| Reel sprinkler irrigation machine has the advantages of strong adaptability,convenient mobility,high automation,low investment in equipment per unit area and so on.It has become one of the most promising irrigation machinery in our country.However,there are the following problems in the domestic reel sprinkler at present: the pressure at the end of the traditional single sprinkler is high,so the head of the matching pump is large,the head loss of the unit is large,and the energy consumption of the whole machine is high.Although the sprinkler irrigation method with low pressure and multi-sprinkler head used in the truss sprinkler irrigation vehicle studied at present greatly reduces the pressure at the sprinkler head and reduces the energy loss of the whole machine.However,it also brings new problems,trusses can not be folded and closed on both sides of the car body,and the labor intensity of manual splicing trusses before and after operation is heavy.In order to solve the above problems,with the support of the national key R & D project "Development of Water and Fertilizer Integrated Sprinkler based on Clean Energy Drive"(2016YFC0400101-04),In order to solve the problem that the truss sprinkler irrigation car matching with the reel sprinkler can not fold automatically at present,The overall structure design of the folding truss sprinkler,the structural parameter design of the folding truss spraying arm,the strength check of the folding truss spraying arm and the car body,and the optimal configuration of the folding truss spraying arm driving mechanism are studied in detail.The main research work is as follows:1.Various mechanisms that can realize multi-folding and joint schemes that can realize sealing are analyzed.On the basis of improving the flapping wing mechanism,a three-fold flapping wing mechanism is designed.On the basis of improving the common hinge joint,a kind of end face seal hinge which can seal after rotating in place is designed.After the motion interference problem is fully analyzed,the three-dimensional model of the spraying arm of the three-fold truss is established in CREO with three-fold flapping wing mechanism as the folding skeleton and the end face sealing hinge as the rotating joint.A set of four-bar linkage mechanism and a group of crank slider mechanism are used to design the driving mechanism of the three-fold truss spraying arm,and the mechanized driving folding andstretching of the three-fold truss spraying arm are realized.Finally,on the basis of improving the original truss sprinkler frame structure,a new type of frame structure is designed,which is convenient for the installation of the three-fold truss spraying arm,the left and right wheelbase can be adjusted,and the body height can be adjusted.2.The fully collapsible and fully deployable motion state of the three-fold flapping wing mechanism hinged by end face seal is planned,and the parameter constraint equations of folding and developability of the spray arm of the three-fold truss are obtained.The kinematics model of the spray arm and its driving mechanism of the three-fold truss is established by using the vector equation method,and the SIMULINK kinematic simulation block diagram of the three-fold flapping wing mechanism is built.Taking JP50 reel sprinkler as the research object,the simulation results show that when the spraying arm of the three-fold truss moves from complete closure to complete extension,the movement of each member is stable,and there is no large fluctuation of velocity and acceleration.The initial rotation angle of the three end seal hinges is 0°,and the complete extension rotation angle is90°.It can be seen that the end face seal hinge can be rotated in place and sealed,and each member can rotate 90° to completely close both sides of the frame.Finally,after selecting the length of the first truss pipe of the three-fold truss spraying arm is 1.4 m-2.0 m,and the length of the second three-truss arm is 0.9m-1.5m,The dimensions of the remaining members of the three-fold truss spraying arm of JP32 to JP75 small and medium-sized reel sprinkler are obtained by the method of parameter constraint equation calculation.3.The effects of five key parameters on the strength of spraying arm were studied by response surface-Latin hypercube experimental design method in ANSYS.The results show that the pipe diameter,pipe thickness and the length of the second third trussed pipe have significant effects on the strength of the spray arm,and the length of the ssecond third trussed pipe has a significant effect on the stiffness of the spray arm.MOG multi-objective genetic algorithm is used to obtain multiple samples to meet the strength requirements,and the pipe diameter and the maximum length model of the first and second third trussed pipe are obtained by using the fitting method.According to the model,the length of the spraying arm of each type of reel sprinkler is checked: the maximum optional span of the spraying arm of JP32 reel sprinkler is 3.2m,and that of JP75 reel sprinkler is 4.5m.Taking JP50 reelsprinkler as the object,the static characteristics of truss sprinkler after optimizing the size parameters of spraying arm are analyzed.The results show that the maximum stress of the spraying arm decreases from 265 MPa to 140 MPA,the maximum stress of the frame is20 MPA,the force of the front and rear wheels is slightly larger than that of the rear wheels,and the forces of the left and right wheels are the same.It can be seen that the mass distribution before and after the sprinkler car is uniform under the current parameters,and the 2mm thickness Q235 steel welded frame far meets the requirements.4.The dynamic virtual prototype model of three-fold truss spraying arm and its driving mechanism based on Lagrange method is established in ADAMS,and the minimum driving force is taken as the optimization goal.Through the ADAMS and Design-Expert joint dynamics simulation test,the experience of optimal configuration design of driving mechanism members is obtained: the longer the drive rod,the shorter the pole,the smaller the angle between the push rod and the frame,the smaller the driving force of the whole movement process.Taking JP50 reel sprinkler as the object,the driving mechanism of its three-fold truss spraying arm is optimized.The results show that the driving force decreases from 875 N to 450 N after optimization.After optimization,the maximum force of Driving mechanism on each joint in X and Y direction decreases from 130 N and 750 N to 90 N and420N;After optimization,the maximum force of three-fold flapping wing mechanism on each joint in X and Y directions decreases from 130 N and 750 N to 90 N and 420 N.It can be seen that after optimization,not only the driving force configuration is greatly reduced,but also the force acting on the members of the spraying arm and the driving mechanism of the three-fold truss is obviously improved. |
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