Design And Experiment Of Attitude Adjustment System For High Ground Gap Plant Protection Machine

As a kind of large field management agricultural machinery,high ground clearance planters are widely used in the field of agricultural engineering with the advantages of high efficiency,high intelligence and green environment protection.Considering its large drug tank load,its own weight,high ground clearance and whole mass center,the machine is susceptible to the influence of field ground excitation and prone to the risk of rollover during field operation and transfer,which affects the safety and stability of plant protection operation.To this end,this thesis designs and develops an upland clearance plant protection machine body attitude control system with the research objectives of improving the stability and safety of the machine and reducing the risk of rollover,and the main research work and conclusions are as follows:(1)Considering the influence of ground excitation in the field on the efficiency and safety of plant protection machine operation and the passability under the transit operation condition,the design of upland gap plant protection machine with attitude adjustment function is proposed.The main frame design is divided into two parts: chassis layout and attitude adjustment mechanism,and Solidworks software is used to establish the model of the whole machine.A hydraulic control system was designed by using the gear pump in the hydrostatic transmission,and the effectiveness of the hydraulic oil circuit design scheme was verified by using Fluid SIM software.(2)The theoretical analysis of the attitude motion process of the upland gap plantation machine,the transformation relationship between the displacement of the hydraulic cylinder and the inclination angle when each support point reaches the horizontal position;on the basis of the control strategy of the four-point leveling system,the control strategy combining the "pre-set point immobility" adjustment method and the angle error method is proposed;by establishing the valve-controlled cylinder By establishing the mathematical model,the PID control algorithm of the attitude control system of upland gap planters is designed comprehensively.(3)Based on Recur Dyn software,we established the dynamics model of the machine,simulated and analyzed the body attitude of the upland gap plant protection machine under three typical adjustment conditions,and verified the feasibility of the machine structure;based on AMESim software,we established the simulation model of the hydraulic control system,and simulated and analyzed it according to the actual working conditions in the field to obtain the dynamic response curve of the electric-hydraulic control system.The simulation results show that: the body chassis can realize the corresponding attitude adjustment smoothly,the maximum adjustment pitch angle is 8.5°,the maximum adjustment side tilt angle is 9.8°,the maximum adjustment of ground clearance is 200 mm,the convergence speed of hydraulic control system is fast,the overshoot is small,which verifies the effectiveness of the attitude control system of upland gap plant protection machine body.(4)The prototype was tested according to the whole machine design plan,and the development of the body attitude control system based on STM32 microcontroller was completed by using Keil u Vision5 software.On this basis,the prototype performance test of the body attitude control system was carried out to check the control effect of the control strategy and control algorithm under the actual operating conditions and to verify the effectiveness of the body attitude control system.Finally,the sealing and weed control field plant protection operation was carried out in the soybean-corn ribbon compound planting demonstration area.The test results show that: the maximum pitch angle of the whole machine attitude adjustment is 8.5°,the maximum deviation of pitch angle is 0.35°,and the steady-state error is 0.2°;the maximum side tilt angle is 9.2°,and the body attitude returns to the horizontal steady state within 0.75～2.8s,which meets the attitude adjustment operation requirements of plant protection operation in the field of soybean and bean composite planting as well as under the transition conditions.