Laser Sensor Detection Of Operation Height And Boundary In Unmanned Helicopter Spraying

Chemical control is the main method of plant protection at the present stage. The basic state policy of our country is to reduce the amount of pesticide, improve the utilization rate of pesticides and promote the restoration of agricultural biological environment. Aerial spraying is a new way of working, which can reach the depth of the ground machinery. The height of unmanned helicopter is the key parameter of aerial spraying. The detection and identification of the boundary is an important part of the unmanned helicopter spraying. Therefore, it is an urgent need to solve the problem of the agricultural biological environment and energy engineering subject that the spray process of unmanned helicopter accurately controls the working height and the detection and recognition of work boundary.In this paper, the characteristics of the laser signal under different flight altitude and flight speed were studied. Spraying experiment was designed to study the relationship between the height and the spray width, and the model of scanning angle and spray height was obtained. The main research work includes the following aspects:(1) Construction of laser detection system for unmanned helicopterThe sensor is installed on the CD-10 unmanned helicopter and the calibration of the laser sensor is carried out. Select the attitude sensor and GPS sensor, which is composed of an unmanned helicopter laser detection system.(2) Laser sensor detection testThe sensing properties of the laser sensor under the condition of soil and crop cover and at different advance speed were studied. The main conclusions are as follows:(1) The variation coefficient of distance test is decreased with height in the range of 0.5m~2.5m under soil surface. The coefficient of variation decreased with the height of the test under the crop canopy. The variation coefficient of the laser to the crop canopy test was higher than that of the soil under the same height. But the trend of both is the same when the height is 1.5m.(2) At different forward speeds, the distance from the laser emission point to the rectangular upper surface is 308 mm, the maximum is 317 mm. When the velocity is 0.3m/s, 0.5m/s and 0.8m/s, the variance of the distance between the center of the laser beam and the surface of the square is basically the same as that of the laser. The velocity has little effect on the laser distance measurement, but it will affect the variance of the laser measurement data.(3) The experimental study of laser sensor detection in the field of unmanned helicopter.The accuracy and performance of the laser with different flying height and different flight speed were studied. The main conclusions are as follows:(1) At the same altitude, the variance of the rice canopy data becomes smaller and then becomes larger with the increase of flight velocity. At the same flight speed, the variance of canopy data of rice increased with the decrease of height. However, when the flight speed is 2.5m/s, the variance increases with the height of the first small and then becomes large.(2) When the flight speed is fixed, the ridge height data variance with height increases first and then decreases. When a certain height, ridge height data variance with height increases first and then decreases.(3) Reflection strength values of rice decrease when the height increases under different flight speeds and different working height. The reflection intensity values of the ridge remained unchanged.(4) The height difference between rice and the ridge is the boundary recognition threshold. The experiment was carried out. The results show that: the signal segmentation point appears near to 1m, the variance is 0.27 m. In the process of segmentation, there are many false points in the left region.(4) Spray width test(1) When the height is below 1.5m, the spray width increases with the increase of the spray height. But when the height is more than 1.5m, the spray amplitude decreases when the height increases.(2) When the spray height reaches about 2.5m, the peak value of the spray is not obvious, droplet distribution becomes uniform. With the increase of the height of the spray, droplet deposition decreased gradually. When the height reaches 2.5m, the droplet deposition did not change.