仿蚯蚓运动多功能开沟器设计及参数优化

Design and parameter optimization of earthworm-like multi-function opener

针对中国东北地区春播时耕种层土壤温度和含水率较低,严重阻碍大豆根系生长,进而影响大豆发育的难题,该文通过仿生结构设计和理论分析的方法,设计了一种集松土、沟底镇压和开沟功能为一体的仿蚯蚓运动多功能开沟器,其设有的仿蚯蚓动态松土开沟机构可模拟蚯蚓的运动方式对种沟上层土壤进行疏松作业,设有的镇压力调节机构可对种沟下方土壤进行镇压作业。通过参数优化试验和回归分析的方法,研究仿蚯蚓运动多功能开沟器关键结构参数和作业速度对平均土壤温度(0~100 mm)、平均土壤含水率(0~100 mm)和大豆出苗时间的影响规律,并运用Design-Expert和Matlab软件对试验结果进行分析,得出最优参数组合为:作业速度8 km/h、松土机构凸起高度6 mm和波纹圆盘波峰数量15。通过对比验证试验,发现仿蚯蚓运动多功能开沟器相较于传统单元盘和双圆盘开沟器,可提升土壤含水率(0~100 mm)5.92%和4.86%,提高土壤温度(0~100 mm)0.5和0.4℃,提前大豆出苗时间0.5和0.92 d。仿蚯蚓运动多功能开沟器可有效改善土壤耕种层结构,使耕种层土壤达到表层松软和下层坚实的状态,有效提高土壤温度和含水率,进而促进大豆发育,可为提高中国大豆产量提供技术装备支撑。

Insufficient soil moisture content and accumulated temperature of the plow layer during springtime tillage inNortheast China severely restrict soybean root growth and soybean development. Aiming at these issues, bionics structuredesign and theoretical analysis were methodologically combined to design an earthworm-like multi-function opener, which hasthe function of loosening, furrowing and compaction. This machine could simulate the movement of the earthworm to loosesurface soil of plow layer and compact subsoil of seed ditch, which could build favorable seedbeds with soft surface soil andthe compacted subsoil, and then significantly raise the soil temperature and soil moisture content of plow layer, which couldsignificantly promote soybean emergence and development. Parameter optimization experiments and regression analysismethods were adopted to study how key structure parameters and operating speed of earthworm-like multi-function openeraffected average soil temperature （0-100 mm）, average soil moisture （0-100 mm） and emergence time of soybean. Experimentdata obtained were assessed by the analysis of variance （ANOVA） and quadratic regression model was set up for optimizationby response surface methodology with Design-Expert. Analyses showed that operating speed, scarification mechanism bumpheight and number of crests of corrugated disk had a significant effect （P〈0.01） on average soil moisture content （0-100 mm）,average soil temperature （0-100 mm） and average emergence time. Operating speed had a significant interaction with bumpheight and number of crests respectively and there was no interaction between bump height and number of crests. The averagesoil moisture content （0-100 mm） decreased with the increase of the advancing operating speed, and the decline trend graduallydecreased. The average soil moisture content （0-100 mm） decreased with the increase of the bump height and the number ofcrests, and the decline trend gradually decreased. The average soil temperature （0-100 mm） increased with the acceleration ofthe operating speed, and the upward trend slowed down gradually. With the increase of bump height and the number of crests,the average soil temperature （0-100 mm） presented a rising tendency, and the rising trend decreased gradually. With theincrease of operating speed, the average emergence time decreased first and then increased. The average emergence time ofsoybean increased after slight decrease with the increase of the height of bump. As the number of crests increased, the averageemergence time decreased at first, and then rose. Earliest average emergence time was taken as main optimization index toobtain the optimal parameters by using MATLAB software based on the analysis of the test results and the model fitting. It wasfound that the optimal parameters of earthworm-like multi-function opener were as follows： operating speed of 8 km/h, bumpheight of 6 mm and number of crests of 15. Compared with traditional single disk and double-disk opener, earthworm-likemulti-function opener could increase average soil water content （0-100 mm） by 5.92% and 4.86%, raise average soiltemperature （0-100 mm） by 0.5 and 0.4 ℃, and advance soybean emergence time by 0.5 and 0.92 d, respectively. The resultsshowed that the scarification furrowing mechanism which simulates the biological behavior of earthworms could effectivelyloosen the plow layer soil and increase the soil porosity in the plow layer so as to effectively improve the soil temperature.Meanwhile, pressure regulating mechanism could significantly accelerate the absorption of moisture from the soil beneath theplow layer by compacting subsoil of seed ditch, and then increase the soil moisture content of the soil in plow layer. This newmachine can improve physical properties of the soil in tillage layer, and ultimately achieve the purpose of promoting soybeandevelopment. This is a powerful guarantee for production of soybean per unit area in Northeast China.