Operation Path Tracking And Auxiliary Navigation Method Of Combine Harvester Based On Beidou

With the development of modern agricultural science and technology in China,the combine harvester has been promoted rapidly and used widely in recent years.In the harvest,the combine harvester driver relies mainly on subjective experience for harvesting operations,which puts high demands on the driver’s operating experience and energy.Especially in busy farming,high-intensity work can easily lead to fatigue work,low work efficiency,and even cause safety hazards.This thesis aims at the situation that the combine harvester navigation system generally needs base stations,the system is complex and the cost is high.To improve the working efficiency and quality of the combine harvester,reduce the working pressure of the driver and ensure the safety of the operation,the position acquisition and operation path tracking methods of the combine harvester are studied,and the operation path tracking system is constructed.The system can update the path according to the real-time operation situation with no base station,which has the advantages of simple system,low cost and strong practicability.The linear test tracking performance of the system was verified by field test and field test,and the indoor steering control simulation test was carried out to verify the feasibility of the steering correction method.This thesis analyzes the operation characteristics of the combine harvester,and combines Beidou positioning technology,embedded technology,geography measurement technology,data processing method and automatic control method.The combined harvester operation path tracking and auxiliary navigation system is constructed.The system includes main controller,Beidou positioning module,angle sensor,voice broadcast,display screen,steering control model,CAN bus and an interface circuits.The main controller obtains the original positioning information of the combine harvester in real time,and compares the real-time position with the planned path to obtain the job deviation information.The system gives the deviation prompt information through the display screen and the voice mode when the driver is operating.In the automatic mode,the controller drives the steering control module to control the working direction.In view of the large fluctuation and the low reliability of the Beidou Positioning Module(BDS),the multi-BDS synchronous observation method is used to monitor the position of the combine harvester in real time.The acquisition of positioning information and preprocessing methods,the combined harvester operation path tracking and steering correction methods are studied in this thesis.First,the complete positioning data is obtained by using the field value processing method with track correction.Then,a multi-BDS relation matrix is established to solve the multi-BDS positioning result based on the relative distance difference.The final positioning data is obtained by Kalman filtering.The working route is planned by the operation baseline based on the characteristics of the combine harvester.According to the operation situation,the path is updated in real time and the real-time deviation data of the operation path is obtained.Finally,the steering correction method is designed according to the established steering control rules to realize the steering correction.According to the system design requirements,the system software and hardware are designed based on the embedded microcontroller combined with the location information acquisition and path tracking method of the combine harvester.The hardware part includes configuration of the main controller input and output port,Beidou positioning module and its application circuit,angle sensor and its interface circuit,human-computer interaction module and its application circuit,CAN bus interface circuit,regulated power supply circuit,steering control module and other Interface circuits,etc.The software part includes the system main program,the collection and pre-processing of positioning information,the path planning and updating program,the real-time tracking program,the human-computer interaction program,the steering correction program,and the communication program.The test was carried out by a combination of indoor and field tests.In the absence of a base station,the Beidou positioning module is installed in a triangular array on the top of the combine harvester cab.The test results show that the combine harvester operation path tracking and auxiliary navigation system can monitor the working position in real time,plan and update the working path,and display the deviation information,which meets the expected design requirements.The feasibility of the steering control method is verified by the indoor steering control simulation test.A combine harvester assisted navigation system and method without a base station is provided,which helps to reduce the cost of the navigation system and improve the efficiency and quality of the combine harvester.