| China ranks first in the world in tea production,and tea grading is particularly important to control the quality of tea.In the process of tea processing,wind separators are used for sorting according to the different bulk density of tea materials,so as to improve the quality of tea leaves.However,the current tea wind separator can only rely on manual judgment of the material type and the rate of impurities and adjust its parameters,there are problems such as strong subjectivity and large tea sorting errors.Therefore,the intelligent identification of tea materials and the intelligent regulation of the wind separator are in urgent need of realization in the wind selection process.In response to the above problems,this thesis builds a tea wind sorting test bench and designs an intelligent control system for tea wind sorting machine based on machine vision and PLC control technology.The main research contents and experimental results of this thesis are as follows:(1)The construction of tea wind selection test bench was completed.Firstly,the tea grade recognition mechanism was built to realize the image acquisition of tea leaves and provide the hardware foundation for the tea grade recognition system.Then the wind sorting mechanism was built to realize the grading of tea leaves by adjusting the vibration feeder frequency,fan frequency and divider position.(2)A tea grade recognition system was designed.Firstly,the construction of tea raw material dataset was completed,then the Faster R-CNN,SSD and YOLOv5 s models were used to train this dataset respectively,and the experimental results of the three models were compared and analyzed,and finally the best performing YOLOv5 s model was selected for tea grade recognition.(3)The PLC control technology was used to realize the automatic regulation and control of the wind selection test bench.Completed the hardware selection,PLC ladder program design,each actuator control circuit design and build the test bench electrical cabinet.Through on-line commissioning,the regulation and control of vibration feeder frequency,fan frequency and divider position were completed.(4)The intelligent control system of tea wind sorting machine was built.Firstly,the Lab VIEW host computer is used to collect data from the tea grade identification system,and then the data is sent to the wind sorting test bench control system,which then automatically adjusts the vibration feeder frequency,fan frequency and divider position of the test bench,and finally realizes the intelligent regulation and control of the tea wind sorting machine.(5)The wind sorting test bench parameter adjustment test was completed.Single-factor tests were used to find the optimal range of the three influencing factors,namely vibratory feeder frequency,fan frequency and separator position,respectively,and then the optimal parameters were obtained by orthogonal tests.Experiment with white tea raw materials,the results show that when the high quality white tea accounts for 85%,setting the vibration feeder frequency to 11 Hz,the fan frequency to 18 Hz,and the moving position of the divider to the right by 3cm,the best effect of wind sorting is achieved,and the content of high quality white tea reaches 95.68%.When the secondary white tea accounted for 85%,setting the vibration feeder frequency to 12 Hz,the fan frequency to20 Hz,and the moving position of the divider to the right by 3cm,the wind sorting effect was the best,and the content of secondary white tea reached 95.43%.(6)Completed the verification test of intelligent control system of wind separator.The test results show that the wind selection test bench operates stably,the system can quickly identify the grade of tea materials,the accuracy rate can reach more than 90%,and the optimal result of tea wind selection test has only 0.4% error with the predicted result of orthogonal test.It verifies the feasibility of the intelligent control system of tea wind separator,and provides technical support for the intelligent control of tea wind separation link. |
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