Spray controller for horizontal boom movements compensation

peer reviewedLongitudinal spray distribution is mainly affected by the horizontal speed variations of the nozzles. Manufacturers classically try to reduce unwanted nozzles movements using horizontal boom suspension but these methods show performance and price limitations. The purpose of this paper is to propose a spray controller aiming to compensate the effect of the horizontal boom movements on the spray distribution besides the effect of tractor speed variations. The controller is based on three main parts: a control law describing the relationship between nozzle speed, nozzle flow and spray coverage; a real time measurement of the boom horizontal speed variations using micro-machined capacitive accelerometers and Pulse Width Modulation (PWM) no zzle flow actuators. A prototype was developed using a processor board controller (dSpace) and tested on a laboratory test bench. The nigrosine solution spray coverage was measured using image analysis for field representative multi-sine nozzle speed variations. The spray coverage uniformity using the spray controller showed about 51% compensation of the spray coverage variations observed without controller