Study On The Key Technology Of Riding Paddy Field Cultivator

In paddy field ecosystem,weeds and rice compete for growth space,fertilizer nutrient,light,heat and other resources,which is one of the main reasons for the decrease of rice yield and quality.Effective control of paddy field grass is of great significance to improve rice yield and quality.Application of chemical herbicides is widely used in a weed control of rice fields,but a large number of high frequency of application will cause weed resistance,crop damage,environmental pollution and other issues.In recent years,mechanical weeding as a non-chemical pollution,environmentally friendly weeding way has been a greater development.The paddy field intertillage weeder can be divided into two types: walking and riding.The riding type intertillage weeder for paddy is more efficient than walking type intertillage weeder for paddy,and the labor intensity is small,but there are problems such as complex structure and high field injury rate.In this paper,we developed a riding type intertillage weeder for paddy with simple structure and automatic avoidance seedlings function,and the theoretical research,structural design and field experiment of the whole machine and the key weed parts were carried out.The main contents are as follows:(1)According to the distribution characteristics of the seedling belt of rice transplanting with machine,the whole body of the riding type intertillage weeder for paddy that match the operation of the high-speed transplanter was designed,and the combination frame with automatic avoidance seedlings function was developed by applying virtual prototyping and hydraulic transmission technology.According to the characteristics of a group of six rows of transplanting seedlings,the whole structure of the riding type intertillage weeder for paddy was designed.The machine was powered by 12 kW paddy field tractor,including combination frame with row-follow and avoidance seedlings function,profiling mechanis m and key herbicidal components.According to adjustable distance and mechanical structure requirements for lateral slip adjustment and angle corrective adjustment of combination frame,the structural parameters of the frame are determined by the motion analysis method,and the combination frame with the function of automatic avoidance seedlings is established.The dynamic requirements of the hydraulic system are analyzed,and the design of the hydraulic system of the riding type weeder for paddy is completed.(2)According to the growth and mechanical characteristics of weeds in paddy field and the mechanical properties of paddy soil,spiral cutter teeth weeding roll was designed.The finite element fluid-solid coupling simulation method was used to optimize the structure of the cutter teeth,and the weeding performance of different width was tested in field.The growth characteristics and mechanical properties of the main weeds in paddy field were analyzed,and the best period of intertillage weeding was de termined.According to the mechanical characteristics of paddy soil,the helical teeth with strong soil action were developed,and the structure and size of the weeding roll were determined.The trajectory analysis of the weeding roll was carried out,obta ining the optimal width of the cutter teeth and the depth of the weeding roll.The finite element flow-solid coupling simulation analysis method is used to simulate the operation process of different tooth width weeding roll.The results show that the resistance and the perturbation ability to the soil are increased with the increase of the tooth width.When the width of the tooth is ?30mm,the disturbance ability of the different tooth width to the soil is not significant.Field weeding performance test was carried out using different width of the weeding roll.The results showed that the weeding rate increased with the increase of the tooth width,and the weeding rate was more than 85% when the width of the teeth was ?30mm.According to the resistance of the weeding roll and the disturbance ability of the soil.The size of cutter teeth are optimized to be 200 mm × 30 mm.(3)The field performance test of the riding type intertillage weeder for paddy was carried out,and the influencing factors affecting the working performance were analyzed.The yield difference between the mechanical weeding and the chemical weeding was compared.The speed of the machine and the depth of the weeding roll were used as the experimental factors in full factorial test.The herbic idal rate and seeding injury rate of the machine were used as the experimental index,The field weeding performance test was carried out on a riding type intertillage weeder for paddy.The weeding rate and seedling injury rate under different factors was compared by range analysis and obtained two optimal combination.When the advancing speed was 0.6m/s and the depth of weeding was 6cm,the weeding rate was 87.2% and the rate of seedling injury was 0%.When the advancing speed was 0.6m/s and the depth of weeding was 9cm,the weeding rate was 92.0% and the rate of seedling injury was 4.3%.Under the condition of different running speed and weeding depth,the average weeding rate of the whole machine was 82% and the average seedling injury rate was 4.8%.Meanwhile,when the working efficiency of the machine was 0.2 hm2/h~0.6 hm2/h,could meet requirements of field intertillage weeding quality and work efficiency.A yield comparative experiment was conducted on different weeds control models.It was concluded that the average yield of mechanical weeding was higher than that of chemical weeding.Mechanical weeding has some damage to the rice seedlings,but the mechanical weeding has the effect of cultivating,which can promote effectively tiller of rice seedling and then increase the yield.