| In the industrialized breeding process of high-grade economic fish,fry classification is an indispensable step before the pond culture.The existing grading technology in China is mainly based on manual grading and weight-sensing grading.The research on fry grading equipment is still insufficient.The working parameters and adaptability of the grading machine are relatively few.There are high labor costs,efficiency and accuracy.Low-level problems require the development of high accuracy and high efficiency roller roller fry classifiers.This thesis focuses on the development of a roller-type fry grading machine.According to the fry size parameters and the three-level grading target,the fry grading is determined by using the body width as the judgment condition,and then the design requirements and structural layout of the whole machine are proposed.The method of analysis and discrete element simulation is used to optimize the working parameters and adaptability of fry classifier.The main work completed in this thesis is as follows:(1)According to the requirements of body width classification,the design requirements and structural layout of the whole machine are proposed,the overall mechanical structure of the whole machine is designed,and three-dimensional and two-dimensional design drawings are drawn.The mechanical analysis of the key mechanism has determined the structural parameters of the tilt adjustment device and the classification device,which lays the foundation for the subsequent exploration of the interaction mechanism between the classification components of the fry classifier and the fry.Based on the design results,a test prototype was made.(2)Taking the accuracy rate of fish splitting and fry entry rate as the grading performance evaluation index,and using the fry-grading component coupling dynamic model established by discrete element software,the interaction mechanism between grading components and fry was studied.Finally,in order to verify the accuracy of the kinetic model,the whole machine test is carried out under actual working conditions.The results show that the prototype test results are in good agreement with the overall change trend of the simulation data.(3)In order to explore the impact of different working parameters on the classification performance,the established single-factor and multi-factor orthogonal tests of the working parameters were used to determine the primary and secondary order of the influence of each working parameter on the classification machine,which were the inclination of the roller table and the fish entering angle Measurement,roller speed.Then,the multi-objective and multi-variable optimization method was used to optimize the orthogonal test.It was found that when the parameter combination was a roller table speed of 138.40 r / min,a roller table inclination angle of 10.47 °,and a fish feed rate of3.00 tails / s,The classification performance is higher.(4)Based on a better combination of working parameters,the accuracy of fishseparation and fry entry rate are adaptive evaluation indicators,and the length,width and height of fry are used as experimental factors to study the classification of fry for different fry.Adaptability under body parameters.The single-factor,three-factor and three-level orthogonal experiments were used to determine the major and minor sequences affecting the adaptability of fry classifiers: body length,body width,and body height.Finally,the adaptability of catfish,grass carp,catfish and catfish was analyzed based on the test results.The results showed that the catfish had the highest adaptability and the catfish had the lowest adaptability. |
