DEM-based parameter optimization and tests of digging green onions

In view of the problems of easy damage and high digging resistance in the process of green onion harvesting,a mechanical model of digging green onions was established by taking the moment of digging and drawing green onions as the research object,and the main factors affecting the digging and harvesting effect were determined as the angle of digging,the dip angle of clamping carrier and the length of shovel.Thus,a complex simulation model of soil-green onion-digging mechanism system reflecting the state of harvesting was established,and the model was verified by testing soil compactness.The simulation tests were carried out by means of the complex simulation model of soil-green onion-digging mechanism system,making it clear that digging angle and the length of shovel have a extremely significant impact on the digging resistance,and the dip angle of the clamping carrier had a significant impact on the digging resistance.Through target optimization,the optimal combination of digging parameters was obtained,namely,the digging angle of 20°,the dip angle of clamping carrier of 25°and the shovel length of 70 mm,with the digging resistance of 1394 N at this moment.The field digging resistance test has showed that the average digging resistance is 1543 N with the average clamping damage rate of 1.27%and the average clamping loss rate of 0.44%,which can meet the requirements of green onion harvesting.

Optimized design of the 4TSQ-2 sugar beet top cutting machine

To solve the problems faced by 4TSQ-2 sugar beet top cutting machine,i.e.large structure,high power consumption and high manufacturing cost,the multi-roller mechanism for leaves removal and fixed-thickness cutting method was studied.Using five-factor and two-level tests,the structure configuration of the leaf removal device was optimized,and the scheme of two roller shafts defoliation,the roller shaft rotation speed of 800 r/min and the forward speed of 0.8 m/s were determined.Through the working process and mechanical analysis of the top cutting device,the cutting device with the slant profiling plate structure characterized by a profiling angle of 25°-45°for the profiling plate and a cutting angle of 20°-40°was studied.With the two-factor and three-level experiments,the profiling angle of profiling plate of the top cutting device was 35°,and the cutting angle was 30°.Compared with the 4TSQ-2 sugar beet top cutting machine before optimization,the structure size of the machine was reduced by 30%,the weight was reduced by 15%,the cost was reduced by 25%,the qualified rate of top cutting wad was increased by 2.6%,and the push over rate of sugar beet was reduced by 0.5%.Besides,each index met the index requirements of beet top cutting harvest.