Study On Adaptive Control System Of Operating Parameters For Threshing Device Of Rice Wheat Combine Harvester

The rice wheat combine harvester is mainly composed of header,threshing,cleaning and grain collection system.In the process of operation,the operation efficiency should be improved on the premise of satisfying the performance of grain entrainment loss,breakage and impurity rate.The operating parameters of threshing device for a rice wheat combine harvester have a significant impact on the performance.There is a complex nonlinear relationship between the operating parameters and the performance indicators of the threshing device,and the performance parameters adjustment effect is often contradictory for the operational performance.Online control of threshing device parameters and efficient and balanced optimization of machine performance have become the key issues in the intelligent research process of rice wheat combine harvester.Reasonable adjustment of threshing device operation parameters and optimization of performance have become the focus of intelligent research for rice wheat combine harvester.Domestic and foreign researchers have carried out a lot of research in the field of combine harvester performance monitoring and threshing device operating parameters control,and there are still some problems.For example,the operation performance parameters selected in the control model are not comprehensive,and the control target of the operation parameters control model of threshing device established based on single operation performance parameters is too single and one-sided,which easily leads to unbalanced operation performance of the machine.In order to solve the above problem,an adaptive control system for operating parameters of threshing device for rice wheat combine harvester is developed in this paper.The data of grain entrainment loss,breakage and impurity rate should be obtained online precisely.On this basis,the operating parameters of threshing device can be automatically controlled to optimize the operation performance of rice wheat combine harvester and improve the intelligence of rice wheat combine harvester.The research contents include the following aspects:(1)The overall scheme design of the adaptive control system for the threshing device of the rice wheat combine harvester.The structure and working process of the rice wheat combine harvester and its threshing device were analyzed.The controllable operation parameters of the threshing device were threshing rotor speed and concave clearance,and the adjustment method of threshing rotor speed and concave clearance was determined.When studying the adjustment method of threshing device operation parameters,scholars often adopt single operation performance as the regulation basis.The threshing rotor speed as a part of the threshing system,its adjustment process must be accompanied by the linkage of other operation parameters.In this study,three harvesting performance parameters of rice wheat combine harvester were used as the control basis.The threshing rotor speed was adjusted independently by electro-hydraulic control valve,and the concave clearance was controlled by a worm gear motor regulating mechanism.The comprehensive performance regulation goal and the independence of operation parameter regulation were realized.(2)Based on Decision Tree algorithm and chromatographic vector algorithm,the performance parameters monitoring method of rice wheat combine harvester was studied.The performance of rice wheat combine harvester is the basis of threshing device parameters control,which needs to be acquired in real time when the machine is working in the field.The recognition algorithm of grain impact signal was developed,the identification model of grain / impurity based on decision tree was established,and the sensor monitoring device of grain loss rate was built.The results of indoor experiment show that when the moisture content of grain is between 10% and 30%,and the ratio of grain / impurity is between 1 / 0.5 and 1 / 2.5,the recognition accuracy of the model is more than 90.7%.Compared with the non recognition model device,the average monitoring accuracy is improved by about 30%.The structure of the sampling and discarding device was designed,and the on-line monitoring device for impurity / breakage rate of grain was developed by using Machine Vision technology.The recognition model of grain / impurity morphological characteristics based on Decision Tree was established.The method of broken / complete grain recognition based on chromatographic vector was studied.The accuracy of the monitoring device was verified on the laboratory test bench by using field test materials.The results of laboratory experiments show that the classification accuracy of the model based on morphological features is more than 78%,and the accuracy of complete and broken grain recognition model based on chromatographic vector is more than 96%.(3)The fuzzy control model of performance balance optimization of rice wheat combine harvester was established.In order to obtain the operating parameters control rules of threshing device for a rice wheat combine harvester,the field test data were obtained by using the developed on-line performance monitoring device.The correlation between working parameters and performance of rice wheat combine harvester was analyzed.The influence rules of operation parameters for threshing device on grain entrainment loss,breakage and impurity rate were summarized.Based on the BP Neural Network technology,the prediction model of the performance of the threshing device was established based on the MATLAB /Simulink simulation platform.The single input and full input fuzzy control models for the operation parameters of the threshing device were designed.The control effects of the four fuzzy controllers were compared.The simulation results show that: when the feed rate step increases,the single input operation parameter control model of threshing device can only optimize the single operation performance,and the other operation performance which is not taken as the control target is easy to deteriorate,and it does not have the efficiency of balancing and optimizing the operation performance parameters.The fuzzy control model of threshing device operation parameters with full input performance can balance and optimize the machine operation performance.When the feeding rate increases slightly(10%? 25%)and the performance parameters deteriorate slightly,the performance parameters decrease by about 5% under the action of the fuzzy controller with full input of operation performance.When the feed rate rises sharply(50% ? 75%)and the performance parameters deteriorate greatly,the performance parameters decrease by about 10% under the action of the fuzzy controller with full input of operation performance ?(4)The self-adaptive control device of threshing system of rice wheat combine harvester was realized.The functional requirements of the operation parameters adaptive control system of rice wheat combine harvester were determined.The adaptive control device was built with ARM as the main control unit.The device was composed of ARM processor,grain entrainment loss / breakage / impurity rate monitoring sensor,concave clearance / threshing speed control module,CAN bus and human-computer interaction key handle.The software of threshing device operation parameter control system is designed.The fuzzy control program of single input and multi input grain entrainment loss / breakage / impurity ratio of threshing device is compiled,and the development of self-adaptive control system of threshing device operation parameters of rice wheat combine harvester is completed.(5)Field experiment on the self-adaptive control system of threshing device for rice wheat combine harvester.Firstly,the self-adaptive control device of threshing system parameters was installed on the machine,and the sensors of grain entrainment loss,breakage and impurity rate were integrated into the rice wheat combine harvester,and the airborne debugging work of each device was completed.Then,the working effect of each controller was evaluated in the field test of single input and multi input rice wheat combine harvester operation parameter control system.The experimental results showed that the single input control system of threshing device could effectively optimize the single operation performance parameters,and the optimization range was more than 30%.However,one or two kinds of operation performance parameters deteriorated,and the deterioration extent was more than 30%.The operation parameter control system of rice wheat combine harvester with multi input balanced and optimized the operation performance,and the optimization range was between10% and 50%.There was no deterioration of operation performance parameters.The effectiveness of the operation parameter control system of rice wheat combine harvester with multi input performance input was verified.Through this study,the harvesting performance of rice wheat combine harvester was optimized,and the intelligent level of parameter regulation of threshing system was improved.At the same time,the on-line monitoring device for grain breakage and impurity content of rice wheat combine harvester developed in this paper enriches the previous research results in the field of operational performance monitoring.The operational performance prediction model of rice wheat combine harvester based on BP Neural Network and the fuzzy control model of threshing device operation parameters provide an effective means to improve the real-time and intelligent level of operation parameter control.The self-adaptive control system of threshing device for rice wheat combine harvester with multi factor input has strong practicability.