| As a large-scale agricultural machinery for field management,the elevated plant protection machine has the characteristics of high center of mass of the whole machine,large clearance from the ground,large drug loading in the medicine box and so on,in order to meet the needs of secondary topdressing and spraying of high-stalk crops such as corn in the middle and late growth stages.However,due to the complex and harsh working environment in the field,the machines and tools are influenced by external incentives and changes of internal system parameters,which easily lead to the risk of tilting in the process of driving and turning,which affects the safety and stability of operation and brings hidden dangers to agricultural production.At the same time,the introduction cost of advanced plant protection machinery abroad is high,and it is difficult to localize it.The research in related fields in China started late,and there is still a certain gap with foreign excellent technologies,and it is affected by agricultural and agronomic factors in various places.Most research institutes’ research,transformation and optimization products have low universality,so it is urgent to develop an overhead plant protection machinery with high universality,which can meet the needs of agricultural fertilization and spraying in most areas.Based on this,this paper takes the elevated plant protection machine as the research object,and studies the main frame and horizontal leveling system of the elevated plant protection machine,aiming at improving the lateral stability of the machine,reducing the risk of tilting and improving the universality of the machine.The main research work is as follows:(1)Collecting field data,comparing the data and analyzing the structural characteristics of the main frame of the overhead plant protection machine,and combining with the planting situation of high-stalk crops such as corn sorghum,measuring the growth height of high-stalk crops such as corn when they grow to the middle and late stage and are in urgent need of pesticide spraying;Measure the planting ridge distance of corn and other crops,and determine the design scheme and design parameters of the main frame of the elevated plant protection machine according to the measurement results.The ground clearance is 2m,and the ridge distance adjustment range is 1.6m to 2.4m The design idea of the horizontal leveling system is determined.(2)According to the design scheme of the main frame of the elevated plant protection machine,the design of the main frame is divided into two parts: the main frame and the ridge distance adjusting mechanism.For the main frame design,the height of the ground clearance of the frame can meet the requirements of the field operation of machines and tools,and the strength can meet the requirements of operation load.The ridge spacing adjustment mechanism is designed,so that the wheel spacing of the overhead plant protection machine can be adjusted synchronously with stepless symmetry.By changing the wheel spacing,the ridge spacing corresponding to the target field operation can be indirectly changed,and the universality of machines and tools can be improved.Solid Works is used to establish a three-dimensional model,and the static stress analysis and modal analysis simulation of key components are carried out.Combined with theoretical calculation,the strength of the designed mechanism meets the working requirements,ensuring that the low-order vibration mode of the frame is within the common excitation frequency range,less than the minimum natural frequency of 93.047 Hz,and avoiding the resonance phenomenon from affecting the safety and stability of machines and tools.(3)Design the horizontal leveling system of elevated plant protection machine,which is divided into two parts: mechanism design and control design.In the design part,combined with the design concept of the main frame,the angle-variable medicine cabinet rack is designed,and the angle of the medicine cabinet rack is changed indirectly by using the expansion and contraction of the push rod of the hydraulic oil cylinder.By taking advantage of the characteristic that the quality of the medicine cabinet on both sides accounts for a high proportion of the whole machine’s quality,the horizontal center of gravity of the machine is shifted,and the vertical distance of the center of gravity is far away from the stress point on one side of the tilting trend.The control part calculates the limit tilt angle,designs the leveling angle corresponding to the tilt of the machine,integrates information technology,sensor technology and mechanical technology,uses the tilt sensor to sense the tilt angle of the machine body and the medicine cabinet,and completes the leveling system design with the change of the medicine cabinet angle.According to the designed functions,the types of components needed in the leveling system are selected,such as 51single-chip microcomputer and MPU6050 tilt sensor.(4)Carry out platform test and field test: make PCB,design circuit diagram,and weld the designed components according to the circuit to complete hardware assembly;According to the overall system design idea,Keiluvivision is used to compile the C language execution program,and then the corresponding program is imported from STC-ISP software into the controller for testing to complete the debugging of the software program import hardware.A test platform is built according to the proportion of the designed main frame,and the actual test is carried out on the platform again to verify the feasibility of the system.The field test of the trial prototype machine is carried out to confirm that part of the machine main frame has good operation passability,and the ridge spacing adjustment mechanism can change the machine operation ridge spacing and improve the universality of the whole machine.This paper provides a new thinking direction for improving the stability and universal operation of the overhead plant protection machine,and is an exploration of modern intelligent agriculture research,which is of great significance. |
