Research progress and prospects of spraying of multi-rotor plant protection UAV
Multi-rotor plant protection Unmanned Aerial Vehicles(UAV)has good terrain adapt ability and efficient ultra-low altitude spraying capacity,which is one of the important development directions of efficient plant protection equipment.However,the interaction mechanisms of wind field,droplet and crop under flight operation are unclear,which has become the bottleneck restricting the improvement of the deposition distribution quality.This study aims to analyze the problems such as insufficient correlation studies and unclear deposition mechanism of various elements in the spray application of plant protection UAV.This study focuses on the whole process of generation,settlement,deposition and drift of pesticide droplet.And based on the previous research,this paper discussed the research status of spray pesticide liquid with nozzle,the interaction between the wind field and the droplet,as well as the coupling of the wind field,the droplet and the canopy.The effect of nozzle atomization on spray effect,the distribution law of wind field under hover and flight conditions of plant protection UAV,the distribution law of droplets deposition and drift in canopy under flight spary conditions were analyzed separately.Based on the above discussion,the application background,research progress and empirical models of aviation application technology at home and abroad were reviewed.Some problems that need to be solved in the spary application process of multi-rotor plant protection UAV were identified.The matching and relationships between nozzle selection(hydraulic nozzle,centrifugal nozzle,etc.)and working parameters(pressure,speed,Angle,flow,etc.),UAV flight parameters(flight speed,rotor rotation speed,etc.),pesticide characteristics(density,viscosity,surface tension,etc.)and initial parameters of liquid droplets(particle size distribution,initial velocity)are not clear,a suggestion was proposed to establish a nozzle selection decision-making expert system for multi-rotor plant protection UAV spray scene.In terms of the coupling effect of flight combination wind field(rotor downwash flow,upwind flow,natural cross wind),pesticide liquid droplets(physical property parameters after atomization),crop canopy(Stems,branches,leaves of a typical growth cycle of a crop),field environment(temperature,humidity)and operation parameters(flight speed and altitude),a proposal was put forward to establish a three-phase coupling model of combined wind field-pesticide liquid droplet-crop canopy based on scientific assumptions of deposition effects.Finally,the future development of application technology of Multi-rotor plant protection UAV was prospected.
万方数据
维普
