Research On Structural Optimization And Control Strategies For Adaptive Wheat Cutting Tables

In the context of the continuous maturation of agricultural mechanization technology,the research and development of combine harvesters with a high level of intelligence and low harvesting losses has become the main development direction,and the cutting table,as the harvesting device of the harvester,has an important impact on the harvesting operation effect.At present,the mechanical harvesting rate of wheat in China is more than 95%,but due to the low level of adaptive wheat cutting table in China,the loss rate caused by improper adjustment of the cutting table in actual production is still at a high level.Therefore,by analyzing the structural deficiencies of the domestic adaptive wheat cutting table and the factors influencing the low harvesting quality of the cutting table,this thesis proposes a structural optimization scheme that can improve the performance of the cutting table,and combines fuzzy control theory to develop a low loss rate and low stubble control strategy,which helps to improve the performance of the adaptive wheat cutting table,improve the harvesting efficiency and promote the development of grain harvesters in the direction of intelligence.The main research contents and conclusions of this thesis are as follows.(1)By comparing the structural and functional differences between the CLAAS VARIO620 and the cutting table of Guwang TB60,and by combining the working principles of the cutting tables,it is analyzed that most of the current domestic cutting table models have deficiencies such as poor crop and harvest versatility and poor real-time adjustment of harvest status.In view of the shortcomings of the domestic adaptive wheat cutting table,an optimization plan is proposed.The optimized structure was modeled using Solid Works,and structural stress simulations were carried out on the optimized parts using finite element analysis.With reference to the optimized structure,the hydraulic system of the cutting table was designed to meet the relevant functional requirements,and the key components were calculated and selected.(2)A single-factor test was carried out with the Guwang TB60 as the test model to investigate the influence law of wheat cutting table harvesting quality,using cutting table loss rate and stubble height as evaluation indexes,and using machine forward speed,cutting table height,vertical height of the reel and reel speed as test factors.The results showed that the forward speed of the implement,the height of the cutting table and the height of the reel had a greater influence on the stubble height.The regression equation for the two indicators was obtained by conducting a three-factor,five-level regression orthogonal test.The results of the regression orthogonal test showed that: the order of significance of the effect on the loss rate of the cutting table was: the forward speed of the implement> reel speed> the height of the reel;the order of significance of the effect on the stubble height was: the height of the cutting table> the forward speed of the implement>the height of the reel.(3)Based on the results of the experimental analysis,a control strategy based on fuzzy control theory using Matlab was designed to help improve the harvest quality.Theoretically,the combination of parameters for the forward speed of the implement and the speed of the reel when the loss rate of the cutting table is the lowest,as well as the combination of the cutting table height and forward speed when the stubble height is low,were obtained.To verify the feasibility of the control strategy,field validation tests were carried out and the results showed that the control strategy was feasible and effective.