Laser Beam Deflection of a 2D LiDAR for Canopy Detection on an Autonomous Spraying Robot

Spraying robots are particularly expected in viticulture and arboriculture to safely target and adapt the quantities of phytosanitary products on canopy. However, to maintain a financial profitability for the farmer wishing to adopt a robotized solution, the cost must be reduced. Therefore, instead of adding expensive and redundant sensors to measure the shape of the vegetation close to the robot, this paper investigates the possibility to deflect by a rotating mirror a part of the laser beams of the horizontal 2D LiDAR positionned in front of most of the current mobile robots for security and navigation purposes. This use of the 2D LiDAR aims to obtain at low cost the required 3D information on the canopy. Experimental results on a real spraying robot enable to highlight the interest of this approach: the presence and height of the canopy can be accurately measured, and the nozzles of the spraying boom can be controlled independantly and accordingly. To focus the measurements on a certain area, the angular variations of the mirror can be reduced or on the contrary increased to have a global overview of the environment. This original approach opens new opportunities with a 2D LiDAR for other configurations and field applications.