农用无人机移动平台自主降落技术研究

Research on Autonomous Moving Platform Landing Technology for Agricultural UAV

针对农药喷洒无人机携带药量和续航能力有限,需返回固定点更换药液或电池导致效率低的问题,为提高无人机田间作业效率,以四旋翼无人机为研究对象,研究农用无人机自主移动平台降落技术,以实现无人机自主降落在装载无人机和药液的移动平台上。将北斗卫星和机器视觉定位相结合,提出将降落过程分为卫星定位、机器视觉定位和超声波测距分别进行控制的策略,设计了无人机平台硬件和软件,以及固定于移动平台的吸附减震结构和嵌套着陆标志,试验结果表明:北斗卫星相对定位方法定位精度在1.5m内;设计的嵌套着陆标志和图像识别算法着陆标志识别率为97.5%,有较高的识别率和鲁棒性;农用无人机移动平台降落系统在移动平台速度为3km/h时,无人机移动降落误差为12.21cm,且飞行性能稳定、着陆安全。研究可为农药喷洒无人机实现自动化、智能化高效作业提供有效支持,也可供其他农用无人机移动平台降落提供参考和借鉴。

Aiming at the problem of low efficiency caused by the limited carrying capacity and endurance of pesticide spraying UAV and the need to return to the fixed point to replace the liquid or battery,in order to improve the field operation efficiency of UAV,this paper takes the quadrotor UAV as the research object,studies the autonomous mobile platform landing technology of agricultural UAV,and realizes the autonomous landing of UAV on the mobile platform loaded with UAV and liquid.By combining Beidou satellite with machine vision positioning,the landing process is divided into satellite positioning,machine vision positioning and ultrasonic ranging,which are controlled respectively.The hardware and software of UAV platform,adsorption damping structure fixed on mobile platform and nested landing mark are designed.The experimental results show that the positioning accuracy of Beidou satellite relative positioning method is within 1.5m;The recognition rate of the nested landing sign and image recognition algorithm is 97.5%,which has high recognition rate and robustness;When the speed of the mobile platform is 3km/h,the mobile landing error of the agricultural UAV is 12.21cm,and the flight performance is stable and the landing is safe.This paper can provide effective support for pesticide spraying UAV to realize automatic,intelligent and efficient operation,and also provide reference for other agricultural UAV mobile platform landing.