Optimization Of Portable Chinese Wolfberry Picker And Development Of Collecting Device

Chinese wolfberry industry is a traditional characteristic industry in northwest China,its nutritional value is rich,is today’s world highly favored dual-use material for medicine and food.With the increasing planting area and production demand,harvesting efficiency has become the key to the development of Chinese wolfberry industry.The current harvesting method is mainly based on manual harvesting,with high labor intensity,low efficiency,high cost,and easy to cause labor waste,so there is an urgent need for mechanized equipment suitable for harvesting.Domestic mainstream harvesting equipment is mainly small machines,but there is a low picking rate,high damage rate,so the "efficient and low loss" mechanized harvesting is still the most important problem to solve.For the portable wolfberry picking machine all kinds of problems,combined with the current planting agronomy,the use of kinematic analysis,kinetic analysis,multi-factor regression test methods and experimental verification technology,to obtain wolfberry biomechanical characteristics parameters,the use of vibration shedding simulation results of vibration type picking machine optimization,for "picking ripe stay green" to provide Theoretical basis,using the prototype machine for field trials,specific research content and results are as follows:(1)Obtaining the Biomechanical Characteristics of Wolfberry.The binding force between ripe fruit,green fruit,and fruiting branches of Chinese wolfberry was measured using a digital push-pull force meter.The connection between the fruit and fruit stem was the most prone to fracture,with a binding force of 0.758 N between ripe fruit and fruit stem and 1.879 N between green fruit and fruit stem.Use a universal testing machine to conduct axial compression test,radial compression test,and radial three-point bending test on the sample of fruit branches,and obtain the elastic modulus and shear modulus in three directions of the fruit branches,providing a basis for the flexibility of the branches in simulation.(2)Simulation of the Flexibility of Fruit Branches and the Dynamics of Picking Structures.Using the field fruiting branches as a prototype,the complete fruiting branches were measured,and 3D modeling was conducted using Solid Works.The flexible branches were analyzed and solved in HyperMesh,and the first 24 natural frequencies of the branches were obtained.The 7th or 8th natural frequencies of nearly 20 Hz were selected for simulation analysis.The preliminarily designed vibration structure and flexible branches were imported into ADAMS for dynamic simulation,select appropriate vibration frequency,amplitude,and spacing between rods,analyze and compare the simulated acceleration of green and ripe fruits with the actual calculated critical acceleration of shedding,and obtain a parameter combination that meets the harvesting requirements.(3)Design of portable goji berry picking machine and collection device structure.According to the best combination of parameters obtained from the simulation,a portable medlar picking machine is designed.The transmission mode is a crank rocker like mechanism without quick return characteristics,which is characterized by the use of the mechanism to convert the circular motion of the motor into the reciprocating swing of the vibrating parts.kinematics analysis is carried out on the key structure,and the picking structures with different parameter combinations are designed according to the factors that affect the picking effect.Design a collection device that cooperates with the harvester based on pre experimental data and agronomic parameters to complete the harvesting process.(4)Field experiments and result analysis.Through the design experiment of Design Expert software,through the quadratic fitting of multiple groups of test results,the polynomial regression equations with statistical significance and without the existence of mismatching factors were obtained,with the ripe fruit picking rate,green fruit false picking rate,ripe fruit damage rate as the response function,and the vibration amplitude,vibration frequency,and spacing between poles as the independent variables,and were imported into Origin to draw the response surface diagram,The order of influence of various vibration factors and their interaction combinations on the picking effect was determined.By setting the optimal effect indicators,the optimal parameter combination was obtained.The best picking effect was achieved at vibration amplitude of 73.66 °,rod spacing of 35.51 mm,and vibration frequency of 19.12 Hz.Field validation tests were conducted,and three indicators were obtained: ripe fruit picking rate of 95.67%,green fruit mispicking rate of 4.68%,and ripe fruit damage rate of 3.70%.Test and evaluate the performance of the collection device based on the collection rate,and it is found that the collection rate is greater than 90%.