",the mechanical analysis and geometric analysis of the double lifting device of the cutting table were carried out,and the adjustment height range of the cutting table was determined to be 150～600 mm,and the best installation position of the push rod was obtained;(6)Completed the power demand analysis and motor selection of each device.The diesel engine with rated power of 11 k W and rotational speed of 3600 r/min was adopted for the walking device.The harvesting system adopts brushless DC motor with rated power of 48 V.The motor power of cutting motor,rotary wheel motor and conveying device was0.6k W,0.2 k W and 0.2k W respectively.The speed was 1000 r/min,120 r/min and 150 r/min respectively.(4)The performance test,bench test and field test of Rapeseed Stalk self-propelled harvester were carried out.Specific as follows:(1)The test results of the performance test showed that the harvester can smoothly complete forward uphill,forward downhill,backward uphill and backward downhill on a 12°slope.The turning radius of the harvester on hard road and soft soil was 1780 mm and 1960mm respectively,and the linear offset was 0.40%and 0.50%respectively,which were both less than 6%of the allowable requirements,and can meet the needs of road transportation and field operation;(2)Single factor test and orthogonal test were carried out using forward speed,cutting line speed,conveyor belt line speed and rotary speed as factor level and the comprehensive score as evaluation index.The single factor test results showed that when the forward speed was0.2-0.8 m/s,the cutting line speed was 0.3-0.5 m/s,the conveyor belt line speed was 0.4-0.6 m/s,and the rotary speed was 40-60 r/min,the harvest loss rate was lower.The results of orthogonal test showed that the order of influencing factors on harvest loss rate was as follows:forward speed>rotary speed>conveyor belt line speed>cutting line speed;The optimal combination of parameters was as follows:forward speed 0.56 m/s,cutting speed0.50 m/s,conveyor belt speed 0.79 m/s and rotary speed 49.70 r/min.Under the optimal combination of parameters,the comprehensive score was 4.74%;(3)Field experiments showed that:after harvester operation,the Rapeseed Stalk plants cut the stubble neatly,and the harvester operation efficiency was 0.36 hm~2/h;Under the optimal parameter combination,the comprehensive score of the first crop and the second crop were 4.95%and 5.13%,the relative errors were 0.21%and 0.39%,the missed cutting rate was 4.28%and 4.84%,and the transport failure rate was 3.42%and 3.73%,The damage rates of stem and leaf were 6.39%and 6.12%,respectively,which could meet the actual production demand of Rapeseed Stalk. |
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