| The agricultural tractor is an indispensable power platform in modern agricultural production,and the adjustment technology of field depth is an important branch of field management.At present,the domestic research on the cultivation depth adjustment technology is still based on a single target,and the research on multi-parameter comprehensive adjustment is not yet in-depth,and no industrialization results have been formed.Based on this,on the basis of comprehensive analysis of a variety of tillage adjustment techniques,this paper proposes a comprehensive adjustment method that takes into account tillage depth and traction,and at the same time combines the characteristics of the working unit and compares the adjustment characteristics of different control strategies.Firstly,based on the traditional hydraulic suspension system,the paper introduces electronic components to build a modern new type of electro-hydraulic suspension system,and analyzes its core components such as electro-hydraulic proportional directional valves and sensors.And by comparing the advantages and disadvantages of a variety of commonly used depth adjustment methods,applicable plots,etc.,the advantages of comprehensive adjustment of the force position are clarified;then the regulation principle and coupling process of this comprehensive adjustment method are further studied.Secondly,according to the working characteristics of the tractor depth adjustment system,combined with the existing control theory,the control principles,advantages and disadvantages of a variety of different control strategies are compared and analyzed.And on the basis of the existing fuzzy control,the variable control domain control theory with high control precision and strong adaptability is introduced into the closed-loop control of the system,the variable domain fuzzy control strategy is constructed,and the controller is designed.Thirdly,combined with the tractor farming environment and the characteristics of the adjustment system,the components of the suspension unit were modeled and analyzed.And the simulation model of the system is established with the help of Matlab/Simulink simulation software,and PID control?fuzzy control and variable domain fuzzy control are compared in step and random signals under the position adjustment,force adjustment and force position comprehensive adjustment models.The response curve below proves that the variable universe fuzzy control has a fast response,no overshoot,and can quickly reach a new steady state under abrupt signals,and has good anti-interference ability.And in order to explore the relationship between the weighting coefficient and the specific resistance of the soil,the weighting coefficients are taken to be 0?0.25?0.5?0.75and 1 in three typical farming environments where the soil specific resistance is 3 N/cm~2?4 N/cm~2and 5 N/cm~2.The group conducted a simulation comparison and obtained the reasonable value range of the weight coefficient under different soil conditions,which also reflected the superiority of the comprehensive adjustment of the force position.Finally,in order to verify the superiority of the variable universe fuzzy control strategy and the comprehensive adjustment of force position in practical work,the appropriate control chip was selected according to the characteristics of the depth adjustment system,and the system main program and key module subprograms were designed.And according to the existing test conditions,a tractor field test platform was built,and the control strategies and adjustment methods proposed in the article were compared in the selected test plots,and the comprehensive adjustment of the force position based on the variable universe fuzzy control was proved.The method is more adaptable to the complex and changing farming environment,and also obtains better load stability while ensuring the farming quality,which has great practical and popularization value. |
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