Research On The Key Technology Of Flexible Reeling Of Wheat Harvester

Wheat,as the second largest food crop in the world,plays an important role in China.With the complex changes in my country’s internal and external environment,the importance of food security has become more and more prominent,so we must pay attention to the planting and harvesting of wheat,and reduce harvest losses while breeding good seeds.Although science and technology have continued to advance in recent years,our country has made great progress in research on wheat harvesters,there is still a big gap compared with foreign wheat combine harvesters with high horsepower,wide cutting width and high intelligence.The intelligence level of domestic wheat harvesters is low,which seriously restricts the development of the wheat industry.The intelligence and mechanization of wheat harvesters urgently need to be improved.In the harvesting process,due to the differences in various regions,plots and wheat varieties,the driver needs to continuously adjust the various parts of the header according to the driving experience and actual conditions during the harvesting process.In addition,spring teeth of different materials and shapes will also cause certain damage to the wheat ear during the harvesting process.In view of the above problems,various sensors were added the overall structure of the original harvester and information was collected from various working parts,the automatic control system of the reel and different spring teeth for simulation analysis were designed.The damage to wheat was judged,and finally the results of the theoretical analysis were verified by field trials.The main research contents of this paper are as follows:（1）The motion parameters of the reel of the wheat combine harvester were analyzed,and the mathematical model of the reel’s rotational speed was established,and the reel rotational speed control based on the fuzzy PID algorithm was designed according to the matching of the traveling speed and rotational speed of the harvester.method.The software of the flexible reel device was designed,the signal acquisition program of the reel speed and height,the control program of the executive element and the optimization program based on the fuzzy PID algorithm were designed.（2）Several different shapes of reel spring teeth were designed,using two materials: nylon plastic and spring steel,and six different spring teeth were designed,namely nylon with lengths of 17 cm,21 cm and 25 cm.Plastic spring teeth,spring steel spring teeth with lengths of 17 cm,21 cm and 25 cm,And ANSYS workbench software was used to simulate their force and deformation respectively to determine the practicality of six types of spring teeth.The wheat model and the wheat harvester table model were imported into the discrete element simulation software EDEM,and the most suitable harvesting speed and teeth were selected by replacing different tines and different rotational speeds of the paddle wheel.The discrete element simulation resulted in the lowest impact loss to the wheat plant when 21 cm long nylon plastic teeth were used and the speed was 37 r/min.（3）After completing the design and simulation analysis,the signal detection of the rotational speed of the paddle wheel and the driving speed of the harvester in the workshop was carried out to compare the errors,and the calibration of the height of the paddle wheel in the workshop as well as the test calibration of the change of the paddle wheel with the vehicle speed were fitted to the equations.It can be concluded from the in-shop test that the error between the collected values and the real measured values was small under no-load conditions.The field test of the modified and commissioned wheat harvester was tested by a third party.During the field test,the error of the tiller wheel speed should be less than 7.1% and the error of the height control should be less than 4% when the manual keypad control was carried out,and the error of the tiller wheel speed control was 6.2% when the field test was carried out.All the indexes have achieved more than 90% of the control accuracy required by the project.In addition,field tests were conducted on 21 cm long nylon plastic teeth and spring steel teeth,and the results of the analysis of the test data showed that the 21 cm long nylon plastic teeth hit the wheat plants less than the spring steel teeth,and a better tooth was selected.