Study On The Design And Parameter Optimization Of The Harvesting Device For Industrialized Shanghaiqing

Various species of leafy vegetable are widely planted in the world.The main cultivation methods are open field cultivation and growing in greenhouse.With the development of human society,more and more industrial technologies are gradually integrated into leafy vegetable cultivation.In recent years,plant factory is rising,which breakthroughs the constraints of natural conditions to a great extent,and has implemented intelligent,automatic control of growth conditions and industrial production line of planting processes.However,the degree of automation in harvesting step of leaf vegetable production is still not high.The harvesting step requires a large amount of manpower,time of hard work.At present,there is little research on automatic harvest equipment of leafy vegetable based on production line.The existing leafy vegetable harvesting machinery cannot be used on plant factories production line at all.Therefore,leafy vegetable harvesting has become a bottleneck restricting to the development of industrialized leaf vegetable industry,and it is urgent to R&D that leaf vegetable harvesting machinery for plant factory production line.This paper,taking a plant factory in Chongqing as the research platform,the representative leaf vegetable named"Shanghaiqing"in existing leaf vegetable planting varieties as the research object,according to the actual needs of Shanghaiqing factory production,under the support of project named"Development and Demonstration of Intelligent Equipment in Vegetable Factory"by Chongqing Science and Technology Division,combining with the features of the Shanghaiqing planting technology in factory,carries out the following main researches:1.To investigate and understand the process of Shanghaiqing industrialized production,find out the structure parameters of cultivation plate and the growing environment of Shanghaiqing.The data of plant height,expansion,diameter of rhizome at cutting point,net weight of plant after cutting,length of rhizome and cup weight of matrix are measured for 60 collected randomly hydroponic Shanghaiqing leaf vegetables.Simultaneously,the mechanical property parameters of the rhizome of Shanghaiqing under compression and shear condition are measured and analyzed by means of texture apparatus.Test results show that the radial elastic modulus of rhizome ranged from 0.93Mpa to 1.83Mpa,the axial elastic modulus of rhizome ranges from 2.43Mpa to 6.02Mpa,and the maximum shear stress ranges from0.641Mpa to 2.29Mpa.The density is 946 kg/m~3.2.Shanghaiqng harvesting device design.The cutting process is firstly analyzed theoretically,and the working principle and parameters of the cutting device are formulated.According to the literature and the previous industry experience,compares the cutting ways,the tensioning ways and the transmission ways,the overall scheme of band saw cutting,screw tensioning and v-belt transmission is selected.Refering to the standards of joinery band saw industry,the tensioning force and cutting speed range are determined by calculation and analysis.According to the measured data of Shanghaiqing leaf vegetable,each component is designed,and uses UG to build a 3D model.Ergonomics and safety requirements are considered in the design to eliminate the potential safety hazards of site space and human operation habits.3.Simulation analysis of cutting device based on Ansys.The 3D part model is imported into the static analysis module of workbench for strength and deformation checking,all parts satisfies the requirements.Meanwhile,the explicit dynamics module is used to simulate the root cutting process,sets at different cutting speeds and tooth shapes,at the feed speed of 0.04m/s,The results show that using toothless saw the cutting stress is the least,the cutting effect is the best and the damage rate is the lowest.The value range of cutting speed which meets the requirement of cutting is determined.Finally,the modal analysis of the disk and the gantry is conduct,consequence indicates that there is no overlap between the vibration of the motor and the frequency range of the disc and gantry,No resonance will cause damage to the cutting device.4.Prototype experimental study on production line.Installs the prototype on the site,the toothless saw,tooth saw and meniscate saw are respectively applied at the feeding speed of 0.04m/s,at different cutting speeds to verify the simulation test results.The results manifest that at the cutting speed of 400r/min-500r/min the toothless saw cutting effect is the best,the end face is neat and tidy,the damage rate of vegetable leaves is the lowest,reach the harvest requirements.In the whole cutting process,the cutting device is normally operating,and no bad results caused by vibration,which is basically consistent with the results of simulation analysis.5.Parameter optimization of cutting device.Adjusts feed speed by gear ratio,frequency converter adjusts cutting speed,the two factors are used as the impact factors,selects the numerical range of the data in the simulation results,uses cutting damage rate as the evaluation index,the design of bivariate quadratic regression orthogonal rotation combination test is carried out.Finally,obtains the regression equation of damage rate,the optimal solution factor combination within the value range is obtained by using the Globalsearch function in MATLAB.Namely,the feeding speed is 0.06m/s and the cutting speed is 420r/min.Through the actual test,it is proved that the optimized feed speed and cutting speed make the damage rate of Shanghaiqing lower and meet the requirements of the design and production.