Device For Electronically Controlling Cutting Table Parameters Of Rice-wheat Combine Harvester And Frequency Segmentation Control Device Of Cutter

The header is an important part of the rice-wheat combine harvester.The reasonable adjustment of its working parameters has an important impact on the crop harvest quality and the machine performance.Some advanced foreign models are equipped with header intelligent control system,which realizes the integrated control of header parameters and the automatic adjustment of some parameters;at present,some of the parameters of the header of the combine harvester in China are in an unregulated state,and the other part requires the operator to be subjective Manual control based on experience,where the frequency of the combine harvester 's cutters usually remains the same during the harvesting process,and it is easy to produce heavy or missing straw cutting,resulting in increased harvesting loss of grain and unstable operating performance.The poor handling of the header restricts the further development of the combine harvester in China.This thesis designs the electric control of the header parameters of the rice-wheat combine harvester and the frequency segmentation control device of the cutter.This device uses the electromechanical-hydraulic integration technology to realize the electric control of the header parameters;the sensor technology is used to collect the header information in real time and controlled After the processor is processed,it is displayed on the display screen in real time and used as the basis for control.The neural network algorithm is used to adjust the frequency of the cutter in sections to provide technical support for the improvement of the combined harvester control system and the improvement of the machine automation level.The main research contents of this article are as follows:(1)The working process of the combine harvester header is analyzed.On the basis of changing the original traditional mechanical transmission to a hydraulic mechanical transmission,the control object of the control device is selected according to the function of each component of the header,and the adjustment of each parameteris analyzed based on this.The overall design scheme of the header control device is determined.(2)Hardware design for the header electronic control device is carried out.The electric control device is composed of an ARM controller,a touch display screen,a sensor element,a signal conditioning module,a key handle and an actuator.This thesis selects the embedded ARM controller as the control core,and designs the button module circuit,signal conditioning module circuit,output power amplifier circuit,and selects different sensors to measure the parameters according to the working process of the header components type selection,and selects the touch screen as the device display module.This thesis uses the sensor and the CAN controller to obtain header parameter information,and displays this information on the touch screen after processing by the controller.According to the parameter information of the header,the driver sends control commands to the controller through the key handle.After processing by the controller,it calls the control subroutine and outputs control signals to realize electric control of the working parameters of the header.(3)This thesis analyzes the cutting principle of the cutter,and establishes the cutting trajectory model,and uses MATLAB to draw the cutting diagram and analyzes the data,and determines the range of the cutting frequency under the conditions of different moving blade height and machine operating speed.The BP neural network is used as the frequency control algorithm of the cutter,and the output value of the neural network is processed to realize the segmented adjustment of the cutter frequency.(4)The software design of the header parameter electronic control device is carried out.In order to give full play to the performance advantages of the ARM core and improve system performance,FreeRTOS is transplanted,and the task design of the real-time operating system is carried out;the underlying driver of the control system is designed according to the task function,mainly including the data acquisition program and CAN message receiving program,control signal output program and data storage program.Based on BP neural network algorithm,this thesis writes the frequency segmentation adjustment program for the cutter.This thesis usesthe graphical software library emWin to design the touch screen display interface,which mainly includes the design of the parameter display interface and parameter setting interface,and transplants the program.(5)On-board debugging and functional test of the designed header parameter electronic control device are carried out.On-board debugging includes device functional test,cutter frequency control accuracy and system dynamic performance,and field function test,in which device function test includes manual Function test,header parameter display,sensor signal acquisition accuracy.The accuracy test data of the airborne sensor shows that the maximum relative errors of the reel speed,cutting frequency,header height,reel height and front and rear position data are 1.5%,2.9%,5.5%,-3.6% and 2.6%,respectively.The signal acquisition accuracy of the onboard sensor can meet the requirements of the subject.According to the cutter frequency control accuracy and the system dynamic performance data table,the deviation of the adjusted cutting frequency of the device is kept within 0.8Hz,the maximum relative error is-8.6%,and the average stable adjustment time of the system is 1.3s,which can meet the design requirements of the device.Field function test data shows that after turning on the frequency segmentation control system of the cutter,there is no phenomenon of missed cutting grain,and the number of short stalks produced by cutting is significantly reduced,and the situation of heavy cutting during cutting is improved.