Design And Test Of Small Crawler Electronic Control Chassis For Orchard

Mountain is an important environment for orchard planting,and mechanized operation is an important link in the modernization of orchard planting in China.The operation mode of mountain orchard not only has high labor intensity,but also has high production cost,and the planting agronomy of low and dense planting makes the traction operation machine unable to turn flexibly into the inside,and it is easy to cause accidental injury to the branches when driving in the orchard.Therefore,it is urgent to develop a small,lightweight and highperformance orchard operation chassis.At present,the goal of modern agricultural development has gradually shifted to intelligent and digital agriculture.The intelligent way of agricultural machinery and equipment has become an important link connecting the rapid development of agriculture and the fundamental demand of future agriculture.Therefore,this paper studies and designs a small crawler electronically controlled chassis for orchards,designs and selects the mechanical structure and power device,optimizes the steering structure,and performs dynamic simulation analysis and control system design on the chassis.The main research contents are as follows :(1)The overall structure design of orchard small crawler electronic control chassis.Acc ording to the characteristics of orchard terrain,the design requirements of crawler chassis are put forward,and the overall design scheme is determined.The walking device,power system,transmission system,steering mechanism and spatial layout of crawler chassis are designed,ca lculated and selected.The static stability analysis of the chassis is carried out,including the ste ering performance and the passing performance analysis.The steering performance results sho w that the greater the difference in the angular velocity of the crawler on both sides,the greate r the steering angular velocity ω of the crawler chassis,and the smaller the steering radius R;the steering resistance torque of the machine increases when the chassis mass becomes larger or the track grounding length becomes longer.In order to ensure the flexibility of steering,the value of L / B is generally set to 1.2 ～ 1.5 when steering with unilateral braking.The performa nce analysis shows that the maximum uphill angle is 25 °,the maximum downhill angle is 22°,and the maximum width of the trench is 581 mm,in order to provide a theoretical basis for simulation.The three-dimensional model of the crawler chassis was created by UG and the fin ite element analysis of the driving wheel and the steering plate was carried out by ANSYS.(2)Crawler chassis dynamics simulation model creation and analysis.With the help of t hree-dimensional modeling software UG and multi-body dynamics software Recur Dyn,the m ulti-body dynamics model of the tracked chassis is established.The simulation parameters are set according to the actual working conditions of the orchard,and the different working condit ions are simulated and analyzed.The climbing angle is 20 ° and the trench width is 550 mm.T hrough the simulation of unilateral tracked braking steering and in-situ steering simulation,the results show that the steering process is stable,the operation trajectory is in line with the actu al,the steering radius is 650 mm,and the theoretical calculation error is 4.85 %.It provides a basis for prototype test.(3)The hardware system and software system design of crawler chassis control system.The wireless transmission module is used to realize the functions of starting and stopping,for ward and backward,turning and variable speed of the crawler chassis.Firstly,the hardware sy stem of orchard small crawler electronic control chassis is designed and selected.It mainly inc ludes STC89C52 single chip microcomputer as the main control module,speed monitoring an d display module,data receiving and sending module and drive module.The circuit of the mai n control system is designed.Finally,it is the design part of the system software program,incl uding the preparation of the program,the page setting of the Bluetooth serial port assistant on the mobile phone,and the use of the industrial general PID motion control algorithm to contro l and adjust the output of the system.(4)Prototype functional test.The deviation rate of small crawler chassis on cement grou nd and the slip rate,passing performance and steering performance in the field were studied.T he test results show that the deviation rate of the crawler chassis on the flat road is 2.32 %,and the slip rate is 2.62 %,which can meet the national standards.Through the analysis of the per formance results,the maximum width of the trench is 500 mm,and the maximum slope is 20 °.For the steering performance test,the theoretical steering radius is 620 mm,the actual turning radius is 660 mm,and the error is 6.45 %.The main reason is that the track chassis is affected by the degree of track wear and the type of ground in the actual steering.The phenomenon of slip will inevitably occur,which is in line with the actual situation.This part is to analyze the p erformance of the chassis prototype and lay the foundation for optimization.