| Under the background of agricultural mechanization,as an important agricultural machine,tractors have shown sufficient advantages and become one of indispensable tools for farmers in the process of agricultural production and transportation.When tractor is working in the field,the agricultural system is connected to the agricultural implement through the hitch system,but there are still some technical barriers to the control of the hitch system,and academic research is also based on the control of the hitch system.Therefore,this paper takes the tractor's hydraulic hitch system as the research object,analyzes its adjustment method,and studies the influence of different control parameters on the hydraulic hitch system.The followings are the main research contents of the paper:(1)Based on the existing related research,the structural characteristics of tractor hitch system are analyzed,and the hydraulic control system is designed according to working principle.Based on this control system,the hydraulic system model and hitch mechanism model of the tractor's hydraulic hitch system were established in SimulationX software,the kinematics and mechanics of hitch mechanism were analyzed to lay the foundation for the control of depth with farming tools.(2)The control strategy of the electronically controlled hydraulic hitch system is studied.Analyzed the commonly used method of tractor depth control of tractor's hitch system and the advantages and disadvantages of various adjustment methods.Comprehensive control strategy of position and slip rate was proposed,and the appropriate control algorithm is chosen to control the tractor's hydraulic hitch system.(3)Using SimulationX/Signal Block,according to the adjustment method of tractor hitch system,a control simulation model was established to study the effect of farming depth control of the suspended agricultural tools under different adjustment methods,and the Comprehensive control strategy of position and slip rate was simulated.The slip rate parameter is involved in the control of the tractor hitch system according to different proportions.(4)According to the tractor's hydraulic hitch system,the hydraulic hitch test bench is designed,position control of the hitch system is tested.Comparison between experiment and simulation,the accuracy and effectiveness of the virtual simulation model of the hydraulic hitch system established are verified,and also verified the applicability of selected PID control algorithm.In this paper,the comprehensive control strategy of position and slip rate proposed takes into account the maintenance of farming depth and slip rate of the tractor,It's conducived to improving the control level of tractor's hydraulic hitch system and improving the tractor's field tillage efficiency,which provides new ideas for the control research of tractor's hydraulic hitch system. |
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