Development and application of intelligent monitoring and controlling system of cotton-picking machine based on virtual instrument technology

Abstract: In order to solve the key problems generated in the development procedure of virtual instrument, this paper used controller area network (CAN) bus and LabVIEW touch panel module to develop virtual instrument based on ARM11 and WinCE. Because of the difference between PC and ARM platform, there are big problems in high-speed CAN data transmission and cross-platform call of dynamic link library (DLL). This paper mainly studied CAN bus communication mechanism and its implementation method, and developed the driver program and DLL in embedded WinCE system. And this paper made it possible to use LabVIEW virtual instrument technology in embedded WinCE platform based on CAN bus communication. LabVEIW graphical design environment not only accelerated the development process but also made it easy to make use of the real-time embedded operating system. There are hundreds of advanced signal analysis modules of LabVIEW, mathematical processing modules and rich human-machine interaction modules in LabVIEW touch panel module which insures the fast and friendly interface design and the powerful signal processing and computing process. This paper thoroughly introduced the implementation method of virtual instrument technology in embedded WinCE system and explained the call flow of cross-platform dynamic link library. To achieve the communication between embedded virtual instrument and CAN bus, this paper firstly developed the bottom driver program and the DLL suitable for Win32 platform and the DLL suitable for embedded platform. And then through the shared library block in LabVIEW, this paper achieved the advanced application of the DLL. At last, this paper finished the virtual instrument development based on the touch panel module in LabVIEW. The interface was well designed which looked very simple but practical. This paper has mastered the key technology of seamless link of CAN data. It took the six-row auto-pack cotton-picking machine as the object to develop an intelligent monitoring and controlling system based on CAN bus and embedded WinCE system. The field test was done in NongYiShi crop construction area of Alar, Aksu, Xinjiang The system achieved online monitoring and error alarming to the work state of cotton harvester. Apart from that, three functional verifications were also done. 1) Central controller can transmit collected data from data acquisition module and state monitoring module to the virtual instrument. 2) Through the touchable embedded virtual instrument interface, people can configure any node in CAN network. The configuration includes parameter setting, task allocation and so on. 3) This system can effectively detect the sensor fault and actuator failure and send the diagnosis messages to the customers. From the data provided by the field test we can see the advantage and promising future of virtual instrument based on embedded system. The system effectively realizes the high-speed CAN bus data communication among multiple CAN nodes, and the system has also strong flexibility and versatility, which can be taken as reference and guide in improving the automation and information level of large equipment in China.