Abstract:
Abstract: UAV (unmanned aerial vehicle) is widely used in modern agriculture because of its various advantages. But it is difficult to detect flight performance and the accuracy of human eye observation is poor. In order to monitor UAV flight status and assess performance of UAV automatically, this paper designed a UAV flight status real-time monitoring and performance evaluation system based on the LabVIEW. The system could be separated to airborne parts and ground parts; airborne parts included information collection module and wireless communication module, and ground parts included wireless communication module and monitoring software. The information collection module used AHRS IG-500N to obtain UAV flight status which consisted of triaxial attitude angle, triaxial acceleration, triaxial angular velocity, triaxial speed, GPS (global positioning system) latitude and longitude, GPS altitude, temperature and barometric pressure. After being preprocessed by MCU STM32F103ZE which converted hexadecimal data to ASCII, these data were sent to the ground computer through a pair of wireless transmission module GE MDS EL 805. The monitoring software based on the LabVIEW extracted these data through serial port for the maximum and minimum filtering. Then it displayed the real-time triaxial attitude angle and flight altitude, and used three-dimensional model created by Solidworks to simulate the real-time attitude of the UAV. In addition, it used Gauss-Kruger projection transformation to transform the latitude and longitude coordinates into the corresponding geodetic coordinates. By accumulating three-dimensional space between adjacent points of real-time trajectory of UAV, the software could calculate air miles. The distribution density of points on the whole original setting route was not uniform, and the software used a setting distance to process the route in order to get a uniformly distributed setting route. It could reduce the computation load and improve the accuracy of flight path deviation calculation. The software displayed the real-time route and the setting route of the UAV in one control at the same time, so the users could clearly see the difference between them from the system. The flight path deviation was the minimum distance between the real-time position and the corresponding position of setting route. By comparing the minimum distance and the offset distance between the real-time position and the corresponding position of the setting route, the system could also achieve and graphically display the flight path deviation of UAV. It showed the rest of the information as real-time value and saved all the data during the test. The system was tested in a university in China on September 15, 2015. The size of the test field was about 50 m × 70 m, and the coordinates of the test field were 23°09′76″N and 113°20′37″E. The UAV used in this test was WSZ-1805 electric octocopter which was designed for plant protection. The flight operator should control the UAV taking off, flying along the setting route, flight altitude keeping, hovering at a special location, and landing at another special location through vision. Results of the visual control test showed that the system software could display all the information clearly, the distances between the flight operator and the UAV were between 25 and 40 meters, the flight path deviation reached 5.2 m, the average position deviation of hovering reached 6.4 m, the average altitude deviation of height keeping flight reached 0.9 m, the fluctuation ranges of roll angle and pitch angle were both within 8°, and the temperature of the sensor dropped by 2℃ during the whole test. Outputs of the monitoring software were the same as the results of data analysis. The system is stable and reliable. It can be used to monitor, display, evaluate and record the flight status of the UAV real-timely. It can improve the accuracy of UAV flight status monitoring, and provide reference for further scientific assessment of UAV flight performance and training UAV flight operator.