Study On Intelligent Yield Monitoring System For Corn Based On ARM7

Along with the rapid development of information technology and artificial intelligence technology, a novel agricultural thinking of production management has come out, which results in the implementation of positioning crop management and variables input according to the actual needs. Then the concept of precision agriculture puts forward. As an important component of information agriculture, precision agriculture is the new trend of the world agricultural development, and is also the hot field of international agricultural research in recent years. It is a set of modern agricultural technology and operation management system which supported by the information technology, according to the spatial variability, location, timing and quantitative implementation. Precision agriculture offers a means how to provide properly input for production in the specific field of small plots, thus potentially reduces the input costs, increases production and crop growth, and reduces the negative affected on the environment by optimizing and matching the needs of the inputs.The yield information is particularly important in technology of precision agriculture system. Gaining the yield information distribution, then generating a digital distribution of production is the basis of precision agriculture. Therefore, we need to install a combine production monitoring system that measured production system. The yield map created by measurement system eventually is a basis for decision making in agriculture. It is the first step in the implementation of precision agriculture. At the same time, it's used to evaluate the result of those decisions of precision agriculture once again. So it can also be said that precision agriculture system is the final step. Doing research on corn yield map, design a practical measurement precision agriculture corn production systems, and then promoting precision agriculture technology have a far-reaching impact and significance about increasing food production, reducing production costs and environmental pollution , and also improving the income of the farmers.This project is a sub-project of variable spraying and fertilization and intelligent measurement of production technology in the state 863 of modern agricultural fields,"research and application of corn precise operating system". In the project we design a feasible yield monitor system for corn crop, which can generate yield map. In the specific implementation process, as domestic mainstream models of corn combine can not thresh in the process of harvesting, the measurement of corn production have to be completed through indirect measurement of the quality of the corn ear. First, we should obtain the total corn ear production, yield and harvest distribution. Finally, using post-processing with scientific sampling statistical analysis, we can complete the design of automated yield monitoring system and get the yield map.The paper determines to use the means of weighing ear of corn by using weighing sensor directly. The whole yield monitor system consists of two parts: part of data acquisition and data processing part. Part of data acquisition include: Weighing sensors and GPS receiver. Weighing sensors is used for collecting information of corn ear weight, which converted to electrical signals. GPS receivers provide real-time location information. Data-processing part, the center of the whole system, is an interactive platform of the operator and the system that collects sensor signals and does the front-end data processing, storage and display. After positioning information and weight information acquisition and processing completed, the upper PC processes data in the database of yield records, in which storage, analysis and management are able to be completed and the data can be expressed in the form of graphics.To ensure the precision of the yield map, the system requires higher accuracy of geographical positioning information. We choose Differential GPS receiver AgGPS132 which produced by the Trimble company of the United States. Through the experiment, we can see that it can provide middle-class precision positioning information, which can be good to meet system requirements. LPC2136 ARM processor is used in the data acquisition and storage, which is powerful and rich in resources, has a good scalability. AT45DB081 FLASH chips with the SPI bus is used as memory chips. The system develops the software with the integrated development environment, ADS1.2. Designing program with C language greatly reduces the development cycle, which also ensures system design flexibility and reliability. Yield and location information will ultimately be uploaded to a PC for analysis and stored. By using the powerful functions of Visual Basic language database and comprehensive management capabilities of Access database, yield records database is designed. Its function includes data entry, data analysis and processing, recording and graphics for display.The paper analyzes the error sources of measuring accuracy in the system, and provides the corresponding solutions. While designing system, hardware circuits should be as simple as possible in order to reduce the error sources, which can be processed by software. In the design of Specific circuit, we can adopt a series of measures like designing the high-precision regulator circuit and using the technology of signal filtering in hardware to reduce the sources of error. Digital filtering techniques are used in Software to analyze and process the error. Also, non-linear algorithms are used to measure and correct circuit error. The error can be automatically correct by the linear interpolation algorithm in the Visual Basic.The paper finally completes the hardware and software design of yield monitoring system and does test in lab and combine. When numerously measuring 100 kg corn, we get the average weight of 107.32 kg measurement, the maximum deviation of 9.2%. The experimental results show that the system is feasible in the function. Also, by filtering the interference and improving the accuracy of measuring production, the system can meet basic needs in the actual work. However, this test is only the first step in precision agriculture research. It is also necessary to be continually improved to meet the operational needs in the future experimental research.Precision agriculture is a multi-disciplinary, involving a wide area of the technology system. Some technology is not yet mature, which requires multidisciplinary close cooperation and efforts. Limited personal level, the design of the system still has many shortcomings, which need to be continually improved. In the next development phase of the yield monitor system, embedded real-time operating system could be introduced. We can write applications software in the real-time operating system platform, which can enhance the efficiency of development process and make sure system stabile. At the same time, the calibration method of the weighing sensor needs to be improved further. When combine works in the fields, the working environment and the situation is not static. Especially after the long hours of work, when the temperature, humidity and speed change, theses factors can affect some impact on the accuracy of yield monitoring. The current calibration method could not completely eliminate the influence of those factors. Therefore, we need to do a lot of experiments and explore more complete calibration method in the future.